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Патент USA US2412156

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Patented Dec. 3, 1946
2,412,156
UNITED STATES PATENT, OFFICE
2,412,156
RETARDER
,
George D. King, Chicago, andManvel C. Iylailey,
Elmhurst, Ill., assignors to. United States, vGyyp
sum Company, Chicago, III-.-, a corporation of
Illinois
No Drawing. Application November 4, 1940, )
Serial No. 364,240
'20 Claims.‘ (Cl. 106-112)
1
2
V The present invention relates to an improved
form of retarder, such as is used for prolonging
of 70 per ‘cent sodium, hydroxide, which is the
commercial strength of caustic soda. The pro
the‘ time of set of gypsum plasters and the like,
and also to methods for its preparation.
tein is heated in this sodium hydroxide solution
at a temperature of about 190° F. for a period
One of the objects of the invention is to pro
vide a retarder which is stabilized against de
terioration by age, so that it will not change in
is mixed with 1200 pounds of quicklime.
of about 3 hours, , The resultant hydrolyzed mass
The
quicklirne reacts with the water in the mixture
to form calcium hydroxide, thus liberating a large
its retarding characteristics when incorporated
amount of heat. As a result of this heating, ex
with plaster and the plaster subsequently is put
10 cess water is evaporated so that eventually a
into storage.
granular product is obtained which is substan
A further object of the invention is to pre
tially dry. ,It is apparent that the quantities re‘
pare‘ a‘ retarder consisting of hydrolyzed kera
cited may be varied as desired to suit the type
tinaceous material, lime, and some form of car
bon dioxide or carbonate, preferably by carbona
tion of the ?nished retarder either by means of
of raw materials employed, strength of retarder
carbon dioxide gas or by means of a water-solu
in amounts insu?icient to effect complete drying
ble carbonate.
While keratinaceous retarders are quite old in
the art of preparing set-retarded plasters, a dif
?culty is found in connection with these retarders
of the mass or hydrated limev may be substituted.
In either case drying is completed by external
means. The ?nal product thus obtained is a pul
required, etc. If desired, quicklime may be added »
verulent granular material which may be ground
?ne enough to permit of mixing with the plaster.
in that their retarding e?iciency changes with
As thus far described, the process is a, descrip
age. Prior art retarded plasters stored under
tion of the prior art. The present invention is
weather conditions‘ favoring rapid change in set
an improvement thereon and di?ers in that car-é
ting time may be affected so that an increase
of 100 per‘ cent in setting time Within a period 25 bon dioxide in some form is introduced into the
retarder. In accordance with this invention, this
of about two weeks is observable. Setting time
may be done in a number of ways, such as by
mayiurther increase 200 to 300 per cent after
carbonating the retarder prior to the elimination
two or three months or storage under such con
of all of the water by introducing carbon dioxide
ditions. This variation in setting time with age
gas into it or by adding a water-soluble carbonate
leads to trouble with slow set on the job when
to the dissolved keratinaceous material prior to
old plasters are used; and in order to be as
the addition of the lime thereto. Both methods
sured of uniform setting characteristics, it is nec
produce similar results. Variations of these proc
essary to use fresh, unaged plaster. On- the other
esses may also be practiced.
_
hand, a plaster containing a retarder made in
In preparing the retarder by the ?rst alterna
accordance with the‘ present invention will in 35
tive (i. e., by the introduction of the carbon di
crease but slowly in setting time and in some
cases not at all, even after storage for six months
oxide gas), in accordance with one‘embodiment
under severe aging conditions, which,- it will at
of this invention, one method of procedure is as
once be apparent, is a very great advantage.
follows: The gelatinous, glue-like hydrolyzed pro
tein is mixed withquicklime in a pressure-tight
vessel in which the original hydrolysis with the
Inaccorda-nce'with the ‘prior art, a retarder may
be prepared» by digesting a quantity of keratina
caustic soda has taken place, either at atmos
pheric or superatmospheric pressure, as above
ceous material,» such as pulverized animal hair
and hoofs, in a- solution of caustic soda at ele
vated temperatures and at atmospheric or super
atmospheric pressures. --To the resulting prop
erly hydrolyzed mass, quicklime or hydrated lime
is added.
described.
Cir
We prefer to regulate the water-.
