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Description  |
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This invention relates to compositions useful for forming abrasion
resistant coatings on rubbery substrates.
Automobile glass run channels used around automobile windows need high
abrasion resistance against the sliding of the window glass edge. Low
abrasion resistance can result in water leakage and freezing around the
glass during cold weather.
Rubber weatherstrip materials used around doors and windows in automobiles
also are subject to extensive wear. Abrasion of the automotive
weatherstrip occurs in various areas around an automobile door opening,
for example, in corner areas as the door is closed and in the lower areas
of the door opening as a result of contact with the feet of passengers
entering or leaving the automobile. This abrasion ultimately results in
severe damage and failure of the weatherstrip.
An object of this invention is to avoid the difficulties alluded to above
and to provide rubbery or rubber substrates with abrasion resistant
coatings from thermoplastic polymers.
Another object of this invention is to provide a composition useful for
forming abrasion resistant coatings on rubbery hydrocarbon polymer
substrates.
These and other objects and advantages of the present invention will become
more apparent to those skilled in the art from the following detailed
description and working examples.
SUMMARY OF THE INVENTION
It has been found that solution of (I) amide group containing thermoplastic
polymers or resins wherein the (--NH--) unit has become a (--NBr--) or
(--NCl--) unit can be mixed in organic solvents with (II) at least one
linear or branched organopolysiloxane or silicone compound which may be
terminally saturated or terminally unsaturated and optionally with (III)
at least one finely divided material selected from the group consisting of
inorganic and organic fillers or pigments. The resulting composition or
mixture when applied directly to a cured or vulcanized rubber substrate,
e.g., an EPDM rubber, dried to remove the solvent and then exposed to
ultraviolet radiation or heated at a temperature and for a period of time
sufficient to remove the chlorine or bromine atoms from the nitrogen atoms
and to reform the (--NH--) units to reproduce the amide group yields an
adherent and abrasion resistant polymer or resin coating on the rubber
substrate. In addition to an improvement in abrasion resistance the
coating provides improvements in other properties such as the coefficient
of friction. For example, the coating composition can be applied directly
to EPDM automotive glass run channels as well as door weatherstrip sponge
type gaskets to significantly improve the abrasion resistance without the
need for napping or flocking.
Based on dry weight the coating or final coating on the substrate
composition contains (I) about 100 parts by weight of the thermoplastic
polymer or resin, (II) from 5 to 80 parts by weight of the siloxane or
silicone and optionally (III) from 5 to 60 parts by weight of the finely
divided inorganic or organic filler or pigment.
DISCUSSION OF DETAILS AND PREFERRED EMBODIMENTS
The amide group containing abrasion resistant thermoplastic polymer is
selected from the group consisting of polyacrylamides, polyamideimides,
polysulfonamides, polyurethanes, polyureas, polyurethaneureas and
polyamides and mixtures of the same. These polymers are well known as
shown by the "Encyclopedia Of Polymer Science And Technology,"
Interscience Publishers, a division of John Wiley & Sons, Inc., New York,
Vol. 1 (1964), Vol. 10 (1969) and Vol. 11 (1969) and "Vinyl And Related
Polymers," Schildknecht, John Wiley & Sons, Inc., New York, 1952. Of these
N-containing thermoplastic polymers it is preferred to use the polyamides
such as the nylons.
Examples of the nylons are those having long chains with recurring
(--CONH--) groups as an integral part of the polymer chain. They are made
by polyaddition of acrylamide, ring opening polymerization of, e.g.,
pyrrolidone, caprolactam and lauric lactam or by polycondensation of,
e.g., aminononanoic acid, 11-aminoundecanoic acid, hexamethylene diamine
with adipic or sebacic acid and p-phenylene diamine with terephthalic acid
and the like and modifications of the same as illustrated by U.S. Pat.
Nos. 4,414,362 and 4,448,956 and others. Mixtures of nylons can be used.
