Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to synthetic resins and to
a method of preparing such resins. The invention
particularly relates to resinous compositions prepared -
from selected methyl branched a-olefins, styrene and
a-methyl styrene. The invention further relates to
rubber-based adhesives and to paint-type resin
composites prepared with such synthetic resins.
Various methyl branched olefins can be polymerized
~- with aluminum chloride to yield useful resinous tackifiers
for natural and synthetic rubbers. However, in general, ~ -
such resins are noticeably better tackifiers for some
rubbers and relatively poor tackifiers for others, unless
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a very substantial amount of the resin is mixed with ~-
the rubber. Indeed, the degree of solubility of a
synthetic resin in the desired rubber appears to play
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a major role in determining whether it is an effective -~
tackifier. ;
;~` It is, therefore, an object of this invention to
provide a thermoplastic resin having an enhanced balance
i 20 of tack imparting and solubility for selected synthetic
rubbers and useful as a solubilizing aid for selected
paint-type resins.
In accordance with this invention, it has been
discovered that a resinous composition is prepared by
polymerizing a monomer mixture comprising about 10 to
about 90~ preferably about 10 to about 80, weight
percent of at least one methyl branched a-olefin having
its tertiary carbon atom removed from the carbon-to-carbon
double bond selected from at least one of 3-methyl-1-butene,
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3-methyl-1-pentene~ ~-methyl-l-pentene and,
correspondingly, about 90 to about 10, preferably
. about 90 to about 20, weight percent aromatic monomers
selected from at least one of styrene and a-methyl
~.:
styrene in the presence of a catalyst selected from
aluminum chloride~ ethyl aluminum dichloride, boron
.: trifluoride and boron trifluoride etherate, and in the
~- presence of a solvent selected from said aliphatic
hydrocarbons containing ~ to 7 carbon atoms, aromatic
hydrocarbons containing 6 to 8 carbon atoms and liquid
`- chloro-substituted hydrocarbons containing 1 to 6,
preferably 1 to 2~ carbon atoms.
In the practice of this invention, particularly ~:
.~ useful resinous compositions, generally suitable as
. 15 rubber tackifiers are prepared by polymerizing a
. monomer mixture comprising about 20 to about 80 weight
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.~ percent of at least one of said methyl branched a-olefins,. and, correspondingly, about 80 to about 20 weight
percent of said aromatic monomers, said aromatic .
: ........................ .
monomers comprising about 80 to about lOO, preferably
. about 90 to about 100, weight percent styrene and,
~: correspondingly, about 20 to about 0, preferably about
10 to about 0~ weight percent a-methyl styrene.
In the further practice of this invention,
particularly useful resinous compositions, generally
. suitable as a solubilizing and/or plasticizing aid for :
- paint-type resins is prepared by polymerizing about 10
to about 50 weight percent of at least one of said
` methyl branched a-olefins, and, correspondingly, about
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90 to about 50 weight percent of at least one of said
aromatic monomers, where said aromatic monomers comprise
about 0 to about 50, preferably about 0 to about 20~
weight percent styrene and, correspondingly, about 100
to about 50, preferably about 100 to about 80, weight
percent a-methyl styrene. ~`
For the preparation of the resin compositions of this
invention, 3-methyl-1-butene is the preferred methyl
branched a-olefin.
- 10 Various hydrocarbon solvents can be used.
Representative of various saturated aliphatic hydrocarbons ~ ;
are butane, pentane, hexane and heptane. Representative -~
.
of various aromatic hydrocarbons are benzene~ toluene~
xylene and tetralin. Representative of various chloro-
substituted hydrocarbon solvents are dichloroethylene,
trichloroethylene~ 2~2-tetrachloroethylene~ methyl
chloroform~ dichloromethane~ 1~2-dichloroethane~
trlchloroethane~ 1,1,2,2-tetrachloroethane and chloro-
benzene. Generally, saturated aliphatic hydrocarbons
are preferred~ particularly hexane and heptane.
For the preparation of the resin compositions of
thls invention, aluminum chloride and ethyl aluminum
dichloride are preferred catalysts.
In the further practice of this invention~ the
olefin portion of the resin can be somewhat modified,
so long as the basic selected methyl branched a-olefin/
selected aromatic backbone is maintained. ~uch
modification can be the addition of minor amounts of
further selected methyl branched olefins. Thus the
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olefin portion of the monomer mixture, or resin
composition~ can be modified by containing
~ 0 up to about 20 weight percent olefins selected from
l 2-methyl-1-butene, 2-methyl-2-butene, 2-methyl-1-pentene,
and 2-methyl-2-pentene.