‘
I
quicklime ratio so that complete drying will not
be effected by the lime added. Preferably, about
The amount’ of- quicklime may be so
5 per cent to 10 per cent of free water should re--_
regulated that it combines chemically with a large
proportion of the water ,present and‘ the re
maining water is driven‘ o? by the heat of re‘-:
action whereby a dry product results. If lesser
amounts of q'uicklin'ie' are used Or if hydrated‘
main‘ in the limed retarder after hydration of
lime is' substituted, the excess‘ water may be re
moved by external means, such as heating. For
example, a retarder of the prior art may be pre-'
pared as follows: 800 pounds of pulverized animal
hoofs, hair, or other type of keratinaceous ma‘-‘
terial, are introduced into‘ 1000 pounds of wa'—"
ter in which there have been dissolved 160 pounds
the lime. Satisfactory results are obtained, how
C ever, with‘ greater or lesser‘ amounts of free wa';
ter than indicated.
Carbon dioxide gas is then
introduced into‘ the vessel so‘ as to build up‘ a pres;
sure inside the vessel of about 5 pounds per
square inch" sup'e‘ratmo'spheric', equivalent‘ to
about 20 pounds absolute pressure. An‘ alterna'-‘
tive process is to proportion the water-quicklime
ratio so as to effect complete drying by reaction
of water with‘ quicklime, seal‘ the pressure-tight
vessel prior‘ to completion of hydration of the
2,412,156
3
thereafter quicklime is added, in exactly the same
manneras in preparing ordinary retarder of the
prior art. The drying and grinding steps are
similar to those employed in the prior art. We
carbonation, the remaining free water will be au
tomatically released.
The pressure vessel may be _ e -
provided with agitators which are kept running
to accelerate the absorption of the carbon diox
.
ide, which may require about 30 minutes. The
amount by weight of carbon dioxide gas which is
allowed to become absorbed by the retarder mix
lies preferably between 5 per cent and 10 per 10
cent based on the total weight of ?nished retard- _
er, or about 20 per cent on the basis'of the ground
hoofs
although
or. other
it has keratinaceous
been found that
material
as little
employed,‘
as 2 per ‘
4
ates within the hydrolyzed keratin solution, and
lime, and carbonate in the manner indicated.
Upon release of pressure following completion of
do not attempt to explain the reaction which oc
ours with carbonation to impart the unique char
acteristics of increased stability to retarders pre
pared in accordance with our disclosure. The re=
action is evidentlymore complex than the mere
carbonation of a portion of the added lime or
caustic soda. We have found, for example, that
‘retarder prepared with addition of powdered
- limestone or calcium carbonate, or a mixture of
cent of carbon dioxide calculated on the dry 15 quicklime and limestone, in place of lime, is no
more stable or resistant to change in strength
weight of the entire mass will give useful results,
with aging than the prior art retarder. It may
and an absorption as high as 15 per cent (calcu
be that carbonation of a limed‘retarder mix, or
lated on ‘the dry weight of the entire mass) is also
addition of a soluble carbonate to such a mix,
effective. However, if the 15 per cent is exceeded
results in the formation of a "complex calcium
the results are notas desirable as they are be
proteinate containing carbonate in the molecule,
tween 5 per cent and 10 per cent, for a decrease
which material is essentially more stable and re
in the efficiency of the retarder occurs. After the
si'stant to chemical changes upon exposure to air
desired amount of carbon dioxide has been ab
than the prior art type of product. Regardless
sorbed,‘ free moisture is removed from the mate
rial by opening the autoclave and allowing the 25 of any theory, it is known that the [process de
material to dry, either naturally or assisted by
scribed produces a retarder which is essentially
arti?cial means. Finally, the dry retarder is suit
stable and ‘resistant to changes in strength on’
ably ground to a ?neness which permits its‘in
passage of time.
I
.
corporation with the plaster. It is not necessary
Both methods of producing the retarder‘ yield
to employ pure CO2 gas for the carbonation. We 30 substantially equivalent results, and they are both
have found, for example, that lime kiln flue gas,
considered to be part of the same invention.
,
containing 20 per cent to 40 per cent of CO2, is
In order to demonstrate the advantages which
a satisfactory source of cheap CO2 for this proc
are obtained by the use of the present invention
ess. Ordinary flue gas from boilers or furnaces,
there is shown hereinbelow, in the form of a table,
with a C02 content as low as 7.5 per cent to 10 35 the setting time of set-stabilized plaster, using on
per cent may also be employed. The other gase
the one hand ordinary untreated retarder and onv
ous constituents of such mixtures do not affect
the other hand the retarder of the present inven
the quality of the ?nal product, although of
tion. The term “set-stabilized plaster” is in
course the carbonation reaction proceeds with
tended to cover a plaster of the calcium sulfate
greater speed as 002 concentration is increased. 40 type which is stabilized as to its setting time
The pressure required for carbonation is not ‘crit
against the adventitious admixture of either re
ical, andour process may be employed under any
tardive or accelerative in?uences, such types of
pressure from atmospheric and upward. How
plasters
being fully described in the patents to
ever, time requirements for effecting the desired
Gallagher, No. 1,683,539, and King,‘ Nos. 1,989,641,
degree of carbonation are reduced by operating
2,078,198, 2,078,199 and 2,078,200. While the
under positive pressure.
