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Патент USA US2413011

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Patented Dec. 24, 1946
2,413,011
UNITED STATES PATENT orrlca
2,413,011
MOLDING COLIPOSITIONS
Waldorf S. Traylor, Mans?eld, Mara, and David
R. Wiggam, West Grove, Pa., asaignors to Her
cules Powder Company, Wilmington, DeL, a
corporation of Delaware
No Drawing. Application June 19, 1943,
Serial N0. 491,552
'
10 Claims. (Cl. 106-173)
2
This invention relates to a thermoplastic com
The completely colloided composition was then
position comprising ethyl cellulose and particu
cooled down to about 65° C. on the mill and then
larly to an ethyl cellulosethermoplastic compo
stripped oil.’ as a sheet.
sition which will provide in its cast condition a
The plastic composition so obtained was molded
hard and substantially mar-resistant surface and 6 by the casting method at a temperature of about
will have high impact strength.
220° C. to give a shaped article suitable for
There has been a need in industry for a plastic
strength tests. The strength characteristics and
composition such as may be formed by the casting
other characteristics of the cast molded article
method which will exhibit high impact strength
were as follows:
characteristics, will be hard, tough, non-brittle 10
Table l
and which will possess a substantially mar-re
sistant surface.
A plastic composition having
such characteristics would resemble metals in
many respects and would replace metals in the
forming and shaping of fabricated articles from
Hardness-Rockwell (M-scale)_.__‘_-.‘_____
33
Izod impact strength (ft, lb./in. of notch) __
1.0
Tensile strength (Ila/in?) _______ _-‘ .... __
920
Melting point (ring and ball) ______ .._°C__
158
the softer metals.
Coe?icient of expansion (in./in./°C.>< 10-5) _
7.5
It has now been found in accordance with this
Mold contraction (in./in.) _____________ __ .009
invention that by a speci?c combination of in
Compressive strength (lbs/in?) ________ __ 9,000
gredients a thermoplastic composition of ethyl
Exuntns 2-4
cellulose base may be prepared which by a casting 20
method will provide articles of the above-men
In a similar manner to that shown in Example
tioned desirable characteristics. It has been
1. plastic compositions were prepared from the
found that such a composition may be prepared
following ingredients:
'
by compounding together in a molten condition
the ingredients given below in the approximate 25
percentage ranges so as to give a fused compo
sition which on solidi?cation will have a melting ~
point ‘by the ring and ball method within the
range of about 120° C. to about 175° C.:
Per cent by weight 30
Ethyl cellulose ____________________ __ 20 to 50
Plasticizer ________________________ __ 2.5 to 35
Thermoplastic resin _______________ __ 3 to 30
Wax ______________________________ __
5
to 25
The following examples will illustrate the prep
aration of the above de?ned plastic compositions.
The parts shown in the examples are all on a
weight basis.
'
2
3
4
Ethyiltoellulose (47.5% ethoxyl, 50 cps. vis- Parztaa5 Parts
Parts
cos
..
Ethyl cellulose (47.5% ethoxyl, N0 cps.
aziis?osnuuf"tii'éé'mt?mTi?o
""""""
"
35 """ "
y as
use
.
e oxy,
cps.
viscosity) ......... -1 ......... _
______________ __
a0
Pentaerythritol ester oi rosin. .
420
20
Hydrogenated methyl abietate
15
15
15
Barnsdail wax (ISO-185° . ___
Red
11 oxide ............... ..
10
20
10
20
10
20
l
1
1
Diphenylamine ......................... .-
20
The characteristics of the cast molded articles
produced from each of the above fused compo
sitions are set forth in Table II below:
‘
Table II
40
EXAMPLE 1
A plastic composition was prepared from the
2
following ingredients in the stated amounts:
Parts
Ethyl cellulose (47.5% ethoxyl, 100 centipoises
viscosity)
35
Pentaerythritol ester of rosin. ___________ .._
Hydrogenated methyl abietate ____________ __
Barnsdall wax (M. P. 180-185° F.) ________ __
Red iron oxide __________________________ _..
