Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
This invention relates to highly oil-extended conjugated diene/
vinyl aromatic teleblock copolymer compositions. In one of its aspects`this
invention relates to preparation of highly oil-extended conjugated diene/
vinyl aromatic teleblock copolymer compositions. In a particular aspect
of the invention, it relates to radial teleblock copolymer compositions.
In another of its aspects, this invention relates to objects molded from
these compositions. In a more particular aspect of this invention it
relates to a molded artificial fishing lure, molded objects that adhere to
a vertical surface instead of rebounding, shock- and energy-absorbing
products, decorative objects, toys, and games. ;~
Highly oil-extended conjugated diene/vinyl aromatic teleblock
copolymer compositions are well known in the art. U.S. Patents such as
3,676,387, issued December 21, 1970 to James A. Lindlof, and 3,827,999,
issued November 9, 1973 to Ronald K. Crossland, disclose stable, highly
oil-extended polymer compositions based on linear teleblock copolymers
and on hydrogenated branched copolymers. Compositions are known to be
suitable for making castings. It has now been found that oil-extended
polymer compositions of radial teleblock copolymers 3 while sharing some
characteristics with oil-extended linear teleblock copolymers, have other
characteristics that differentiate the radial copolymers from the linear
copolymers.
Prior art compositions containing linear polymers and high amounts
of plasticizer or extender were frequently prepared by adding extender to
linear polymer in a mill or in an internal mixer, by blending a solution
of linear polymer and appropriate solvent with extender followed by strip-
ping the solvent, or by adding linear polymer to stirred extender at either
ambient conditions or slightly elevated temperature. These methods have
various disadvantages among which are: long mixing times, large power re-
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quirements, and environmental contamination by solvent vapors. The
present invention provides means Eor preparing the highly oil-extended
radial copolymer compositions of this invention conveniently and rapidly
with a minimum of environmental problems.
The compositions that can be prepared by the method of this
invention contain highly oil-extended conjugated diene/vinyl aromatic
radial teleblock copolymers, preferably radial or branched teleblock co-
polymers of butadiene and styrene. The compositions exhibit a number of
useful and interesting properties. The compositions are highly elastic
and can be extruded, injection molded, transfer molded, solution cast,
hot melt cast, etc., into a wide variety of useful articles, films,
coatings, etc. In addition to the hereinafter described artificial fishing
lures and shaped objects that can be pressed, such as by being thrown,
against flat surfaces without rebounding, the compositions can be formed
into shock- and energy-absorbing products; toys; objects used in playing
games; coatings for insulative or protective purposes, such as encap-
sulating fragile and delicate mechanical or artistic objects or electronic
components. A coating of one of these compositions on glass bottles
will provide protection from breakage and will also serve to contain glass
fragments should breakage occur. Flexible molds can be prepared from the
compositions by coating a solid object with the composition and, after the
composition sets, removing the solid object from the coating to leave a
cavity in which replicas of the solid object can be prepared using any
suitable molding material.
By appropriate selection of radial teleblock copolymer, oil, and
the proportions in which they are combined, finished articles which slowly
exude oil from the surface can be obtained. Compositions are also avail-
able withïn the scope of the invention which are highly oil-extended yet
which do not exude or "bleed" oil from the surface or which "bleed-out" oil
at a considerably reduced rate as compared to prior art materials.
3l~3~ 3
~ ased on the appearance and physical characteristics of finished
articles that can be molded from compositions prepared by the process of
this invention, a molded object has been produced that, surprisingly, is
uniquely suited to the purpose for which it was conceived. It has been
found that objects molded in the form of a fishing worm have not only that
appeal, perhaps as much to fisherman as to fish, that perfectly adapts it
as an artificial bait, but also has physical properties that are superior
to similar artificial lures known to the prior art.
Artificial, rubbery fishing lures in the form of worms are
currently made commercially from poly(vinyl chloride) (PVC) highly extended
with high-boilingesters such as dibutyl phthalate. Such artificial worms
are a commercial success, although fishermen report varying degrees of
success in using them to catch fish. Unfortunately, current commercial
worms generally "bleed out" a significant amount of extender which fre-
quently necessitates segregation from other fishing tackle. The fishermen
must also exercise caution in using these commercial worms since contact
of the worms with polystyrene lures, floats, or tackle boxes results in
rapid softening and deterioration of the polystyrene. The artificial
fishing lures of the present invention have been especially successful
employed by fishermen in catching bass. In addition, "bleed-out" is re-
duced and the problem of deterioration of polystyrene in contact with the
PVC worms is eliminated. The compositions of the present invention do
not attack polystyrene.
