Note: Descriptions are shown in the official language in which they were submitted.
~1~62734
:: The present invention relates to curable or settable
compositions, method of preparing the compositions, and methods
for curing the compositions. -
The present invention is particularly useful in obtain-
ing molding compositions such as refractories, abrasive articles,
and molding shapes such as foundry cores and molds,
~Certain inorganic materials have been suggested as the
- major component in curable compositions for various uses includ- :~
~`ing molding compositions, EIowever, various prior art
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~2734
binders from inorganic substances have suffered from one or
more deficiencies. Typical of the deficiencies exhibited by
prior art inorganic binders including the silicates suggested
for molding shapes such as cores and molds have been poor
collapsibility of the shape and poor removal or "shake out"
of the molding shape from the metal casting.
Also, many of the suggested inorganic binders
exhibit inade~uate bonding strength properties and/or unde-
sirable cure characteristics.
Moreover, various prior art inorganic binders such
as the silicates provide molding shapes and particularly am-
bient temperature cured shapes which possess poor scratch
resistance at strip; and accordingly, such shapes require at
least a few additional hours after strip time has been
achieved to develop adequate scratch resistance. In view of
` the poor scratch resistance at strip, such shapes cannot be
`~ readily handled at strip because of the danger of damage to
the shape, Moreover, the sag resistance at strip of the
shapes prepared from various prior art binders is not good,
Another problem which may exist is the degradation
of physical properties such as tensile strength and hardness
of molded articles after storage for only a few hours.
It is therefore an object of the present invention :
to provide curable inorganic systems which possess acceptable
strength characteristics.
It is another object of the present invention to
provide curable inorganic systems wherein the cure characteristics
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~an be manipulated within certain limits.~
It is a further object of the present invention to
provide settable inorganic binder systems for molding shapes
which possess relatively good collapsibility and shake out
properties as compared to various other suggested inorganic
binders.
It is another object of the present invention to
provide molding shapes employing inorganic binders which
possess good scratch and sag resistance at strip. Likewise,
it is an object of the present invention to provide molding
shapes from inorganic binder systems which can be readily
;~ and easily handled at strip. --~ -
It is also an object of the present invention to
provide molded articles which demonstrate improved resistance
to deterioration of physical properties such as tensile
strength and hardness due to storage.
Summary of the Invention
One aspect of the present invention is concerned with
a process for preparing settable composition which comprises:
~; 20 A) providing aluminum phosphate;
` B) providing solid organic carboxylic acid;
; C) providing alkaline earth material; ~
D) providing water; and -` -
`, E) providng an admixture of the aluminum phosphate; ;
the solid organic carboxylic acid, the alkaline earth material,
` and water provided that the solid organic carboxylic acid and
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alkaline earth material are not precontacted with each o~her
prior to contact of the alkaline earth material with the alum- .
inum phosphate; and wherein .
F) the aluminum phosphate contains O to about 40
mole % of boron based upon the moles of aluminum and contains
: a mole ratio of phosphorus to total moles of aluminum and
boron of at least about 2:1;
G) said solid organic carboxylic acid being soluble
in aqueous solutions o the aluminum phosphate and containing
~ at least two substituents being either at least carboxylic
; groups or at least one carboxylic group and at least one
hydroxyl group; or keto tautomers thereof;
H) said alkaline earth metal material contains
alkaline earth metal and an oxide.
`' The amount of aluminum phosphate is from abou-t 50
~' to about 95% by weight based upon the total wei~ht of aluminum
phosphate and alkaline earth material; and the amounts o~ alka-,
line earth material is from about SO to about 5% by weight
based upon the total weight of aluminum phosphate and alkaline
ear~h material. The amount of water is from about 15 to about
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: 50% by weight based upon the total weight of aluminum phosphate
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and water. The amount of the solid carboxylic acid is from
about 0.5 to about 25% by weight based upon the total weight
:~ of aluminum phosphate and solid organic carboxylic acid.
:-
The present invention is also directed to settable
. composition comprising:
. A) aluminum phosphate containing O to about 40
;
~62'~3~
mole ~ of boron based upon the moles of aluminum and
containing a mole ratio of phosphorus to total moles of
aluminum and boron of at least about 2:1;
B) solid organic carboxylic acid being soluble in
aqueous solutions of the aluminum phosphate and containing at
least two substituents selected from the group consisting of
at least two carboxylic acid groups; and at least one carboxylic
acid group and at least one hydroxyl group; or keto tautomers
thereof;
C) alkaline earth material containing alkaline
earth metal and an oxide; and
D) water; and wherein the amount of the alkaline
earth material is from about 50 to about 5~ by weight based
upon the total weight o~ the aluminum phosphate and alkaline
earth material; the amount of the aluminum phosphate is from
about 95 to about 50% by weight based upon the total weight :
of the aluminum phosphate and alkaline earth material; the
amount of water is from about 15 to about 50% by weight based
upon th~ total weight of the aluminum phosphate and water;
and the amount o~ the solid organic carboxylic acid is ~rom
about 0.5 to about 25% by weight based upon the total weight ~: -
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` of aluminum phosphate and the organic carboxylic acid; and
.~ wherein the composition is obtained by providing an admixture
of the aluminum phosphate, the solid organic carboxylic acid,
`. the alkaline earth material, and water whereby the solid organ-
ic carboxylic acid and alkaline earth màterial are not pre- :
contacted with each other pxior to contact of the alkaline ~ :
earth material with the aluminum phosphate. : .
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~L~6273~
Another aspect of the present invention is a two-
package system capable of curing at ambient temperature con-
sisting essentially of containing in a first package a cur-
able composition of:
A) aluminum phosphate containing 0 to about 40
mole % of boron based upon the moles of aluminum and contain-
ing a mole ratio of phosphorus tototal moles of aluminum and
boron of at least about 2:1;
B) solid organic carboxylic acid being soluble in
10 aqueous solutions of the aluminum phosphate and containing at : .
least two substituents being at least two carboxylic acid
groups3 or at least one carboxylic acid and at least one
hydroxyl group; or keto tautomers thereof; and
C) water; wherein the amount of aluminum phosphate
is from about gO to about 85% by weight based upon the total
weight of aluminum phosphate and water; the amount of water
is from about 15 to about 50~ by weight based upon the total
weight of the aluminum phosphate and water; and the amount of
the solid organic carboxylic acid i5 from about 0.5 to about
25% by weight based upon the total weight of aluminum phosphate
and acid; and containing in a second package a hardening agent
for the curable composition in the first package and being an
alkaline earth material containing alkaline earth metal and
an oxide wherein the amount of the alkaline earth material is
from about 50 to about 5% by weight based upon the total weight .
of the alumin.um phosphate and alkaline earth material.
The present invention is also concerned with the
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~62 ~3~
fabrication of molded articles such as refractories, abrasive
articles such as grinding wheels and shapes used for molding
which includes providing a major amount of aggregate in ad-
mixture with an effective bonding amount up to about ~0% by
weight of the aggregate of the settable composition defined
above.
The present invention is also concerned with a pro-
cess for casting of relatively low melting point nonferrous -
type metal which comprises fabricating a shape as defined -~
above; pouring the relatively low melting point nonferrous type
metal while in the liquid state into the shape; allowing the
nonferrous type metal to cool and solidify; then contacting
the shape with water in an amount and for a time sufficient to
cause degradation of the bonding characteri~tics of the binder
system; and separating the molded article.
Description of Pxeferred Embodiments
; The present invention can be achieved by admixing
the aluminum phosphate, the solid organic carboxylic acid,
the alkaline earth material, and the water in any suitable
manner and in an~ se~uence provided that the solid organic
carboxylic acid and the alkaline earth material are not pre-
, contacted with each other prior to contact of the alkaline
`, earth material with the aluminum phosphate. ~ ~ `
Precontacting of the solid organic carboxylic acidand alkaline earth material greatly reduces the reactivity
,i between the alkaline earth material and aluminum phosphate.
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which reactivity is essential in achieving the type of cur-
ing characteristics which are desired in accordance with the
present invention.
The preferred means of practicing the present in-
vention is to provide an aqueous solution of the aluminum
phosphate material and water followed by addition of the solid
organic carhoxylic acid per se or as an aqueous solution to
the aqueous solution of the aluminum phosphate. Next, the
; alkaline earth material can be contacted with the aqueous
solution of the aluminum phosphate material, water, and solid
organic car~oxylic acid.
At the present time, it is contemplated that the
present invention be carried out by making the compositions
available as a two-package system comprising the aluminum
phosphate, solid organic carboxylic acid, and water components
in a first package and the alkaline earth metal component in
a second package. For instance, when the compositions are to
! be employed along with an aggregate, the contents of the package
containing the alkaline earth metal component are usually ad-
mixed with the aggregate, and then the contents of the aluminum
phosphate containing package are admixed with the aggregate and
alkaline earth metal component composition. After a uniform
distribution of the curable system on the particles of aggregate
has been obtained, the resulting mix is molded into the desired
shape. Methods of distributing the }inder on the aggregate
particles are well known to those skilled in the art. The mix
can, optionally, contain other ingredie~ts such as iron oxide~ ~ -
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~[)6273~
ground flax fibers, wood cereals, clay, pitch, refractory
flours and the like.