The thermoplastic (--CONH--) polymer to be brominated or chlorinated can be
used in finely divided or pelletized form. If the thermoplastic is in
massive form as obtained, it may be reduced in size using granulators,
dicers, die face cutters, strand pelletizers, underwater pelletizers and
so forth. If necessary, the thermoplastic may first be cooled or frozen to
facilitate size reduction.
Various reagents and mixtures thereof can be used to brominate or
chlorinate the thermoplastic (--CONH--) polymers including sodium
hypobromite, hypochlorous acid, salts of hypochlorous acid (aqueous
calcium hypochlorite or aqueous sodium hypochlorite (preferred)), alkyl
hypochlorites (t-butyl hypochlorite), elemental bromine or chlorine,
dibromomonoxide and dichloromonoxide. Aqueous solutions of hypobromous
acid or hypochlorous acid and the like are preferably used for bromination
or chlorination. These solutions are most conveniently obtained by
addition of acids such as aqueous hydrobromic, hydrochloric (preferred),
sulfuric or acetic acid to solutions of the sodium salts of hypobromic or
preferably hypochloric acid.
The halogenation reaction is carried out in the presence of an organic
solvent. This solvent has to be immiscible with water and inert under the
reaction conditions; it has to dissolve the N-halogenated polymer with
ease but not the original amide group containing polymer. Examples of
solvents are methylene chloride (preferred), carbon tetrachloride,
chloroform, tetrachloroethane, trichloroethane, benzene and toluene.
A preferred procedure for the preparation of the N-halogenated material
used in the invention is to disperse the (--CONH--) polymer in a mixture
of an aqueous solution of Na-hypochlorite (CHLOROX, 5.25% Na-hypochlorite)
and the organic solvent (CH.sub.2 Cl.sub.2) and add concentrated
hydrochloric acid in a nearly stoichometric amount based on the
Na-hypochlorite. The mixture is slurried at room temperature (ca
25.degree. C.) or below until the polymer dissolves. The organic layer
containing the desired product is separated and washed with water. The
solution obtained can be used in the coating process directly or after
appropriate dilution. Or, a solid product can be obtained by solvent
evaporation for easier shipment.
The brominated or chlorinated thermoplastic (--CONH--) polymer or mixture
thereof is used in an amount of from about 1 to 50%, preferably about 2 to
4%, by weight solids in a solvent such as one or more of the above
chlorinated hydrocarbons like methylene chloride for use as a coating
material. A uniform application of the coating can be obtained with a low
solids content solution.
The siloxane or silicone compound used with the halogenated polymer is at
least one linear or branched (T-structure) siloxane or silicone compound
which may be terminally saturated or terminally unsaturated. These
polymers have the formula:
##STR1##
where R and R.sup.1 may the same or different and are selected from the
group consisting of H, --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7,
--CH.sub.2 CH.sub.2 CF.sub.3 and so forth, where R" is selected from the
group consisting of H, --Si(CH.sub.3).sub.3,
##STR2##
and the like and where n is a number. Examples of the siloxanes are
trimethylsiloxy terminated polydimethylsiloxane, dimethylvinylsiloxy
terminated polydimethylsiloxane, glycidyloxypropyl-branched T
structure-trimethylsiloxy terminated polydimethyl siloxane,
aminoalkyl-branched T structure-trimethylsiloxy terminated polydimethyl
siloxane, acetoxy terminated polydimethyl siloxane and
polymethylphenyl-diphenyl siloxane copolymer and the like and mixtures
thereof. These siloxanes or silicones can be liquids, oils or greases and
have a viscosity of from about 25 to 2,750,000, preferably from about 50
to 300,000, centistokes at 25.degree. C. They should dissolve or disperse
in the same solvent used to dissolve the brominated or chlorinated
polymer. For information on silicones please see "Encyclopedia of Polymer
Science And Technology," Volume 12, 1970, John Wiley & Sons, Inc., New
York and Kirk Othmer, "Encyclopedia Of Chemical Technology," 3rd Edition,
Volume 20, 1982, John Wiley & Sons, Inc.
