U.S. patent number RE30,450 [Application Number 06/026,380] was granted by the patent office on 1980-12-16 for surface modified pigments.
This patent grant is currently assigned to J. M. Huber Corporation. Invention is credited to Joseph Iannicelli.
United States Patent |
RE30,450 |
Iannicelli |
December 16, 1980 |
**Please see images for:
( Certificate of Correction ) ** |
Surface modified pigments
Abstract
.Iadd.Finely divided particulate inorganic pigment is surface
modified with from about 1% to about 15% of an amino organosilane,
particularly gamma-aminopropyltriethoxy silane. Thermosetting
resins incorporating such modified inorganic pigments exhibit
improved physical properties.
Inventors: |
Iannicelli; Joseph (Macon,
GA) |
Assignee: |
J. M. Huber Corporation
(Locust, NJ)
|
Family
ID: |
21831498 |
Appl.
No.: |
06/026,380 |
Filed: |
April 2, 1979 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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189321 |
Apr 23, 1962 |
|
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Reissue of: |
269695 |
Apr 1, 1963 |
03290165 |
Dec 6, 1966 |
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Current U.S.
Class: |
106/475; 106/420;
106/465; 106/486; 106/490 |
Current CPC
Class: |
C08K
9/06 (20130101); C09C 3/12 (20130101); C01P
2004/84 (20130101) |
Current International
Class: |
C08K
9/06 (20060101); C08K 9/00 (20060101); C09C
3/12 (20060101); C09C 003/12 () |
Field of
Search: |
;106/38B,38N,38O
;428/405 ;260/42.15 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Jellinek et al., Silane Finishes for Fibrous Glass, Presented
Before the Society of Plastic Industries, Chicago, Ill., Feb. 5-7,
1957..
|
Primary Examiner: Poer; James
Attorney, Agent or Firm: Price; Robert L. Flanders; Harold
H.
Parent Case Text
This is application is a .Iadd.reissue of U.S. Pat. No. 3,290,165,
Ser. No. 269,695 filed April 1, 1963, which is a
.Iaddend.continuation-in-part of applicant's copending application
Ser. No. 189,321, filed April 23, 1962, entitled "Surface Modified
Pigments," and now abandoned.
Claims
I claim:
1. A .Iadd.filler comprising a .Iaddend.finely divided particulate
inorganic pigment surface .Iadd.selected from the group consisting
of synthetic silicas, silicates, metal oxides, calcium carbonates,
zinc sulfides, and carbon blacks, said pigment surface having been
.Iaddend.modified .Iadd.by treatment .Iaddend.with from about 1% to
15%, based on the weight of the dry pigment, of an amino
organosilane of the formula ##STR2## wherein R.sub.1 is selected
from the group consisting of hydrogen, alkyl, aryl, cycloalkyl, and
alkylaryl, R.sub.2 is selected from the group consisting of
hydrogen, alkyl, aryl, cycloalkyl and alkylaryl, R.sub.3 is
selected from the group consisting of hydrogen, lower alkyl, aryl,
lower alkylaryl and lower arylalkyl, R.sub.4 is selected from the
group consisting of hydrogen, lower alkyl, aryl, lower alkylaryl
and lower arylalkyl, R.sub.5 is selected from the group consisting
of hydrogen, lower alkyl, aryl, lower alkylaryl, and lower
arylalkyl, X is selected from the group consisting of alkylene,
arylene, alkylarylene, arylalkylene, cycloalkylene containing
secondary amino nitrogen, and cycloalkylene containing tertiary
amino nitrogen.Iadd., the modification of said pigment surface by
said organosilane comprising spray drying slurries of said pigment
having one or more of the amino organosilanes dispersed therein.
.Iaddend. .[.
2. A compound as in claim 1 wherein the finely divided particulate
filler is selected from the group consisting of synthetic silicas,
silicates, metal oxides, calcium carbonates, zinc sulfides, and
carbon blacks..].
3. A compound as in claim 1 wherein the amino organosilane is gamma
aminopropyltriethoxysilane.
4. A compound as in claim 1 wherein the amino organosilane is a
diamino functional silane.
5. Finely divided particulate hydrated silica, surface modified
with from about 1% to 15% by weight based upon the weight of the
silica of gamma aminopropyltriethoxysilane.
6. Finely divided particulate sodium alumino silicate pigment,
surface modified with from about 1% to 15% by weight, based upon
the weight of the pigment, of gamma aminopropyltriethoxysilane.
