Note: Descriptions are shown in the official language in which they were submitted.
~:~57~54
~ 1 - DDJ-7581
FLOCCED MINERAL MATEE`~IALS AND WATER-RESISTANT
ARTICLES MADE THEREFROM
Backyround of the Invention ...
.
It is known that non-asbestos papers and/or
5 sheets may be produced from water-swellable inorganic .
materials and, in particular, swelled silicate gels.
For example, United States Patent No. 4,239,519 is
di~ected to the preparation of synthe~ically derived;
inorganic, crystal-containing gellable, water-swelling
sheet silicate~ and certain articles, such as papers,
fibers, film~, boards, and coatings, produced therefrom. '''F
These non-asbestos papers and/or sheets exhibit good
high temperature stability and good chemical resistance~
Furthermore, sinc~ asbestos fibers are not utilized in~.
their manufacture, such articles will not have the
health hazards which are associated.with asbestos
contai~ing articles.
U. S0 Patent 4, ~39,519 teaches the method for
making the precursor gellable silicates used to produce
said papers or sheet articles, as involving three
fundamental step~: ~a) a fully or predominantly
crystalline body is formed which contains crystals
~onsisting essentially of a lithium and/or sodium water-
swelling m~ca selected from the group of fluorhectorite,
hydroxyl hectorite, boron flurophlogopite fluorphlogo-
pite, hydroxyl boron phlogopite~ and solid solutions
between those and o~her structurally compatible species
~:~5~0~4
- 2 - DDJ-7581
selected from the group of talc, fluortalc, polylithio-
nite, fluorpolylithionite, phlogopite, and fluorphlogo-
pite; (b) that body is contacted with a polar liquid,
normally water, to cause swelling and disintegration of
S the body accompanied with the formation of a gel; and
(c) the solid:liquid ratio of the gel is adjusted to a -L
desired value depending upon the application therefor.
Glass-ceramics are the preferred crystalline starting
bodies. Those products are then contacted with a source
of large cations, i.e., with an ionic radius larger than
that of ~he lithium cation, to cause macro flocculation
of the gel and an ion exchange reaction to take place
between the large cations and the Li+ and/or Na~ ions
from the interlayer of the crystals. .. -
Alternatively, U. S. Patents No. 3,325,340 and ...
3,454,917 teach producing aqueous dispersions of
vermiculite flaked crystals which have been caused to
swell due to the introduction therein of interstitial
ions such as ~1) alkylammonium cations having between 3
and 6 carbon atoms inclusive in each carbon group such
as methylbutylammonium, n-butylammonium, propylammonium :
and iso-amylammonium, (2) the cationic form of amino- -
acids, such as lysine and ornithine, and/or (3) lithium. .. ~.
While the articles, such as papers, sheets
25 and films, prepared via the prior art processes set
forth above exhibit excellent heat resistance and are
useful in a wide variety of applications, it has b~en
discovered that such articles generally do not exhibit
good sealing characteristics, thus curtailing their use t
30 as gasket materials. The prior art articles also
exhibit a certain amount of water sensitivity which is
generally exhibited by the articles having a
considerable loss of strength and general deterioration
of mechanical and electrical properties when exposed to
35 high humidity environments or submerged in water or
other polar liquids. This sensitivity to water
correspondingly limits the utility of these articles in
certain applications, such as, for example, head
~2 57 ~ ~
_ 3 _ DDJ-7581
~ske~r ~l~ctr~Leal ~nsulators, environmental protective
coa~1ngs, ~nd w2lshable ~nd environmerltally stable
building m~S:eri~
Fire-resistant, non-asbestos articles can be mac.e from
a swelled,:layer~d flocced silicate gel material that is
prepared by u~ iæ~ng ~n exchang4 cation ~hat is
~electe~ from guanidin~ deriv~ti~es~ Such articles were
10 ~urpr~ ly ~hown to exhibit more water resistance than
articles prepar~d via prior ~t pr~cesses and have
excel~ent elecerical p~operties.