The resin compositions of this invention have a
wide range of softening points, according to ASTM
; Method E28-58T, such as less than about 20C, or a
liquid at room temperature such as about 250C, up to
about 105C, primarily because of the large impact
`~ of the difference in structure provided by the range
;
of methyl branched olefin and aromatic monomer mixtures.
It was an important discovery that resin
- compositions of this invention can be useful as
tack-imparting resins, particularly for rubber-based
adhesives, including pressure sensitive adhesives.
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Therefore in further accordance with this
invention, a rubber-based composition is provided
` which comprises in the range of 30 to about 200
parts by weight of said resinous composition of this
invention and about 100 parts by weight of a rubbar
selected from natural cis 1,4-polyisoprene rubber
and synthetic rubber selected from cis l~-polyisoprene,
polybutadiene~ and copolymers and block copolymers of
isoprene or 1,3-butadiene with styrene or acrylonitrile.
Particularly advantageous compositions are comprised
of the resin of this invention and a rubber selected
- from natural rubber, copolymers and block copolymers
of 1,3-~utadiens and styrene containing about 60 to
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about 9~ units derived from styrene and polymers
and copolymers of 1,3-butadiene and acrylonitrile.
The tackified rubber composition can typically
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be adaptable for use as a pressure sensitive adhesive,
particularly when the rubber is selected from natural
rubbar and unvulcanized block copolymers of 1~3-butadiens
or isoprene with styrene or acrylonitrile. Particularly
useful are natural rubber and unvulcanized block
- copolymers of styrene-isoprene-styrene and styrene-
butadiene-styrene.
` Surprisingly, resin compositions of this
-~ invention can be provided which are valuable as
solubilizing aids, agents or additives for selected
paint-type resins which require highly aromatic solvent. -
Therefore, in further accordance with this
invention a fluid mixture is provided which comprises
about 30 to about 70 parts by weight of a resin of this
invention~ 100 parts by weight of a normally solid~
; thermoplastic resin characterized by requiring, at
`i 20 about 250C, a hydrocarbon solvent having a KB in the
range of about 50 to about 110 to form a solution
` thereof~ and sufficient solvent having a KB in the
range of about 30 to about ~0 to provide a concentration
of said resins in the range of about 30 to about 60
preferably about 35 to about ~5 weight percent based
on said resin-solvent mixture.
The invention includes a coating prepared by
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applying a mixture comprised of said fluid mixture to a
substrate and drying said applied mixture.
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In the practice of this invention, the optimum ~ -
amount of resin, amount of solvent and KB of the
solvent is to be determined for individual application,
depending somswhat on the resins and solvents used as
well as the desired application. It is to be understood
that various typical paint additives can be added to
the fluid mixture, or solution, such as various
pigments, thickeners, leveling agents and plasticizers. -
Representative of well known paint-type resins
are copolymers of a first monomer selected from at
least one of styrene and vinyl toluens with at least
one second monomer selected from 2-ethylhexyl acrylate,
ethyl acrylate, butyl acrylate, butyl methacrylate and ~
1,3-butadiene; as well as chorinated natural rubbsr. ~ ;
Preferred are styrene/2-ethylhexyl acrylate,
vinyl toluene/2-ethylhexyl acrylate, styrene/1,3-butadiene
and chlorinated natural rubber.
The KB value (Kauri-Butanol) of a hydrocarbon
solvent is a measure of its aromatic content. Thus~
a mineral spirits solvent can have a KB value of about
28 to about 70, where a B value of about 26 represents
a negligible aromatic content. For further example,
toluene has a KB value of about 102. The important -
part of this invention resides in that generally a
hydrocarbon solvent having a B value at least about
50 is added to the various of such paint-type resins in
order to provide a satisfactory fluid coating mixture
or solution. However, when the resin of this invention
is added to the paint-type resins, it may then be
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satisfactory to use a hydrocarbon solvent having a -
substantially lower KB value in the range of about 30
to about 40. Of course, solvents of higher KB values
can still be used~ if desired. Thus~ a solvent having
a substantially lower aromatic content may be used.