Another shaped, preferably molded, object of special interest is
a ball or object of another shape, that, because of a special property of
compositions of this invention, can be pressed against a vertical surface,
as by being thrown, without rebounding and, depending on the smoothness or
slickness of the surface, will stick to the surface or adhere sufficiently
to roll down the vertical face. Such objects can be rounded or can have
flat surfaces.
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At one end of the spectrum of suitable shapes are objects cut
from sheet material, thereby being virtually two-dimensional, which will
adhere to the spot on the vertical surface onto which they are pressed.
Such objects in various shapes and colors can be used to define and
decorate the transparent surface of a window. At the other end of the
spectrum are spheroids which tend to roll down a vertical surface. In
between, there is a relationship between the amount of flat surface on the
molded object that is pressed against the vertical surface and the total
weight of the object which determines the ability of an object of the
inventive composition to "stick" to a vertical surface. The invention
contemplates objects of any shape, but particularly those of size to be
easily thrown by hand. The object can be regular as a parallelepiped,
spheroid, dodecahedron, etc., or totally irregular in shape, but with
sufficient surface to allow adherence to a vertical surface. All of the
shapes are adaptable in preparing objects useful as toys or useful as
objects employed as part of a game or recreational activity.
As mentioned above, the smoothness of the surface against which
the object is pressed directly affects the ability of the object to remain
on the surface. Glass, polished marble, polished metal, and concrete
formed against plywood or other smooth surface have surfaces that do not
cause rebound of objects of this invention that are thrown thereagainst.
It is therefor an object of this invention to provide a highly
oil-extended conjugated diene/vinyl aromatic radial teleblock copolymer
composition. It is another object of this invention to provide a method
for preparing a highly oil-extended conjugated diene/vinyl aromatic radial
teleblock copolymer composition. It is another object of this invention to
provide an artificial fishing lure molded from a highly oil-extended
conjugated dienetvinyl aromatic teleblock copolymer composition. It is
still another object of this invention to provide an object molded from
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a highly oil-extended radial teleblock copolymer suitable preferably to
adhere to a vertical surface against which it is thrown; but, at least,
sufficient not to rebound from the surEace.
Other aspects, objects, and the various advantages of this in-
vention will become apparent upon a study of this specification and the
appended claims.
Statement of the Invention
According to this invention, a composition is provided that is
a blended mixture of a conjugated diene/vinyl aromatic radial teleblock
copolymer extended with a hydrocarbon oil.
Also, according to this invention, a method is provided for pre-
paring a highly oil-extended conjugated diene/vinyl aromatic radial
teleblock copolymer in which a conjugated diene/vinyl aromatic radial
teleblock copolymer and a hydrocarbon oil are admixed and the mixture
raised to an elevated temperature of about 120C to about 205C until a
homogeneous blend is produced. In preferred embodiments of the invention,
the copolymer and hydrocarbon oil are stirred together to form a mixture
at a temperature elevated to about 175C to about 205C with stirring
continued until a homogeneous blend is produced or a mixture of the co-
polymer and hydrocarbon oil is prepared and the mixture elevated to a
temperature in the range of about 120C to about 200C without stirring
until a homogeneous blend is produced.
In an embodiment of the invention, a fishing lure comprising a
highly oil-extended conjugated diene/vinyl aromatic radial teleblock
copolymer composition molded in a suitable conformation is provided.
In another embodiment of the invention, shaped objects that
do not rebound from vertical surfaces against which they are thrown and
which tend to remain in place on surfaces against which they are pressed
are also provided.
Among the conjugated diene/vinyl aromatic teleblock copolymers
which can be oil-extended and cast into useful objects are radial or
branched teleblock copolymers of butadiene and styrene which are prepared
by methods which are well known in the art. For example, use of an
organolithium initiating species to polymerize styrene monomer to form a
living polymer of polystyryllithium represented by:
polystyrene--Li
followed by addition of butadiene monomer to the polystyryllithium to
form a living polymer represented by
polystyrene-polybutadiene-Li
and subsequent coupling of the living polymer with a multifunctional
coupling agent, such as silicon tetrachloride, results in polymers which
are represented by
(polystyrene-polybutadiene) Y
wherein Y represents a coupling agent residue and n is a number greater
- than 2 and preferably from 3 to 5. Such polymers are characterized as
..
being elastomeric in the unvulcanized state as well as thermoplastic
since they can be molded.