~ntion
It ha~ now been unexpectedly discovered that
15 high temperatur~, ~ire-resistant, non-asbestos, water-
reslstant articles, ~uch as s)~eet, paper, board, film,
f~ber ~nd coating ~rt~cle~, c~n be made from a swelled,
l~yered flocced ~ilicate gel ~terial tb~t is prepared
by utlli2~ng ~ exchange cation that ls selected rom
mult~amine deri~t~ve~. Such 8rticles 5urprisingly have
been ~ound to exhibit, ~n general, ~uch improved results
in ten~le ~trength and puncture Ees~ stant tests that
are conducted when the ~rticles are we~ than do
~aterial~ that ~re prepared utilizing prior art exchange
cation3. Further~ore, the articles made according to
the pr~sent lnventlon gene~ally display superior
~lectrical ~nd mechanical propertie~ o~er those
materials ~ade by pr~or ~r~ m~thods.
Wit~ ~efe~ence ~o heat resistance, ~e
article~ that are produced according ~o the present
inYent~on ~re co~pletely ~table ~o temperatures o~
zpprox~ma~ely 350-400C ~nd ma~ntain their structural
stability to approxi~ately 80DC~
~etai~ed DescriPtion of the Invention
~h~ ~rt~cles snd the ~locced mineral
~uspen~ons o the pres~nt in~ention are, in one embodi-
~ent o~ the ~nven~ion, prepared by u~ilizingr ~s a
~ta~ing ~terial, ~ w~ter-s~e~li~ sheet silicate that
~ZS7~5~
- 4 - DDJ-7581
has an average charge per structural unit of from about
-.4 to about -1 and which contains interstitial
exchangeable cations that promote swelling~ The
speeifie exchange cations in the starting material will
depend on the silicate being utilized. For example, if
a synthetieally derived gellable silicate, which is made
aceording to the procedures of U. S. Patent 4,239,519,
is utilized as a starting material, the exchange cations
will generally be Li+ and/or Na+ ions. If a natural
vermiculite dispersion, such as made according to U~ S.
Patent 3,325,340, is utilized, the exchange cations will
generally inelude alkylammonium cations and the other
eations speeified in U. S. Patent 3,325,340. The silicate,
whether synthetic or natural in origin, will most often
have morphologies that are represented by thin flakes
whieh are generally dise, strip, and/or ribbons.
Although I do not wlsh to be limited to any specifie
measurements for the flakes, they will typically have
measurements whieh are from about 500 A to 100,000 A,
and preferably 5,000 A to 100,000 A in length, 500 A to
100,000 A in width, and less than 100 A thick.
The term "eharge per structural unit" as used
in the speeifieation and elaims refers to an average
eharge density as speeified by G. Lagaly and A. Weiss,
~Determination of Layer Charge in Mica Type Layer
Silieates,~ Proceedings of International Clay
Conferenee, 61-80 ~1969) and G. Lagaly,
~Characterization of Clays by Organic Compounds,l' Clay
Minerals, 16, 1-21 (1981).
The starting silieate ean be made according to
the afore-mentioned procedures of U. S. Patent
4,239,519; 3,3250340i or 3,434,917 or other methods
which result in dissoeiated layer materials with charge
densities in the desired ranges.
The silieate is then contacted with a source
of at least one species of multiamine derived cations to
thereby effect an ion exchange reaetion to occur between
the cations and the interstitial ions. This ion
~.2~i~054
_ 5 _ DDJ-7581
exchange reaction may be carried out between the cations
and the silicate material to thereby form a floc which
is then utilized to form the articles o~ the present
invention. In another embodiment of this invention, the
starting silicate can be directly formed into a product,
such as a lithium fluorhectorite fiber or film by using
the procedures of U. S. Patent 4,239,519, and a cationic
exchange reaction utilizing the multiamine derived
cations can be ca~ried out with ~he product, such as by
immersing Sh~ product into a solution of multiamine
derived cations. Thus, the ion exchange reaction may be
carried out in situ during the actual forming process
for the product. -
The term ~multiamine derived cations", when
used in refe~ence to the exchange cations that may be
utilized in the present invention, refers to low
molecular weightt non-polymeric, di, tri and/or tetra
amino functional compounds, wherein the amine moieties
have been modified, such as by being protonated, to
thereby be positively charged. Diamines are the
multiamine compounds of choice. The preferred diamines
will generally correspond to the Formula
R3N - tCX2)n - NR3 wherein (1) each R is
independently selected from hydrogen, a Cl-C8 straight
or ~ranched chain alkyl group, a C3-C6 ayclic alkyl
group, or an aryl group, with the proviso that there be
no more than one aryl group on each nitrogen, t2) each X
is independently selected from l-ydrogen, an alkyl group
or an aryl group and (3) n represents an integer from 2
to 15, with the option that, when n is 3 or more, the
CX2 groups may form ringed moieties which may be
aromatic.
