Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2002-03-19
2003-06-17
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S135000, C526S147000, C526S237000, C526S348700, C525S267000, C525S270000, C525S288000, C525S313000, C525S918000
Reexamination Certificate
active
06579959
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a production process of isobutylene polymers.
PRIOR ART
The polymerization of isobutylene is known to proceed in a manner of cationic polymerization. As a technology for conducting such a cationic polymerization, there is known the inifer process which comprises using a compound having halogens bound to tertiary carbons (e.g. 1,4-bis(&agr;-chloroisopropyl)benzene; hereinafter abbreviated as p-DCC) as a polymerization initiator in the presence of a Lewis acid catalyst (U.S. Pat. No. 4,276,394). This technology provides for free molecular weight design through modulation of the molar ratio between an initiator and a monomer and thus allows product designs according to the application use.
The problem with the inifer process is that the initiator efficiency is decreased by side reactions such as indanylation of the initiator. To cope with this problem, methods employing electron donor or the like have been proposed (Japanese Kokai Publication Hei-02-245004, Japanese Kokai Publication Hei-01-318014, Japanese Kokai Publication Hei-03-174403, Japanese Kokai Publication Hei-08-301955).
Meanwhile, for efficient production of isobutylene polymers on a commercial scale, the technology employing a reaction solvent having a dielectric constant within a certain range and the technology which comprises purifying the used solvent and reusing it are known (Japanese Kokai Publication Hei-08-53514, Japanese Kokai Publication Hei-09-071611, Japanese Kokai Publication Hei-11-255819).
Isobutylene polymers can be converted to cured products having excellent characteristics by introducing functional groups such as vinyl groups into molecular termini and curing the polymers by means of vulcanization and crosslinking. Particularly the telechelic polymers obtainable by using a bifunctional initiator such as said p-DCC are capable of forming dense networks on curing so that cured products can be provided with high strength. However, when the functional group introduction rate is low, the number of molecules having a functional group only at one terminus is increased so that many intermolecular discontinuities are produced on curing to markedly lower the strength of the cured product.
For the introduction of functional groups into the termini of isobutylene polymers, the technology using allylsilane, 1,9-decadiene or the like is known. However, according to the prior art, the reaction for introducing functional groups into the polymer termini is inhibited by indanylation of the molecular terminus, chain transfer reaction, etc., which take place during the polymerization reaction, so that it has been difficult to obtain an isobutylene polymer with a sufficiently high functional group introduction rate.
SUMMARY OF THE INVENTION
In view of the above state of the art, the present invention has for its object to produce an isobutylene polymer having excellent performance characteristics with good efficiency on a commercial scale by suppressing side reactions at the polymer growth termini during synthesis of an isobutylene polymer.
More particularly, the object of the present invention is to produce an isobutylene polymer having a carbon-carbon unsaturated bond at a terminus thereof and adapted to express high strength on curing with good efficiency on a commercial scale through inhibition of side reactions at polymer growth termini during synthesis of the isobutylene polymer and consequent improvement in the introduction rate of the carbon-carbon unsaturated bond into the polymer terminus.
The present invention, therefore, is directed to a production process of an isobutylene polymer
which comprises carrying out a cationic polymerization of a monomer component containing isobutylene in the presence of a polymerization initiator, a catalyst, an ether compound, and an electron donor.
In a preferred embodiment, the present invention is directed to a production process of an isobutylene polymer having a carbon-carbon unsaturated bond at a terminus thereof
which comprises carrying out a cationic polymerization of a monomer component containing isobutylene in the presence of a polymerization initiator, a catalyst, an ether compound, and an electron donor, and
adding a compound having the carbon-carbon unsaturated bond for introducing the carbon-carbon unsaturated bond into the polymer terminus.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is now described in detail.
In the production process according to the present invention, an isobutylene polymer is produced by carrying out a cationic polymerization of a monomer component containing isobutylene in the presence of a polymerization initiator, a catalyst, an ether compound, and an electron donor.
In the present invention, the polymerization initiator is not particularly restricted provided that it is capable of initiating a polymerization in the presence of a catalyst, but from reactivity points of view, a compound having a halogen atom bound to a tertiary carbon is preferred. The more preferred among them is a compound in which at least one of the substituents bound to the tertiary carbon is an aromatic ring. Specifically, 1,4-bis(&agr;-chloroisopropyl)benzene (hereinafter abbreviated as p-DCC) and tricumyl chloride, etc. can be mentioned.
The amount of use of the polymerization initiator may be properly selected according to the molecular weight of the polymer to be produced. Specifically, the monomer component containing isobutylene can be used in an amount of 500 to 500,000 g relative to each mole of the polymerization initiator. To produce a polymer having a molecular weight of about 10,000, for instance, it is reasonable to use 10,000 g of the monomer component containing isobutylene for each mole of the polymerization initiator.
In the present invention, various catalysts can be used according to the combination with the polymerization initiator used but, from reactivity points of view, Lewis acid catalysts are preferred. Specifically, TiCl
4
, AlCl
3
, BCl
3
, ZnCl
2
, SnCl
4
, ethylaluminum chloride (C
2
H
5
AlCl
2
), SnBr
4
, etc. can be mentioned. The catalyst can be used in an amount of 0.1 to 1,000 molar equivalents relative to each mole of the polymerization initiator. It can also be used in an amount of 0.0001 to 10 molar equivalents relative to each mole of the monomer component containing isobutylene.
As the ether compound in the present invention, there can be mentioned, for example, cyclic ethers such as tetrahydrofuran, trimethylene oxide, pentamethylene oxide, 1,4-dioxane, etc. and chain ethers such as diethyl ether, ethyl n-propyl ether, n-propyl ether, and so on. The ether compound not containing a cationically polymerizable carbon-carbon unsaturated bond is preferred. To maximize the effect of the invention, the ether compound is preferably an ether compound containing 2 to 20 carbon atoms, more preferably a cyclic ether containing 2 to 10 carbon atoms, still more preferably a cyclic ether containing 2 to 10 carbon atoms one oxygen atom.
The amount of use of said ether compound is preferably 0.01 to 5 moles, more preferably 0.035 to 2.3 moles, relative to each mole of the polymerization initiator, because if the amount is too small, the effect of the invention will not be expressed and if it is too large, the polymerization reaction itself will be interfered. Also, the preferred amount of use is 0.007 to 0.32 weight % relative the total amount of the reaction mixture.
Since the ether compound is added for the purpose of inhibiting side reactions at polymer growth termini, it is preferably added at a start of polymerization.
In the present invention, the monomer component containing isobutylene may be a monomer component composed exclusively of isobutylene or a monomer component containing other cationically polymerizable monomers in addition to isobutylene. In cases where the monomer component contains other monomer or monomers, isobutylene preferably accounts for not less than 50 weight %, more preferably not less than 70 weight %, still more preferably not less than 90
Furukawa Naoki
Hagimori Shigeru
Hayashi Keizo
Yoshimi Chiho
Foley & Lardner
Kaneka Corporation
Teskin Fred
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