Useful polymers which also contain outward polystyrene blocks
and inward polybutadiene blocks can be prepared by employing a polyfunc-
tional initiating species, such as an organopolylithium compound, onto
which polybutadiene blocks are polymerized with subsequent polymerization
of polystyrene blocks. Such polymers are represented by
(polystyrene-polybutadiene) Z
wherein Z represents the residue of the polyfunctional initiating speçies
and n is as described above.
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The copolymers will generally contain from~about 50 to about 95
weight percent butadiene and from about 5 to about 50 weight percent styrene;
preferably from about 50 to about 70 we:Lght percent butadiene and about 30
to about 50 weight percent styrene. Copolymers particularly useful in
producing compositions that do not rebo~md from surfaces against which they
are thrown are in this preferred range -- most particularly in the range of
about 60 to about 70 weight percent butadiene. When less than 5 weight
percent styrene is employed, the resulting copolymers do not possess the
requisite green tensile strength. More than 50 weight percent styrene in
~'10 the copolymer results in a composition in which hardness is increased at
the expense of elasticity. Useful copolymers will generally exhibit
a weight average molecular weight in the range of about 75,000 to about
500,000, but a range of about 100,000 to about 350,000 is preferable.
It is also within the scope of this invention to employ radial
block copolymers in which the above-described polybutadiene block is not
pure polybutadiene but is a block of random butadiene/styrene copolymer or
a "tapered" block of butadiene and styrene in which the ratio of butadiene
to styrene changes from one end of the block to the other. If such
polymers are employed the amount of butadiene and styrene in the total
polymer must be within the ranges given above, with the further proviso
that the above-described polystyrene blocks must constitute at least 5
weight percent by weight of the total polymer.
The oil which is useful in the practice of this invention is
generally selected from those hydrocarbon oils characterized as naph-
thenic, paraffinic, or aromatic or mixtures thereof. Commercial oils,
although typically classified as one of these types, normally are mixtures
and are usually classified according to major component. Impurities such as
2~
unsaturated heterocyclic compounds and aromatic heterocyclic compounds can
also be present in small amounts. Oils which are referred to in the
industry as heavy white mineral oils are also suitable as extender oils
for rubbery polymers. These are usually produced by refining a naphthene-
base oil or a mixed naphthene-paraffin-base oil by removal of all hetero-
cyclic, unsaturated aliphatic, and aromatic hydrocarbons. Oils in which
this removal is not complete are often described as technical grade white
mineral oils, whereas when the removal of these impurities is essentially
cluantative the product is identified as a U.S.P. white mineral oil.
~aphthenic oils (including heavy white mineral oils) are generally preferred
because they do not usually impart an undesirable color to the composition
and they exhibit less tendency to exude or "bleed" from the composition.
Aromatic oils are normally used in applications where color of the finished
product is not critical, since commercially available aromatic oils gen-
erally have characteristic color associated with them. Exudation or
"bleed-out" of oil is most likely to occur with oils high in paraffinic
content, but is also a function of the physical properties of the oil,
such as, for example, viscosity and specific gravity. Exudation is also a
function of the rubber used in the composition, heavy mineral oils and
naphthenic oils generally exhibiting less exudation with rubbers which
have higher conjugated diene content. Some degree of exudation or slow
release of oil is desirable or tolerable for specific end-uses. It is
also within the scope of this invention to employ vegetable oils in the
compositions. The choice of oil for a specific application depends on
several factors, such as, for example, the rubber chosen, the degree of
exudation desired or allowable, and the required color of the finished
product.
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It is frequently desirable to include other additives well known
in the rubber art in the inventive compositions. Stabilizers,
antioxidants, fillers, reinforcing agents, reinforcing resins, pigments,
fragrances, and the like are examples of such types of addi-tives. Specific
examples of useful antioxidants and stabilizers include
2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, nickel dibutyldithiocar-
bamate, tris(nonylphenyl)phosphite, 2,6-di-t-butyl-4-methylphenol, and the
like. Exemplary fillers, reinforcing agents, and pigments include clay,
silica, carbon black, titanium dioxide, and the like. Titanium dioxide
present in a range up to about 500 parts per hundred par-ts by weight
copolymer is of special usefulness in producing shaped objects that do not
rebound from a vertical surface against which they are thrown.
Polypropylene and polystyrene are examples of thermoplastic resins which
function as reinforcing resins.