plasters of the aforementioned patents maintain
If instead of using carbon dioxide gas it is de
their setting time irrespective of whether further
sired to‘introduce the carbonate ingredient by
retarder or further accelerator gets into them,
means of a salt, the process may be carried out
as follows: After the keratinaceous material has 50. they nevertheless exhibit an increase in setting
time as they get older, and it is this defect that
been digested by the caustic soda, which in this
the present invention cures. In other words, the
case,~if desired, need not be done under pressure,
plasters made in accordance with the present in
there is added to the glue-like mass, prior to the
vention are set-stabilized not only against job re
introduction of the lime, a suitable quantity of a
soluble carbonate, such for example as ammoni 55 tardive and accelerative influences but also
against lapse of time, which is a distinct improvee
um carbonate, ammonium bicarbonate, sodi
ment-over anything that has ever been done in
um carbonate, sodium bicarbonate, or equiv
this art. In the table therefore, where mention
alent other water-soluble salts of carbonic
is made of a lime-alum plaster formula with un
acid. Sufficient carbonate is preferably added
treated retarder, this refers, for example, to'the
to’ produce a C02 content Of about 5 per cent
plaster of King patent No.1,989,641, while where
on the basis of the ?nished dry retard
mention is made of carbonated retarder, the re
ers. The agitators are kept running to insure a
tarder of the present invention is referred to.
complete solution or dispersion of these carbon
Setting times of aged plasters
Plaster
-
I
Mix
_
‘
1
Fresh
2 wks
4 wks
6 mo.
Hrs. Min
Hrs. Min
Hra. Min.
Hrs. Min.
Lime-alum plaster formula with untreated retarder ..................... __ gz/gasg?aéa‘if 4
6
g8
£7‘
Lime~alum plaster formula with 00: treated retarder ................... ._ gizastg?gei _ I i
2
2(5)
2
Lime-alum formula with untreated retarder _____________________________ _.
Lime-alum formula with carbonate-treated retarder ((NH4)HCO3) ...... _.
2% sanded. _ ..
2% sanded. . ._
I 1 Neat: Mixed with water only on glass mixing board.
I 2% sanded: Mixed with 2% parts of washed sand and water on glass mixing board.
4
5
40
20
‘ég
______________________ __
______________________ ._
13
28
g
353
12
6
00
15
2,412,150
6
Referring to the above table, the terms"‘neat”
andpartially carbonating the resultant material
and “sanded” are fully explained in the table
itself. All plasters therein mentioned were aged
by vadding carbon dioxide gas thereto.
,7. The process of producing a plaster retarder
comprising hydrolyzing a protein material'with
an alkali, adding- lime to the resulting mixture,
under similar temperature and humidity condi
tions.
It will be seen, referring for the moment to the
CO2 treatedretarder and comparing it with un
and partially carbonating the resulting material
by adding a water-soluble carbonate theretoin
an amount to provide a carbonated retarder hav
treated retarder in the set-stabilized plaster, that
ing a combined carbon dioxide content of less
in the neat test the original setting time of the
latter was 3 hours and 55 minutes, which in 10 than about 15 per cent by weight (dry basis).
8. The process of producing a calcined gypsum
creased at the end of 6 months to 13 hours, while
plaster retarder which comprises hydrolyzing
in the sanded test the original setting time was
keratinaceous material with alkali, adding lime
4 hours and 55 minutes, which increased in 6
thereto and treating the said retarder mixture by
months to 9 hours and 50 minutes. In the case of
the gas-carbonated retarder, however, on the 15 con?ning it in a closed airtight space and. forcing
into said space carbon dioxide so as to build up
sanded test the setting time originally Was 4 hours
superatmospheric pressure within the space to
and 10 minutes, at the end of four weeks it was
facilitate the absorption of the carbon dioxide.
4 hours and 45 minutes, and at the end of six
9. The process of producing a calcined gypsum
months it had increased to only 5 hours and 50
minutes. These tests indicate what a remarkable 20 plaster retarder which comprises treating
keratinaceous material, such as animal hoofs,
degree of stabilization has been attained. Com
with water and sodium hydroxide at a tempera
paring this with a retarder carbonated with, for
ture of about 190° F. for about three hours to hy
example, ammonium bicarbonate, it will be seen
drolyze the said keratinaceous material, carrying
that the setting time was 5 hours and 20 minutes
when freshly made and at the end of 6 months 25 out the aforesaid operation in a vessel capable of
being made pressure tight, adding quicklime
it had increased by only 55 minutes to a time of
thereto and then introducing into the resultant
6 hours and 15 minutes. Comparing this with a
mixture carbon dioxide at superatmospheric pres
set-stabilized plaster with an untreated retarder,
sure while maintaining in the vessel a pressure
it will be seen that the latter when freshly made
had a set of 4 hours and 40 minutes, and at the 30 above that of the atmosphere, to carbonate the
alkaline content of the mixture to a degree suf
end of six months it, had increased to 12 hours.