The finely divided or powdered material is elected from the group
consisting of inorganic or organic fillers or pigments and can have a
particle size of from about 0.1 to 100 microns, preferably from about 2 to
70 microns. Silica can be used and can be a thermal or pyrogenic silica or
a precipitated silica. Nylon can be used and can be any one of the nylons
disclosed herein such as nylon 6, 6,6, 11, 12 and so forth. Carbon black,
also, can be used in the coating composition. Divinylbenzene crosslinked
polystyrenes and fluorocarbon resins such as polytetrafluorethylene and
the like can be used. Mixtures of the inorganic and organic fillers and
pigments can be used. They are dispersed in the solvent used for the
brominated or chlorinated thermoplastic polymer or resin.
The rubber substrate such as a weatherstrip or glass run channel and so
forth can be a rubbery hydrocarbon polymer selected from the group
consisting of natural rubber; high cis-polyisoprene; emulsion
styrene-butadiene copolymers; solution styrene-butadiene copolymers which
may be low vinyl, medium vinyl, high vinyl or high trans; solution BRs;
butadiene- or isoprene-styrene star copolymers; block (thermoplastic
elastomer) styrene-butadiene-styrene or styrene-isoprene-styrene
copolymers; butyl rubber; high molecular weight polyisobutylenes; EPDMs
(ethylene-propylene-nonconjugated diene copolymers) (preferred) and so
forth and mixtures of the same. These polymers are well-known. These
rubbery polymers are mixed with the usual curing and compounding agents
for the particular polymers being used and cured or vulcanized. Examples
of some agents are reinforcing blacks; silica; clay; TiO.sub.2 ; stearic
acid; zinc oxide; sulfur; dibenzo GMF with red lead or with peroxides;
sulfur furnishing materials; retarders; accelerators; antioxidants;
blowing agents like azodicarbonamide, p,p'-oxybis(benzenesulfonyl
hydrazide) and dinitrosopentamethylene tetramine (preferred) and so forth.
The rubber may be solid or blown (cellular--open or closed cell) depending
on the ultimate use.
Ethylene-propylene-nonconjugated diene rubbery terpolymers (EPDMs) are made
by the copolymerization of ethylene, propylene and a non-conjugated diene
such as 1,4-hexadiene, ethylidene norbornene or dicyclopentadiene. They
may be crystalline or non-crystalline and may be random, block or sequence
terpolymers. Their relative unsaturation can vary from about 0.7 to 7.5.
The mole % of ethylene can vary from about 50 to 85 and the raw (uncured
and uncompounded) Mooney viscosity (ML 1+8 at 250.degree. F.) can vary
from about 14 to 84. Rubbery or elastomeric EPDM terpolymers, methods for
making them and methods for curing them are shown by "Rubber Chemistry And
Technology," Volume 45, No. 1, March, 1972, Division of Rubber Chemistry,
Inc., American Chemical Society, pages 709 to 881; "Rubber Technology,"
2nd Ed., Morton, Van Nostrand Reinhold Company, New York, 1973, Chapter 9;
"Polymer Chemistry of Synthetic Elastomers," Part II, High Polymers
Series, Vol. 23, John Wiley & Sons, Inc., New York, 1969, Chapter 7;
"Encyclopedia Of Polymer Science and Technology," Interscience Publishers
a division of John Wiley & Sons, Inc. New York, Vol. 6 (1967) pages 367-8
and Vol. 5 (1966) page 414 and "The Synthetic Rubber Manual,"
International Institute of Synthetic Rubber Producers, Inc., 10th Ed.,
1986.
