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
1999-08-17
2002-03-12
Sellers, Robert E. L. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S322000, C525S324000, C525S333800, C525S903000
Reexamination Certificate
active
06355735
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to semi-interpenetrating polymer networks comprising polyepoxy and polyolefin chains formed during the catalyzed reaction of solutions containing epoxy monomers and alpha-olefin monomers. Reaction of the monomers, promoted by a metal catalyst, proceeds under ambient conditions.
BACKGROUND OF THE INVENTION
Polymerization of &agr;-olefins using either heterogeneous Ziegler-Natta systems or homogenous metallocene complexes is well known. Both of these catalytic systems are based on early metals such as Ti or Zr. The oxophilic nature of these metals results in catalysts that are extremely sensitive to both environmental conditions and functionalized monomers. As such, polymerizations utilizing these early metal catalyst systems must be done under rigorously inert conditions and in the absence of any monomers containing functionality such as ketones, esters, or epoxy groups.
Recently, a new class of &agr;-olefin polymerization catalysts based on late metals such as Ni and Pd has been developed. The relatively robust nature of these metals endows these complexes with functional group tolerance that is unprecedented for an olefin polymerization catalyst. Using these catalysts, polymerization of &agr;-olefins in air and even in water is possible for the first time.
PCT published application WO 96/23010 discusses the use of Ni and Pd catalysts for polymerization of olefin monomers. The published application further discusses blend combinations with other polymers including epoxy polymers. However, the reference does not address the formation of semi-interpenetrating networks comprising epoxy polymers and olefin polymers, which form in-situ from solutions containing epoxy and olefin monomers.
U.S. Pat. No. 5,393,867 discloses the use of Pd(0) compounds and nuclcophilic initiators to prepare linear polyethers from 3,4 epoxy-1-butene under inert conditions. PCT application WO 98/37110 discloses homopolymers and polyolefin copolymers containing pendant epoxy groups. Neither of these patents discloses simultaneous homopolymerization of epoxy and olefin monomers.
It has now been discovered that a semi-interpenetrating network may be formed from reactive co-monomer mixtures comprising an epoxy monomer, an olefin monomer, and an effective amount of an organometallic nickel or palladium complex.
SUMMARY OF THE INVENTION
The current invention provides a semi-interpenetrating network polymer formed from reactive co-monomer mixtures comprising at least one epoxy monomer and at least one olefin monomer. An effective amount of an organometallic nickel or palladium complex, uniformly distributed in the co-monomer mixture, promotes formation of a polyolefin polymer. The organometallic complex of nickel or palladium includes a bidentate ligand, sufficiently bulky to favor the formation of high molecular weight polyolefin polymers. Using selected materials, the polyolefin polymer formation occurs under ambient conditions and may be accompanied by polymerization of epoxy monomer to produce the interpenetrating network polymer of the invention. This is viewed as simultaneous polymerization of epoxy and olefin monomers with formation of a semi-interpenetrating network. Alternatively, the olefin monomer, in the co-monomer mixture, may first be converted to an olefin polymer, using an organometallic complex of nickel or palladium, as previously described, with subsequent formation of the epoxy polymer through thermally activated epoxy initiators such as Ar
3
S
+
SbF
6
−
and (mesitylene)
2
Fe
+
SbF
6
−
.
Semi-interpenetrating network polymer systems comprising polyolefin and epoxy polymers combine the advantages of low-cost, hydrophobic and chemically resistant polyolefins with improved adhesion and durability of polyepoxides. Additional benefits arise from the convenience of use of compositions of the invention. For example, the reactive mixture of monomers has a low viscosity that facilitates penetration and application of material into small spaces, followed by curing-in-place under ambient conditions. As evidence of further flexibility, the epoxy cure may be delayed until polymerization of olefin monomers occurs. This allows use of a multiple cure system which promotes cure of the olefin monomers under ambient conditions and subsequently polymerizes the epoxy monomers with traditional thermally activated catalysts, or through thennal activation of the palladium complex.
Whether formed by simultaneous or sequential polymerization processes, semi-interpenetrating networks, disclosed herein, exhibit a range of characteristics, from soft, predominantly polyolefin compositions to harder, predominantly polyepoxy compositions. Typical uses for these compositions include gels, sealants, coatings, adhesives, gaskets, vibration dampening materials, and reactive diluents/solvents.
As used herein, these terms have the following meanings.
1. The term “semi-interpenetrating network polymer” means a polymer system containing intimately mixed thermoplastic and thermoset polymeric species in which each polymer is independent of but thoroughly interspersed with the other. Polymer formation may occur simultaneously or sequentially.
2. The term “admixture of monomers” means a fluid system containing monomeric species one of which may act as a solvent or dispersion medium for another monomer.
3. The term “internal epoxy monomer” means a reactive monomer containing at least one &agr;, &bgr; di-substituted non-terminal epoxy group.
4. The term “functional group tolerance” refers to the relatively low susceptibility of certain catalysts to be de-activated/inhibited by oxygen containing species, such as alcohols, ketones and the like.
5. The term “metal catalyst” refers to donor ligand containing, organometallic compounds of nickel and palladium having ligands of sufficient steric bulk to facilitate formation of polyolefins and a metal to R bond, wherein R is H, a hydrocarbyl radical, or a hydrocarbyl radical substituted by at least one alkyl, haloalkyl or aryl group, each group having up to 20 carbon atoms.
6. The term “alpha olefin” (or &agr;-olefin) and “alpha olefin hydrocarbon” are equivalent and mean a hydrocarbon containing a double bond in the 1-position, more particularly, ethylene or a 1-olefin containing three or more carbon atoms which may be cyclic or acyclic and preferably is an acyclic alpha-olefin.
All parts, percents and ratios herein are “by weight” unless expressly otherwise noted.
DETAILED DESCRIPTION OF THE INVENTION
The present invention describes a semi-interpenetrating network formed from an alpha-olefin hydrocarbon monomer, an epoxy monomer, and an effective amount of an organometallic catalyst comprising a Group VIII metal (CAS version of the Periodic Table), preferably Ni or Pd, and a polydentate ligand having steric bulk sufficient to permit formation of high polymer, and at least one of water and air (oxygen).
Polyolefins are used in a wide range of product applications. The breadth of potential applications for a polyolefin depends largely upon characteristics attainable through catalyst and/or monomer selection, including e.g., polymer regiochemistry and stereochemistry, molecular weight and molecular weight distribution, and chain branching. Extension of the versatility of olefin-containing materials results from incorporation of alpha functionalized monomers with olefin polymers in the form of copolymers and block copolymers. In these cases, both olefinic and functionalized monomers are incorporated into a common polymer chain.
Another way to include contributions from different chemical species is the formation of stable, non-separating blends of homopolymers or the production of one homopolymer species in the presence of another homopolymer to yield some form of interpenetrating network polymer. Preferably, for the present invention, the interpenetrating network is a semi-interpenetrating network formed from a co-monomer mixture, in which epoxy monomers homopolymerize simultaneously with olefin monomer homopolymerization. Anoth
Meyer Stephen D.
Wagner Mark I.
3M Innovative Properties Company
Dahl Philip Y.
Fonseca Darla P.
Sellers Robert E. L.
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