7. Finely divided particulate carbon black, surface modified with
from about 1%to 15% by weight, based upon the weight of the carbon
black, of gamma aminopropyltriethoxysilane.
8. Finely divided particulate kaolin clay, surface modified with
from about 1% to 15% by weight, based upon the weight of the kaolin
clay, of gamma aminopropyltriethoxysilane. .Iadd. 9. A filler
comprising a finely divided particulate inorganic pigment surface
selected from the group consisting of synthetic silicas, silicates,
metal oxides, calcium carbonates, zinc sulfides, and carbon blacks,
said pigment surface having been modified by treatment with from
about 1% to 15%, based on the weight of the dry pigment, of an
amino organosilane of the formula
wherein R is selected from the group consisting of phenylene lower
alkyl substituted phenylene, lower alkoxy substituted phenylene,
and lower alkylene, R' is a monovalent hydrocarbon group free of
aliphatic unsaturation selected from the group consisting of lower
alkyl, aryl, lower alkaryl and lower aralkyl, wherein R' can
represent the same or different groups. .Iaddend.
Description
This invention relates to finely divided particulate inorganic
pigments modified with amino organosilanes and the process for
their production.
When inorganic pigments are modified with the silanes according to
this invention, the properties imparted to them are such that they
can advantageously be used as fillers for thermosetting resins such
as polyurethanes, epoxy polymers, melamine polymers, phenolic
polymers, ureaformaldehyde polymers, unsaturated polyesters, as
well as other polymers and elastomers including polyethylenes,
polypropylenes, polystyrenes, saturated polyesters, polyamides,
polyvinyl compounds, polyisoprenes, polybutadienes,
polystyrenebutadienes, and the like.
The modified pigments can also be advantageously used as fillers
for paper, paints, varnishes, inks, and paper coating
compositions.
By the use of these modified finely divided particulate inorganic
pigments, improved physical properties are imparted to the vehicles
into which they are incorporated.
Inorganic pigments modified with amino organosilanes have affinity
for direct dyes and are useful for imparting various colors to the
vehicles.
An object of this invention is to provide modified pigments
especially useful as fillers.
Another object of this invention is to provide modified pigments
which are dyeable with direct dyes and are useful as
color-imparting fillers.
A further object of this invention is to provide modified pigments
which can be used as fillers in applications where they had
heretofore been unsatisfactory.
A still further object of the invention is to provide
cross-linkable fillers capable of imparting improved abrasion
resistance among other improved properties to elastomers.
Other objects and advantages will be apparent from the following
specification.
I am aware of extensive efforts in the prior art to improve
properties of filler pigments by modification with organosilanes.
Hydrocarbon silane modifications of pigments do impart improved
dispersions in organic vehicles but such modifications do not
normally increase reinforcement in vinyl addition polymers unless
the hydrocarbon silane carries specific types of unsaturation which
serves to promote a more tenacious bridge between the filler and
the vehicle. In any case, all these prior art modified pigments are
rendered hydrophobic by modification with either saturated or
unsaturated hydrocarbon silanes and, furthermore, such silane
modified pigments are not valuable reinforcing fillers in saturated
thermosetting resins.
I have discovered that modification of filler pigments with
saturated amino organosilanes improves reinforcement in a wide
variety of vinyl addition as well as thermosetting polymers in that
a strong chemical bridge between filler pigment and polymer
results. Bridging is accomplished through the amino modified
surface of the pigments. Surprisingly, amino organosilane
modification improves reinforcement in both vinyl addition and
thermosetting polymers, whereas unsaturated organosilane fillers
are generally only effective in vinyl addition polymers where
unsaturation is present. Another important advantage of amino
organosilane modified fillers is that they are usually hydrophilic
whereas prior art silane modified fillers are hydrophobic.
The modified pigments of this invention can be prepared by
dissolving the desired amount of amino organosilane in a suitable
solvent, adding the pigment and heating until the reaction is
complete. The amount of modifier added depends upon the particular
pigment being modified and the use for which it is intended.
Generally up to about 15% by weight of the modifier is sufficient
for most purposes.
A particularly useful process of modifying pigments according to
this invention involves spray drying pigment slurries having one or
more of the amino organosilanes dispersed therein. The spray drying
process effects a uniform distribution of the modifier on the
pigment and virtually instantaneously cures the modifier on the
pigment.