The coating composition can be applied to the rubbery substrate such as a
weatherstrip or glass run channel using any conventional coating technique
(brush, print roller, dip or spray). The coating may be applied to one
side or to all sides. Generally, it is applied only to the side requiring
improved abrasion resistance. After application to the substrate the
solvent is evaporated leaving a film comprising N-brominated or
N-chlorinated thermoplastic, silicone and optionally the finely divided
pigment on the surface. By application of heat or UV irradiation the
bromine or the chlorine is released from the nitrogen atoms and the
(--NH--) units are reformed to provide the recurring amide groups. Some
cross-linking may take place during this process. These treatments result
in formation of strong, abrasion resistant and non-tacky coatings. Good
adhesion to the rubber results since the N-brominated or N-chlorinated
thermoplastic is a strong oxidizing agent which can react with the rubbery
substrate generating polar groups on its surface and/or giving primary
bonding between the rubber and the coating at the interface. The preferred
method is to use UV treatment which is much faster and gives a consistant
product. The irradiation with ultraviolet light should be done at
wavelengths of not over about 375 nm, preferably not over about 350 nm
(nanometer or millimicron). Other treatments may be effective in
converting the N-brominated or N-chlorinated thermoplastic back to the
amide form (e.g., treatment with steam, aqueous base and/or a solution of
a reducing agent such as sodium bisulfite or sulfite). The heat treatment
or other treatment is conducted for a period of time and at a temperature
sufficient for complete conversion of the N-brominated or N-chlorinated
units of the thermoplastic back to the amide NH form.
Although the working examples are directed mostly to improvement of the
abrasion resistance of automotive weatherstrip and glass run channel, the
coating material may be useful to improve the abrasion resistance and
reduce the surface friction of other substrates such as windshield wipers,
vinyl films, upholstery, luggage and so forth.
The following examples will serve to illustrate the present invention with
more particularity to those skilled in the art.
EXAMPLE 1
Into a 2-liter reaction flask equipped with an air-driven stirrer was
placed nylon 6 powder (30 g, prepared by grinding in a Wiley mill and
passing through a 10 mesh screen), CHLOROX (750 g, 5.25% aqueous solution
of sodium hypochlorite), conc. HCl (51 g) and methylene chloride (791
g=600 ml). The mixture was stirred for 30 minutes and poured into a
separatory funnel. The bottom (methylene chloride) layer was separated,
washed with 1.5 liters of water, and poured into about 500 ml of hexane to
precipitate N-chlorinated nylon 6 (41 g) with chlorine content of 25.9%
(c.f. theoretical chlorine content in the case of all nitrogen atoms being
chlorinated, 23.8%). Finely divided nylon 6,6, nylon 11, nylon 12 and a
polyurethane also were chlorinated in similar ways as described above.
Nylon 6 is a type of nylon made by ring opening polymerization of epsilon
caprolactam. Nylon 6,6 is a type of nylon made by condensing hexamethylene
diamine with adipic acid. Nylon 11 is a type of nylon derived from
11-aminoundecanoic acid. Nylon 12 is a type of nylon made by the
polymerization of lauryl lactam (dodecanoic lactam) having 11 methylene
groups between the linking (--CONH--) groups in the polymer chain. The
polyurethane was the reaction product of adipic acid, a polyetherglycol
and diphenylmethane-4,4'-diisocyanate.
EXAMPLE 2
4% methylene chloride solutions of the N-chlorinated nylons and the
polyurethane with or without 10% by weight (based on the N-chlorinated
materials) of silicone oil (50 centistrokes, trimethylsiloxy-terminated
polydimethyl siloxane) were sprayed onto vulcanized EPDM rubber extrudate
(solid) sheets. The coated sheets were air-dried overnight to eliminate
the solvent (methylene chloride), treated for 5 minutes at 110.degree. C.
in an oven to melt the coating layer and passed 3 times under three
high-pressure mercury lamps (UV) (200 Watts/inch, 10 inches long) for a
total exposure of about 7.5 seconds to cure the coating (dry thickness
15-20.mu.). After one day for maturation and, also, to evolve residual
chlorine, each of the coated sheets was tested on a glass edge scuff type
abrasion tester equipped with a ground-glass abrasion tool. Addition of
the silicone oil improved the abrasion resistance as shown in Table I,
below, where the number of cycles of the glass edge sliding (1 kg load)
used to abrade the coating layer to expose the EPDM extrudate substrate is
listed.