The present invention can be carried out by methods
such as adding the aluminum phosphate and the solid organic
carboxylic acid separately and preferably as aqueous solutions
to the alkaline earth metal material at substantially the same
time, or by admixing the alkaline earth metal material and
aluminum phosphate first, followed shortly therea~ter and be-
fore substantially reaction occurs between the aluminum phosphate
and alkaline earth metal material by admixing with the s~lid
organic carboxylic acid. -
In addition, when the compositions are to be employed
along with an aggregate, the alkaline earth metal component
can be admixed with the aggregate, and then the aluminum phos-
phate preferably as an aqueous solution is admixed with the
aggregate and alkaline earth metal component composition sub-
stantially simultaneously with or shortly prior to the admixing
of the organic carboxylic acid with the aggregate composition.
Also, it may be desirable to first admix the aluminum
phosphate and organic carboxylic acid with the aggregate, and
then admix the alkaline earth material with the aggregate com-
position or to first admix either the aluminum phosphate or
organic carboxylic acid with the aggregate and then admix the
other of the aluminum phosphate or organic carboxylic acid
which was not previosuly admixed prior to or substantially
simultaneously with admixing of the alkaline earth material
with the aggregate composition.
~627'3~
The aluminum phosphate constituent of the curable
system of the present invention is an aluminum phosphate
which can contain boron in an amount up to about 40 mole %
based upon the moles of aluminum of the aluminum phosphate.
Also, the aluminum phosphate contains a mole ratio of phos-
phorus to total moles of aluminum and boron of at least about
2:1, usually from about 2:1 to about 7:1, and preferably from
about 2,5:1 to about 3.5:1 and more preferably from about
2,8:1 to about 3,~:1.
Any of the several known methods may be employed to ~ ;
produce an aluminum phosphate suitable for the present purposes.
In particular those methods wherein the aluminum oxide containin~ -
reactant is completely dissolved are preferred.
The aluminum phosphate also is preferably prepared
from either P2O5 or concentrated phosphoric acid of from about
70 to about 86% by weight H3PO4 concentration, The preferred
phosphoric acid solutions contain about 80 to about 86% by
weight of H3PO4. Of course, other sources of phosphorus such
as polyphosphoric acids, can be employed, if desired.
'! 20 The amount of aluminum phosphate employed in the
curable or settable system is from about S0 to about 95% by -
weight and preferably from abo~t 65 to about 90~ by weight
based upon the total weight of aluminum phosphate and alkaline
earth material, and the amount of alkaline earth material is
from about 5 to~about 50% and preferably from about 10 to
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about 35% by weight based upon the total weight of aluminum
phosphate and alkaline earth material.
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~627~34
The preferred aluminum phosphates employed in the
present invention contain boron. Usually the boronated alumi-
num phosphates are prepared from boric acid and/or boric
oxide and/or metallic borates such as alkali metal borates
which include sodium borate (Na2B4O7.10H2O). These preferred
aluminum phosphates are preferably, but not necessarily, pre-
pared by reacting together the phosphoric acid or P2O5; and
alumina such as alumina trihydrate tA12O3 3H2O); and boric
acid or boric oxide. It is preferred to use boric acid rather
than boric oxide since the acid is in a more usable form than
the oxide because of its greater solubility in the reaction
system as compared to the oxide.
Since the reaction is exothermic, it can generally
proceed by merely admixing the reactants and permitting the
exotherm to raise the temperature of the reaction mass until
the exotherm peaks, usually at about 200 to 230F. Ater the
- exotherm peaks, it may be advantageous to apply external heat
~ for about 1/2 to 2 hours to maintain a maximum reaction tem-
i perature between about 220 and about 250 to ensure completion
of the reaction, Also, in some instances it may be desirable
to initiate the reaction by applying external heat just until
the exotherm begins.
The reaction is generally carr-ed out at atmospheric
i~ , . . .
pressure. However, higher or lower pressures can be employed -
if desired. In addition, the reaction is generally completed ~ ;
within about 1 to about 4 hours and more usually from about 2
to about 3 hours.
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The preferred aluminum phosphates contain from
about 3 to about 40 mole ~ of boron based upon the moles of
aluminum. The more preferred quantity of boron is between
about 5 and about 30 mole ~ while the most preferred quantity
is between about 10 and about 25 mole % based upon the moles
of aluminum.
Those aluminum phosphates which contain the boron
are preferred because of improved tensile strength achieved
in the final cured molded articles. The increased tensile
;~ 10 stren~th is even evident at the lower quantity of boron such
as at 3 mole %.
In addition, the modification with boron is ex-
tremely advantageous since it alters the reactivity of the
aluminum phosphate with the alkaline earth material in the
. j . .
presence of aggregate. As the level of boron in the aluminum
phosphate increases, the rate of reaction with the alkaline
earth material in the presence of aggregate decreases. This
is particularly noticeable at boron concentrations of at
least about 10 mole ~ based upon the moles of aluminum.
Therefore, the boron modification aspect of the present in-
vention makes it possible to readily manipulate the cure
characteristics of the binder system so as to tailor the
binder within certain limits, to meet the requirements for
a particular application of the binder composition.
The alteration in the cure characteristics and
particularly with the free alkaline earth oxide; ho~ever,
has not been observed in the absence of aggregate s~ch as
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~L~62~73~
sand. This may be due to the exothermic nature of the re-
action between the aluminum phosphate and free alkaline earth
metal oxide whereby the presence of aggregate acts as a heat
sink reducing the reactivity-to a level where the effect of
the boron modification becomes noticeable. On the other hand, `
the reaction is so fast in the absence of aggregate that any
effect which the boron may have on cure is not detectable and,
even if detectable, it is of no practical value.
In addition,the boron modification provides alumi-
num phosphate water solutions which exhibit greatly increased
shelf stability as compared to unmodified aluminum phosphate ~ ~;
materials. The enhanced shelf stability becomes quite signifi-
cant when employing quantities of bor~n of at least about 5
mole % based upon the moles of aluminum.
!` .
Moreover, the use of the solid organic carboxylic acid
is most effective when boronated aluminum phosphates are used.
In particular, the effectiveness of the organic carboxylic acid
on improving the sta~ility of physical properties of cured
.j , . .
molded articles is increased when using boronated aluminum phos-
phates, and especially when using the larger quantities of boron
such as from about l0 to about 30 mole % based upon the moles of
aluminum. Moreover, the effect of the organic carboxylic acid
has been quite notdceable when binder-aggregate compositions ~-
have been baked such as at about 300-350F. for up to about 30
minutes.
The organic carboxylic acids employed according to
the present invention are solid at normal room temperature (ile.
the normal or usual form in which the acids exist is as a solid)and `
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)62~34
are soluble in aqueous solutions o~ the aluminum phosphate,
In addition, the organic carboxylic acids contain at least
two "functional" substituents being either at least two car-
boxylic acid groups or at least one carboxylic acid group and
at least one hydroxyl group, or a keto tautomer thereof.
The organic carboxylic acids usually contain from
about 2 to about 20 of such "functional" substituents or
groups and preferably from about 2 to about 10 of such
"functional" substituents or groups in the molecule. In
ad~ition, these substances employed according to the present
invention generally contain 2 to about 20 carbon atoms and
preferably from about 2 to about 10 carbon atoms. In addition,
the organic carboxylic acids can contain other groups or atoms
which do not adversely affect the function of the material in
the compositions of the present invention to an undesirable
extent, For instance, the organic carboxylic acids employed
in the present invention can contain moieties. Also, the
organic carboxylic acids are generally nonpolymeric, saturated
aliphatic carboxylic acids. In addition, many of the organic
carboxylic acids employed in this invention contain at least
-two adjacent carbon atoms each having directly attached thereto
a carboxylic acid or hydroxyl group. Examples of some suitable
organic carboxylic acids include lactic acid, tartaric acid,
citric acid, oxalic acid, malonic acid, and gluconic acid.
The preferred acid is tartaric acid.
The amount of organic carboxylic acid employed in
the present invention i5 usually from about 0.5 to about 25% by
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6273~e
weight and preferably from about 2 to about 15~ by weight
based upon the total weight of the aluminum phosphate and
alcohol.
Although certain carboxylic acids have apparently
been suggested in certain inorganic compositions, the present ~ -
invention including various advantages achieved thereby are
neither suggested by nor apparent from these prior suggestions
of employing carboxylic acids.