Lower aromaticity is particularly of interest where such
aromaticity is a potential toxic hazard. For the
purpose of determining the KB of a hydrocarbon solvent,
ASTM Method D-1133 is satisfactory.
In the practice, various hydrocarbon solvents can
be used. Generally a mineral spirits mixture is used,
comprised of liquid àliphatic and aromatic hydrocarbons~
having a KB in the range of about 28 to about ~0
to which is added, if desired~ an aromatic hydrocarbon
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such as toluene~ xylene~ ethylbenzene~ liquid ketones
and ethylene glycol ethers to achieve the desired KB -
~ value.
j The preparation of the resin of this invention
can conveniently be carried out in the presence of a
solvent or diluent because it is exothermic in nature.
.
The diluent can be added solvents or unreacted
hydrocarbons in the polymerization mixtura. The
polymerization can generally be carried out at a
temperature in the range of about 0C to about 800C,
and more preferably in the ranga of about 15C to about
~0C. A temperature of about 20C to about 30C is
particularly useful, accompanied by the slow addition
of the volatile reactants. Thus it is particularly
preferred that the monomers be added to the reaction
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somewhat simultaneously and slowly enough that only a
negligible amount of monomer is allowed to accumulate
in the reaction mixture. The polymerization pressure
can be atmospheric or above or below atmospheric
pressure. However, if the higher range of reaction
temperatures are desired, the polymerization may optional-
ly be conducted under a pressure greater than atmospheric
and/or a reduced rate of addition might alsobe provided.
The time of polymerization reaction can vary considerably,
such as from a few minutes to 1 or 2 hours or more.
The resin can then be conveniently recovered by steam
stripping to remove volatiles after deactivating the
catalyst with lime~ for example, and filtering, if
; desired, to remove deactivated catalyst residues.
.,
If a boron trifluoride etherate complex is to be
i used as a catalyst for preparation of the resin
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composition~ complexes of the type derived from boron
~` trifluoride and an ether having from 2 to about 12,
and preferably from 2 to about 6~ carbon atoms are
20 contemplated. The complex is generally represented by
the formula:
BF3-0R2
Representative of various ethers for preparation of the
- etherate are those having the structure ROR', where R
25 and R' are individually selected from saturated alkyl
radicals having from 1 to about 6~ and preferably from
1 to about 3, carbon atoms, such as methyl~ ethyl~
n-propyl, isopropyl~ n-butyl, isobutyl, sec-butyl,
t-butyl~ n-pentyl, isopentyl~ t-pentyl~ isohexyl~
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n-hexyl and t-hexyl radicals The ethyl radical is
usually preferred. The complex, when not available
commercially, can generally be prepared by reacting
boron trifluoride gas with an ether in about equimolar
quantities in an inert atmosphere at a temperature in
the range of about -250C to about 250C, and usually -
in the range of about lO~C to about 250C.
Representative of various ethers are dimethyl ether~
diethyl ether, methyl ethyl ether, di-n-propyl ether,
diisopropyl ether, di-n-butyl ether~ diisobutyl ether,
di-t-butyl ether~ di-n-amyl ether~ diisoamyl ether~
di-t-amyl ether, ethyl amyl ether, diisohexyl ether,
di-n-hexyl ether, di-t-hexyl ether and butyl (2-ethyl
hexyl) ether. Diethyl ether is usually preferred.
The following examples further illustrate the
invention and are not intended to be limiting. In
these examples, parts and percentages are by weight
unless otherwise indicated.
EXAMPLE I
Various resin compositions were prepared and
identified herein as Experiments A-0. For the
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preparation of these resin compositions, desired amounts
of 3-methyl-1-butene along with styrene andior ; -
a-methyl styrene were charged to a small storage
container and pressured to about 75 psi (pounds per
square inch gauge). To suitable reactor was charged
` 150 grams n-heptane and 2 grams catalyst which was
aluminum chloride, unless otherwise noted. While
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stirring the heptane slurry or solution~ the monomer
mixture was slowly charged to the reactor from the
storage container over a period of about 1.5 hours.
The mixture was stirred for an additional hour. The
reaction temperature was maintained throughout at
~;~ about 240C to about 260C. The catalyst was then
~` deactivated and decomposed with the addition of 10 grams
methanol to the mixture following which the resin
solution was filtered through a mixture of asbestos
and chemically inert silica. The resin product was
isolated by steam stripping the filtrate to remove
solvent and volatiles at a temperature of about 2350C.