TABLE I
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Abrasion Resistance (Cycles)
N--chlo- N--chlo- N--chlo- N--chlo-
Silicone
rinated rinated rinated rinated
Oil Nylon 6* Nylon 6,6* Polyurethane*
Nylon 11*
______________________________________
None 260 296 6 50
10% 865 807 807 2,000
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*After irradiation, the --NCl-- units of the chlorinated nylons and
urethane had been reformed to(--NH--) units.
The EPDM used was a carbon black reinforced compounded and sulfur
vulcanized, non-staining and random ethylene-propylene-ethylidene
norbonene terpolymer.
For more information on the bromination or chlorination of thermoplastic
polymers having (--NH--) units and to convert the (--NBr--) or (--NCl--)
units back to (--NH--) units see copending patent application of Hubert J.
Fabris et al, U.S. Ser. No. 832,281, filed Feb. 24, 1986 and entitled
"Abrasion Resistant Coatings," the disclosure of which is incorporated
herein and made a part hereof by reference to the same.
EXAMPLE 3
A mixture of N-chlorinated nylon 11 (1 g), silica micropowder (fumed
silica, particle diameter 2-10.mu., 0.1 g), methylene chloride (24 g) and
various amounts of the silicone oil (same as in Example 2, above) was
applied to the same type of vulcanized EPDM rubber extrudate sheet,
processed and tested in the same way as described in Example 2, above. The
abrasion resistance varied with the silicone oil as shown in Table II,
below:
TABLE II
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Abrasion Resistance
Silicone Oil Silica Micropowder
(% of nylon weight)
(% of nylon weight)
Cycles
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0 0 50
0 10 240
5 10 2,000
10 10 4,300
20 10 4,600
30 10 43,300
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EXAMPLE 4
A mixture of N-chlorinated nylon 11 (4 g), silica micropowder (same as in
Example 3, above) (0.4 g), various amounts of
dimethylvinylsiloxy-terminated polydimethyl siloxane (100 centistokes) and
methylene chloride (96 g) was applied to the same type of vulcanized EPDM
rubber extrudate sheet and processed in the same way as described in
Example 2. Each of the coated sheets was tested in a crock meter abrasion
tester [a glass edge with 3 kg load sliding at 66 Hz on the test specimens
(flat sheets)]. The abrasion resistance varied with the level of vinyl
group-terminated polydimethyl siloxane as shown in Table III, below. The
cycle numbers in Table III cannot be directly compared to those in Table I
or Table II, because the test methods are different.
TABLE III
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Abrasion Resistance
Silicone Oil Silica Micropowder
(% of nylon weight)
(% of nylon weight)
Cycles
______________________________________
0 10 201
10 10 929
20 10 1,229
30 10 2,903
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EXAMPLE 5
A mixture of N-chlorinated nylon 11 (3 g), the above
trimethylsiloxy-terminated silicone oil (1.2 g), the above
dimethylvinylsiloxy-terminated silicone oil (0.8 g), the above silica
micropowder (0.4 g) and methylene chloride (97 g) was applied to a sample
of the same type of extruded and vulcanized EPDM rubber sheet, processed
and tested as shown in Examples 2 and 4, above.
The crock meter abrasion resistance was 6,144 cycles.
EXAMPLE 6
A mixture of N-chlorinated nylon 11 (3 g), the above
trimethylsiloxy-terminated silicone oil (1.2 g), the above
dimethylvinylsiloxy-terminated silicone oil (0.8 g), nylon 11 micropowder
(average particle diameter of about 70.mu.) (0.8 g) and methylene chloride
(97 g) was applied to a sample of the same type of vulcanized EPDM rubber
sheet, processed and tested as shown in Examples 2 and 4, above.
The crock meter abrasion resistance was 4,975 cycles.