For instance, in U,S. patent 2,450,952 to Gregor
on column 5, line 6 et seq., it is stated:
! "The properties of the aluminum phosphates
vary with the A12O3 to P2Os ratio. For
practical purposes, the range of 1 to 1.64
- moles of A12O3 to 3 moles of P2Os is of
principal interest, Adjustments and allow-
ances must be made for the lower reactivity -
in the higher alumina ranges up to the di-
aluminum phosphates, either by using a
chemically very active filler or by causing
an increased acidity and solubility by the
addition of a solid organic acid in small
quantities such as 1/2% of oxalic or tar- -
~; taric acid."
i~ The reason for employing the acid according to the
aboye disclosure of Gregor would not be applicable in the pre-
sent invention since the aluminum phosphate employed in the
,! . present invention contains a minimum of moles of phosphorus
~; to aluminum and boron of about ~:1 (i.e. maximum moles of
aluminum to phosphorus being a~out 1.5 moles per 3 moles of
^ 30 phosphorus).
; On the other hand, Gregor seemingly does not contem-
plate using nor needing the acid until the aluminum is present
, in amounts exceeding about 1.64 moles per 3 moles of phosphorus
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and up to about 2 moles per 3 moles of phosphorus ~o the
dialuminum phosphate. This difference is believed in part
to be due to the differences in relative amounts of aluminum
phosphate and magnesium compound employed by Gregor
Contrary to the disclosure of Gregor of accelerating
cure, U.S. patent 2,345,211 to Neiman suggests on column 3,
lines 47-51:
"The use of organic acids and temporary binders,
such as gelatin, is not recommended but may be used
where certain effects, such as slower setting time,
is desired."
However, the advantages achieved by the present in-
vention are not suggested by Neiman, and a review of Neiman
illustrates that such is directed to compositions quite differ-
ent from that of the present invention.
U,S. patent 3,511,674 to Harris et al suggests pre-
" treating calcium silicate with certain acids to stabilize it
;~ against immediat~ reaction with monoaluminum phosphate This
is contrary to the manner in which the present invention is
carried out. Moreover, the various advantages achieved by thepresent invention are not suggested by Harris et al. Moreover~
the compositions of Harris et al in addition to the differences
in the manner in which the acid is employed, differ from the
present invention in various aspects such as the relative -
amount of the aluminum phosphate and calcium silicateD Also,
when the present aspect of the present invention of using a
`-~ boronated aluminum phosphate is being ollowed, the need for
stabilizing calcium silicate is not even existent in view of
` ~ the relatively low reacti~ity between calcium silicate and
boronated aluminum phosphates.
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It has also been stated elsewhere that normal
aluminum orthophosphate is insoluble in water but soluble in :
dilute mineral acids (for example, hydrochloric acid and
nitric acids) and in some carboxylic acids (for example, citric
acid). However, the reason for employing the acid in that . .
case would not be applicable in the present invention since
normal aluminum orthophosphate refers to aluminum phosphate from
a mole ratio of phosphorus to aluminum of 1:1. Contrary to this, ..
the present invention is concerned with aluminum phosphates
which are from a minimum mole ratio of phosphorus to aluminum
and boron of 2:1 and accordingly are not water insoluble.
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U.S. patent 2,690,377 to Leffarge et al discusses
the addition of axalic acid instead of boric acid to aluminum
phosphate (see column 4, lines 21-43),but such did not
accomplish the results desired by them of stabilizing the
` aluminum hydrogen phosphate solution against crystallization.
The alkaline earth metal material employed in the
present invention is any material containing an alkaline earth
metal and containing an oxide which is capable of reacting
with the alurninum phosphate. When the alkaline earth metal
material is a free alkaline earth metal oxide or a free alka-
line earth metal hydroxide, it preferably has a surface area
no greater than about 8.5 m /gram as measured by the BET pro-
cedure. More preferably it has a surface area no greater than
about 3 m2/gram. Those free oxides and free hydroxides having
surface areas no greater than about 8.5 m2/gram are preferred
when the compositions are employed in molding compositions
such as for preparing refractories, abrasive articles_and par-
ticularly or making shapes such as foundry cores and molds.
It has been observed that composi~ions of the pre-
, 20 sent invention which employ the preferred oxides and hydroxides
have sufficient work times to be ade~uately mixed in the more
conventional types of commercially available batch type mixers -
~, before introduction into the mold or pattern for shaping. Al-
~` though free oxides and free hydroxides having surface areas ~
greater than about 8.5 m~/gxam generally are too reactive for ~ -
use with the more conventional types of co~nercially available
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batch type mixers, they are suitable when much faster mixing
operations are employed such as those continuous mixing opera-
tions which may require only about 20 seconds for adequate
mixing or when the binders are to be employed for purposes
wherein substantially instantaneous cure is desirable and/or
can be tolerated.
Those materials which contain an oxide or hydroxide -
and an alkaline earth metal, in chemical or physical combina-
tion with other constituents are less reactive than the free
oxides and hydroxides. Accordingly, such materials can have
surface areas greater than about 8.5 m /gram and be suitable
for use even when employing mixing operations which require
- about 2 to 4 minutes or more.
These other constituents may be present such as
being chemically combined with the oxide and alkaline earth
metal and/or being physically combined such as by sorption
or in the form of an exterior coating. However, the mere
mixing of a material with a free ~xide or hydroxide without
achieving ~he above type of uniting of the material would
not materially reduce the reactivity. Therefore, such mere
mixing is not included within the meaning of chemical or ~`
physical combinations as used herein.
However, it is preferred that all of the alkaline
earth metal materials employed in the present invention have
a surface area of no greater than about 8.5 m /gram and more
preferably have a surface area of no greater than about 3
m /gram. Usually the surface areas are at least about 0.01
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6~73~
m2/gram. ~11 references to surface area unless the contrary
is stated, re~er to measurements by the BET procedure as set
forth in tentative ASTM-D-3037-71T method C-Nitrogen-~hsorp-
tion Surface Area by Continuous Flow Chromatography, Part 28,
page 1106, 1972 Edition, employing 0.1 to 0.5 grams of the
alkaline earth materialO
Included among the suitable materials are calcium
oxides, magnesium oxides, calcium silicates, calcium alumi~
nates, calcium aluminum silicates, magnesium silicates, and
magnesium aluminates. Also included among the suitable ma-
terials of the present invention are the zirconates, borates,
and titanates of the alkaline earth metals.
It is preferred to emplo~ either a free alkaline
earth metal oxide or a mixture of a free alkaline earth metal
oxide and a material which contains the alkaline earth metal
, ,
and oxide in combination with another constituent such as
calcium aluminates. In addition, the preferred alkaline earth
metal oxides are the magnesium oxides.
Those materials which include com~onents in combi-
;
nation with the oxide or hydroxide, and the alkaline earth
:
metal, in some instances can be considered as being a latent
source of the alkaline earth metal oxide for introducing the
~ alkaline earth metal oxide into the ~inder c-~stem.
,J` Some suitable magnesium oxide materials are avail-
able under the trade designations of Magmaster l-A from
~ Michiga~ Chemical, Calcined Magnesium Oxide`r -325 mesh, Cat~
i, No. M-1016 from Cerac/Pure, Inc.; H-W Periklase~rain 94C `
.
* Trade Mark
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~62~73~
Grade (Super Ball Mill Fines); H-W Periklase* Grain 94C Grade
(Regular Ball Mill Fines); and H-W Periklase* Grain 98,
(Super Ball Mill Fines) from Harbison-Walker Refractories.
Magmaster*l-A has a surface area of about 2.3 m2/gr~m and
Cat. No. M-1016 has a surface area of about 1.4 m /gram.
A particularly preferred calcium silicate is
Wollastonite which is a particularly pure mineral in which
the ratio of calcium oxide to silica is substantially equal
.. .
molar.
Generally commercially available calcium aluminate
compositions contain from about 15 to about 40% by weight of
calcium oxide and from about 35 to about 80% by weight of
alumina, with the sum of the calcium oxide and alumina being
at least 70% by weight. Of course, it may be desirable to
obtain calcium aluminate compositions which contain greater
~percentages of the calcium xoide In fact, calcium aluminates
' containing up to about 45.5% by weight of calcium oxide have
been obtained. Some suitable calcium aluminate materials
can be obtained commercially under the trade designations -~
20 J Secar* 250 and Fondu* from Lone Star Lefarge Company, Lumnite* ;~
and Refcon* from Universal Atlas Cement and Alcoa* Calcium
Aluminate Cement CA-25 from Aluminum Company of America.
Fondu* has a minimum surface area as measured by ASTM C115 of
s about 0.15 m2/gram and 0.265 m2/gram as measured by ASTM C205.
Lumnite* has a Wagner specific surface of 0.17 m2/gram and
Yi~ Refcon* has a Wagner specific surface of 0.19 m /gram.