The compounds used to modify the pigments can be depicted by the
formula: ##STR1## wherein R.sub.1 is hydrogen, alkyl, aryl,
cycloalkyl, or alkylaryl; R.sub.2 is hydrogen, alkyl, aryl,
cycloalkyl or alkylaryl; R.sub.3 is hydrogen, lower alkyl, aryl,
lower alkylaryl, or loer arylalkyl; R.sub.4 is hydrogen, lower
alkyl, aryl, lower alkylaryl or lower arylalkyl; R.sub.5 is
hydrogen, lower alkyl, aryl, lower alkylaryl or lower arylalkyl;
and X is alkylene, arylene, alkylarylene, arylalkylene,
cycloalkylene having secondary and/or tertiary nitrogen present in
the chain, and/or primary, secondary, and/or tertiary nitrogen
pendant from the chain. Some of these amino organosilanes are
disclosed along with methods for their preparation in U.S. Pat.
Nos. 2,832,754; 2,930,809; 3,007,957; and 3,020,302. Commercially
available amino organosilanes include "A-1100" (gamma
aminopropyltriethoxysilane) and "Y-2967" (an amino silane which is
a modified gamma aminopropyltriethoxysilane) sold by Union Carbide
Corporation, N.Y., N.Y., and "Z-6020" (a diamino functional silane)
sold by Dow Corning Corporation, Midland, Michigan.
.Iadd.Preferred compounds to modify the pigments are amino
organosilanes of the formula:
wherein R is selected from the group consisting of phenylene, lower
alkyl substituted phenylene, lower alkoxy substituted phenylene,
and lower alkylene, R' is monovalent hydrocarbon group free of
aliphatic unsaturation selected from the group consisting of lower
alkyl, aryl, lower alkaryl and lower aralkyl, wherein R' can
represent the same or different groups. .Iaddend.
Pigments advantageously modified in the practice of this invention
are finely divided particulate inorganic pigments such as, for
example, inorganic compounds of silicon, including hydrated or
anhydrous silicas, calcium silicates, magnesium silicates,
calcium-magnesium silicates, barium silicates, aluminum silicates,
sodium-alumino-silicates, calcium-alumino-silicates, calcium-sodium
alumino silicates; clays such as kaolins which include dickite,
kaolinite and nacrite, halloysite, montmorillonites including
sodium and magnesium bentonites, synthetic or natural zeolites;
various metal oxides and carbonates such as zinc oxide, alumina,
titania or magnesia, calcium carbonate; and various non-white
pigments like carbon blacks, zinc sulfide, ferric oxide and the
like.
All the above fillers are available on a commercial scale and
include the following, all of which are finely divided, particulate
substances.
Zeolex.RTM., very finely divided precipitated sodium alumino
silicate pigments of submicron particle size and disclosed in U.S.
Pat. Nos. 2,739,073 and 2,848,346.
Zerosil.RTM., very finely divided precipitated hydrated silicas of
submicron particle size and disclosed in copending U.S. Pat.
applications Ser. No. 144,168 filed Oct. 10, 1961, and 149,964
filed Nov. 3, 1961.
Suprex.RTM., an air floated kaolin clay with platelike particles of
which 87-92% are minus 2 microns.
Aromex.RTM., intermediate super abrasion furnace carbon blacks.
Essex.RTM., semi-reinforcing furnace blacks.
Silene EF.RTM., a precipitated hydrated calcium silicate of very
fine particle size.
Hi-Sil.RTM., a precipitated hydrated silica of very fine particle
size.
Celite.RTM., a diatomaceous earth which is principally a hydrated
silica.
Alumina C.RTM., a hydrated aluminum oxide of small particle
size.
Kadox.RTM., a zinc oxide filler.
Titanox.RTM., a pigment grade commercial titanium dioxide.
Cab-O-Sil.RTM., a very finely divided anhydrous silica.
Ludox.RTM., a precipitated silica of very fine particle size.
The following examples illustrate typical methods by which various
pigments are surface modified in accordance with this
invention.
Example 1
8 grams of gamma aminopropyltriethoxysilane (A-1100) was dissolved
in 3.3 liters of benzene in a 5-liter round bottom flask. 400 grams
of carbon black (ISAF) was added and the resulting mixture was
refluxed 2 hours. The resulting product contained 2% of the
modifier based on the weight of the carbon black.
Example 2
"Suprex" was modified with 1.0% by weight with gamma
aminopropyltriethoxysilane by adding the appropriate amount of the
modifier using water as a solvent and then adding the clay and
refluxing for 21/2 hours. The products were recovered and dried.
The example was repeated with 2.0% and 3.0% gamma
aminopropyltriethoxysilane.