The compositions of this invention generally contain the
above-described ingredients in amounts given in the following tabulation:
Parts by Weight per 100 Parts by
IngredientWeight of Radial Teleblock Copolymer
Broad Preferred
Oil 200-1000 300-700
Filler or reinforcing
agent 0-500 3-70
Reinforcing resin 0-200 0-100
Stabilizer 0-5 0.5-3
Pigment 0-10 0.05-1
The compositions of this invention can be prepared by any of the
means well known in the art for combining the above ingredients such as
solution blending, milling or continuous extrusion. This invention also
provi~es specific embodiments for rapid and convenient preparation of the
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compositions by heating a mixture of the components to a temperature range
of about 120C to about 205C with separate specific embodiments preEerably
conducted by stirring a mixture of the components at about 160C to about
205C, preferably 175C to about 205C, or by heating the mixture without
stirring in a temperature range of abou-t 125C to about 200C, preferably
125C to about 165C.
One method of preparing a composition consisting of a conjugated
diene/monovinyl arene teleblock radial copolymer and a high level of
hydrocarbon extender oil requires placing a mixture of the teleblock co-
polymer (preferably in particle form) and extender oil in a suitable con-
tainer, such as a flat metal pan, and heating said mixture, such as in an
oven, without agitation at a temperature whlch normally falls within the
range corresponding to about the melting point of the rubber as the lower
limit, about 120C, up to about the flash point of the oil as the upper
limit, about 200C. Normally and preferably, heating ls conducted within
a temperature range of about 125C to about 165C. The composition can be
formed of the mixture within a time of several seconds to several hours
but the mixture is normally maintained at this temperature for about 15
minutes to several hours. The time required is dependent on such things
as the type and quantities of rubber and oil employed, the temperature
used and the physical size of the pieces of rubber to be used in the ~;
preparation of the composition. Furthermore, the time required to make a
homogeneous mixture can normally be reduced by physically mixing the rubber
and the oil prior to the heating step. Additional additives and formulation
ingredients can be added to the rubber-oil blend prior to or during the
heating step. After the heating step, the composition is normally cooled
prior to its use in the fabrication of articles.
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The composition can be further treated if desired, or required,
in any conventional mixer, such as a roll mill, particularly if small
amounts of undissolved rubber remain after the oven heating step, or if it
is desirable to add other ingredients~ or if the ingredients, such as
fillers, added prior to or during the heating step have not been uniformly
distributed throughout the composition. This additional treatment, if
desired, is normally conducted within a temperature range of about 75C to
about 125C, preferably maintaining the composition below its melting
point, and can be conducted for a few minutes up to several hours,
preferably three to 15 minutes, the resulting composition normally being
completely homogeneous.
In another embodiment the components of the composition can be
mixed and then heated to 175-205C with stirring. Alternatively, and
preferably, the oil (with or without the other ingredients exclusive of
radial teleblock copolymer) can be heated to 175-205C with subsequent
addition with stirring of the copolymer and remaining ingredients.
Solution of the ingredients in the composition at about 175C to about
205C is generally accomplished with stirring during a time period of
several seconds to several hours, usually from 0.5 minute to about one
hour, although a stirring time of one-half minute to twenty minutes usually
ensures complete solution and homogenizing of the blend.
The hot fluid composition from the above-described inventive pre-
paration can immediately after preparation be placed in a mold, cast as a
film, applied as a coating, etc., and allowed to cool and solidify. Alter-
natively, the composition can be cooled in bulk with subsequent sufficient
heatings to produce a fluid state for molding, casting, coating, and
other uses. Molding can be accomplished by well-known techniques such
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as by iniection, compression, or transfer techniques or simply by pouring
the hot fluid composition into a mold.
The artificial lures of this invention can be readily pre-
pared from the hot fluid composition immediately after preparation or from
a batch of the composition previously prepared. The techniques described
above are especially suitable for molding the lures.
Artificial lures can be made in any desired size, shape or
color. Their particular attractiveness to fish can be measured only by
the success of fishermen employing them. At present, artificial worms are
the form most preferred by fishermen, but various insects, spiders, frogs,
small fish, and even abstract shapes can be contemplated; therefore,
variations from simple monocolored worm can be employed to create a
lure with special allure. These variations are considered to be within
the scope of this invention. For example, batches of the composition
containing different pigments can be placed sequentially in a single
mold to produce multicolored lures. Alternatively, small pieces of metal-
lic foil or brightly colored particles can be mixed with the inventive
composition prior to molding to produce lures impregnated with reflective
or brightly colored particles.
Molded objects useful in other aspects of this invention can
be made decorative similarly to the artificial lures.
EXA~LE I
The following runs illustrate several methods of preparation
of compositions according to this invention.
Radial teleblock copolymer of butadiene/styrene weight ratio
60/40 with weight average molecular weight 216,000, prepared using n-butyl-
lithium as initiator and silicon tetrachloride as coupling agent was extended
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8;~
with 50 phr (parts by weight per 100 parts by weight rubber) of naphthenic
extender oil. Extended rubber, as produced above, and additional naphthenic
extender oil were employed in the preparation of composi-tions according
to the invention.
