Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-11-30
2003-11-11
Zitomer, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S177000, C526S178000, C526S182000, C526S233000, C526S237000, C526S252000
Reexamination Certificate
active
06646075
ABSTRACT:
TECHNICAL FIELD
This invention relates to high molecular weight perfluorocyclobutane polymers and methods of polymerizing trifluorovinyl monomers to form such polymers in the presence of a catalyst or initiator.
BACKGROUND
A number of references disclose the thermal polymerization of trifluorovinyl-containing monomers, typically bis-trifluorovinyl monomers, to form perfluorocyclobutylene polymers, including U.S. Pat. Nos. 5,037,917, 5,159,038, 5,364,917, 5,066,746, 5,159,037, 5,023,380, 5,162,468, 5,037,919, 5,198,513, 5,021,602, 5,210,265, 5,037,918, 5,159,036, 5,246,782, 5,409,777, and 5,364,547, the teachings of which are incorporated herein by reference. Disclosed reaction conditions involve heating monomers to temperatures of typically about 150-210° C. for several hours. The resulting polymers “preferably have a molecular weight of from about 300 to about 30,000.” (U.S. Pat. No. 5,037,917 at col. 2, ln. 38).
U.S. Pat. Nos. 5,037,918 and 5,159,036 disclose the use of “crosslinking initiating means” on perfluorocyclobutane polymers, subsequent to a completed step of polymerization, to obtain crosslinked polymer gels. Such crosslinking is further described in co-owned U.S. Pat. No. 5,246,782, at col. 3 ln 48—col. 4, ln. 28 and at col. 11, lns. 11-31.
DISCLOSURE OF INVENTION
Briefly, the present invention provides high molecular weight perfluorocyclobutane polymers and methods of polymerizing trifluorovinyl containing monomers to form high molecular weight perfluorocyclobutane polymers in the presence of a catalyst or initiator.
In this document:
“C(number)” refers to a chemical moiety containing the indicated number of carbon atoms; and
“substituted” when used without reference to a particular substituent, means substituted by conventional substituents which do not interfere with the desired product or process, e.g., substituents can be alkyl, alkoxy, aryl, phenyl, halo (F, Cl, Br, I), cyano, nitro, etc.
DETAILED DESCRIPTION
The present invention provides high molecular weight perfluorocyclobutane polymers and methods of polymerizing trifluorovinyl containing monomers to form high molecular weight perfluorocyclobutane polymers in the presence of a catalyst or initiator.
Monomers useful in the method of the present invention contain two or more polymerizable trifluorovinyl groups. Monomers are preferably of the formula CF
2
═CF—X—R
1
—X—CF═CF
2
, where each —X— is independently selected from the group consisting of: —O—, —S—, —SO—, —SO
2
—, —CO—, —NH—, and —NR
2
—, wherein R
2
is C1-C25 substituted unsubstituted, saturated or unsaturated alkyl or aryl and R
1
is a substituted or unsubstituted C1-C30 aryl or alkyl moiety which may additionally comprise heteroatoms. Preferably X is oxygen. Preferably, R
1
is a C1-C16 aryl or alkyl moiety. Suitable monomers disclosed in the background references cited above may be used. Mixtures of monomers may additionally be used. PCFB oligomers or lower molecular weight PFCB polymers can also be used in place of or along with monomers to produce higher molecular weight polymers according to the present invention. Monomers containing three or more polymerizable trifluorovinyl groups may be added to create branch points.
We have found that the use of initiators or catalysts can result in a higher molecular weight polymer. Preferred initiators or catalysts include salts comprising fluorine-containing anions, more preferably anions selected from F
−
, BF
4
−
, PF
6
−
and SbF
6
−
, more preferably F
−
or PF
6
−
and most preferably PF
6
−
. Useful initiators or catalysts include alkylammonium, alkylsulfonium or alkylphosphonium salts and salts of organometalic complex cations. Preferred initiators or catalysts include alkylammonium salts. Most-preferred initiators or catalysts include (alkyl)
4
N
+
PF
6
−
, wherein the alkyl group is a C1-C8 alkyl group, including (CH
3
)
4
N
+
PF
6
−
and (n-C
3
H
7
)
4
N
+
PF
6
−
(available from Aldrich Chemical Co., Milwaukee, Wis.). Without wishing to be bound by theory, it is believed that preferred initiators or catalysts include fluoride generators.