The flocced mineral suspensions of the present
invention are prepared, for example, by reacting,
generally with agitation, a sui~able silicate gel with a
source of exchange cations derived from suitable
multiamine compounds in order to effect an ion exchange
between the multiamine derived cations and the
.
~LZ5705a,
-- 6 -- DDJ--7581
interstitial cations in the silicate gel to form
exchanged macro 1Occulated particles.
As stated above, one or more exchange cations
can be utilized in the cationic exchange reaction.
S Since the various cations will give floc, and eventually
articles~ with differing physical properties, the
specific cation or combination of cations will be chosen
by the practitioner of this invention based on the
desired end use.
~he terms ~multiamine derived cations" or
"cationic derivative" or the like is used in the
specification and claims to indicate that the center for
cationic activity is centered on the nitrogen groups in
the multiamines. Generally, this is accomplished by
protonating the multiamines to thereby form ammonium
groups which are positively charged. This protonation
has to take place before the cationic exchange can be
made with the swelled silicate gel.
The flocced mineral suspension may be used to
20 form the desired articles. The specific treatment steps -
applied to the floc will depend on the particular
article being formed. For example, if the articles of
the present invention are to be formed into sheet
materials, the resultant exchanged floc will be agitated
with sufficient shear to produce a particle size
distribution which leads to suitable particle packing in
the sheet forming operation. Following this process the
floc is optionally washed to remove any excess salt
solution and the consistency of the flocced slurry is
adjusted to ~rom about 0.7S% to about 2% solids. To
promote better drainage rates on a fourdrinier wire,
polyelectrolyte flocculating agents can then be added to
the slurry at a level of from about 0.1% to about 1~,
and preferably 0.2%-0.3% of floc solids. One example of
a suitable polyelectrolyte flocculating agent is Polymin
P, which is a trademark of BASF Corporation for a
polyethylene imine.
T~is slurry is then.fed to a papermaking
~2~;70~;4 :
7 - DDJ-7581
apparatus where it is dewatered by free drainage and/or
vacuum drainage followed by pressing and drying on drum
driers. The thu formed sheet material can be used in
applications such as gaskets and the like.
Xf desired, and depending on the intended end
use of the articles, additional inert materials may be
added to th~ flocced mineral suspension. For example~
if desired one or more fibrous materials from the group
of natural or synthetic organic fibers or inorganic
fibers may be added to the floc to improve its drainage
rate and to provide an end product that has improved
strength and/or handleability. For example, when the
desired end products are gaskets, the fibers of choice ;
are cellulose fibers, glass fibers, and/or Kevlar fibers
(Kevlar is a trademark of DuPont Corporation for an
aromatic polyamide fiber). In addition, synthetic latex
or other binders may be added to the floc to provide for
a product with improved strength characteristics.
Alternatively, the cationic exchange reaction
can be conducted directly on a product formed from the
silicate starting material. In this ca~e, any desired
additional inert materials would be added to the slurry
containing the silicate starting material prior to the
~ormation of the product and, of course, the subsequent ;~
cationic exchange reaction.
It has been discovered that epoxy resins are
particularly useful additives to articles formed
according to the present invention. The use of such
resins adds strength to the final product and, when used
30 i~ conjunction with diamine exchanged floc, seem to i~
promote a dual functionality in the diamines, which act,
not only as exchange cations for the sheet silicate
material but also as a crosslinking agent for the epoxy
resins. The resultant product has enhanced strength,
chemical resistance and dielectric properties.
The term ~water resistant" as used in the
specification and claims is not meant to imply that the
articles of the present invention are waterproof or are
~257~5a~
- 8 - DDJ-7581
completely impervious to water. By contrast, the term
is used to indicate that the materials do not substan-
tially degrade, at least in their tensile strength and
puncture resistant properties/ when exposed to water.
