Interpenetrating polymer networks patents

Interpenetrating polymer networks are defined in their broadest sense as an intimate mixture of two or more pol)Mners in network form [1,2]. Ideally, they can be synthesized by either swelling the first crosslinked polymer with the second monomer and crosslinker, followed by in-situ polymerization of the second component (sequential IPN s) or by reacting a pair of monomers and crosslinkers at the same time through different, non-interfering reaction mechanisms, simultaneous interpenetrating networks, SIN s. In fact, many variations of these ideas exist in both the scientific and the patent literature. In any case, at least one of the two components must have a network structure, as an IPN prerequisite. ... 

Turner J, Cheng Y-L (2001) Process for preparing interpenetrating polymer networks of controlled morphology. US Patent 6331578... 

Robert C, Bunel C, VaironJ-P (1995) Hydrophilic, transparent material with high oxygen permeability containing interpenetrating polymer networks for use in soft contact lenses. EP Patent 643 083... 

Crosby JM, Hutchins MK (1986) Fiber-reinforced thermoplastics containing silicone interpenetrating polymer networks. EP Patent 194350... 

Fujiki M, Furuta D, Naito M (2004) Manufacture of semi-IPN (interpenetrating polymer network) composite and the composite made of crosslinkable siloxane and radically polymerized polymer. JP Patent 2 004 263 062... 

The field of IPNs has a special problem relating to nomenclature. Since no standard nomenclature yet exists, and many works on IPNs do not contain the phrase interpenetrating polymer networks, it is difficult to identify quickly many IPN-related papers and patents. While this work is also incomplete in this respect, many new workers in the field are included. 

It is especially interesting to note that this patent, issued in 1955, was written before the term interpenetrating polymer network was coined (see Section 1.3). 

Danger, R. S. Elisseeff, J. H. Anseth, K. Sims, D. Semi-interpenetrating or interpenetrating polymer networks for drug delivery and tissue engineering. U.S. Patent 6224893, 2001 Chem. Abstr. 2001,134, 331625. 

In 1986, there were approximately 150IPN patents and 15 products identified as interpenetrating polymer networks. This compares to 1979, when there were approximately 75 patents and only three IPN products. While much of the patent and product literature has been recently reviewed, a brief update is warrented. 

FalcettaJJ, Friends GD, Niu GCC (1975) Molding from an interpenetrating network polymer. DE Patent 2 518 904... 

He X et al. (1995) Preparation of interpenetrating acrylic polymer-siloxane networks. US Patent 5424375... 

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