Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-05-22
2002-01-29
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
active
06342563
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not applicable.
BACKGROUND OF THE INVENTION
The present invention relates to the synthesis of adhesive compositions and more particularly to the synthesis of telechelic polymers of selected narrow molecular weight distribution for use in adhesives, coatings, and like applications. For present purposes, “telechelic” polymers are polymers that contain reactive end groups. “Polytelechelic” (co)polymers, then, contain two or more reactive pendant groups which often are end groups. For present purposes, “polymers” include homopolymers and copolymers (unless the specific context indicates otherwise), which may be block, random, gradient, star, graft (or “comb”), hyperbranched, or dendritic. The “(co)” parenthetical prefix in conventional terminology is an alternative, viz., “(co)polymer” means a copolymer or polymer, which includes a homopolymer.
Conventional free radical polymerization leads to synthesis of polymers with a fairly broad molecular weight distribution, Mw/Mn (weight molecular weight
umber molecular weight), or polydispersity, in the range of 2.5 to 3. Number molecular weight (Mn) relies on the number of molecules in the polymer, while weight molecular weight relies on the weight of the individual molecules. See, e.g., Solomon,
The Chemistry of Organic Film Formers
, pp. 25, et seq., Robert E. Krieger Publishing Co., Inc., Huntington, N.Y. (1977), the disclosure of which is expressly incorporated herein by reference. The basic theory that applies to the control of the growth of the polymer chains and Mw/Mn ratios in a free-radical initiated polymerization reaction is well documented in the literature by P. J. Flory,
JACS
, Vol. 96, page 2718 (1952).
State of the art practice used to prepare polymers with a narrow molecular weight distribution in the range of, say, 1.05 to 1.4, rely on living polymerization techniques, such as anionic and cationic polymerization. These ionic living polymerization techniques have several limitations including, for example, restrictions on the types of monomers that can be polymerized, low temperature and purity process requirements, the inability to synthesize high molecular weight polymers, etc. Because of these constraints, ionic polymerization processes are limited to the synthesis of polymers based on styrene, isoprene, isobutylene, and like monomers to produce synthetic elastomers and thermoplastic rubbers.
Telechelic polymers prepared from either living polymers or condensation polymers, such as polyesters, for example, tend to be of low molecular weight, typically on the order of several hundreds to several thousands (e.g., 500-10,000). This low molecular weight limitation makes conventional telechelic polymers impractical for a variety of applications including, for example, adhesives.
Recent work on atom transfer radical polymerization (ATRP) has shown the potential of using this pseudo-living polymerization technique to prepare high molecular weight polymers based on acrylic monomers, vinyl monomers, and other common monomers which polymers exhibit a fairly narrow molecular weight distribution, say, in the range of 1.05 to 1.5. Molecular weights up to 10
5
have been claimed to have been synthesized by ATRP techniques. See Patten, et al., “Radical Polymerization Yielding Polymers with Mw/Mn ~1.05 by Homogeneous Atom Transfer Radical Polymerization”,
Polymer Preprints
, pp. 575-576, No. 37 (March 1996); Wang, et al., “Controlled/”Living” Radical Polymerization. Halogen Atom Transfer Radical Polymerization Promoted by a Cu(I)/Cu(II) Redox Process”,
Macromolecules
1995, 28, 7901-7910 (Oct. 15, 1995); and PCT/US96/03302, International Publication No. WO 96/30421, published Oct. 3, 1996, the disclosures of which are expressly incorporated herein by reference.
BRIEF SUMMARY OF THE INVENTION
Disclosed is a method for preparing adhesive polymers which commences with the formation of a poly-telechelic polymer of narrow molecular weight distribution (Mw/Mn), say from about 1-3, by polymerizing one or more radically-polymerizable monomers in the presence of a transition metal, a ligand, and an initiator, under atom or group transfer radical polymerization conditions. In this polymerization step, OH groups are contained on one or more of said initiator, an initiating monomer, a polymerizable monomer, a terminating monomer, or combinations thereof, that is, (i) one or more of the initiator, an initiating monomer, a hydroxy monomer, or combinations thereof; on (ii) one or more of a hydroxy monomer, a terminating monomer, or combinations thereof; or on (iii) one or more of the initiator, an initiating monomer, or terminating monomer, or combinations thereof. The poly-telechelic polymer, then, is chain extended with a chain extension agent, such as a polyisocyanate, to form the adhesive polymer.