Run 1 (Method 1)
Extended rubber (80 gm) and oil (200 gm), which is a total of
425 phr oil, were mixed at room temperature in a stirred open vessel with
external heating. I~hen the temperature of the stirred heated mixture reached
199C, solution of the rubber was complete giving a smooth, fluid, homo-
geneous composition which cooled to give an elastic composition with a
slightly oily surface.
Run 2 (~ethod 2)
Extended rubber (80 gm) and naphthenic oil (240 gm), which is a
total of 500 phr oil, were mixed and allowed to stand at room temperature
for 15 minutes. With subsequent stirring and heating for 30 minutes in the
vessel of Run 1 the temperature reached 202C and complete solution was
observed.
Run 3 (Method 3)
Naphthenic oil (240 gm) was heated in the vessel of Run 1 to
205C at which time extended rubber (80 gm), which is a total of 500 phr
oil, was added. After continuous stirring for 20 minutes, solution was
complete. After pouring into a mold and cooling, an elastic composition
was obtained with a slightly oily surface.
Run 4 (Method 4)
For this run, radial teleblock copolymer of butadienelstyrene
weight ratio of 70/30 with weight average molecular weight of about 300,000,
prepared using n-butyllithium, as initiator, and silicon tetrachloride,
as coupling agent, was employed.
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2~
Ground rubber (400 grams) and a U.S.P. heavy white mineral oil
(1200 grams; 300 phr), and titanium dioxide (80 grams; 20 phr) were poured
into a flat metal pan, stirred briefly with a spatula, and then placed in a
forced air oven at 125C for one hour. The mixture was removed from the
oven and allowed to cool. Although all the oil had been absorbed into the
rubber, there remained a few particles of undissolved rubber and the
titanium dioxide was concentrated in the lower part of the composition. A
sample of this composition (600 grams) was milled on a 6 x 12 inch roll
mill at 121C for five minutes. This milling incorporated the remaining
undissolved rubber and produced a smooth homogeneous composition.
EXA~IP~E II
The following comparative runs illustrate attempts to prepare
inventive compositions using non-inventive methods.
Run 5
Toluene (400 ml), extended rubber (80 gm), as prepared in Example
I, and naphtenic oil (240 gm) were mixed at room temperature. After
complete solution of components was achieved (two hours) the solution was
poured into an open pan for removal of solvent. At ambient conditions a
skin formed on the surface of the composition which prevented further
solvent removal. Subjecting the composition to a vacuum of 67 to 85 kPa
and a temperature of 70C also resulted in a skin on the surface of the
composition which prevented further drying. Conse~uently, the
toluene-containing composition was discarded.
Run 6
Extended rubber was banded (at 121C) on a 15 cm x 30 cm labora-
tory roll mill. ~aphthenic oil was added to the rubber during milling as
rapidly as the rubber would take it up. After two hours milling, only
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~32~83
25~ phr (total) oil had been added. The softnes~ of the composition hsd
reduced shear to the point that little, if any, more oil could be added to
the composition. The difficulty and time required to prepare a composition
using the method of this run would greatly limit its utility.
EXAMPLE III
The following runs demonstrate a variety of copolymer-extender
oil combinations useful in the compositions of this invention.
Butadiene~styrene radial teleblock copolymers having varying
butadiene/styrene weight ratios were mixed according to the method of
Example I, Run 4 (Method 4) with 300 phr of various oils and 20 phr of
various fillers and the exudation or "bleed-out" evaluated after two weeks
o~ aging at ambient room temperature. The results are given in Table I.
In addition to the oils in Table I, soybean oil and a co~mercial
non-detergent 20W motor oil were tested with the same 60/40 butadiene/
styrene radial telebloc~ copolymer but without added filler and at a
different oil/copoly~er ratio than the compositions in Table I. Bleed-out
was heavy with both of these oils and a strong odor was clea~ly evident.
In contrast~ the compositions of Table I had only a very slighS odor.
These data illustrate that the extent of bleed-out is a function
of the extender oil used and the butadienelstyrene weight ratio of the
teleblock copolymer, and that the mineral and naphthenic oils evaluated
have a lower level of exudation with polymers having a higher weight ratio
of butadiene. With the teleblock copolymer having a 60l40 butadiene/
styrene weight ratio, Flexon 766 naphthenic oil provided the lowest level
of exudation of the oils evaluated, while the teleblock copolymers having a
70/30 butadiene/styrene weight ratio, exudation was essentially non-
existent with any of the oils evaluated at a 300 phr oil level. The type
of filler employed clid not appear to influence the level of exudation at
the conditions of this study.