`~ Mixtures of a free alkaline earth metal oxide and
.~ ' .
~ * Trade Marks
. .
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1` - 21 -
.. ' ' ~ ~
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a material containing components in combination with the
free oxide or hydroxide and alkaline earth metal preferably
contain from about 1 part by weight to about 10 parts and
more preferably from about 2 to about 8 parts by weight of
the free alkaline earth metal oxide per part by weight of - -
the material containing substituents in combination with
the free metal oxide or hydroxide and alkaline earth metal.
Preferably such mixtures are of magnesium oxides and calcium
aluminates. The free alkaline earth metal oxide such as mag-
nesium oxides in such mixtures are primarily responsible for
achieving fast cure rates while the other component such as
the calcium aluminates are mainly responsible for improving~
the strength characteristics of the final shaped article.
Since the free metal oxide is a much more reactive material
than those materials which are latent sources of the free metal
oxide, those other materials will only have a minimal effect
upon the cure rate when in admixture with the alkaline earth
metal oxide.
Someti~mes it may be desirable to employ the alka-
line earth metal materials in the form o~ a slurry or suspen-
sion in a diluent primarily to facilitate material handling.
Examples of some suitable liquid diluents include alcohols
such as ethylene glycol, furfuryl alcohol, esters such as
cellosolve acetate, and hydrocarbons such as kerosene, min-
eral spirits (odorless), mineral spirits regular, and 140
Solvent available from Ashland Oil, Inc., and Shellflex* 131
from Shell Oil, and aromatic hydrocarbons commercially
* Trade Marks
; ,; -
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~0~2'~3~
available under the trade designations Hi-Sol* 4-2 and Hi-Sol*
10 Erom Ashland Oil, Inc. Of course, mixtures of different ~-
diluents can be employed, if desired. In addition, it may
be desirable to add a suspending agent to slurries of the
alkaline earth material such as Bentone*, Cabosil*, and ~ ---
Carbopol* in amounts up to about 10% and generally up to less
than 5% to assist in stabilizing the slurry or suspension in
the diluent.
General~y, the alkaline earth metal material and
diluent are mixed in a weight ratio of about 1:3 to about
3:1 and preferably from about 1:2 to about 2:1. It has been
observed that the nonpolar hydrocarbons provide the best
strength characteristics as compared to the other diluents
which have been tested, when a diluent is employed. In
addition, the alcohols such as ethylene glycol and furfuryl
alcohol are advantageous as liquid diluents since they in-
~' crease the work time of the foundry mix without a corres-
`~ ponding percentage increase in the strip time. However, the
strength properties of the final foundry shape are somewhat
reduced when employin~ alcohols such as ethylene glycol and
~ ~ur~uryl alcohol.
;~ The other necessary component of the binder system
employed in the present invention is water All or a por-
tion of the water can be supplied to the system as the car-
rier for the aluminum phosphate material, Also, the water can
?~
be introduced as a separate ingredient. Of course, the desired
~uantity of water can be incorporated in part as the water in
the aluminum phosphate and in part from another source. The
* Trade Marks
. ' .,: .
.
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.
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amount of water emplo~ed is from about 15 to about 50~ by
weight and preferably from about 20 to about 40~ by weight
based upon the total weight of the aluminum phosphate and
water.
The present invention makes possible the obtainin~
of molded articles including abrasive articles such as
grinding wheels, shapes for molding and refractories such
as ceramics having improved resistance to deterioration of
physical properties such as tensile strength and hardness due
to storage. The loss in such physical properties after stor-
age for several hours (i.e. 24 hours or more) is less when
employing the composition of this invention as compared to
employing compositions which differ only in not including a
solid organic carboxylic acid of the type employed in the pre-
sent invention. The improvement in the stability of physical
properties of the cured articles such as molds and cores is
most pronounced when the aluminum phosphate is a boronated
~` aluminum phosphate. The efect of the solid organic carboxylic
acid is much greater when a boronated aluminum phosphate is `
used instead of a nonboronated aluminum phosphate.
- In addition, it has been observed that the presence
of the solid organic carboxylic acid in the composition of the
present invention improves the flowability of mixtures of the
composition and aggregate for molding operations. ~ `
It has further been observed that the surface finishes
of articles cast in molds or cores prepared from composi-
tions of the present invention are improved as compared to
. ',',''' ''' ' '
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6~34
compositions which do not contain the solid organic carboxylic
acid constituent. It has further been observed that the solid
organic carboxylic acids in the amounts employea increase both
the work and strip times of molding compositions.
Also, other materials which do not adversely affect
the interrelationship between the aluminum phosphate,
solid organic carboxylic acid, alkaline earth metal component,
ancl water can be employed, when desired.
When the composition of the present invention is used
in molding compositions such as for preparing abrasive articles
including grinding wheels, refractories including ceramics and
structures for moldiny such as ordinary sand type foundry shapes
and precision casting shapes, aggregate is employed along with
the compositions.
`~ When preparing an ordinary sand type foundry shape,
i the aggregake employed has a particle size large enough to
.~ .
provide sufficient poroslty in the foundry shape to permit es-
~; cape of volatiles from the shape during the casting operation.
The term "ordinary sand type foundry shapes" as used herein re-
fers to foundry shapes which have sufficient porosity to permit
, escapa of volatiles from it during the casting operatlon. Gen-
erally, at least about 80% and preferably at least about 90%
.: . .
by weight of a~gregate employed for foundry shapes has an aver-
age particle size no smaller than about 150 mesh (Tyler Screen
~; Mesh). ~he aggregate for foundry shapes preferably has an aver-
age particle slze between about 50 and about 150 mesh (Tyler
`~ Screen Mesh~. The preferred aggregate employed for ordinary
:~L06~734
foundry shapes is silica wherein at least about 7~ weigh~ %
and preferably at least about 85 weight % of the sand is silica.
Other suitable aggregate materials include zircon, olivine,
alumino-silicate sand, chromite sand, and the liXe.
When preparing a shape for precision casting, the
predominate portion and generally at least about 80% of the
aggregate has an average particle size no larger than 150 mesh
(Tyler Screen Mesh) and preferably between about 325 mesh and
200 mesh (Tyler Screen Mesh). Preferably at least about 90%
by weight of the aggregate for precision casting applications
has a particle size no larger than 150 mesh and preferably be-
tween 325 mesh and 200 mesh. The preferred aggregates employed
for precision casting applications are fused quartz, zircon
sands, magnesium silicate sands such as olivine, and alumino-
silicate sands.
Shapes ~or precision casting differ from ordinary
sand type foundry shapes in that the aggregate in shapes for
precision casting can be more densely packed than the aggre-
gate in shapes for ordinary sand type foundry shapes. There-
fore, shapes for precision casting must be heated before being
:.
~utilized to drive off volatilizable material, present in the
... .
molding composltion. If the volatiles are not removed from a
`precision casting shape before use, vapor created during cast-
... .
!ing will diffuse into the molten metal since the shape has a
relatively low porosity. The vapor diffusion would decrease
the smoothness of the surface Oe the precision cast article.
-~When preparing a refractory such as a ceramic, the
.
26
~36273~
predominant portion and at least about 80 weight ~ of the
aggregate employed has an average particle si~e under 200
mesh and preferably no larger than 325 mesh. Preferably at
least about 90% by weight of the aggre~ate for a refractory
has an average particle size under 200 mesh and preferably
no larger than 325 mesh. The aggregate employed in the pre-
paration of refractories must be capable of withstanding the
curing temperatures such as above about 1500F which are
needed to cause sintering for utilization. Examples of some
suitable aggregates employed for preparing refractories in-
clude the ceramics such as refractory oxides, carbides,
nitrides, and silicides such as aluminum oxide, lead oxide,
chromic oxide, zirconium oxide, silica, silicon carbide,
titanium nitride, molybdenum disilicide, and carbonace~S
; material such as graphite. Mixtures of the aggregates can
also be uced, when desired, including mixtures of metals and
the ceramics.
Examples of some abrasive grains for preparing
abrasive articles includb aluminum oxide, silicon carbide,
boron carbide, corundum, garnet, emery, and mixtures thereof.
The grit size is of the usual grades as graded by the United
States Bureau of Standards. These abrasive materials and
their uses for particular jobs are understood by persons
skilled in the art and are not altered in the abrasive articles
contemplated by the present invention. In addition, inorganic -
fillers can be employed along with the abrasive grit in pre-
paring abrasive articles. It is preferred that at least about
- ~7 -
., . , .~ . . :,
~62~34
85% of the inorganic fillers have average particle size no
greater than 200 mesh. It is most preferred that at least
about 95~ of the inorganic filler has an average particle
size no greater than 200 mesh. Some inorganic fillers in- -
clude cryolite, fluorospar, silica and the like. When an
inorganic filler is employed along with the abrasive grit,
it is generally present in an amount from about 1 to about
30% by weight based upon the combined weight of the abrasive
grit and inorganic filler.