Polymerization involves joining trifluorovinyl groups of different monomer molecules to form linking perfluorocyclobutylene (PFCB) groups. Any suitable reaction conditions and equipment may be used, including batch or continuous processes. Suitable conditions and equipment disclosed in the background references cited above may be used. In addition, the present method has the advantage of allowing the use of lower reaction temperatures.
In the present method, the initiator or catalyst is preferably added to the reaction mixture (comprising monomers, oligomers, or combinations thereof) prior to heating the reaction mixture to reaction temperature or after the reaction mixture reaches reaction temperature, during polymerization. The initiator or catalyst is preferably added to the reaction mixture before it reaches reaction temperature or more preferably before heating. Reaction temperature may be between 100 and 300° C. but is more typically between 120 and 250° C. and preferably 150-200° C. Reaction time is typically 1-24 hours. Solvent may be added. Addition of solvent may improve the activity of the initiator or catalyst by solvating initiator or catalyst.
Crosslinkers or branching agents containing three or more reactive trifluorovinyl groups may be added. Exemplary agents include tris(trifluorovinyloxyaryl)alkanes such as 1,1,1-tris(4′-trifluorovinyloxyphenyl)ethane and others cited in U.S. Pat. Nos. 5,037,918 and 5,159,036, incorporated herein by reference. Preferably the polymer according to the present invention is not crosslinked after polymerization and no crosslinking step is carried out after polymerization.
The resulting polymers have typical weight average molecular weights of two to eight or more times higher than the same polymerization performed without added initiator or catalyst. For comparison, polymers made under typical conditions of about 200° C. for about 72 hours demonstrate typical weight average molecular weights of about 60,000. Preferably polymers of the present invention (made without added crosslinking or branching agents) have a weight average molecular weight (Mw) of 100,000 or greater, more preferably 130,000 or greater, more preferably 160,000 or greater, and most preferably 190,000 or greater.
This invention is useful in the manufacture of high molecular weight PFCB polymers.
Objects and advantages of this invention are further illustrated by the following examples. The particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention.
REFERENCES:
patent: 3418302 (1968-12-01), Darby
patent: 4337211 (1982-06-01), Ezzell et al.
patent: 4358412 (1982-11-01), Ezzell et al.
patent: 4812352 (1989-03-01), Debe
patent: 5021602 (1991-06-01), Clement et al.
patent: 5023380 (1991-06-01), Babb et al.
patent: 5037917 (1991-08-01), Babb et al.
patent: 5037918 (1991-08-01), Babb
patent: 5037919 (1991-08-01), Clement et al.
patent: 5039561 (1991-08-01), Debe
patent: 5066746 (1991-11-01), Clement et al.
patent: 5159036 (1992-10-01), Babb
patent: 5159037 (1992-10-01), Clement et al.
patent: 5159038 (1992-10-01), Babb et al.
patent: 5162468 (1992-11-01), Babb et al.
patent: 5198513 (1993-03-01), Clement et al.
patent: 5210265 (1993-05-01), Clement et al.
patent: 5246782 (1993-09-01), Kennedy et al.
patent: 5264508 (1993-11-01), Ishibe et al.
patent: 5338430 (1994-08-01), Parsonage et al.
patent: 5364547 (1994-11-01), Babb et al.
patent: 5364917 (1994-11-01), Babb et al.
patent: 5393852 (1995-02-01), Ishibe et al.
patent: 5409777 (1995-04-01), Kennedy et al.
patent: 5426164 (1995-06-01), Babb et al.
patent: 5449825 (1995-09-01), Ishibe et al.
patent: 5620807 (1997-04-01), Mussell et al.
patent: 5879828 (1999-03-01), Debe et al.
patent: 5910378 (1999-06-01), Debe et al.
patent: WO 97/25369 (1997-07-01), None
patent: WO 99/05126 (1999-02-01), None
patent:
Mao Shane S.
Siedle Allen Raymond
3M Innovative Properties Company
Dahl Philip Y.
Zitomer Fred
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