Hardness—Rockwell (M-scale) ............. _.
Surface hardness égencil) ..... -.
...Tensile strength
s./in.!) ____ __
3
46
F
55
F
8
H
_ __ 4, 100
1, 200
500
Melting point (ring and ball), ......... ..° 0.153
166
Coe?icient of expansion (ln./in./° (LX104)-.. 10.0
8. 9
20
Mold contraction (in./in.) _ . __..-_
.
. 010
. 013
Compressive stre h (lbs./ln.*)__
5, 300 6, 000
15
Flemral strength lbs.lin.l).____
_ 7,000 8,700
10 50 Specific gravity............................. -- 1. 28 1. 24
20
The above ingredients were compounded together
by mixing the ingredients and then colloiding the
mixture on a heated two-roll mill at a tempera
4
149
5. 5
. 000
6, 150
4,100
1. 26
Exmus 5-9
Fused compositions were prepared
following ingredients using the method of formu
ture of 150° to 160° C. until completely colloided. 55 iation described in Example 1:
9,418,011
4
5
0
7
8
9
Ethyl cellulose (47.5% eth- Pam Park Park Pom Pom
oxyl,100c .visc.) ....... ..
Pentaer thr tol ester oi\rosin_
35
20
85
20
35
20 ............ ._
Glycero ester of hydrogen-
20
s“.:1:"Ba:“---..--.--~.-.
-sue
me
a ------e
y
..... ..
-
"0
f ____________ "y. .................. -_
'l‘ricresyl phosphate ........ ..
Nev
5 on account of their low strength characteristics.
-
ated rosin ______ __
5
15
15
15
........................... __
15
10
..... -
Barnsdall wax (ISO-185° F.)._
10
10
10
10
10
Red iron oxide ............. __
20
20
1)
20
20
Dlphenylamine ............ __
- 1
1
1
1
1
.
The characteristics of the molded articles ob
tained from the above compositions by the cast 15
ing method at a temperature of.~2_20° C. are set
, forth in Table III.
Table III
5
.
6
7
8
20
9
Hardness—Rockwell (M
scale) .................... --
---22
19
-25
17
55
lb./in.ol notch) __________ ..
0.5
0.34
0.37
0.4
0.4
EB
H
F
H
Inod impact strength (it.
Surface hardness
ncil)_._._
Tensile strength
./in.l)._.- 2,900 3,100 1,100 3,000
ng point (ring and
ball) ................ -.°
--
155
106
170
2B 25
2,200
157
163
13. 3
Coe?lcient of expansion (in./
in./° (LX104) ............ __
10
9. 5
5. 5
5. 5
Mold contraction (in./in.)____
.006
.017
.009
.006
.006
in.a ........ __. ........... ._ 4,000
5,000
4,500
6,200
0,500
Flexural strength (lbs.lin.1)_- 3,300 5,500 2,400 3,000
3,900
Com ressive strength (lbs./
Specific gravity ____________ ._
1.34
1.34
1.31
1.32
.
colloiding characteristics and exhibits graining.
Similar de?ciencies exist for ethyl cellulose of
above 50% ethoxyl content. Viscosity types be
low 20 centipoises are unsatisfactory particularly
30
1.33
Viscosity types above 1000 centipoises are not
satisfactory because of low pourability. It has
been found, in accordance with this invention,
that the operable range of ethoxyl contents for
use in the compositions of this invention is from
45.5 to 50%, and the operable range of viscosity
is from 20 centipoises to 1000 centipoises. An
ethoxyl content from about 48.8 to about 49%
and a viscosity from about 50 to about 1000
centipoises have been found particularly desir
able and are preferred. The viscosities indicated
are those of a 5% by weight solution of ethyl
cellulose in a solvent consisting of 80% toluene
and 20% 2B-alcohol at 25° C. The amount of
ethyl cellulose to be included in the compositions
of the invention will be from about 20 to about
50% by weight based on the weight of the total
composition, and preferably will be from about
30 to about 40% of the composition.