Although the aggregate employed is preferably dry,
it can contain small amounts of moisture, such as up to about
0.3% by weight or even higher based on the weight of the ~
aggregate. Such moisture present on the aggregate can be ~ `
compensated for, by altering the quantity of water added to
the composition along with the other components such as the
aluminum phosphate, solid organic carboxylic acid and alkaline
earth metal material.
In molding composition, the aggregate constitutes
the major constituent and the binder constitutes a relatively `
minor amount. In ordinary sand type foundry applications, the
amount of binder is generally no greater than about 10% by
weight and frequently within the range of about 0.5 to about
7% by weight~ based upon the weight of the aggregate. Most
often, the binder content ranges from about 1 to about 5% by
weight based upon the weight of the aggregate in ordinary sand
type foundry shapesO
In molds and cores for precision casting applications,
.,;
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:
6;~'~3~
the amount of binder is generally no greater than about 40%
by weight and frequently within the range of about 5 to about
20% by weight based upon the weight of the aggregate.
In refractories, the amount of binder is generally
no greater than about 40% by weight and frequently within the
range of about 5~ to about 20% by weight based upon the weight
of the aggregate.
In abrasive articles, the amount of binder is
generally no greater than about 25~ by wei`ght and frequently
within the range of about 5% to about 15% by weight based upon
the weight of the abrasive material or grit.
The systems of the present invention are capable
of ambient temperature cure which is used herein to include
curing by chemical reaction without the need of external
heating means. However, within the general description of
ambient temperature cure, there are a number of different
ambient temperature curing mechanisms which can be employed.
For example, ambient temperature cure encompasses both "air
cure" and "no bake". Normally, ambient temperature cure is
effected at temperatures of from about 50F to about 120E.
Moreover, the molding shapes of the present inven-
tion have good scratch resistance and sag resistance immedia-
tely at strip. Accordingly, the molding shapes of the pre-
sent invention can be easily and readily handled and employed
immediately after strip.
In addition, the systems of the present invention
make possible the achievement of molding shapes which possess
'~ ' . `
. :, `,
- 29 - ~ ~
.
. .
1a~6Z:73~
improved collapsibility and shake out of the shape when used
for the casting of thP relatively high melting point ferrous-
type metals such as iron and steel which are poured at about
2500F, as compared to other inorganic binder systems such
as the silicates.
Furthermore, the systems of the present invention
make possible the preparation of molding shapes which can be
employed for the casting of the relatively low melting point
nonferrous type metals such as aluminum, copper, and copper
alloys including brass. The temperatures at which such metals
are poured in certain instances may not be high enough to
adequately degrade the bonding characteristics of the systems
of the present invention to the extent necessary to provide the
degree of collapsibility and shake out by simple mechanical ~ -
forces which are usually desired in commercial type of appli-
cations. `
However, the systems of the present invention make
it possible to provide molding shapes which can be collapsed
and shaken out from castings of the relatively low melting
point nonferrous type metals and particularly aluminum, by ~
~ater leaching, The shapes can be exposed to water such as - ~ -
by soaking or by a water spray, Moreover, it has been observed
that the surface appearance of aluminum cast articles when em-
ploying shapes according to the present invention is quite good.
The s~stems of the present invention further make
possible the achievement of molding shapes which can be
successfully used for casting molten refractory particles in
~ : . ....
~. ......... ..
- 30 -
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, . .. . .. . .. .. . ~ . .
~D6;2 734
fused casting processes.
It has been also observed that with the systems of
the present invention~ it is possible to readily reclaim and
reuse the aggregate employed in such applications as foundry
cores and molds after destruction of the shape. In fact,
sand aggregate has been successfully reclaimed and reused for
at least seven cycles in foundry cores and molds.
When the compositions of the present invention are
used to prepare ordinary sand type foundry shapes, the follow-
ing steps are employed:
tl) forming a foundry mix containing an
aggregate (e.g., sand) and the con- -
tents of the curable system;
(2) introducing the foundry mix into a
mold or pattern to thereby obtain a
green foundry shape;
(3) allowing the green foundry shape to
remain in the mold or pattern for a
time at least sufficient for the shape
`' 20 to obtain a minimum stripping strength
(i.e., b~come self-supporting); and ~ -
(4) thereafter removing the shape from
the mold or pattern and allowing it to
cure at room temperature, thereby obtain- ~ -
-~ ing a hard, solid, cured foundry shape.
In order to further understand the present invention
the following nonlimiting examples concerned with foundry shapes
. .
- 31 -
, .
~L~62'739~
are provided. All parts are by weight unless the contrary
is stated. In all the examples, the samples are cured by
no-bake procedure at room temperature unless the contrary is
stated. The core hardness in the examples was measured on a
No.674 Core Hardness Tester commercially available from
Harry W. Dietert Co., Detroit, Michigan.
Example 1
To a round bottom, 3 liter, 3-necked reaction flask -~ -
fitted with a heating mantle, mechanical stirrer, reflux con-
10denser and thermometer~are added 1650 parts of 85% phosphoric
acid. Under mild agitation, 50 parts of granular boric acid
- are charged to yield a boric acid-phosphoric acid dlspersion.
The boric acid is added as a smooth steady "stream", as op-
posed to dumping in bulk, to avoid clumping. To the agitated
dispersion are added 310 parts of hydrated alumina (Alcoa*,
C-33 grade) as a smooth steady stream to give a milky-white
slurry.
The reaction mass is heated to a temperature of
about 110-120F in about 1/2 hour at which time external heat
is removed, The reaction is continued for about another 20 to
30 minutes with the temperature rising to a maximum of about
. : .....
220-230F due to the reaction exotherm. Then external heat
-is applied and reaction temperature rises to a maximum of
about 245-250F at which point refluxing occurs. The reaction
mass is held at about 245-250F for about 1.5-2 hours to en-
sure complete reaction. The reaction mass is cooled to about
`:~ '. '
.
* Trade Mark
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- 32 -
.. ..
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~(~6~,734
200~F in about 45 minutes at which time about 260 parts of
water are slowly added with agitation. The temperature of
the reaction mass then drops to about 150-160F. About 2270
parts of product are then collected in glass-line polypropylene
containers. The product is a boronated aluminum phosphate
product having a solids content of 66.6~, a viscosity of 700-
750 centipoises, mole ratio of phosphorus to total moles of
aluminum and boron of 3:1, and about 20 mole ~ boron based
upon the moles of aluminum; a pH of 1.5-2,0 and Gardner color
of 2.
5000 parts of Port Crescent sand and about 25 parts
of-a mixture of magnesium oxide having a surface area of about -~
2.3 m2/gram (Magmaster* l-A) and Calcium Aluminate (Refcon*) in
a ratio o~ 5 parts of magnesium oxide to 1 part of calcium
a~uminate are admixed for about 2 minutes. To this mixture
are added a mixture of about 158 parts of the boronated alumi-
num phosphate product prepared above and about 7 parts of
gluconic acid. The mixture is then agitated for 2 minutes,
The resulting foundry mix is formed by hand ramming
into standard AFS tensile strength samples using the standard
procedure. The tensile strength of the test bars and core
hardness are set forth in Table I below. The composition has
a work time of about 19 minutes and a strip time of about 62
minutes.
_ ample 2
Example 1 is repeated except that about 10.3 parts
.''.
* Trade Marks - -
.
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~(~62,73~
of gluconic acid and about 154.7 parts of the boronated alumi-
num phosphate are employed. The resulting foundry mix is
formed into standard AFS tensile strength samples using the
standard procedure. The tensile strength of the test bars
and core hardness are set forth below in Table 1. The COMpO-
sition has a work time of about 23 minutes and a strip time
of about 58 minutes.
xample 3 --
Example 1 is repeated except that about 16.5 parts
of gluconic acid and about 148.5 parts of the bornated alumi- ;
num phosphate are employed. The resulting foundry mix is
formed in standard AFS tensile strength samples using the
standard procedure. The tensile strength of the test bars
, and core hardness are set forth below in Table I. The compo- -
sition has a work time of about 18 minutes and a strip time of
about 55 minutes.
Example 4
. ... ..
Example 1 is repeated except that 165 parts of the
boronated aluminum phosphate without any gluconic acid are em-
ployed, The resulting foundry mix is formed into standard A~Stensile strength samples using the standard procedure. The
tensile strength of the test bars and core hardness are set
forth in Table I below. The composition has a work time of
` about 14 minutes and a strip time of about 40 minutes.
':
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3106Z734
Table I
Example 1 Example 2
% gluconic acid
based upon total
of gluconic acid 4.25 6.25
and aluminum phos-
phate solution
Work time
(minutes) 19 23
Strip time
(minutes) 62 58
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
~ psi psi
! 2 95 88 100 90
4 160 90
6 220 91
24 200 90 240 89
48 245 88 215 88
72 lS0 92 23~ 91
.
