PolyOne Corporation (Avon Lake, OH) unveils heftier nanonylon composites prepared by chain extension reactive extrusion in U.S Patent 7,642,308. The process hurdles previous manufacturing limits in loading nanoclays into nanonylon.
According to Polyone inventors Joseph C. Golba, Roger W. Avakian and William F. Boye chain-extended nanonylon is made from the reaction of oligomeric nanonylon and chain-extending agents. Such chain-extended nanonylon contains concentrations of organoclay exceeding 10 weight percent. High concentrations of organoclay permit the chain-extended nanonylon to be used as either a concentrate or a compound that provides good barrier properties for thermoplastic articles made from the chain-extended nanonylon.
The mixture of organoclays and polyamides, commonly called nanonylons, is highly desired because the organoclays can contribute barrier properties to polyamides for food packaging and other situations where the contained product within packaging must not leach, escape, or decay.
Polyamides have been useful since the mid-20th Century. Organoclays, nanoclays intercalated with organic ions, such as quaternary ammonium, have become useful in the last decade.
Presently, nanonylons can be made using two conventional processes: (1) melt mixing of the organoclay into the previously polymerized nylon, in which the clay is added to a nylon melt by mechanical action; and (2) in-situ polymerization of the nylon in the presence of the organoclay, in which a batch of monomer such as caprolactam is brought to polymerization in a vessel also containing organoclays. Unfortunately, there are difficulties with both preparation methods for nanonylons.
Presently, nanonylons can be made using two conventional processes: (1) melt mixing of the organoclay into the previously polymerized nylon, in which the clay is added to a nylon melt by mechanical action; and (2) in-situ polymerization of the nylon in the presence of the organoclay, in which a batch of monomer such as caprolactam is brought to polymerization in a vessel also containing organoclays. Unfortunately, there are difficulties with both preparation methods for nanonylons.
The problem in the art is that nanonylon presently has a practical concentration limit of about 8%, while there are many who desire a concentration of organoclay in a concentrate that exceeds well beyond 8%.
PolyOne researchers solved this problem by using chain extension chemistry in a reactive extrusion process. More precisely, the process begins with a preliminary low molecular weight nanonylon to make a final high molecular weight nanonylon of 10% to 20% weight and possibly more.
PolyOne researchers solved this problem by using chain extension chemistry in a reactive extrusion process. More precisely, the process begins with a preliminary low molecular weight nanonylon to make a final high molecular weight nanonylon of 10% to 20% weight and possibly more.
PolyOne nanocomposites offer flame-retardancy properties because such nanocomposite formulations burn at a noticeably reduced burning rate and a hard char forms on the surface. They also exhibit minimum dripping and fire sparkling. Moreover, nanocomposites made from nylon as the thermoplastic matrix also have barrier properties useful in films, fibers, and other forms.
In exfoliated form, nanoclay platelets have a flexible sheet-type structure which is remarkable for its very small size, especially the thickness of the sheet. The length and breadth of the particles range from 1.5 microns down to a few tenths of a micrometer. However, the thickness is astoundingly small, measuring only about a nanometer (a billionth of a meter). These dimensions result in extremely high average aspect ratios (200-500). Moreover, the miniscule size and thickness mean that a single gram contains over a million individual particles.
Nanocomposites are the combination of the organoclay and the plastic matrix. In polymer compounding, a nanocomposite is a very convenient means of delivery of the nanoclay into the ultimate compound, provided that the plastic matrix is compatible with the principal polymer resin components of the compounds. In such manner, nanocomposites are available in concentrates, masterbatches, and compounds from Nanocor, Inc. of Arlington Heights, Ill. (www.nanocor.com) and PolyOne Corporation of Avon Lake, Ohio (www.polyone.com) in a variety of nanocomposites. Particularly preferred organoclays are I24P, I30P, and I44P from Nanocor, Inc.
With respect to oligomeric nanonylons, as explained above, Nanocor has commercially available an oligomeric nanonylon meeting the specifications of molecular weight, melt flow index, or viscosity.
Nanocomposites are the combination of the organoclay and the plastic matrix. In polymer compounding, a nanocomposite is a very convenient means of delivery of the nanoclay into the ultimate compound, provided that the plastic matrix is compatible with the principal polymer resin components of the compounds. In such manner, nanocomposites are available in concentrates, masterbatches, and compounds from Nanocor, Inc. of Arlington Heights, Ill. (www.nanocor.com) and PolyOne Corporation of Avon Lake, Ohio (www.polyone.com) in a variety of nanocomposites. Particularly preferred organoclays are I24P, I30P, and I44P from Nanocor, Inc.
With respect to oligomeric nanonylons, as explained above, Nanocor has commercially available an oligomeric nanonylon meeting the specifications of molecular weight, melt flow index, or viscosity.
Organoclay is obtained from nanoclay. Nanoclay is a clay from the smectite family. Smectites have a unique morphology, featuring one dimension in the nanometer range. Montmorillonite clay is the most common member of the smectite clay family. The montmorillonite clay particle is often called a platelet, meaning a sheet-like structure where the dimensions in two directions far exceed the particle's thickness.
Nanoclay becomes commercially significant if intercalated with an organic intercalant to become an organoclay. An intercalate is a clay-chemical complex wherein the clay gallery spacing has increased, due to the process of surface modification by an intercalant. Under the proper conditions of temperature and shear, an intercalate is capable of exfoliating in a resin matrix, such as a polyamide.
Nanoclay becomes commercially significant if intercalated with an organic intercalant to become an organoclay. An intercalate is a clay-chemical complex wherein the clay gallery spacing has increased, due to the process of surface modification by an intercalant. Under the proper conditions of temperature and shear, an intercalate is capable of exfoliating in a resin matrix, such as a polyamide.
An intercalant is an organic or semi-organic chemical capable of entering the montmorillonite clay gallery and bonding to the surface. Exfoliation describes a dispersion of an organoclay (surface treated nanoclay) in a plastic matrix. In this invention, oligomeric nanonylon has exfoliated organoclay at least to some extent and preferably in excess of that achievable using the conventional melt mixing, process for making polymerized nanonylons.
Polyone's nanotechnology patent is one of 102 nano patents granted in the first week of 2010, a portent of a record year to come.