Example 3
"Zeolex 23" was modified with 1% by weight with gamma
aminopropyltriethoxysilane by adding the "Zeolex" to a benzene
solution of the modifier and refluxing for 21/2 hours. The product
was recovered and dried.
Example 4
"Suprex" was modified with 1.0% of "Z-6020" by adding 3.33 pounds
"Z-6020" to 667 pounds of water while under agitation. 333 pounds
of "Suprex" was slowly added to the solution while continuing the
stirring until a homogeneous clay slip resulted. The clay slip was
then spray dried in a 7-foot conical spray dryer operated at an
inlet temperature of 600.degree. F. and an outlet temperature of
250.degree. F. A finely pulverized, chemically modified clay
product was obtained. The example was repeated to produce 2.0% and
3.0% modifications of the "Suprex."
Example 5
Example 4 was repeated using "Y-2967" instead of "Z-6020."
Example 6
Example 4 was repeated using "A-1100" instead of "Z-6020."
Example 7
"Suprex" was modified with 1% of gamma aminopropyltriethoxysilane
by adding 10 grams gamma aminopropyltriethoxysilane to 3.5 liters
benzene, then adding 1 kilogram "Suprex" clay and refluxing for 3
hours. The modified clay was recovered and dried. This example was
repeated using 2% and 3% instead of 1% gamma
aminopropyltriethoxysilane.
Example 8
Example 7 was repeated using "Z-6020" in place of gamma
aminopropyltriethoxysilane.
Example 9
Example 7 was repeated using "Y-2967" in place of gamma
aminopropyltriethoxysilane.
The above examples illustrate the facility with which various
inorganic pigments are modified with amino organosilanes.
The examples were repeated using each of the pigments named herein
to produce modified pigments having properties similar to those
discussed below.
While only three modifiers are exemplified, this is done for
convenience since all those disclosed herein have been used for the
purpose and come within the scope of this invention.
The physical properties of the various pigments disclosed herein
are significantly altered by modification with the group of silanes
disclosed herein. For example, when kaolin clay is so modified, a
dramatic change in its properties is apparent. Where, before, the
clay lacked significant affinity for direct dyes, it is modified by
the process of this invention to be readily dyeable with direct
dyes. The modified kaolin clays can be used as a filler for
polyurethanes where, before modification, it was unusable since it
prevented a cure of the polymer. This is illustrated in Table I in
which the following formation was employed:
______________________________________ Parts
______________________________________ Vibrathane 5003.sup.1 100
Stearic acid 0.25 Di-Cup 40C.sup.2 5 Clay 60
______________________________________ .sup.1 A polyurethane
produced by Naugatuck Chemical Division of U.S. Rubber Company.
.sup.2 A polymerizing crosslinking agent produced by Hercules
Powder Company.
The compounds were mixed on a 6-inch by 12-inch laboratory mill and
cured for 30 minutes at 307.degree. F., except for the NBS abrasion
test where the cure was for 60 minutes at 307.degree. F.
TABLE I
__________________________________________________________________________
Example 2 Suprex Suprex Suprex plus 1% plus 2% plus 3% Control
Suprex Modifier Modifier Modifier
__________________________________________________________________________
Parts filler/100 parts polymer None 60 60 60 60 Tensile, p.s.i
5,240 No cure 3,680 3,770 3,840 Stress, 300%, p.s.i 830 No cure
2,070 3,190 -- Elongation, percent 500 No cure 470 425 265 Shore A
Hardness g 56 No cure 71 71 75 NBS Abrasion, percent of standard
129 No cure 122 172 202
__________________________________________________________________________
The results illustrate the improved properties of modified kaolin
clay filled polyurethane over both the compound filled with
unmodified kaolin and the unfilled compound. Note, for example, the
increase in abrasion resistance with increased modification of
kaolin. It is also apparent from the data that unmodified kaolin is
unsatisfactory as a filler for polyurethanes since the polymer did
not cure. The use of modified kaolin clay not only improves the
properties of the polyurethane but also decreases the raw material
cost since the filler is much less expensive than the polymer.