The plasticizer included in the compositions of
the invention provides pourability and operates
to soften the ethyl cellulose. The plasticizer also
reduces mold shrinkage and prevents mold dis
tortion. Suitable plasticizers are, for example,
methyl abietate, hydrogenated methyl abietate,
hydrogenated ethyl abietate, tricresyl phosphate.
triphenyl phosphate, tributyl phosphate, methyl
phthalyl methyl glycollate, ethyl phthalyl ethyl
glycollate, mineral oil, "Nevinol" (coal tar dis
EXAMPLES 10-14
Additional fused compositions were prepared
35 tillate of B. P. 300-370° 0.), raw and blown soya
bean oil, raw and blown castor oil. butyl stear
according to the fusion procedure described in
Example 1 utilizing the following ingredients:
ate, tallow, di-2-ethylbutyrate of triethylene gly
col, etc. The amount of plasticizer which is de
sirable will vary with the other ingredients used
40 in the compositions and with the different plasti
cizers themselves. Usually an amount of plasti
Ethyl cellulose (47.5% eth- Pom Part: Part: Part: Part:
cizer in the range of about 2.5 to about 35% will
oxyl, 100 c . visc.) _______ __
35
35
35
35
35
Pentaerythr m1 ester of rosin_
20
20
20
20
20
be used, and preferably from about 5 to about
Hydrogenated methyl able
15%. Some resins and some waxes exert a
tate ...................... ._
15
15
15
15
35
Paraffin (56° C.) ........... ._
l0
45
softening
action on ethyl cellulose and thus act
Acrawax.
10
ll
l2
l3
l4
as plastcizers.
Superla we!
Barnsdail wax (ISO-185° F.)-.
Red iron oxide ............. Zinc nxida
Diphenylamine ____________ ..
10
_____ __
l
10
m
1
1
1
l
2.5%.
50
The molded articles obtained by casting the
When such resins or waxes are
used the amount of plasticizer needed is reduced
and may in certain cases be reduced to less than
-
A wax is included in the compositions of the
invention to improve the pourability of the com
positions and to provide good mold release char
above fused compositions at a temperature of
acteristics. The wax also .exerts a softening
220° 6‘. had characteristics as set forth in Table
action on the composition in the amounts used.
IV below.
55 Both low melting and high melting waxes are
Table IV
useful. Waxes of petroleum origin are quite
satisfactory. Waxes which are particularly de
10
11
12
' 13
14
sirable are, for example, high melting. micro
crystalline petroleum waxes, such as "Barnsdall"
Hardness-Rockwell
>
(M-scal ________________ __
29
10
21
23
17 6° wax, "Syncera” wax, “Stanolind,” “Superla," and
Izod impact strength
“Cerlse," carnauba wax, montan wax, beeswax,
(it. lb./in. oi notch) _______ __
. 19
27
.18
. 54
. 70
Surface hardness (pencil)--- ..
F
F
F
Tensile strength (lb./in.1)-._-_ 4, 000 3, 700 4, 300
Melting point (ring and ball)
F
980
2, 300
hydrogenated castor oil, “Acrawax," candelllla
wax, stearic acid, para?ln waxes. para terphenyl,
“Rezo” wax,‘ etc. The proportion of wax in
°C..
150
140
153
162
157.
Coefficient of expansion
'
65
cluded will generally be from about 5% to about
(in./in./°C.Xl0--") ________ -- l4. 5
14. 5
8. 3
8. 6
18
25% by weight based on the total weight of
Mold contraction (in/in.) -_-_
. 004
. 003
. 000
. 008
. 008
Compressive strength
the composition and preferably from about 10%
(lbs/in!) ................. _- 7, 300 8, 900 7, 800 4, 300
6, 900
Flexural strength (lbs/in 1)... 7, 300 5, 700 4, 800 5, 000 5, 800
to about 15%.