EXAMPLE 7
A mixture of N-chlorinated nylon 11 (2 g), the above
trimethylsiloxy-terminated silicone oil (0.6 g), the above
dimethylvinylsiloxy-terminated silicone oil (0.4 g), the above silica
micropowder (0.1 g), the above nylon 11 micropowder (0.2 g), thermal
carbon black ASTM N-990 (0.025 g) and methylene chloride (48 g) was
applied to a sample of the same type of vulcanized EPDM rubber formed as a
glass run channel (shaped for use). It was processed and tested as shown
in Examples 2 and 4, above.
The crock meter abrasion test was stopped at 10,000 cycles. The coating
layer did not show any abrasion after the test.
The N-chlorinated nylon 11 is readily soluble in methylene chloride and the
resulting composition can be applied directly to the EPDM. Unmodified
nylon 11, on the other hand, is only soluble in solvents such as formic
acid and meta-cresol which are not suitable for coating applications.
EXAMPLE 8
A mixture of N-chlorinated nylon 12 (4 g), the above
trimethylsiloxy-terminated silicone oil (0.8 g), the above
dimethylvinylsiloxy-terminated silicone oil (1.2 g), ASTM N-990 carbon
black (0.1 g), the above silica micropowder (0.4 g), and methylene
chloride (96 g) was applied to a sample of the same type of vulcanized
EPDM rubber formed as a glass run channel, processed and tested as shown
in Examples 2 and 4, above.
The crock meter abrasion resistance was 17,000 cycles.
EXAMPLE 9
The same coating composition as described in Example 6, above, was applied
to the sponge part of cured EPDM rubber weatherstrip to give a 2-3.mu.
(dry thickness) layer. After overnight drying, the coated weatherstrip was
passed under the foregoing UV lamp system 3 times for about 2.5 seconds
each time.
After one day maturation, the coating layer was tested on a Wyzenbeek
abrasion tester and showed no abrasion after 100,000 cycles. The coated
weatherstrip had a friction coefficient (Fisher Body specification test)
of 0.21. Uncoated weatherstrip showed Wyzenbeek failure and abrasion of
less than 20 cycles and friction coefficient of only 1.7.
The cellular or sponge part of the EPDM weatherstrip was blown during the
vulcanization step with dinitrosopentamethylene tetramine.
EXAMPLE 10
A 4% methylene chloride solution of N-chlorinated nylon 11 (50 g) and
trimethylsiloxy-terminated polydimethyl siloxane (viscosity 300,000
centistokes, 1.0 g) was applied to an uncoated cured EPDM rubber glass run
channel. The coating was processed and tested in the same way as described
in Example 4 except that the coating was cured by passing it 5 times under
a medium-pressure mercury lamp system.
The crock meter abrasion resistance was greater than 25,000 cycles.
EXAMPLE 11
A 4% methylene chloride solution of N-chlorinated nylon 11 (50 g),
trimethylsiloxy-terminated polydimethyl siloxane (viscosity 2,500,000
centistokes, 1.0 g), carbon black (0.3 g), silica micropowder same as
above and nylon 11 powder same as above (0.2 g) was applied to an uncoated
cured EPDM rubber glass run channel. The coating was processed and tested
in the same way as described in Example 4.
The crock meter abrasion resistance was greater than 10,000 cycles.
EXAMPLE 12
Into a quart reaction bottle was placed nylon-6/9 pellets (Aldrich) 10 g,
CHLOROX 214 g, methylene chloride 264 g (200 ml), and conc. HCl 14.4 g.
