Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-06-16
2002-12-31
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S186000, C501S148000
Reexamination Certificate
active
06500892
ABSTRACT:
FIELD OF THE INVENTION
The invention is in the chemical arts. It relates to clays, the particles of which are water swellable, the intercalation and exfoliation of such particles, and synthetic resin compositions comprising the exfoliated particles.
BACKGROUND OF THE INVENTION
Clays are silicate minerals, the particles of which have equivalent spherical diameters of less than 2 &mgr;m. For many years clay has been used in synthetic resin compositions (in more common terminology, polymer compositions) to enhance or impart toughness, heat deflection temperature, oxygen barrier and optical properties of or to the compositions. Such use has led to the development of nanocomposites. These are compositions that comprise normally solid, polymer material and, highly dispersed in the matrices of the polymer material, diminuted clay particles. These particles are in the form of platelets, the thicknesses of which are measured in nanometers. Diminuted clay particles of such fineness are obtained from water swellable clays which include crystalline clays that belong to the class of layer silicates, also referred to as phyllosilicates. The phyllosilicates include the smectite (or montmorillonite), mica and vermiculite groups of clays. The particles of these minerals are formed by layers or laminates of crystalline silicate platelets. The layers are strongly held together by electrochemical attraction. When these minerals are exposed to water, it diffuses into the particles between the layers, and causes the layers to move apart, (as evidenced by expansion or swelling of the particles), whereby the layers are not as strongly held together. When these minerals are subjected to drying conditions, water between the layers escapes and evaporates, and the particles shrink.
One method of obtaining the diminuted clay particles is based on this water swelling effect. In the method, an aqueous solution or dispersion of an organoelectrolyte, and water swellable clay such as a phyllosilicate are admixed. The solution or dispersion migrates into the phyllosilicate particles between the layers, and forces the layers apart. Water is evaporated from the particles. However, because of the electrolytic portion of the organoelectrolyte, it remains between the layers of silicate platelets, and because of the bulk of the organo portion, the layers remain spaced apart. The resulting swollen particles are described as intercalated, and the organoelectrolyte is referred as the intercalant. In such condition substantially less shear is needed to separate the platelet layers from each other. Sufficient shear is applied to the intercalated particles to overcome the forces holding the layers together, and delaminate them, whereby diminuted clay particles are obtained. Such particles are referred to as exfoliated clay particles. In most instances, the shear involved in the melt blending of the polymer material and the intercalated, phyllosilicate particles is sufficient to exfoliate the particles.
There are numerous patent and other publications relating to nanocomposites, how to make them, and the preparation of intercalated clays for use in making nanocomposites. Representative of such publications is the U.S. Pat. No. 5,552,469 to Beall et al. This patent discloses nanocomposites in which examples of the matrix polymers (from which the normally solid polymer material of the patent is selected) comprise such homopolymers as polyethylene and polypropylene, and such copolymers as propylene copolymers and ethylene copolymers with ethylene-propylene copolymers and ethylene-propylene-diene terpolymers being mentioned. The clay disclosed in the patent is a phyllosilicate such as a smectite clay and the intercalant disclosed in the patent includes an oligomer with carbonyl, hydroxyl, carboxyl, amine and/or ether functionalities.
SUMMARY OF THE INVENTION
The invention comprises a clay material intercalated with intercalant material comprising an organic compound having a nonpolar portion bonded to a polar portion. The nonpolar portion for the most part is a saturated oligomer of isoprene. It resembles or mimics the basic structure or parts of the basic structure of the hydrocarbon backbone of homopolymers and copolymers of propylene and of ethylene. This portion, therefore, tends to be compatible with such polymers, especially copolymers of both propylene and ethylene. The polar portion tends to have an affinity for the silicate platelets of the clay material. Consequently, the organic compound enhances the compatibility with such polymers of the exfoliated, clay material that results when melt blending, with sufficient shear to exfoliate the intercalated clay material, the polymers and the clay material intercalated with the intercalant material.
The invention further comprises a nanocomposite containing a C
2
-C
3
&agr;-olefin polymer material and dispersed in the matrix thereof an exfoliated, clay material that before exfoliation had been intercalated with intercalant material comprising the foregoing organic compound. The C
2
-C
3
&agr;-olefin polymer material is material selected from the group consisting of homopolymers of propylene and ethylene, &agr;-olefin copolymers in which polymerized propylene units predominate, &agr;-olefin copolymers in which polymerized ethylene units predominate, copolymers of propylene and ethylene or propylene and butene-1 in which the polymerized propylene and ethylene units or propylene and butene-1 are substantially equal in number and together predominate, the latter copolymers of propylene and ethylene or propylene and butene-1 being with or without other different polymerized C
4
-C
10
&agr;-olefin units, and mixtures thereof
DETAILED DESCRIPTION OF THE INVENTION
In the more specific aspects of the invention, the essential component of the intercalant material, that is, the above mentioned organic compound, has the general formula:
in which R is H or a normal or branched C
1
-C
4
alkyl, n is 2-17, and R′ is a radical with at least one polar group or moiety. In most embodiments of the compound, R′ is X, COOR″, CN, NR″′
2
or NR″′
2
·HX with R″ being R″′, NR″′
2
, NR″′
2
·HX or a monovalent metal cation, R″′ being H or a normal or branched C
1
-C
4
alkyl and X being I, Br, Cl or F. In each of NR″′
2
or NR″′
2
·HX, each R″′ can be the same or different. However, in preferred embodiments, R″ is NHR″′·HX. Examples of a normal or branched C
1
-C
4
alkyl are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl and tert-butyl. Examples of a monovalent metal cation include cations of an alkali metal in Group 1A of the Periodic Table of the Elements (e.g., Li, Na, and K).
One way to make the generic compound comprises condensing isoprene anionically with a C
1
-C
4
alkyllithium to form an oligomer of 3-18 isoprenoid units with C
1
-C
4
alkyl being a substituent of a methyl carbon of the end isopropyl group of the unsaturated hydrocarbon backbone, and with lithium being an ionically attached to the methylene carbon at the other end of the backbone. The oligomer is reacted with either ethylene oxide or carbon dioxide, and then with water, to replace the lithium ion with a hydroxyethyl group or a carboxyl group. In either case the resulting compound is hydrogenated over a Pt or Rh catalyst to saturate the backbone. The hydrogenation reaction is typically done at 35 to 40° C. in hexane for 8-12 hours.
The saturated, hydroxyethyl substituted compound is halogenated with a hydrogen halide (hydrogen bromide or iodide being preferred because of the ease of reaction) to form a compound of the formula in which R′ is X. This halide compound is reacted with (1) an alkali metal cyanide to obtain a compound in which R′ is CN, and (2) ammonia (or ammonium hydroxide), or a mono- or di(C
1
-C
4
alkyl)amine to obtain a compound in which R′ is NR″′
2
. The latter compound is reacted with a hydrogen halide to obtain a comp
Bishop C. Edward
Niyogi Suhas G.
Basell Poliolefine Italia S.p.A.
Cain Edward J.
Lee Kat Wyrozebski
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