In addition to being water resistant and
having excellent fire and heat resistant, it has ~een
discovered that the articles of the present invention
possess excellent electrical properties and are thereby
suitable for a variety of applications, including
electrical insulators, cable wrap and, in particular,
printed wiring boards.
In these following Examples, unless otherwise
specified, the starting material utilized was a lithium
fluorhectorite made according to procedures taught in
U. S. Patent No. 4,239,519.
Example 1
~his example illustrates a method of producing
both a diamine exchanged fluorhectorite flocced silicate
and a formed shee~ that was prepared therefrom.
A slurry o 1,6 hexanediammonium fluorhec-
torite (made from the corresponding diamine) was ;~-
prepared by adding 200 grams of a 10~ dispersion of
lithium fluorhectorite to 2 liter~ of lN 1,6 hexane~
diamine HCl solution. The slurry was then agitated with
a high shear mixer to reduce the particle size of the
resultant floc, was washed and then was analyzed for
water content and diluted to result in a 2% solids
slu~ry. The slurry was transferred to a 11.5" x 11.5"
hand sheet mold (manufactured by Williams Apparatus Co.~ ;
and dewatered. The resultant formed
sheet was then wet pressed and dried on a drum drier.
The sheet had good flexibility and performed well in the
gasket sealing test.
Example 2
3S Using the procedures of Example 1, a handsheet
was prepared from the following slurry:
~2S7054
_ g _ DDJ-7581
Wt. Percent
Hexamethylene diammonium fluorhectorite 58.7
NBR latex 3.2
Alum 2.9
Micro Talc 5.9
Redwood Fiber 20 9 `
Kevlar~ Fiber 2.9
Mineral Wool 23.5
Total 99O2
~he resulting handsheet was subjected to .
gasket sealing tests which were electro-mechanical air
lea~age tests conducted according to the specifics set
forth in pages 1-3 of the SAE (Society o~ Automotive ,:.-
Engineers, Inc.) technical paper No. 83022 (ISS~
0148-7191 (83/0228-0220, 1983).
The results of the tests were: .~.
Initial Flange P~essure (psi) Leakage Rate - :
(psi/min) :~
570 1.389
20 915 1.587
2500 0.529 !:
Example 3
This example illustrates a method of producing
films of the present invention wherein the cationic .~s
25 exchange is made in situ. ~.
A 10% ~olids lithium fluorhectorite gelled
dispersion was prepared according to proeedures taught
in U~ S. Patent No~ 4~239,519. A film was made of this
material by using a 4.5 mil Byrd applicator, which was 5 i~
30 inches wide, to draw down a 4~ mil thick wet film of the !
dispersion on a glass plate. The glass plate, with the
film attached, was then immersed in a 0.25M solution of
1,6 hexanediamine HCl solution to cause a cation
exchange between the 1,6 hexanediammonium cations and
the fluorhectorite's interlayer cations. A skin was
formed, seemingly instantaneouslyt on the film which
indicated such an exchange was taking place. In 10
minutes the film was removed.from the plate, washed in
'
.
.
~s~s~
- 10 - DDJ-7581
deionized water to remove residual salts, and dried.
The film had good flexibility and strength retention
when wet. - --
Exam~les 4-15
For each of these examples, the procedure
of Exampl~ 3 was substantially repeated with the
exchange cation (all made from the corresponding
diamine~ as specified to form the corresponding film.
Example Exchange Cation
4 N,N,N',N-tetramethylethylenediammonium
O-phenylenediammonium
S 1,2 diammonium propane
7 lt8 diammonium octane
8 2,5 toluenediammonium
lS 9 1,7 diammoniumheptane
1,9 diammoniumnonane
11 1,5 diammoniumpentane
12 1,2 ethylenediammonium
13 1,3 diammonium propane
20 14 1,4 diammonium butane
1,12 diammoniumdodecane
Comparative Examples 1~3
These comparative examples illustrate fluorhec-
torite films that are made with various prior art
exchange cations. Four and one half mil thick films o
potassium fluorhectorite (XFH) and ammonium
fluorhectorie ~N~4FH) were separately prepared by the
process specified in UO SO Patent Wo. 4,239,519. A
film was then cast of both the KFH and a NH4FH slurry.