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Two parts steam per 1 part resin was used. Several
of the prepared resins were mixed with pale crépe
natural rubber and tested for tac~ and shear values
for use as a pressure sensitive adhesive composition.
A mixture of 100 parts resin~ 100 parts rubber and
600 parts toluene was prepared, cast, dried as a film and
compared to a control using a resin having a softening
point of about 920C-960C derived by polymerizing a
: - :
monomer mixture with aluminum chloride comprised
- primarily of a mixture of piperylene and 2-methyl-2-butene
- in about a 1.2/1 mole ratio, except for Experiments E-I & 0.
In Experiment 0~ a block copolymer of styrene-
~ isoprene-styrene was used for the rubber. In E-I the control
resin had a softening point of about 112C~ and had a
minor amount of dicyclopentadiene added to its piperylene
and 2-methyl-2-butens monomsrs used in its preparation.
The Experimant parameters and results are in Table 1.
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h O C~J O ~) O - O ~1 ~) - O ~
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Y~ ~ O co 0-) o ~ u~
c) ~ ~co~C)~ C~J C'C~O 1
~O O 00 ~i r~ O I I I I I ~
.. ,I h
0~(~)0~1 r~ JOO~O h
``" ~~ ~ ~CO ,i- ~OCO CO CO C~ C' ~ 1~ C~ I ~
~ ~1 0 ~ co co ~rl
,, ~ I o~ CUCO~u~ccO~OO~ ¢ coco ~ ~ CJ`_~`D`D ~
',i H o ~ O
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. h ~hd ~I r~l~l~l~ (U~ ~1~ ~ c~ u~ a)
a) j~ h
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o c~lco cu~1 a) .
.' ~ ~ ~I I I I I I I I I ~o,~co~ ~o
E~ 0 ~ tq h~ ~ ah~
O ~d
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h0~0~ CU O ~ ~co ,1 1~ u~ O C)
. ~1~ o~ o~o c~ o~ a) ,~ u~ ~, a)
q ih ~C~ 0
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u~a~oo~ oc~)~l~o(~ h ~ h
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EXAMPLE II
,'~ Mixtures and solutions were prepared by mixing
12 parts of various resins prepared from several of the
Experiments in Example I with 23 parts paint-type
granular thermoplastic resins selected from styrene/
2-ethyl hexyl acrylate copolymers and vinyl toluene/
~ 2-ethylhsxyl acrylate copolymers along with 65 or 71
r',,' parts of a hydrocarbon solvent having a KB value of
about 28 or 35 comprised of 65 parts mineral spirits
`~ 10 having a KB of 28 and, optionally~ 6 parts toluene. The
mixtures are identified herein as Experiments P-W and
, .
~ were prepared by simply mixing the materials with slow
I,
agitation at about 250C for about 18-20 hours. The .
, results are more clearly shown in the following Table 2.
TABLE 2
Resin styrene/ toluene/ of SolutiOn
Exp from Exp acrylate acrylate sol- Appearance
resin resin vent _ _
P F 23 - 28 I
Q F 23 - 35 CL
R H 23 - 28
S H 23 - 35 CL
T I 23 - 28
U I 23 - 35 CL
V N - 23 28 CL
W N - 23 35 CL
- 1 CL indicates a cloudy solution
;, 2 I indicates that the resin was insoluble in the KB-
28 hydrocarbon solvent
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The tack and shear values are obtainable
according to Methods PSTC-6 and PSTC-7 of the Pressure
. Sensitive Tape Council. These methods can be found in
the publication "Test Methods for Pressure Sensltive
Tapes" developed by the Pressure Sensitive Tape Council~
1201 Waukegan Road, Glenview, Illinois. For example,
the tack can be measured by rolling a ball down an
incline and onto a horizontally positioned sample.
The distance in inches is measured which the ball
travelled across the sample. Thus, the larger the
value for the test, the smaller the amount of tack. ~;
The shear strength can be measured by applying a
500 gram weight to the sample and measuring the time
in minutes required for the tape to separate from the
;l 15 substrate.
While certain representative embodiments and
: details have been shown for the purpose of illustrating
the invention~ it will be apparent to those having
. :
~ skill in this art that various changes and modifications -~ ~
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may be made therein without departing from the spirit
or scope of the invention. -~
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