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133
(a) Radial teleblock copolymer prepared using n-butyllithium
as initiator and silicon tetrachloride as coupling agent.
(b) 300 phr total oil in each composition.
(c) 20 phr filler in each composition.
(d) Determined visibly and to the touch after the compositions
had aged at ambient room temperature for two weeks.
(e) Naphthenic oil (AST~I Type 104A) from Exxon Company.
(f) Kaolin (hard) clay from R. T. Vanderbilt.
(g) Type R-101 from duPont.
(h) Fine precipitated CaC03 of 0.15-0.30~ particle size from
BASF Wyandotte.
(i) U.S.P. heavy white mineral oil composed entirely of
saturated aliphatic and naphthenic hydrocarbons from Witco Chemical,
Sonneborn Division.
(j) Naphthenic type technical grade heavy white mineral oil
from Atlantic Richfield Company.
(k) U.S.P. heavy white mineral oil from Marathon Norco Co.
EXAMPLE IV
The following inventive runs 16, 17, and 18 illustrate other
radial teleblock copolymers which are useful in the inventive composition.
Accompanying comparative run 19 illustrates the use of a random copolymer
of butadiene and styrene that is not within the scope of this invention.
Preparation ~ethod 3 of Example I with a five-minute mixing time
after addition of rubber was employed in these runs. Naphthenic oil (500
phr total) was employed in the preparation of the compositions. Table II
contains data obtained in runs 16 to 19.
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2ZB3
TABLE II
Run Solut:ion Cooled
No. Rubber Appearance Appearance
16 A Gelled --
17 B Lumpy Normal with
resinous particles
18 C3 Small lumps Normal with small
resinous particles
19 D4 Didn~t dis- --
solve
(1) 60/40 Butadiene/styrene radial teleblock copolymer
initiated with n-butyllithium and coupled with SiC14.
M~ = 300,000. Contains 0.5 phr 2,6-di-t-butyl-4-
metholphenol and 1.5 phr tris(nonylphenyl)phosphite.
(2) 70/30 Butadiene/styrene radial teleblock copolymer
initiated with n-butyllithium and coupled with SiC14.
Mw = 304,000. Contains same stabilizer system as
footnote 1 above.
(3) 52.5/47.5 Butadiene/styrene radial teleblock copolymer
initiated with n-butyllithium and coupled with SiC14.
Extended with 60 phr naphthenic oil. Mw = 200,000.
(4) 65/35 Butadiene/styrene random copolymer. Extended
with 37.5 phr aromatic oil.
In Run 16, solution of rubber in oil appeared to proceed
normally until near the end of the heating period when the polymer appeared
to gel. The conclusion is that insufficient stabilizer was present in
the rubber of that composition and molecular weight to protect it
adequately during the heating period.
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~322~33
In Runs 17 and 18 the solution of the rubber in the oil appeared
to proceed normally except for the presence of swollen pieces of polymer.
The cooled compositions appeared to be normal except for the appearance of
resinous particles. Apparently the original rubber contained some particles
of gel or resinous material prior to addition to the hot oil.
In comparative Run l9 the rubber did not dissolve in the oil
under the employed mixing conditions; therefore, the composition was dis-
carded.
EXA~fPLE V
The following inventive runs illustrate inventive compositions
~ith varying amounts of oil and properties thereof.
Preparation Method 3 of Example I was employed with ten minutes
mixing time after rubber addition. The extended rubber described in
Example I was employed. Table III contains the resultant data.
TABLE III
Run No. 20 21 22 23 24
Naphthenic oil, phr400 500 600 700 0
Mineral oil, phr 0 0 0 0 400
Specific gravity 0.90 0.90 0.90 0.90 0.90
Tensile, psi 49 28 15 14 15
Elongation, %700 600 500 500 600
Hardness 87 81 73 70 83
Tear, lb/in 4 3 2 2 5
Permanent set, %4 11 10 10 11 11
~eight change, % :
48 hr. in water~0.05 0 0.05 0.41 0.29
48 hr. in air0.05 0.15 0.34 0.56 0.42
(continued)
-18-
~3~2~3~
(1) ASTM D-412-66.
(2) Sponge gauge hardness - measured using Sponge Rubber Gauge
Model 302-S (Pacific Transducer Corp., Los Angeles, CA). 0
to 100 scale with 100 being hardest, 0 being softest.
(3) Measured according to ASTM-624-54.