A Kymene (a trademark of Hercules, Inc. for a cationic,
polyamide-epichlorohydrin resin) fluorhectorite film
was also prepared by the procedure of Example 2, except
that (1) a 3.0% Kymene solution was used and ~2) the
lithium fluorhectorite film had to be immersed in the
Kymene solution for 2 hours until the resultant
exchanged film was sufficien~ly self-supporting to be
~Z57054
- 11 - DDJ-7581
removed from the glass plate. These films, along with
the f ilms made in Examples 2-9, were then subjected to
tensile strength and puncture resistance tests which
were conducted as follows:
Tensile Stren~th Measurements
Dry tensile strength measurements were
determined using an Instron at 1~" jaw separation and
0.2n/min. crosshead speed. Wet strength measurements
were made ~y bringing water-saturated sponges in contact
with both sides of the film sample for 10 seconds ~Jhile
the sample was positioned in the Instron clamps just
before the strength test was conducted.
Puncture Resistance Measurements
A sample of film was secured in a retaining ; -
device which held the film securely. A stylus which
could be loaded was impinged on the film in the .
direction normal to the surface of the film and loaded
with increasing weight until the stylus penetrated the
film. In the wet test the film in the retaining device
was submerged in deionized water for 10 seconds
immediately proceeding the puncture resistance test.
The data from these tes~s is shown in ~he ~:
table below.
TABLE
Tensile Puncture
Film of Strength Resistance
Example Exchange ~psi) (gr/mm)
# _ Cation ~y Wet ~ Wet
3 1,6 hexanediammonium 1600017000 13000 ~000
3 0 4 N~N~N ~ ,N te'cramethyl-
ethylenediammonium 1800016000 11000 5100
O-pehnylenediamine 1300015000 7600 3000
6 1,2 diammonium propane 13000 11000 14000 4200
7 1,8 diammoniumoctane 12000 11000 6500 1700
8 2,5 toluenediammonium 9800 11000 6500 1800
9 1,7 diammoniumheptane 7300 8800 16000 7500
1,9 diammoniumnonane 70005000 3600 1400
~25705~ -
- 12 - DDJ-7581
11 1,5 dia~moniumpentane 6600440005700 5200
12 1,2 ethylenediammonium 520036001200 600
13 1,3 diammonium propane 330014003500 680
14 1,4 diammonium butane 300014006600 900
15 1,12 diammoniumdodecane 1800 2900 3100 570
,. ..
Comparative
Example #
1 Kymene (protonated) 7,0002,700900 260
2 Ammonium 3,3001,4003,500 680
3 Potassium 1,1002003,300 440
The data indicates that the films made accor- ;.
ding to the procedures of the present invention have
markedly superior wet tensile strength and/or superior
wet puncture resistance when compared to prior art
compositions.
Fire and Smoke Resistance
A film prepared according to Example 3 was, -:
after being dried, subject to fire and smoke resistant
test~ in accordance to the procedures speci~ied in . :
ASTM-E-662-79. Three separate tests were made and the
results are set forth below.
Test 1 - Flameability
(The numerical values correspond to the
maximum specified optical density as per N.B.S.
Technical Note ~708.)
Flaming Mode O
Smoldering Mode O
Test 2
Oxygen Index Type C ASTM D2863-77
Critical Oxygen Index 100~ 2
Test 3
Radiant Panel AST~E162 79
Flame Spread Factor 1.00
Heat Evolution 0.0
Flame Spread Index 0.0
~2S70~
-- 13 - DDJ-7581
Electrical Pro~erties
A film of Example 2 was, when dried, tested
for dielectric constant and dissipation factors using
the procedures of ASTM D150 and for dielectric strength
using the procedures of ASTM D149. The results, set
forth below, indicate the ilm has utility in a variety
of elec~rical insulating properties.
Dielectric Dissipation
Constant Factor
100 HZ at 25C 26.53 .288
100 HZ at 300~C 3~.9 .37
100 HZ return to 25C 10.7 .049
100 RHZ at 25C 12.19 .153 :
100 KBZ at 300C 15.0 .202
100 KHZ return to 25C 9.52 .024
Dielectric strength measured at 577v/mil.
