Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
1997-05-06
2003-07-01
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S462000, C526S314000, C526S346000
Reexamination Certificate
active
06586082
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for the polymerization of mixtures impregnated into or supported on paper, that comprise one or more ring-strained olefinic monomers, the polymerization of each monomer being mediated by a transition metal-containing species.
2. Description of Related Art
Polymer films coated on substrates and as stand-alone constructions find a multitude of uses. Likewise, methods of producing polymer films are myriad, depending upon a variety of factors such as, for example, the polymer, the substrate, and the intended end use.
Polymeric coatings are most often produced by distribution of a thin layer of an already-formed polymer onto a substrate from a solvent, an emulsion or a suspension. Alternatively, the polymer may be extruded or hot-melt coated directly onto a substrate so that no solvent or suspending medium is involved.
Free-standing polymer films are prepared by a number of methods, including extrusion, blow molding, and casting, the latter method including the variant of coating onto a release liner and removing the release liner at some later time. In most cases, these methods use already-polymerized compositions.
Coating of monomeric compositions followed by on-substrate polymerization to obtain free-standing films or coated substrates is a less-common procedure. Typically, such procedures involve free-radically polymerizable monomers such as (meth)acrylates and a suitable free-radical initiator; require application of energy to initiate polymerization; normally include a means for controlling the polymerization exotherm associated with highly-reactive monomers; and require the provision of an atmosphere that does not inhibit free-radical polymerizations (i.e., is essentially free of oxygen).
Non-free radical polymerizations of ethylenically-unsaturated monomers are well known. These polymerizations typically use catalysts instead of initiators to effect polymerization. Examples of such polymerizations include Ziegler-Natta polymerizations (ZN), ring-opening metathesis polymerizations (ROMP), group transfer polymerizations (GTP), and cationic and anionic polymerizations. Catalysts for these polymerizations can be more susceptible to deactivation by adventitious oxygen and water, requiring that such deactivating materials be rigorously excluded from all reagents as well as the reaction vessel.
Specifically, ZN (co)polymerizations of monoolefins, particularly &agr;-olefins, are well known in the art. Typically, extreme care is taken to exclude both oxygen and water from these polymerizations.
Likewise, ROMP (co)polymers are known in the art. Examples of ROMP processes in both inert conditions and in the presence of water, oxygen, or both are known.
The properties of various papers can be improved when polymeric materials are used as saturants or coatings. When the polymer saturates at least a portion of the paper, improved adhesion between the polymer and the paper is obtained. Such a configuration is most often obtained by coating a solution of the polymer onto the paper, allowing the solution to penetrate at least a portion of the paper, and subsequently evaporating the solvent. Solvent processing has fallen into disfavor because of cost and environmental consequences, however.
Water suspensions or emulsions of polymers can also be used to produce polymer-saturated paper in those limited situations where an aqueous dispersion or emulsion of the polymer is feasible. Even when such a dispersion or emulsion is possible, the coated paper can absorb larger quantities of water. This can lead to configurations quite different from those achieved by solvent coating.
Neat polymerizations within the paper itself (e.g., saturating the paper with monomer and polymerizing the monomer) are normally unavailable because most polymerization systems are sensitive to one or more of oxygen, water, acids, bases, certain functional groups (e.g., those containing an active hydrogen-containing group), etc., any or all of which can be present in paper.
SUMMARY OF THE INVENTION
Briefly, the present invention provides a process for making a poly(olefin) film in an in-line procedure comprising the steps:
a) providing a substrate coated with a layer of a mixture comprising
(1) at least one olefinic monomer, having 5 to 30 carbon atoms, having one of the formulae
wherein
(A) R
1
is hydrogen and R
2
, R
3
, and R
4
are independently hydrogen or a C
1
-C
27
aryl, aralkyl, aliphatic, or cycloaliphatic group with the provisos that at least one of R
2
, R
3
, and R
4
must be hydrogen and that R
2
, R
3
, and R
4
cannot all be hydrogen, or
(B) R
1
and at least one of R
2
, R
3
, and R
4
, as well as the carbon atoms to which they are attached, form at least one strained aliphatic ring, or
(C) R
5
is (CR
2
R
3
)
m
where m is 1 or 2 and R
2
and R
3
are independently hydrogen or a C
1
-C
27
aryl, aralkyl, aliphatic, or cycloaliphatic group with the provisos that R
2
and R
3
cannot be hydrogen when m is 1 and that R
2
and R
3
cannot both be hydrogen when m is 2; and
(2) an effective amount of a catalyst system comprising a transition metal-containing species; and
b) allowing the monomer(s) to polymerize to a poly(olefin) film. This process is performed in an environment that is inert toward the above-described catalyst system. By “in-line” is meant a sequential, substantially continuous process whereby monomer-catalyst mixture is coated directly onto a substrate, preferably a moving substrate.
The process described above involves olefinic monomers whose polymerizations are mediated by a transition metal-containing species. The term “mediated by” means that the transition metal-containing species plays an integral role in the polymerization of the olefinic monomer(s). Common olefinic monomers that polymerize in this manner include &agr;-olefins and ring-strained non-conjugated cyclic olefins. The term “&agr;-olefin” means a compound of the formula H
2
C═CHCR
2
R
3
R
4
wherein R
2
, R
3
, and R
4
are independently hydrogen or a C
1
-C
27
aryl, aralkyl, aliphatic, or cycloaliphatic group which can optionally contain one or more heteroatoms.
In another aspect, the present invention provides a composite article comprising paper, at least a portion of which is at least partially saturated by (1) a composition comprising a ring-strained cyclic olefinic monomer and a transition metal-containing compound or (2) the polymerization product of such a composition.
In yet another aspect, the present invention provides a method of making the above described composite article comprising the steps of at least partially saturating at least a portion of a paper with the above-described composition and allowing the monomer to polymerize.
Ring-strained non-conjugated cyclic olefin monomers undergo a ring opening metathesis polymerization (ROMP) that can be summarized as follows:
wherein
is a ring-strained non-conjugated cyclic olefin monomer and
illustrates the structure of the resultant ring-opened polymerized unit with n being from 5 to 100,000.
Common catalyst systems in which a transition metal-containing species plays an integral role in the polymerization of one or more olefinic monomers include ZN catalyst systems, metallocene systems, as well as inorganic compounds and organometallic complexes that comprise a metal from Periodic Group 4 to Group 10. Those skilled in the art will readily recognize which catalyst system(s) is/are useful with a given olefin or olefin combination.
The in-line process described above has several advantages over traditional means for making poly(olefin) composite structures. One is increased ease in handling and processing. Traditional methods call for the preparation and collection of poly(olefin) in a batch or continuous process and then solvent or hot melt coating the poly(olefin) onto a substrate with subsequent processing and curing. In the in-line process of the present invention, the need to solvent or hot melt coat the poly(olefin) in a separate step has been elimina
3M Innovative Properties Company
Dahl Philip Y.
Ferguson L.
Kelly Cynthia H.
McGeehan Lisa M.
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