Speci?c gravity ____________ __ 1. 29
1. 30
1. 31
. 27
1. 09
The resin component of the plastic composition
70 adds hardness, rigidity and mar resistance to the
formulation and enables the production of high
The ethyl cellulose which may be used in the
plastic compositions of the invention is quite
melting compositions of desirable strength char
critical as to ethoxyl content and viscosity.
acteristics. The resins which are desirable are
Ethyl cellulose of less than about 45.5% ethoxyl
those which are compatible with ethyl cellulose
contei t has too high a fusion point, provides poor 75 in the proportion used and which are thermo
2,413,011
plastic. The resins utilized should have low acid
numbers to avoid any degrading in?uence on the
ethyl cellulose at the elevated temperatures.
phenylamlne'which may be used are, for exam
ple, phenyl beta naphthylamine, carbazole, di
phenylguanidine, sym. dibetanaphthyl paraphen
ylene diamlne, hydroquinone monobenzyl ether,
Resins which are particularly suitable are the
glycerol. pentaerythritol or higher polyhydric 5 hydroquinone monomethyl ether, hydroquinone"
alcohol esters of rosin, hydrogenated rosin, poly
merized rosin or heat-treated rosin, alkyd resins
modi?ed with any of the above rosins, oil modi
?ed alkyds, maleic modi?ed rosin-polyhydric al
cohol esters, phenol-formaldehyde resins modi?ed
with any of the above rosins, 100% phenolic
monobutyl ether, hydroquinone monoamyl ether,
copper salts such as copper naphthenate, cupric
nitrate, copper ammonium chloride, cupric sul
fate, cupric chloride, cupric acetate, etc. The
amount of stabilizer included in the composition
will preferably be no more than the amount nec
resins, coumarone-indene resins, etc. The pro
essary to provide the desired heat stability and
portion of resin included in the formulation will
will not exceed about 5 parts per 100 parts of
generally be from about 3% to about 30% by
the fused composition. Preferably the amount of
weight based on the total weight of the composi 15 stabilizer used, if any is necessary, will be from
tion and more preferably from about 10% to
about 0.5 to about 1.5 parts ‘per 100 parts of
about 20%. The amount of resin used will de
composition.
pend somewhat on the characteristics of the par
The designated ingredients of the cast mold
ticular resin and on the amounts of vplastlcizer
ing compositions described above are formulated
and wax included in the formulation. The melt 20 by the indicated method and in the ranges given
ing point of the resin will also control the amount
so as to provide fused compositions which on
to be used in general, since the softer resins
solidi?cation will have a melting point by the
when used in large amount exert too great a
ring and ball method within the range of about
softening action.
The ?ller shown in most of the examples serves
principally as a cheapening ingredient and is not
necessary to provide the desirable strength char
acteristics, as will be readily evident from Ex
ample 14 which contains no ?ller. The ?llers
120° C. to about 175° C. and preferably from about
140° C. to about 160° C. Within these melting
point ranges, the combinations of ingredients
shown will be useful in their cast molded form
as substitutes for zinc alloy in the making or dies,’
tools, jigs and ?xtures for the forming and shap
which may be used are those which are of the 30 ing of light metals such as aluminum. The com
non-flocculent and non-?brous type and which
positions have been found to be very suitable in
do not decompose at the temperatures used. The
forming and shaping tools used in the aircraft
extremely hard ?llers such as silicates are unde
industry for sheet aluminum. A particular ad
sirable because they scratch soft metal surfaces
vantage of the compositions in the tool, die and
brought in contact with the cast molded article. 35 jig industry is the possibility of remelting the
Red iron oxide is a. very desirable ?ller. Zinc
composition when desired for reshaping. In this
oxide is also very satisfactory. Other ?llers
manner, the composition of a particular tool, jig
which may be used with good results are, for ex
or die may be used over and over again. This has
ample graphite, bentonite, barytes, chalk, carbon
not been possible practically with the metal tools,
black, burnt umber, asbestine, etc. The amount 4 0 jigs and dies used. The hardness of the compo
of ?ller to be incorporated will depend on the
sitions is slightly less than the hardness of alumi
amount of cheapening desired for any particular
num and as a consequence no marring 0f the
commercial application.