(4) Set measured after 50 percent compression for 24 hours at room
temperature followed by one hour relaxation.
(5) Cylindrical pellets 3.2 cm diameter X 1.3 cm length. Recorded
as percentage weight loss except where recorded as "+" which
refers to weight gain.
The data in Table III show characteristic desirable properties
of the compositions of this invention. Varying the amount of oil in
compositions can provide a range of properties to correspond with the
desired application.
EXA~IPLE VI
Compositions of this invention and commercial artificial
fishing worms were contacted with polystyrene to determine the relative
sensitivity of polystyrene to these compositions.
A polystyrene sheet 3.2 mm thick was contacted at room tem-
perature for 48 hours with cylindrical pellets 3.2 cm diameter X 1.3 cm
length of the inventive compositions of Runs 20 to 24 and with pellets of
commercial artificial fishing worm compositions based on poly(vinyl chloride)
highly extended with dibutyl phthalate (worms were melted and cast into
pellets). The inventive compositions produced no detectable change in
the polystyrene surface; whereas the commercial artificial worm compositions
caused serious softening, sagging, and even dissolution of the polystyrene
surface.
--19--
:~3~
The results of the above-described tests indicate that the
inventive artificial fishing worms can be contacted with polystyrene tackle
boxes, floats, lures, etc., wthout the detrimental effect characteristic
of the poly(vinyl chloride)/dibutyl phthalate worms.
It should be noted that contacting artificial worms of the
composition of this invention with poly~vinyl chloride)/dibutyl phthalate
worms resulted in rapid deterioration of both worms. Hence, such contact
should be avoided.
E.YAMPLE VII
The following inventive runs are illustrative of the additives
successfully employed in inventive compositions.
The extended rubber described in Example I and naphthenic oil
were employed. Mixing was as generally described in Preparation Method 3
of Example I with minor variations in mixing times after rubber addition.
Table IV lists the additives and composition proportions.
-20-
33
TABLE IV
Run Naphthenic
No. Oil, PHR Additive PHR
400 Silica 10
26 500 Silica 67
27 700 Silica 4
28 400 Talc 10
29 500 Clay 17
400 Silica 25
Coumarone-indene resin 30
31 400 Clay 50
Coumarone-indene resin 30
32 400 Polystyrene 100
33 300 Polypropylene 50
34 500 Stabilizer Al 2
500 Stabilizer B 2
36 500 Stabilizer C3 1 ~-
37 500 Stabilizer D 2
(1) 2,6-di-t-butyl-4-methylphenol.
(2) tris(nonylphenyl)phosphite.
(3) Nickel dibutyldithiocarbamate.
(4) 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.
EXA~IPLE VIII
Inventive artificial fishing worms were prepared from inventive
compositions.
The mold employed for hot melt casting had a cavity approximately
18 cm deep with the upper 16 cm being cylindrical with varying diameter
(1 cm maximum, 0.5 cm minimum) along the length of the cylinder. The lower
2 cm of the cavity was flattened to provide an oblong flat tail on the -
resultant worm 2 mm thick, 1.5 cm across at the widest point, and 2 cm long.
:'~
-21-
Compositions containing the extended rubber described in
Example I, naphthenic oil (300 to 700 phr total oil), various of the addi-
tives given in Table IV, and various pigments were prepared generally as
described in ~lethod 3 of Example I and while being maintained at 190-205C
were poured into the above-described molds. After cooling the molds were
opened and the artificial fishing worms were removed.
The artificial worms were also prepared by injection molding of
compositions as described above in molds with cavities approximately 11 cm
long the upper 5 cm of which was semicylindrical with varying diameter (1
cm maximum, 0.5 cm minimum) along the length of the semicylinder. The
lower 6 cm of the cavity was ilattened and curved to provide a long curved
tail varying from 6 mm to 3 mm in width and 1 to 2 mm thick.
The resultant worms from the hot melt casting and injection
molding were successfully employed to catch fish. They were especially
successful in the catching of large mouth bass.
E ~PLE IX
This example illustrates the preparation of inventive balls from
the inventive composition. Oil-extended stock representing each of the
compositions described in Table I of Example III and similar stock repre-
senting each of the compositions described in Table V was loaded into a
transfer mold having 26 spherical cavities measuring 3.18 cm in diameter.
The loaded transfer mold was placed in a heated hydraulic press and main-
tained at 121C for a ten-minute warmup period without any applied pressure.
A pressure of 30 tons was then applied and maintained for 15 minutes.