The mixture was stirred with a magnetic stirrer for 2 hours at about
0.degree. C. N-chlorinated nylon-6/9 was separated and purified in the
same way as shown in Example 1. N-chlorinated nylon-6/10 and -6/12 were
prepared in a similar way. Separate solutions of 4% methylene chloride
solutions of N-chlorinated nylon-6/9, -6/10, and -6/12 each containing 30%
(by N-chlorinated nylon weight) of trimethylsiloxy-terminated
polydimethylsiloxane (300,000 centistokes) were applied to uncoated cured
EPDM rubber glass run channels. The coatings were air-dried overnight,
melt-heated in an oven for 5 minutes at 50.degree.-60.degree. C. and
passed 5 times under a medium pressure mercury lamp system (3
Sylvania-made H2200T4/24Q) at 50 feet/min. The crock meter abrasion
resistance of the coatings were 3,800, >25,000, and 25,000 cycles for
N-chlorinated nylon 6/9, 6/10, and 6/12, respectively. Nylon 6/9 is poly
(hexamethylene nonanediamide). Nylon 6/10 is poly (hexamethylene
sebacamide). Nylon 6/12 is poly (hexamethylene dodecanediamide).
EXAMPLE 13
A mixture of 2 grams of N-chlorinated nylon 6/10, 0.2 g of
trimethylsiloxy-terminated polydimethylsiloxane, 48 g of methylene
chloride and 0.2 g each of powdered Nylon 11 about 70 microns particle
diameter, TEFLON (400 mesh), 2%-divinylbenzene-crosslinked polystyrene
(200-400 mesh), Degussa-TS-100 (silica), "Cabosil" N70-TS (fumed
colloidal silica), and carbon black (Raven 450, Columbia Co.) was applied
to uncoated cured EPDM rubber glass run channels, processed, and tested as
shown in Example 12, above. The crock meter abrasion resistance (cycles)
obtained is shown in the Table IV below.
TABLE IV
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Fillers Cycles
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Nylon-11 micropowder 10,100
2% divinylbenzene crosslinked polystyrene
14,600
(200-400 mesh)
TEFLON (duPont, fluorocarbon resin)
6,300
Degussa-TS-/100 (Silica) 11,100
"Cabosil" N-70-TS (Silica)
4,200
Raven 450 (carbon black) 5,400
______________________________________
EXAMPLE 14
Mixtures of 2 grams of N-chlorinated nylon 6/10, 48 g of methylene chloride
and 0.2 g each of polysiloxanes: a
glycidoxypropyl-branched-T-structure-trimethylsiloxy terminated
polydimethylsiloxane (Petrarch Systems, Inc. PS-404),
aminoalkyl-branched-T-structure trimethyl siloxy terminated
polydimethylsiloxane (Petrarch Systems, Inc. PS-054), acetoxy-terminated
polydimethylsiloxane (Petrarch Systems, Inc. PS-363.5) and
polymethylphenyl-diphenyl siloxane copolymer (Petrarch Systems, Inc.
PS-162) were each applied to uncoated and cured EPDM rubber glass run
channels, processed and tested according to Example 12, above. The crock
meter abrasion resistance obtained is shown in Table V below:
TABLE V
______________________________________
Silicone oil Cycles
______________________________________
Glycidoxypropyl-T-structure branched (PS-404)
3,000
Aminoalkyl-T-structure branched (PS-054)
647
Acetoxy-terminated (PS-363.5)
9,737
Polymethylphenyl diphenylsiloxane copolymer
44
(PS-162)
______________________________________
EXAMPLE 15
Mixtures of 2 grams of N-chlorinated nylon 6/12, 0.2 g of
trimethylsiloxy-terminated polydimethyl siloxane (300,000 centistokes), 48
g. of methylene chloride (as solvent), and different levels of
2%-divinylbenzene-crosslinked polystyrene (200-400 mesh) were applied to
uncoated and cured EPDM rubber glass run channels, processed and tested as
shown in Example 12, above. The crock meter abrasion resistance obtained
is shown in Table VI, below:
TABLE VI
______________________________________
2%-divinylbenzene-
crosslinked polystyrene level
(% by weight)
of N--chlorinated nylon 6/12
Cycles
______________________________________
0 8,600
5 17,900
10 25,000
15 25,000
20 25,000
30 15,000
50 8,500
______________________________________
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