aluminum surface occurs in contacting with the
The ingredients of the plastic composition in
cast. composition. The compositions are also
the above stated amounts may be compounded
either by a hot melt method involving stirring of
the ingredients together until a uniform compo
sition is provided or by milling on hot rolls or in
internal mixers of the Banbury type. The mill
ing method is advantageous since it requires rela
tively lower temperatures for successful com
pounding than are necessary in the hot melt
method. In using the hot melt method of com
pounding care should be exercised to prevent lo
cal superheating with consequent degradation
of the ethyl cellulose which will detract from the
strength characteristics of the cast molded article.
In employing the hot melt method, temperatures
of about 200° C. to about 240° C. are desirable,
while in the case of the milling method, the tem
perature of the heated rolls may be from about
135° to about 160° C. to provide plastic compo
sitions of good uniformity. Other methods of
compounding the components may be used if
desired.
In most of the examples a small amount of
diphenylamine has been included to serve as a
45 well adapted for other uses where a hard and
tough remeltable plastic composition is desired.
The various physical characteristics which have
been shown in the examples in describing the
cast molded articles obtained from the fused com
50 positions described were measured according to
the well recognized methods for each as applied
in the plastics industry. The surface hardness
values given as pencil hardness serve as a meas
ure of the mar resistance of the surface of the
55 cast plastic. The method of determining pencil
hardness is that used on protective coating ?lms.
A mar resistance in terms of pencil hardness of
at least 43 is generally desirable in the composi
tions of this invention, but preferably a pencil
60. hardness of H3 or harder is desirable.
What we claim and desire to protect by Letters
Patent is:
1. A thermoplastic casting composition suitable
to be melted and poured into molds to form such
65 objects as tools, dies, and jigs comprising the fol
lowing ingredients in the following percentage by
weight ranges:
.
stabilizing agent for the ethyl cellulose. In melt-r
Ethyl cellulose (45.5 to 50% ethoxyl, vis
ing and remelting the compositions of the inven
cosity 20 to 1000 centipoises) _______ __ 20' to 50
tion some degradation and decrease in viscosity 7O Plasticizer
2.5 to 35
of the ethyl cellulose may occur in the absence
Thermoplastic resin, compatible with
of the stabilizing agent. Thus, the stabilizing
agent is not essential but is desirable when the
composition is to be subjected to repeated remelt
ing operations. Stabilizing agents besides di
the ethyl cellulose in the proportion
used and having substantially no de
grading in?uence thereon at elevated
temperatures _____________________ __
75 Wax---"
_
'
3130 30
2,413,011
7
8
the above ingredients being proportioned within
the above ingredients being proportioned within
the above stated ranges to give the composition
the above stated ranges to give the composition
the characteristic of ready ?owability for casting
without pressure and without substantial decom
the characteristic of ready ?owability for casting
without pressure and without substantial decom
position at a temperature of 220° C. and a melting
position at a temperature of 220° C. and a melting .
point by the ring and ball method between about
point by the ring and ball method between about
140° C. and 160° C., the said composition being
further characterized by having at normal tem
120° C. and 175° C., the said composition being
further characterized by having at normal tem
peratures in its solidi?ed condition a hard, sub
peratures in its solidified condition a hard. sub
10 stantially mar-resistant surface.
stantially mar-resistant surface.