TABLE II
__________________________________________________________________________
MODIFIED SUPREX CLAYS IN VIBRATHANE 5003 Example 2 Minutes Suprex
1% 2% Example 4 Example Example 9 Cured at Unfilled Filled Modifier
Modifier 1% Z-6020 1% Z-6020 1% Y-2967 Physical Properties
305.degree. F. Control Control Water Water Water Benzene Benzene
__________________________________________________________________________
200% Modulus 30 430 1,270 1,340 2,900 -- 2,900 1,710 60 500 1,310
1,530 2,990 2,890 1,710 -- 75 510 1,330 1,480 2,820 -- 2,860 1,840
300% Modulus 30 830 1,570 2,070 3,190 -- 3,270 2,060 60 1,050 1,640
2,220 3,340 3,330 3,270 2,090 75 1,040 1,630 2,520 3,200 -- 3,240
2,170 Tensile Strength 30 5,240 4,340 3,680 3,770 2,960 3,470 4,040
60 4,890 3,850 3,920 3,490 3,620 3,290 3,610 75 5,320 3,640 3,560
3,510 -- 3,240 3,950 Elongation 30 500 570 470 425 190 365 560 60
440 525 450 335 360 315 500 75 450 505 440 370 -- 300 510 Hardness,
Shore A 30 56 72 71 71 75 75 70 60 59 74 73 73 76 76 71 75 59 74 73
73 13 76 71 Crescent Tear 30 65 285 280 238 225 235 303 60 68 270
230 243 205 193 220 75 73 243 231 225 -- 193 225 NBS Abrasion
Index, Percent 60 74.8 63.6 77.2 109.5 143.5 131.4 68.2 75 80.3
62.2 87.4 137.0 105.5 152.1 81.5 Hardness, Shore A, NBS Specimens
60 55 71 72 75 76 76 71 75 56 73 73 75 76 76 72 NBS Abrasion
(Gum=100%) 60 100 85 103 147 192 176 91 75 107 83 117 183 141 204
109 Compression Set "B" 22 hrs./158.degree. F. 60 5.5 34.0 17.5
11.3 10.1 12.0 25.0 75 5.1 36.7 16.5 12.0 9.5 11.0 23.9 Mooney
Viscosity, ML 4'/212.degree. F. -- 44 60 65 65 83 65 64 Mooney
Scorch, MS/265.degree. F. -- 23 26 20 16 12.5 18 23
__________________________________________________________________________
Table II demonstrates dramatic improvements in properties of
polyurethane filled with amino organosilane modified clays.
When modified carbon black is used as the filler in a rubber
recipe, good results compared to unmodified black are achieved with
a 2% by weight modification using gamma aminopropyltriethoxysilane.
The results listed in Table III are based upon tests in the
following recipe.
______________________________________ Parts/100 RHC
______________________________________ Smoked sheet 100.0 ISAF
carbon black 45.0 Zinc oxide 3.0 Stearic acid 3.0 Pine tar 3.0 Age
rite HP.sup.1 1.0 NOBS special.sup.2 0.35 Sulfur 2.75 Total 158.10
______________________________________ .sup.1 An antioxidant
containing phenylbeta-naphthylamine and
N,Ndiphenyl-para-phenylenediamine. .sup.2 Accelerator containing
Noxydiethylene benzothlazol2-sulfenamide.
The batches were mixed on a Banbury using speed #1, ram pressure of
30 p.s.i., and a starting temperature of 125.degree. F.; the final
batch mix was on a 6-inch by 12-inch mill and the inlet water
temperature was 158.degree. F. The compound was cured for 70
minutes at 275.degree. F., then tested. The results are listed in
Table III.
TABLE III ______________________________________ Abrasion, Percent
Modulus, Tensile, Huber- Pigment Modifier p.s.i. p.s.i. Williams
______________________________________ ISAF Carbon Black None 1,780
4,590 100.0 Control. ISAF Carbon Black .sup.1 1,970 4,720 107.9
______________________________________ .sup.1 2.0% gamma
aminopropyltriethoxysilane.
This data indicates that when carbon black is modified with
controlled amounts of modifier, the properties which it imparts to
rubber are improved in respect to modulus, tensile, and abrasion
resistance.
When modified Zeolex is used as a filler for rubber compounds, it
imparts to the rubber improved properties of modulus, tensile
strength, tear resistance and abrasion resistance when compared to
these same properties in rubber filled with unmodified Zeolex. The
results in Table IV are based upon the following recipe:
______________________________________ Parts/100 RHC
______________________________________ GRS 1502.sup.1 100.0
Pliolite S6B.sup.2 20.0 Zinc oxide 3.0 Stearic acid 2.0 Cumar MH
21/2.sup.3 7.5 Zeolex 23 66.5 Santocure.sup.4 2.0 DOTG.sup.5 1.0
Sulfur 2.5 Total 204.5 ______________________________________
.sup.1 Emulsion copolymer of 23.5% styrene and 76.5% butadiene.
