Low gel high cis polydiene

Details Low gel high cis polydiene Low gel high cis polydiene

2002-07-30

2003-07-22

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S340400, C526S171000, C526S226000, C526S237000, C526S208000, C526S209000, C526S210000

Reexamination Certificate

active

06596825

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to the field of diene polymerization. More particularly, this invention relates to the field of high-cis diene polymerization.
High cis polydienes have been prepared using an organonickel based catalyst system. The use of the organonickel based catalyst system can result in a rapid rate of polymerization, and the ability to control various polymer properties by varying the catalyst ratios. Moreover, organonickel based catalyst systems are generally hardy catalysts that may be able to maintain catalytic activity at a wide range of polymerization conditions. The use of organonickel catalysts to form high cis polydienes relies on the need for a fluorine-containing co-catalyst, such as HF or BF
3
. These co-catalysts, however, may be cumbersome to work with as they tend to generate strong acids when contacting water, leading to possible equipment corrosion and possible gel-formation of the polymer. Moreover, the reaction products of the co-catalysts include trialkylboranes when BF
3
is used, which can react with molecular oxygen to form peroxyboranes, compounds that may spontaneously homolytically break to form radicals, increasing the gel content upon aging of the finished products.
A variety of terminators, including water, alcohols, polyols, amines, and carboxylic acids have been used to terminate nickel-catalyzed diene polymerizations. Each of these methods, however, may suffer from several deficiencies. The use of protic terminating agents, i.e., water, alcohols, polyols, and carboxylic acids, may lead to substantial gel formation and corrosion of polymerization and finishing equipment. Additionally, many of the protic compounds will not react with trialkylboranes, which therefore remain available for later reaction with oxygen to generate radicals and gels in the polymerization mixture. Moreover, the protic solvents are capable of reacting with fluoride containing compounds in the polymerization mixture, generating strong acids, which may lead to corrosion problems in the finishing equipment and can also lead to cationic coupling (gelation) of the finished polymer.
Amine termination is another method that has been used in previous syntheses of high-cis polydienes, with the amine acting as a base to neutralize any acidic compounds in the polymerization mixture, reducing corrosion and cationic gellation. The bases thus formed also react with trialkylboranes to form Lewis acid-Lewis base complexes. These complexes reduce the reactivity of trialkylboranes toward oxygen, thus reducing the generation of radicals, which leads to gel formation. Unfortunately, the amines may also react with other catalyst components, making it necessary to add excess amounts of the amines to achieve complete termination, thereby increasing the cost of the overall process.
It would thus be desirable to develop a system for terminating the synthesis of high-cis polydienes that would be capable of overcoming the above-referenced problems.
SUMMARY OF THE INVENTION
The present invention is directed to a process for forming a high-cis polydiene. The process includes catalyzing a diene polymerization, and terminating the polymerization with an amine-water termination mixture.
In another embodiment, the present invention is directed to a polymer composition including a high-cis polydiene. The polydiene preferably has a cis content greater than about 85-90%, a microgel content less than about 20%, and a static gel content less than about 10%.
In a third embodiment, the present invention is directed to a process for producing high-cis polydienes. The process includes a continuous polymerization of a nickel catalyzed polydiene terminated by at least one amine-water terminator.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
A process for forming a high-cis polydiene composition is provided. The process includes catalyzing a polydiene polymerization, followed by termination with an amine-water termination mixture. The catalyzation of the polymerization reaction is preferably carried out with a catalyst system including at least one organonickel compound, at least one organoaluminum compound, and at least one fluorine-containing compound. When a mixture of slightly basic water and an amine are used to terminate the polymerization, the water reacts with the organoaluminum compounds and/or fluorine containing compounds to deactivate the catalyst components, leaving the amine available to react with the trialkylboranes.
The resultant high-cis polydiene composition preferably has a cis content greater than about 85%, more preferably greater than about 92%. The composition preferably has a microgel gel content less than about 20%, more preferably less than about 10%. The static gel content is preferably less than 20%, more preferably less than 10%.
The component of the catalyst of this invention which contains nickel may be any organonickel compound. It is preferred to employ a soluble compound of nickel. Thus, nickel salts of carboxylic acids and organic complex compounds of nickel are suitable. These soluble nickel compounds are normally compounds of nickel with a mono- or bi-dentate organic ligand containing up to 20 carbons. “Ligand” is defined as an ion or molecule bound to and considered bonded to a metal atom or ion. Mono-dentate means having one position through which covalent or coordinate bonds with the metal may be formed; bi-dentate means having two positions through which covalent or coordinate bonds with the metal may be formed. By the term “soluble” is meant soluble in inert solvents. Thus, any salt of an organic acid containing from about 1 to 20 carbon atoms may be employed. Representative of organonickel compounds are nickel benzoate, nickel acetate, nickel naphthenate, nickel octanoate, bis(alpha-furyl dioxime)nickel, nickel palmitate, nickel stearate, nickel acetylacetonate, nickel salicaldehyde, bis(salicylaldehyde) ethylene diimine nickel, bis(cyclopentadienyl) nickel, cyclopentadienylnickel nitrosyl and nickel tetracarbonyl. The preferred component containing nickel is a nickel salt of a carboxylic acid or an organic complex compound of nickel, such as a nickel boroacylate in which the acyl group is derived from the organic acids cited above.
By the term “organoaluminum compound” it is meant any organoaluminum compound responding to the formula:
AlR
1
(R
2
)(R
3
)
in which R
1
is selected from the group consisting of alkyl (including cycloalkyl), aryl alkaryl, arylalkyl, alkoxy, and hydrogen; R
2
and R
3
being selected from the group of alkyl (including cycloalkyl), aryl, alkaryl, and arylalkyl. Representative of the compounds corresponding to the formula set forth above are diethyl aluminum hydride, di-n-propyl aluminum hydride, di-n-butyl aluminum hydride, diisobutyl aluminum hydride, diphenyl aluminum hydride, di-p-tolyl aluminum hydride, dibenzyl aluminum hydride, phenylethyl aluminum hydride, phenyl-n-propyl aluminum hydride, p-tolyl ethyl aluminum hydride, p-tolyl n-propyl aluminum hydride, p-tolyl isopropyl aluminum hydride, benzyl ethyl aluminum hydride, benzyl n-propyl aluminum hydride, and benzyl isopropyl aluminum hydride and other organoaluminum hydrides. Also included are trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, triisopropyl aluminum, tri-n-butyl aluminum, triisobutyl aluminum, tripentyl aluminum, trihexyl aluminum, tricyclohexyl aluminum, trioctyl aluminum, triphenyl aluminum, tri-p-tolyl aluminum, tribenzyl aluminum, ethyl diphenyl aluminum, ethyl di-p-tolyl aluminum, ethyl dibenzyl aluminum, diethyl phenyl aluminum, diethyl p-tolyl aluminum, diethyl benzyl aluminum and other triorganoaluminum compounds. Also included are diethylaluminum ethoxide, diisobutylaluminum ethoxide and dipropylaluminum methoxide.
Another component of the catalyst system employed in this invention is a fluorine containing compound. The fluorine may be supplied by hydrogen fluoride, boron trifluoride, or by hydrogen fluoride and boron trifluoride being complexed with a member of the class consisting of monohydric alcohols, phenol

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