2. In a process for preparing a die useful for
5. A thermoplastic casting composition suitable
shaping metals such as aluminum and magnesi
um, the steps comprising mixing the following in
gredients in the following percentage by weight
'00 be melted and Poured into molds to form such
objects as tools, dies, and Jigs comprising the fol
lowing ingredients in the following percentage by
ranges:
weight ranges:
Ethyl cellulose (46.8 to 49% ethoxyl, vis
Ethyl cellulose (46.8 to 49% ethoxyl, vis
cosity 50 to 1000 centipoises) _______ __ 20 to 50
cosity 50 to 1000 centipoises) ______ __ 20 i050
Plasticizer _________________________ __ 2.5 to 35
Plasticizer _________________________ __
Thermoplastic resin, compatible with
the ethyl cellulose in the proportion
5 to 15
Thermoplastic resin, compatible with the
ethyl cellulose in the proportion used
and having substantially no degrading
in?uence thereon at elevated tempera’
used and having substantially no de
grading in?uence thereon at elevated
temperatures _____________________ __
Wax ______________________________ __
'
3 to 30
5 to 25
tures
________________ _..- __________ __ 10 to 20
the above ingredients being proportioned within
Wax _______________________________ -_ 10 to 15
the above stated ranges to give the composition
said composition also containing a ?ller, the above
ingredients being proportioned within the above
the characteristic of ready ?owability for casting
stated ranges to give the composition the char
acteristic of ?owability without pressure at a tem
perature of 220° C. and a melting point by the
ring and ball method between about 120° C. and
175° C., the said composition being further char
acterized by having at normal temperatures in
its solidi?ed condition a hard, substantially mar
resistant surface, and by its substantial resistance
to decomposition at melting and casting tem
without pressure and without substantial decomposition at a temperature of 220° C. and a melt
ing point by the ring and ball method between
about 120° C. and 175° C., the said composition
being further characterized by having at normal
temperatures in its solidi?ed condition a hard,
substantially mar-resistant surface, colloiding the
resulting mixture, heating said colloided mixture
to about 220° 0., and pouring the heated colloided
peratures.
' mixture into a die mold.
3. A tool or die suitable for forming sheet metal
composed of a cast composition comprising the
following ingredients in the following percentage
by weight ranges:
Ethyl cellulose (45.5 to 50% ethoxyl, vis
40
to be melted and poured into molds to form such
objects as tools, dies, and jigs comprising the fol
lowing ingredients in the following percentage
by weight ranges:
cosity 20 to 1000 centipoises) _______ __ 20 to 50
Ethyl cellulose (46.8 to 49% ethoxyl, vis
Plasticizer _________________________ __ 2.5 to 35
cosity 50 to 1000 centipoises) _______ .. 30 to 40
Hydrogenated methyl abietate_.._' _____ __ 5 to 15
Pentaerythritol ester of rosin _________ _- 10 to 20
Thermoplastic resin, compatible with
the ethyl cellulose in the proportion
used and having substantially no de
grading infiuence thereon at elevated
temperatures _____________________ __
Wax _______________________________ __
_
6. A thermoplastic casting composition suitable
Wax -
__
____ 10 to 15
said composition also containing an iron oxide,
3 to 30
5 to 25
the above ingredients being proportioned within
the above stated ranges to give to the compo
the above ingredients being proportioned within
the above stated ranges to give the composition
the characteristic of ready ?owability for casting
v pressure at a temperature of 220° C. and a melt
without pressure and without substantial decom
position at a temperature of 220° C. and a melt
about 140° C. and about 160° 0., the said com
sition the characteristics of ?owability without
ing point by the ring and ball method between
position being further characterized by having
ing point by the ring and ball method between
about 120° C. and 175° C., the said composition
at normal temperatures in its solidi?ed condition
a hard, substantially mar-resistant surface, and
by its substantial resistance to decomposition at
being further characterized by having at normal
temperatures in its solidi?ed condition a hard, 60
melting and casting temperatures.
substantially mar-resistant surface.