' .
.
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~1~'6273~ ,
Table I
(Continued)
Example 3Example 4
% gluconic acid
based upon total
of gluconic acid 10 0
and aluminum phos-
phate solution
Work time
. (minutes) 18 14
Strip time
(minutes~ 55 40
Time (hours) Tensile CoreTensile Core
~trength hardness strength hardness
psi psi
2 105 91 130 35
4 160 91 190 90
;
', 6 205 91 215 85
~` 24 220 92 85 72
, 48 250 90 110 67
72 225 86 gO 7
. . .
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~L~62~73~
Example 5
5000 parts of Port Crescent Lake sand and abou, 25
parts of a mixture of magnesium oxide haviny a surface area
of about 2.3 m~/gram (Magmaster*l-A) and calcium aluminate
(ReEcon) in a ratio of 5 parts of magnesium oxiae to l part
of calcium aluminate are admixed for about 2 minutes~ To this
mixture are added a mixture of about 156.65 parts of an alum-
inum phosphate prepared along the lines of the procedure in
Example l and having a solids content of 66.6%, viscosity of
700-750 centipoises, le ratio of phosphorus to total moles
of aluminum and boron o~ 3:1, about 20 mole % boron based upon
the moles of aluminum, pH of 1.5-2.0 and Gardner color of 2,
and about 8.35 parts of d-tartaric acid. The mixture is then
agitated for 2 minutes.
The resulting foundry mix is formed into standard
AFS tensile strength samples using the standard procedure.
The tensile strength of the test bars and core hardness are
set forth below in Table II. The composition has a work time
o~ about 16 minutes and a strip time of about 52 minutes.
': ' - '-~ . . '
Example 6
.
Example 5 is repeated except that about 13.5 parts
of d-tartaric acid and about 151.5 plrts of the bc~onated alum- ~;
inum phosphate are employed. The resulting foundry mix is -~
formed into standard AFS tensile strength samples using the -
standard procedure~ The tensile strength of the test bars and
core hardness are set forth below in Table II o The composition
.
37
Trade Marks
,
. . .. .
62~73~
has a work time of about 15 minutes and a strip time of about
51 minutes. -
Example 7
Example 5 is repeated except that about 2 parts of
d-tartaric acid and about 163 parts of the boronated aluminum
phosphate are employed. The resulting foundry mix is formed
into standard AFS tensile strength samples using the standard
procedure. The tensile strength of the test bars and core
hardness are set forth below in Table II. The composition haS
a work time of about 16 minutes and a strip time of about 58
minutes. -
Example 8
Example 5 is repeated except that about 4 parts of
d-tartaric acid and about 161 parts of the boronated aluminum
phosphate are employed. The resulting foundry mix is formed
into standard AFS tensile strength samples using the standard
procedure. The tensile strength of the test bars and core
hardness are set forth below in Table II. The composition has
a work time of about 15 minutes and a strip time of about 42
minutes.
Example 9
Example 5 is repeated except that 165 parts of the
boronated aluminum phosphate without any d-tartaric acid are
employed. The resulting foundry mix is rormed into standard
'','` ~'.
:: : :
.. ':
- 38 -
,
1~i2~3~
AFS tensile strength samples using the standard procedure,
The tensile strength o the test bars and core hardness are
set forth below in Table II. The composition has a work time
of about 14 minutes and a strip time of about 40 minutes.
Table II
-
Example 5 Example 6
% d-tartaric acid
based upon total of
d-tartaric acid and 5 06 8 2
aluminum phosphate
solution
Work time
(minutes) 16 15
Strip time
~minutes) 52 51
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
psi psi : ,.
2 130 94 145 89
4 165 92 ~ :
6 195 91
24 270 91 260 86 .. :
48 220 88 225 85
72 195 86 215 88
'~
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- 39 -
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- ~06273q
Table II
(Continued)
Example 7 Example 8
% d-tartaric acid
based upon total of
d-tartaric acid and 1.2 2.43
aluminum phosphate
solution
Work time
(minutes) 16 15
Strip time
(minutes) 58 42
Time (hours) Tensile Core Tensile Core
. strength hardness str~ngth hardness
~si psi
2 150 91 105 9o
4 200 85 180 88
6 200 85 205 84
24 260 86
48
~: 72 185 85 240 86
; 96 195 88 215 85
120 210 88
.
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~6Z73~
Table II
(Continued)
Example 9
% d-tartaric ~cid
based upon total of
d-tartaric acid and o
aluminum phosphate
solution
Work time
(minutes) 14
. Strip time
(minutes) 40
` Time (hours) Tensile Core
strength hardness
psi
2 130 95
~;
` 4 190 90
` 6 215 85
24 85 72
48 110 67
,:
: 72 90 74
'. ' :
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41
.
~ 062734
Example lO
S000 parts of Port Crescent Lake sand and about 35
parts of a mixture of magnesium oxide having a surface area
of about 2.3 m2/gm (Magmaster*l-A) and calcium aluminate ~Refco~)
in a ratio of 5 parts of magnesium oxide to l part of calcium
aluminate are admixed for about 2 minutes. To this mixture are
added a mixture of about 156.65 parts of an aluminum phosphate
prepared along the lines of the procedure in Example 1 and
having a solids content of 66.6%, viscosity of 700-750 centi-
poises, mole ratio of phosphorus to total moles of aluminum and -
boron of 3:1, about 20 mole % boron based upon the moles of
aluminum, pH of 1.5-~.0 and Gardner color of 2, and about 8.35
parts of malonic acid. The mixture is then agitated for 2 minutes.
The resulting foundry mix is formed into standard
AFS tensile strength samples using t:he standard procedure. The -~
tensile strength of the test bars and core hardness are set
forth below in Table III. The composition has a work time of
. ~ . .
~` about 18 minutes and a strip time o about 58 minutes. -
.~ - ~, .
.~ ,
`~ Example ll
.
~ ~ .
Example lO is repeated except that about 16.3 parts-
of malonic acid and about 148.7 parts of the boronated alumi-
num phosphate are employed. The re~ulting foundry mix is formed
~,~ into standard AFS tensile strength samples using the standard
` procedure. The tensile strength of the test bars and core hard-
~ ness are set forth below in Table III. The composition has a
'~ work time of about 23 minutes and a strip time of about 77 minutes, ~' -
42 ~ ~
* Trade Marks ~ -
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Z73~
Example 12
Example 10 is repeated except that about 2 parts of
malonic acid and about 163 parts of the boronated aluminum
phosphate are employed. The resulting foundry mix is formed
into standard AFS tensile strength samples using the standard
procedure. The tensile strength of the test bars and core
hardness are set forth below in Table III. The composition has
a work time of about 15 minutes and a strip time of about ~6
; minutes.
Example 13
.
Example 10 is repeated except that about 4 parts of
malonic acid and about 161 parts of the boronated aluminum phos-
phate are employed. The resulting oundry mix is formed into -
standard AFS tensile strength samples using the standard pro-
cedure. The tensile strength of the test bars and core hardness
are set forth below in Table III. The composition has a work
time of ahout 17 minutes and a strip time of about 54 minutes.
Example 14 ;
Example 10 is repeated except that 165 parts of the
boronated aluminum phosphate without any malonic acid are em-
ployed. The resulting foundry mix is formed into standard AFS
tensile strength samples using the standard procedure. The
tensile strength of the test bars and core hardness are set
forth below in Table III. The composition has a work time of
abo~t l4 minutes and a strip time of about 40 minutes,
;';
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- 43 - ~ ~-
~;273~
Table III
Example 10 Example 11
% malonic acid
based upon total of
malonic acid and 5.06 g.go
aluminum phosphate
solution
Work time
(minutes) 18 23
Strip time
tminutes) 58 77
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
psi psi
2 95 84 60 87
4 -- -_ ___ __
6 180 86 170 8~
24 145 83 250 83
48 195 ~5 175 8
72 180 gl 165 86
,~ .
44
.
~ILC~6273~
Table II~
(Continued~
Example 12 Exampl_ 13
% malonic acid
based upon total of
: malonic acid and 1.23 2.44
aluminum phosphate
solution
Work time
(minutes) 15 17
S~rip time
(minutes) 46 54
Time (hours~ Tensile Core Tensile Core
s~rength hardness strength hardness
psi psi
2 145 89 100 85
; 6 155 80 225 82
24 80 68 80 78
48 85 76 90 75
! 72 100 85 135 80
"
. .
:, ., '
';.
.