Regression analysis reveals that the adhesive properties of the chain extended polymers is dependent primarily upon the Mn of the telechelic polymer and the hydroxyl monomer and/or initiator used in forming the telechelic polymers. Data demonstrating such adhesive properties is set forth herein.
DETAILED DESCRIPTION OF THE INVENTION
In the polytelechelic polymer formation step of the process, atom or group transfer radical polymerization conditions are used. Such conditions can be found described in, for example, the art cited above and incorporated herein be reference. Included in this step are a transition metal, a ligand, and an initiator.
Preferred transition metals are Cu
+1
, and Co
+1
, although many other transition metals have been disclosed in the art and may find advantage in the present invention. Cu
+1
halides, for example, arc described with respect to catalyzed reactions of organic polyhalides with vinyl unsaturated compounds are well known by Bellus, Pure and
Applied Chemistry
, Vol. 57, No. 12, pp. 1827-1838 (1985). Complexing of transition metal halides with organic ligands as part of the initiator system is described in U.S. Pat. No. 4,446,246, for example. Cu
+1
halide-bipyridine complexes with active organic halide compounds are described to react with vinyl unsaturated compounds by Udding, et al.,
J. Organic Chemistry
, Vol. 59, pp. 1993-2003 (1994). Organocobalt porphyrin complexes (alkyl cobaloximes) are described in the polymerization of acrylates by Wayland, et al.,
JACS
, Vol. 116, pp. 7943-7966 (1994). Cu
+1
carboxylate complexes formed from thiophene carboxylates are described by Weij, et al.,
Polymer Preprints
, Vol. 38, No. 1, pp. 685-686 (April 1997). The disclosures of the foregoing references are expressly incorporated herein by reference.
The generation of radical intermediates by reacting some transition metal species, including salts and/or complexes of Cu, Ru, Fe, Va, Nb, and others, with alkyl halides, R-X, is well documented (see Bellus,
Pure & Appl. Chem
., 1985, 57, 1827; Nagashima, et al.,
J. Org. Chem
., 1993, 58, 464; Seijas, et al.,
Tetrahedron
, 1992, 48(9), 1637; Nagashima, et al.,
J. Org. Chem
., 1992, 57, 1682; Hayes,
J. Am. Chem. Soc
., 1988, 110, 5533; Hirao, et al.,
Syn. Lett
., 1990, 217; Hirao, et al.,
J. Synth. Org. Chem
., (Japan), 1994, 52(3), 197; Iqbal, et al.,
Chem. Rev
., 94, 519 (1994); Kochi,
Organometallic Mechanisms and Catalysis
, Academic Press, New York, 1978. Moreover, it also is known that R-X/transition metal species-based redox initiators, such as Mo(CO)
6
/CHCl
3
, Cr(CO)
6
/CCL
4
, Co
4
(CO)
12
/CCl
4
, and Ni[P(OPh))
3
]
4
/CCl
4
, promote radical polymerization (see Bamford,
Comprehensive Polymer Science
, Allen, et al., editors, Pergamon: Oxford, 1991, vol. 3, p. 123). The participation of free radicals in these redox initiator-promoted polymerizations was supported by end-group analysis and direct observation of radicals by ESR spectroscopy (see Bamford,
Proc. Roy. Soc
., 1972, A, 326, 431). The disclosures of the foregoing references are expressly incorporated herein by reference.
Ligands useful in the polytelechelic polymer formation step of the process also have be
McGinniss Vincent D.
Vijayendran Bhima R.
Yamamoto Michiharu
Lipman Bernard
Mueller and Smith LPA
Nitto Denko Corporation
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