'7. A thermoplastic casting composition suitable
4. A thermoplastic casting composition suitable
to be melted and poured into molds to form such
to be melted and poured into molds to form such
objects as tools, dies, and jigs comprising the fol
lowing ingredients in the following percentage by
- objects as tools, dies, and jigs comprising the
following ingredients in the following percentage
weight ranges:
by weight ranges:
Ethyl cellulose (46.8 to 49% ethoxyl, vis
Ethyl cellulose (46.8 to 49% ethoxyl, vis
cosity 50 to 1000 centipoises) _______ __ 30 to 40
Plasticizer __________________________ __
cosity 50 to 1000 centipoises) _______ -_ 20 to 50
5 to 15
Thermoplastic resin, compatible with
the ethyl cellulose in the proportion
Plasticizer _________________________ __ 2.5 to 35
70 Thermoplastic resin, compatible with the
ethyl cellulose in the proportion used
and having substantially no degrading
used and having substantially no de
grading in?uence thereon at elevated
temperatures _____________________ _. -10 to 20
Wax ________________________________ _- 10 to 15
in?uence thereon at elevated tem
peratures ________________________ __
75
Wax
________________ -_' ____________ __
3t030
5f025
2,413,011
10
said composition also including an ethyl cellu
lose stabilizing agent, the above ingredients being
proportioned within theabove stated ranges to
give the composition the characteristic of ready
flowability for casting without pressure and with
such objects as tools, dies, and jigs comprising
i the following ingredients in the following per
centages by weight:
Ethyl cellulose (47.5% ethoxyl, 100 centi
out substantial decomposition at a temperature
of 220° C. and a melting point by the ring and
ball method between about 120° C. and 175° 0.,
the said composition being further characterized
by having at normal temperatures in its solidi 10
?ed condition a hard, substantially mar-resistant
surface.
-
poises viscosity) _____________ __' ________ .._
35
.Pentaerythritol ester of rosin ____________ __
20
Hydrogenated methyl abietate __________ _--_
Paraffin (M. P. 56° C.) __________________ __
15
10
Red iron oxide ____ __'___..; _________ __-_____
20
Diphenylamine _________________________ __
1
the above composition having the-characteristic
of ?owability without pressure at a temperature
of 220° C., a melting point by the ring and ball
-
8. A thermoplastic casting composition suitable
to be melted and poured into molds to form such
objects as tools, dies, and jigs comprising the 15 method of about 150° C. and a Rockwell hardness
of about 29, said composition being further char
following ingredients in the following percent
acterized by its substantial resistance to decom
ages by weight:
position at melting and casting temperatures.
Ethyl cellulose (47.5% ethoxyl, 50‘ centi
10. A thermoplastic casting composition suit
poises viscosity) _______________________ __ 35
.
Pentaerythritol ester of rosin ____________ __
20
Hydrogenated methyl abietate ___________ __
15
20 able to be melted and poured into molds to form
such objects as tools, dies and jigs comprising
the following ingredients in the following pro
portions by weight: ethyl cellulose about 35%, a
Microcrystalline petroleum wax (M. P. 180
185° F.) ______________________________ __
10
Red iron oxide ___________________ __- _____ __
20
Diphenylamine _________________________ __
1
' thermoplastic resin compatible with the ethyl
25 cellulose and having substantially no degrading
the above composition having the characteristic
20%, inorganic?ller about 20%, the remainder
in?uence thereon at elevated temperature about
of ?owability without pressure at a temperature
of the composition comprising a plasticizer for
of 220° C., a melting point by the ring and ball
the ethyl cellulose and a wax, as a, mold lubri
method of about 153° C. and a Rockwell hard 30 cant, said composition being. characterized by
ness of about 46, said composition being further
characterized by its substantial resistance to de
composition at melting and casting temperatures.
9. A thermoplastic casting composition suit
_ able to be melted and poured into molds to form 85
having at normal temperatures in its solidi?ed
condition a hard, substantially mar-resistant sur
face.
WALDORF'v S. TRAYLOR.
_
DAVID R. WIGGAM.
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