At the end of this time, the pressure was released and the mold removed
and placed in a second hydraulic press cooled with circulating cold tap
water and maintained at 30 tons pressure until the mold cooled. This
procedure produced good smooth balls from each of the compositions.
2~B3
The oil-extended stocks of the compositions described in Table
I were cut into thin strips and then f ormed by hand into a spherical
mass slightly larger than the 4.32 cm diameter spherical cavities of a
compression mold. These hand-shaped masses were placed in these cavities
and then compression molded using the same basic procedure described earlier
for transfer molding. Several of the compression molded balls contained
flaws in the form of small holes due to air trapped in the compression
mold.
.
~32~83
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--24--
.2~33
Molded balls prepared from the highly oil-extended radial
teleblock copolymer compositions described in Tables I and V were observed
to have the unique property of not rebounding when thrown against or
dropped on a hard solid surface. Furthermore, molded balls from certain
of these formulations not only failed to rebound but also when thrown against
certain smooth or slightly rough vertical surfaces maintained contact with
that surface and slowly rolled down. Molded balls from certain other of
these formulations while having the same smooth outward appearance, and
although likewise not rebounding when thrown against a solid surface,
did not have the tendency to stick and slowly roll down, but rather after
striking a vertical surface immediately fell to the floor. In general,
copolymers having higher butadiene content and those containing filler were
observed to have a greater tendency to stick or maintain contact with
a vertical surface. This is illustrated by the observation that molded
balls from Runs 12-15, 46, and 47 (all from copolymers containing 70
weight percent butadiene) all stuck and slowly rolled down a vertical sur-
face, while molded balls from Runs 38-42 and 45 (all from copolymers
containing 60 weight~ percent butadiene~ did not stick at all, but fell
immediately to the floor. Furthermore, a ball from Run 44 which contains
a 60 weight percent copolymer but having a very high 375 phr titanium
dioxide stuck well, while a ball from Run 8 containing the same copolymer
but only 20 phr titanium dioxide had considerably less tendency to stick,
although better than balls from Run 43 which contain no filler. The
amount of exudation of oil likewise was observed to affect this property,
washing the ball with soap to remove excess surface oil often leading to
improved adhesion of the ball to a vertical surface.
28~
EX~LE X
This example illustrates the amount of exudation as a function
of the oil level employed for a composition consisting of the 70/30 butadiene/-
styrene radial ~eleblock copolymer used in Runs 12-15 of Example III, 20 phr
of titanium dioxide, and varying levels of Sontex 35 U.S.~. heavy white
mineral oil from Marathon Norco Company.
The compositions were prepared according to the method of Example
I, Run 4 (Method 4). Each composition was transfer molded into a ball
according to the procedure described in Example IX and was aged for three
days at room temperature. Each sample was then placed on a stack of
white writing paper for 24 hours to evaluate oil migration. ~ second ball
molded from each composition was aged for six days under the same con-
ditions described above and then evaluated both visibly and to the touch
for oil bleed-out. The results of this evaluation, as tabulated in
Table VI, indicate that for this particular combination of ingredients,
the amount of oil migration and bleed-out is a function of the oil
concentration in the composition.
-26-
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-27
~i3~83
EXAMPLE ~I
This example illustrates a difference in properties of a
composition of the present invention using butadiene/styrene radial
copolymer as compared to a composition outside the present invention using
a butadiene/styrene linear copolymer. Compositions were prepared according
to the method of Example I, Run 4 (Method 4) by blendin~ for Run 53 a 70/30
butadiene/styrene radial block copolymer with 300 parts Marathon-Norco
U.S.P. heavy white mineral oil and 20 parts TiO2 per 100 parts of the
rubber compound. For Run 54 a 70/30 butadiene/styrene linear block
copolymer was blended with 300 parts Marathon-Norco U.S.P. heavy white
mineral oil and 20 parts TiO2 per 100 parts of the rubber compound. In
each formulation all of the ingredients were mixed in a pan and then placed
in an oven without further stirring for 30 minutes at 164C. The
composition was let cool and the masterbatch was blended on a roll mill for
five minutes at 120C. The material in each run was then molded into
balls. The results of observations of the balls are reported in Tab~e VII
below.
-28-
~3~83
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-29-
~32'~
The above Table shows that while both radial copolymer and linear copolymer
originally produce spherical moldings that seem to be equivalent in bleed-
out and ability to stick to a wall upon being thrown thereagainst, that
upon aging the linear polymer produces more bleed~out and loses its ability
to stick to the wall unless the exuded oil is removed from the surface
of the ball. The sticking to the wall is an important factor in a desired
end use of the highly oil-extended compositions of this invention.
-30-