~6~'734
Table III
(Continued)
Example 14
% malonic acid
based upon total of
malonic acid and 0
aluminum phosphate
solution
Work time
(minutes) 14
Strip time
(minutes) 40
Time (hours) Tensile Core
; strength hardness
psi
2 130 95
4 190 90
6 215 85
24 155 7~
48 110 67
7~ 90 74
:
46
3~ [96Z73~
Example 15
5000 parts of Port Crescent Lake sand and about 35
parts of a mixture of magnesium oxide having a sur~ace area
of about 2.3 m2/gm (Magmaster*l-A3 and calcium aluminate
(Refcon~ in a ratio of 5 parts of magnesium oxide to 1 part
of calcium aluminate are admixed ~or about 2 minutes. To this
mixture are added a mixture of about 156.65 parts of an alumi-
num phosphate prepared along the lines of the procedure in
Example 1 and having a solids content of 66.6%, viscosity o~
700-750 centipoises, mole ratio of phosphorus to total moles
of aluminum and boron of 3:1, about 20 mole % boron based upon
the moles of aluminum, pH of 1.5-2.0 and Gaxdner color of 2,
and about 8.35 parts of citric acid. The mixture is then
agitated *or 2 minutes~
The resulting foundry mix is formed into standard
AFS tensile strength samples using the standard procedure.
The tensile strength of the test bar~ and core hardness are
,: :
set forth below in Table IV. The composition has a wor~ time
of about 15 minutes and a strip ~ime of about 54 minutes.
. . .::
Example_16
Example 15 is repeated escept that about 16.3 parts
of citric acid and about 148.7 parts of the boronated aluminum
phosphate are employed. ~The resulting foundry mix is formed
into standard AFS tensile strength samples using the standard
procedure. The tensile strength o~ the test bars and core hard~
ness are set orth below in Table IV. The composition has a work
time of abou~ 23 minutes and a strip time o~ about 71 minutes.
~`~ 47 -
* Trade Marks
.;. .. :, .. . .
-
11D6273~
Example 17
Example 15 is repeated except that about 2 parts of
citric acid and about 163 parts of the boronated aluminum phos-
phate are employed. The resulting foundry mix is formed into
standard AFS tensile strength samples using the standard pro-
cedure, The tensile strength of the test bars and core hardness
are set forth below in Table IV. The composition has a work
time of about 18 minutes and a strip time of about 53 minutes,
Example 18
Example 15 is repeated except that about 4 parts of
citric acid and about 161 parts of the boronated aluminum phos-
phate are employed, The resulting foundry mix is formed into .
standard AFS tensile strength samples using the standard pro- ..
cedure, The tensile strength of the test bars and core hardness :
are set forth below in Table IV, The composition has a work
time of about 18 minutes and a strip time of about 5~ minutes,
~xample 19 .
Example 15 is repeated except that 165 parts of the
boronated aluminum phosphate without any citric acid are em-
ployed, The resulting foundry mix is formed into standard AFS : ~.
tensile strength samples using the standard procedure, The
tensile strength of the test bars and core hardness are set
forth below in Table IV, The composition has a work time of
about 14 minutes and a`-.strip time of.about 40 minutes,
'-'
. .
- ' "
- 48 - .:
- . . - . ,
~162734
_able IV
Example 15 Example 16
% citric acid
based upon total
amount of citric acid 5.06 9,90
and aluminum phos-
phate
Work time
(minutes) 15 23
Strip time
(minutes) S4 71
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
psi psi
2 ~ - 75 86
4 165 78 155 82
6 190 81 --- --
24 --- -- 225 79
~8 --- -- 210 80
72 ~40 92 220 75
96 250 75 255 84
; 120 215 80 --- -~
.:
49
l~D62734
Table IV
(Continued)
Example 17 Example 18
% citric acid
based upon total
amount of citric 1.23 2.44
acid and aluminum
phosphate
; Work time
(minutes) 18 17
Strip time
(minutes) 53 48
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
psi psi
2 95 83 115 80
4 180 80 210 77
~ 6 205 79 225 81
;, 24 235 80 220 79
48 225 82 205 ~1
72 ~
'~ : 96 220 81 220 85
: .
120 -__ __ ___ __
.
.
62t73~
Table IV
(Continued)
Example 19
% citric acid
based upon total
amount of citxic 0
acid and aluminum
phosphate
Work time
(minutes) 14
: Strip time
(minutes) 40 .`
Time (hours) Tensile Core
strength hardness
psi
2 130 95
4 190 90
6 2:L5 ~5
24 ~35 72
48 l:L0 67
72
: 96 ___ __
120 --- ~~
, ....
: , . .
.
. 51
~62~739~
Exc~ple 20
5000 parts of Port Creseent Lake sand and about 35
parts of a mixture of magnesium oxide having a surface area of
about 2.3 m2/gm (Magmaster*l-A) and calcium aluminate (Refcon)
in a ratio of 5 parts of magnesium oxide to 1 part of calcium
aluminate are admixed for about 2 minutes, To this mixture
are added a mixture of about 156.65 parts of an aluminum phos-
phate prepared along the lines of the procedure in Example 1
and having a solids content of 66~6%t viscosity of 700-750
centipoises, mole ratio of phosphorus to total moles of alumi-
num and boron of 3:1, about 20 mole % boron based upon the moles
of aluminum, pH of 1.5~2,0 and Gardner color of 2, and about
8,35 parts of oxalic acid. The mixture is then aqitated for 2
minutes.
The resulting foundry mix :Ls formed into standard
AFS tensile strength samples using the standard procedure,
The tensile strength of the test bars and core hardness are
set forth below in Table V. The composition has a work time
of about 17 minutes and a strip time of about 60 minutes,
,, .
Example 21
Example 20 is repèated except ~at about 16.3 parts
of oxalic acid and about 148,7 parts of the boronated aluminum
phosphate are employed. The resulting foundry mix is formed
into etandard AFS tensile strength samples using the standard
procedure. The tensile strength of the test bars and core hard-
ness are set forth below in Table V. The composition has a ~ork
time of about 26 minutes and a strip time of about 75 minutes.
52
.'~ .. j ,
~ * Trade Marks
`` 1~162734
Example 22
Example 20 is repeated except that about 2 parts of
~; oxalic acid and about 163 parts of the boronated aluminum phos-
phate are employed. The resulting foundry mix is formed into
standard AFS tensile strength samples using the standard pro-
, . . ~ . .
cedure. The tensile strength of the test bars and core hard-
ness are set forth below in Table V. The composition has a work
time of about 17 minutes and a strip time of about 52 minutes.
Example 23
10Example 20 is repeated except that about 4 parts of
oxalic acid and about 161 parts of the bornated aluminum phos-
phate are employed. The resultlng foundry mix is formed into
standard AFS tensile strength samples using the standard pro-
cedure. The tensile strength of the test bars and core hardness
are set forth below in Table V. The composition has a work time
~ of about 19 minutes and a strip time of about 51 minutes. -
`~ Example 24 -
Example 20 is repeated except that 165 parts of the
boronated aluminum phosphate without any oxalic acid are employed,
The resulting foundry mix is formed into standard AFS tensile
strength samples using the standard procedure. The tensile ```
strength of'the test bars and core hardness are set forth below
in Table V. The composition has a work time of about 14 minutes
and a strip time of about 40 minutes.
' ' ' ":
! - 53 - -:
.'.:', .
i- ... .
~1~62734
Table V
Example 20 ExamPle 21
% oxalic acid
based upon total
amount of oxalic 5.06 9,90
acid and aluminum
phosphate
Work time
(minutes) 17 26
Strip time
(minutes) 60 75
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
psi psi
2 115 81 70 84
4 155 84 145 85
6 230 88 ~
24 285 86 250 81
48 300 ~5 245 79
72 ~ - 220 82
96 --- -- 230 8
120
~ .
~' .
,:
54
~1~62'734~
Table V
(Continued~
Example 22 Example 23
% oxali~ acid
based upon total
amount of oxalic 1.23 2.44
acid and aluminum
phosphate
Work time
(minutes) 17 19
Strip time
(minutes) 52 51
Time (hours) Tensile Core Tensile Core
sirength hardness strength hardness
psi psi
2 1~5 7~ 100 79
4 ~ 5 ~5
6 ~
24 190 74 215 83
48 210 ~6 210 81
72 --- -- ___ __
96 250 83 230 83
120 230 84 200 ~5 .
.~ . .
.~ , .
. .
,, .
. .
- ~
6273~
Table V
(Continued~
Example 24
% oxalic acid
based upon total
amount of oxalic o
acid and aluminum
phosphate
Work time
(minutes) 14
Strip time
(minutes) 40
Time (houxs) Tensile Core
strength hardness
psi
2 ~.30 95
.
4 ~.90 90
~ ~'15 85
24 85 72
48 110 67
72 90 74
96 ___ __
, 120 ___ __
... .
`:
.
':
.