?cient to stabilize the resulting retarder.
Our new stabilized retarder may of course also
10. The process of producing a retarder which
be used to advantage in plasters which do not
comprises
hydrolyzing keratin by means of so
contain the job set-stabilizing ingredients such
dium hydroxide, adding a soluble carbonate
as alum and lime.
'
thereto in an amount such that the total com
From what has been said hereinabove, it will be
bined carbon dioxide content of the resulting
quite apparent that a great advance has been
retarder is less than about 15 per cent by weight
made in the stabilization not only of the retarders
(dry basis), and then adding quicklime, and dry
but of set-stabilized plasters containing the same.
40 ing the resulting mixture.
It is to be understood that the use of equivalent
11. The method of protecting ' hydrolyzed
keratinaceous materials or the substitution of
proteid retarder against changes in its e?iciency,
other proteins therefor, such as soy bean meal,
which comprises partially carbonating the
sponge waste, ?sh scrap, etc., is to be considered
retarder with a carbonating agent under con
as within the scope of the present invention, for
ditions to produce a carbonated retarder having
which the following is claimed.
less'than about 15 per cent by weight (dry basis)
We claim:
of combined carbon dioxide.
1. The process of producing a plaster retarder
12. A plaster retarder comprising a carbonated
comprising partially carbonating an alkaline, hy
hydrolyzed protein having a combined carbon
drolyzed, proteinaceous material with a carbonat 50 dioxide content of less than about 15 per cent by
ing agent to produce a retarder containing less
weight (dry basis).
than about 15 per cent by weight of combined
[13. A plaster retarder comprising a carbonated,
carbon dioxide (dry basis).
hydrolyzed keratin having a combined carbon
2. The process of producing a plaster retarder
dioxide content of less than about 15 per cent by
comprising partially carbonating an alkaline, hy
drolyzed, proteinaceous material by addition of
55
carbon dioxide.
3. The process of producing a plaster retarder
comprising partially carbonating an alkaline, hy
drolyzed, proteinaceous material by the addition
weight (dry basis).
14. A plaster retarder comprising a hydrolyzed
protein, lime, and a carbonate formed therein by
chemical means, the carbonate having a com
bined carbon dioxide content of less than about
15 per cent by weight (dry basis) of the retarder.
of 2 to 15 per cent by weight of carbon dioxide
_ 15. A plaster retarder comprising a mixture of
hydrolyzed keratin and lime, protected against
gas thereto based on the dry weight of the ?n
deterioration by absorbed carbon dioxide.
ished retarder.
16. A set-stabilized gypsum plaster comprising
4. The process of claim 2 in which the carbona
tion is carried out at superatmospheric pressure. 65 a set-accelerating material and a protein re
tarder, the latter containing combined carbon
5. The process of producing a plaster retarder
dioxide in an amount less than about 15 per cent
comprising partially carbonating an alkaline, hy
drolyzed, proteinaceous material by the addition
by weight (dry basis) of the retarder.
-17. A set-stabilized gypsum plaster composition
of a water-soluble carbonate thereto in an amount
to provide a carbonated retarder having a com 70 comprising a major portion of calcined gypsum
bined carbon dioxide content of less than about
15 per cent by weight (dry basis).
6. The process of producing a plaster retarder
comprising hydrolyzing a, protein material with
an alkali, adding lime to the resulting mixture, 75
and a minor portion of a set-stabilizing composi
tion which comprises an accelerator and a re
tarder which has absorbed carbon dioxide.
18. A set-stabilized plaster comprising a major
portion of calcined gypsum and a minor portion
2,412,156
3
.
‘of a' set-stabilizing composition which'com‘p'rises
'20.'The gypsum plaster recited in claim’ 16
alum, lime and a keratinaceous retarder, which
"latter has absorbed a form of carbon dioxide.
wherein the combined carbon dioxide content of
the'retarder constitutes between about 5 and 10
‘ 19. The retarder recited in claim 14 wherein
per cent by weight of the retarder.
the carbon dioxide of the carbonate constitutes 5
between about 5 and 10 per cent by weight of the
GEORGE D. KING.
retarder.
'
-
'
Y»
C.
DAILEY.
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