Com~arative Examples 4 and 5
These examples illustrate using, as a starting
material, silicate materials which fall outside the
scope of the present invention in their charge per
structural unit and their physical measurements.
For comparative Example 4, a 10% aqueous
dispersion was made from a natural hectorite obtained
from the source clay minerals depository of the Clay ---
Minerals Society, Bloomington, Indiana. For Comparative
Example 5, a 10% aqueous dispersion utilizing sodium
montmorillonite, which was obtained from the same
so~rce. In each example, a film was drawn down using
the procedures set forth in Example 2. The glass plates
were then immersed for 10 minutes in a 0.25 M 1,6
diammonium hexane solution~ In both instances, a
coherent film was not produced.
Exam~le 16
Thi~ example illustrates a method of preparing
a film of ~he present invention utilizing a vermiculite
starting material:
A 10% solids suspension of n butylammonium
vermiculite, whlch was prepa~ed according to the
~L~57(~54
-- 14 -- DDJ-75~1
procedu~es specified in U. S. Patent 3,325,340, was cast
as a film on a glass plate according to the procedure
set forth in Example 2. The glass plate, with the film
a~tached, was immersed for 10 minutes in a 0.25 M
l,S hexanediamine HCl solution. The resulting fil~ was
removed from the plate, washed, and dried. The film
displayed wet strength in the tensile strength and
puncture res;stance tests that a comparable unexchanged
vermiculite film does not display.
~
This example illustrates preparing fibers
utilizing the method of the invention. A 15% solids
suspension of lithium fluorhectorite (prepared as above)
was extruded through an 11 mi~ opening needle into a 2N ~'
lS solution of 1,6 hexanediamine HCl. The extruded fiber
was carried by a porous belt and delivered to a second
bath of 2N 1,6 hexanediamine HCl. The fiber so produced
was washed via submersion in deionized water and dried.
The re~ultant fiber was strong and flexible.
Example 18
This example illustrates the addition of an
epoxy to sheet silicate composites.
Codispersions of the diglycidyl ether of
bisphenol A (DG~A~ and lithium fluorhectorite ~LiFH)
were prepared by adding the epoxy to a 10% (solids)
aqueous lithium fluorhectorite dispersion. The
codispe~sion was then mixed via a high shear processO
The codispersions were formed in the following ratios of
LiFH to DGBA:
1. 100 gr. 10% solids LiFH dispersion (10 gr.
LiFH solids) 0.1 gr. epoxy tapprox. 1% on solids basis).
2. 100 gr. 10% solids LiFH dispersion 1.1 gr.
epoxy (approx. 11~).
3. 100 gr. 10% solids 2.5 gr. epoxy (approx.
25~).
The films were prepared by producing 4.5 mil
wet films on glass plates with a Byrd applicator and
immersing the film in a 0.25M hexamethylene diamine HCl
~25705a~
-- 15 -- DDJ--7581
soln. at a pH of 7Ø The resultant films had good wet
strength characteristic of hexamethylene diammonium
exchanged fluorhectorite. The resultant film was washed
with deionized water to remove excess hexamethylene
5 diamine HCI and dried at 60C. The dry films which were
flexible were heated to 150C for 3 hours. rrhe
resultant films exhibited increased rigidity as would be
expected with epoxy curing. Therefore, it appears that
the hexamethylene-diammonium cation is effective in
performing the layered silicate exchange function and
epoxy curing.
For an alternative method of making the
articles, epo%y/fluorhectorite codispersions as
described above were converted to floc form through the
addition of the codispersion to a 0~25M
hexamethylenediamine HCl solution with agitation. After
washing the excess hexamethylenediamine HCl from the
floc the 10c solids content was adjusted to 2% and
subjected to high shear mixing to reduce the particle
size. The resultant material was transferred to a
nonporous mold and allowed to dry to coherent flexible
films of approximately 10 mils thickness.
The films were hot pressed at 150C for 3
hours and the films become more rigid.
From 1 to 80 weight parts of epoxy resins can
be utilized in producing articles according to the
present invention~ based on the solids weight of the
sheet silicate starting material.