56
~LID627'3~
Example 25
To a reaction vessel equipped with a stirrer,
thermometer, and reflux condenser are added about 2445 parts -
of 8S% phosphoric acid. Then about 67 parts of sodium borate
are added with agitation, and the agitation is continued for
about 10 minutes until the borate dissolves in the acid to form
a clear solution. To this solution are added about 540 parts
of hydrated alumina (Alcoa*C-33) under agitation. The reaction
proceeds for about 40 minutes with the temperature rising to a
maximum of about 220~ F due to the reaction exotherm. Then
external heat is applied and reaction temperature rises to a
maximum of about 245 F. The reaction mass is held at about
~45 F for about 2 hours to ensure complete reaction. The re-
action mass is then cooled to room temperature and about 3052
parts of a boronated aluminum phosphate having a solids content
of about 75%, a vi~scosity of about 40,000 centipoises, a mole
ratio of phosphorus to total moles of aluminum and boron o~ 3:1
and about 10 mole % boxon based upon the moles of aluminum are
.:
obtained. This aluminum phosyhate is diluted with water to pro-
vide a solids content of about 66% and having a viscosity of
400-500 centipoises.
5000 parts of Port Crescent Lake sand and about 30.5
parts of a mixture of magnesium oxid~ ~master*l-A) and a
calcium aluminate containing 58% A12O3 and 33% CaO (Refcon~ in
a ratio of 5 parts of magnesium oxide to 1 part of calcium al-
uminate are mixed for about 2 minutes. To this mixture are
added a mixture of about 156.6 parts of the 66% solids solution
., ' '' . ~ .
`~ * Trade Marks
' 57
~: .
~6273~
of the boronated aluminum phosphate prepared above and about
8.4 parts of d-tartaric acid. The mixture is then agitated
for 2 minutes. The resulting foundry mix is foxmed by hand
ramming into standard AFS tensile strength samples using the
standard procedure. The tensile strength of the test bars and
core hardness are set forth below in Table VI. The composition
has a work time of about 11 minutes and a strip time of about
32 minutes.
Example 26
Example 25 is repeated except that 165 parts of the
boronated aluminum phosphate without an~ organic carboxylic acid
are employed. The resulting foundry mix is formed into standard
AFS tensile strength samples using the standard procedure. The
~ensile strength o the test bars and cora hardness are se~ forth
below in Table VI. The composition has a work time of about 13
minutes and a strip time of about 42 minutes.
. .
' .
.
58
~2734
Table VI
Example 25 Example 26
5.1% 0% organic
tartaric acid carboxylic acid
Work time
(minutes) 11 13
Strip time
(minutes) 32 42
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
- psi psi - -
2 115 7~ 125 75
4 145 -- 165 72
6 ~ 160 74
24 110 6'; 120 65
48 110 7~
: '
~ ~ '
-:
:` :
.
.
:
`~
.
59
~6;~734
Example 27
Example 25 is xepeated except that a boronated alum-
inum phosphate containing 20 mole % boron and 20 mole % sodium
based upon the aluminum and prepared according to the procedure
of Example 25 is employed. The resulting foundry mix is formed
by hand ramming into standard AFS tensile strength samples using
the standard procedure. The tensile strength of the test bars
and core hardness are set forth below in Table VII. The compo~
sition has a work time of about 12 minutes and a strip time of
about 30 minutes.
Example 28
Example 27 i~ repeated except that 165 parts of the
boronated aluminum phosphate wi~hout any organic carboxylic
acid are employed. The resulting foundry mix ls formed into
standard AFS tensile strength s~nples using the standard pro-
cedure. The tensile strength o~ the test bars and core hardness
are set forth below in ~able VII. The composition has a work
time of about lS minutes and a strip time of about 33 minute~.
:` ~
~0~273~ :
Table VII
Example 27 Example 28
5.1% 0% organic
tartaric acid carboxylic acid
Work time
(minutes) 12 15
Strip time
(minutes) 30 38
Time (hours) Tensile Core Tensile Core
strength hardness strength hardness
' psi psi ,
2 1~5 74 100 58
4 150 69 155 77
6 170 78 110 50
24 185 ~7 65 32
48 155 ~i8 ~
.
', :
;
':~
'
'~ '
61
~\6273~
A comparison of Examples 1-3 with 4, Examples 5-8
with 9, ExampleS 10-13 with 14, Exarnples 15-18 with 19,
Examples 20-23 with 24, Exarnple 25 with 26, and Example 27
with 28 demonstrates that after storage for several hours,
the general trend is improvement in physical properties such
as tensile strength and core hardness due to the presence of
the type of organic car~oxylic acids employed in the present
invention, although a few of the samples do not fit the general
behavior due to some normal experimental error. Although the
systems of the present invention may not possess as great
initial physical properties as those corresponding systems
which do not include the organic carboxylic acids, the higher
physical properties after storage for several hours is quite
important from a practical and commercial viewpoint.
The following Examples 29-33 demonstrate that the
use of organic carboxylic acids outs,ide the scope of the pre-
sent invention does not xesult in the type of improved tensile
strengths as is obtained by practicing the present invention.
"' .
Example 2
3000 parts of Port Crescent 1ake sand and about 20 -~
parts of a mixture of magnesium oxide having a surface area of
about 2.3 m2/gm ~Magmaster* 1-A) ana calcium aluminate (Refcor~
in a ratio of 5 parts of magnesium oxide to 1 part of calcium
aluminate are admixed for about 2 rninutes. To this mixture are
added a mixture of about 94.1 parts of an aluminum phosphate
prepared along the lines of the procedure in Example 1 and having
~'', .
62 ;
* Trade Marks
~L~16Z7;~4
a solids content of 66,6%, viscosity of 700-750 centipoises,
mole ratio of phosphorus to total moles of aluminum and boron
of 3:1, about 20 mole ~ boron based upon the moles of aluminum,
pH of 1.5-2.0 and Gardner color of 2, and about 1.9 parts of
acetic acid. The mixture is then agitated for 2 minutesO
The resulting foundry mix is formed into standard
AFS tensile strength samples using the standard procedure.
The tensile strength of the test bars and core hardness are set
forth below in Table VIII.
` 10 Example 30
Example 29 is repeated except that about 4.8 parts of
acetic acid and about 91.2 parts of the boronated aluminum phos- ~ -
phate are employed. The resulting foundry mix is formed into
standard AFS tensile strength samples using the standard proce-
dure. The tensile strength of the test bars and core hardness
are set forth below in Table VIII.
Example 31
,~
~1~ Example 29 is repeated except that about 7.7 parts of
;` acetic acid and about 88.3 parts of the boronated aluminum phos-
' 20 phate are employed. The resulting foundry mix is formed into
' standard AFS tensile strength samples using the standard proce-
!- dure, The tensile strength of the test bars and core hardness
are set forth below in Table VIII.
. ,
. .
- 63 ~
, ;~:, "
j;Z734
Example 32
Example 29 is repeated except that about 9.6 parts
o~ acetic acid and about 86.4 parts of the boronated aluminum
phosphate are employed. The resulting ~oundry mix i5 formed
into standard AFS tensile strength samples using the standard
procedure. The tensile strength of the test bars and core
hardness are set forth below in Table VIII.
Example 33
Example 29 is repeated except that 96 parts of the
boronated aluminum phosphate without any acetic acid are em-
ployed. The resulting foundry mix is formed into standard AFS
tensile strength samples using t:he standard procedure. The
tensile strength o~ the test bars and core ~hardness are set
~orth below in Table VIII.
., .` ~ '
:'
.
:,.,
64
1~D62~3~
Table VIII
Example 29 Exampl~ 30
% acetic acid
based upon total
weight of acetic 2 5
acid and aluminum
phosphate solution
Hours Tensile Core Tensile Core
strength hardness strength hardness.
psi psi
2 75 71 70 62
2 85 69 65 62
3 95 68 100 73
3 ~05 74 105 70
72*
. .
* At 72 hours all samples contai.ning acetic acid were ver~
fragile and could not be measured ~or tensile strenyth
and core hardnes6.
.
62734
Table VIII
(Continued)
Example 31 Example_32 .
% acetic acid
based upon total
weight of acetic 8 10
acid and aluminum
phosphate solution
Hours Tensile Core Tensile Core
strength hardness strength hardness
psi psi
2 65 70 40 80
2 60 63 55 85
: .
72 65 50
. 3 90 71 75 57
72*
* At 72 hours all samples containing acetic acid were very
fragile and could not be measured for tensile strength
and core hardness.
.. .
i .
,
` :
, .
, .
, ~
,:
66
:-
.
, .
'
lO~Z~3~
Table VIII
(Continued)
ExampIe 33
% acetic acid
: based upon totaI
weight of acetic o
acid and aluminum
phosphate solution
Tensile Core
Hours strength hardness
psi
2 105. 72
2 90 80
3 100 74
3 105 74
72 90 69
* At 72 hours all samples containing acetic acid were vexyfragile and could not be measured for tensile strength
and core hardness.
~ '
. .
~7 .