.sup.2 A styrenebutadiene copolymer of high styrene content. .sup.3
Paracumarene-indene resin. .sup.4 nCyclohexyl-2-benzothiazole
sulfenamide accelerator. .sup.5 Diortho-tolylguanidine.
The recipe was mixed on a Banbury mixer at speed #1, ram pressure
of 30 p.s.i., and at a starting temperature of 125.degree. F. The
final batch was mixed on a 6-inch by 12-inch mill with a water
inlet temperature of 158.degree. F. The compound was cured at
292.degree. F., then tested. The results are shown in Table IV.
TABLE IV ______________________________________ Cure 200% 300% 400%
Minutes Modulus Modulus Modulus Tensile Elongation
______________________________________ PIGMENT-ZEOLEX 23
UNMODIFIED-CONTROL 5 80 -- -- 80 280 10 80 -- -- 80 280 15 470 650
860 1,300 605 20 720 1,000 1,350 1,640 460 30 750 1,060 1,450 1,560
420 ______________________________________ PIGMENT-ZEOLEX 23
MODIFIED WITH 10% GAMMA AMINO-PROPYLTRIETHOXYSILANE 5 690 1,010
1,340 1,970 580 10 910 1,300 1,710 2,480 550 15 1,010 1,400 1,820
2,360 510 20 1,070 1,480 1,920 2,280 470 30 1,090 1,480 1,940 2,360
480 ______________________________________ Abrasion Index.sup.1
Shore Hardness Pigment 10' 15' 20' 10' 15' 20'
______________________________________ Zeolex 23 Control .sup.2
41.5 47.5 60 72 77 Modified Zeolex 23 61.7 63.0 62.3 76 76 77
______________________________________ Tear Resistance, Avg.
Pigment 5' 10' 15' 20' ______________________________________
Zeolex 23 Control 37.5 38.5 174 160 Modified Zeolex 23 216.5 193.5
195 187.5 ______________________________________ .sup.1 Percent of
NBS Standard sample. .sup.2 Not cured.
The results indicate that Zeolex 23 modified with gamma
aminopropyltriethoxysilane, when compared with unmodified Zeolex 23
used as a filler for rubber, is faster curing, has increased
modulus, increased tensile strength, and improved tear resistance
and abrasion resistance.
It should also be noted that physical and "wet" electrical
properties of filled resin systems can be significantly improved by
treating the fillers in accordance with this invention.
I have found that in addition to the concepts disclosed above, the
properties of the modified pigments are affected by the solvent
used in their preparation.
The properties of carbon blacks, clays and silicates modified in
aqueous systems, such as disclosed in Example 2, vary markedly from
the properties of these same pigments modified in nonaqueous
systems as disclosed in Examples 1 and 3.
In order to demonstrate these differences, regular Suprex clay,
Suprex clay of Example 2, and Suprex clay modified in nonaqueous
solvent according to the teachings of Example 7 were used in
producing rubber compounds using the following recipe.
______________________________________ Parts by weight
______________________________________ Smoked sheet.sup.1 100 Clay
(as specified in Table V) 104 Zinc oxide 5 Sulfur 3 Captax 1
Stearic acid 4 ______________________________________ .sup.1
Natural rubber.
The compounds were mixed on a 6-inch by 12-inch laboratory mill and
then cured at 260.degree. F. to produce 30-, 45-, and 60-minute
cures of each.
Table V below compares the abrasion index and the 200% modulus
level of each of the test materials.
TABLE V ______________________________________ Abrasion Index, 200%
Modulus Percent p.s.i. Clay 30' 45' 60' 30' 45' 60'
______________________________________ Suprex Control 55.0 55.9
53.7 760 960 990 Suprex 3% Modifier 72.8 68.6 65.2 2,000 2,070
2,170 (Benzene) Suprex 3% Modifier 84.6 85.5 70.7 1,740 1,970 1,990
(Water) ______________________________________
The results as set forth in Table V clearly indicate that clays
modified in accordance with the invention impart superior
properties to rubber compounds when used as a filler therein. These
results also demonstrate that the clays modified in an aqueous
system give a higher abrasion resistance and a lower modulus than
clays modified in a nonaqueous system.
While natural rubber was used in the recipes tested in Table V,
these tests were also conducted with similar results from recipes
using SBR, polyurethanes and polybutadiene.
The foregoing is illustrative only and additional modifications may
be made without departing from the substance of the invention as
defined in the appended claims.
* * * * *