Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Reexamination Certificate
2000-09-27
2003-07-29
Ball, Michael W. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
C152S525000, C152S539000, C152S541000, C152S564000, C152S547000, C524S445000, C524S791000
Reexamination Certificate
active
06598645
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a tire with a rubber/cord laminate, sidewall insert and/or apex of a rubber composition which contains a reinforcement as oriented clay particles of which at least a portion thereof is exfoliated.
BACKGROUND OF THE INVENTION
The invention relates to use of oriented intercalated clay and exfoliated portions thereof in rubber compositions for certain components of a tire of a conventional toroidal shape having an inherent cavity wherein the cavity is designed to be closed by a rigid rim. Such tires may sometimes be referred to as having an open toriodal shape.
In particular, tire carcass plies, carcass belts, sidewall inserts and apex components are addressed for use of such oriented intercalated clay and exfoliated portions thereof
Such intercalated clay particles and exfoliated platelets are envisioned as being of relatively thin, elongated shapes.
In practice, intercalated clay and exfoliated portions thereof are contained substantially in a primary orientation in a direction of the elongation of the clay particles and platelets and a secondary orientation essentially at right angles to the elongation of the clay particles and platelets in the associated rubber compositions for such tire components.
Rubber compositions for such tire components are typically reinforced with particulate carbon black and/or synthetic amorphous silica to aid in achieving one or more desired physical properties.
Clay has also been suggested for use in various rubber compositions for various purposes.
U.S. Pat. No. 5,840,796, for example, describes a polymer nanocomposite comprised of a mica layered silicate and a fluoroelastomer, wherein the nanocomposite has an intercalated structure and/or exfoliated structure. A multilayered Montmorillonite clay is said to be an example of a suitable clay. Its examples utilized an organophyllic clay which contained a dimethyl dioctadecyl ammonium salt within its layered structure which had been prepared by mixing the clay with an aqueous solution of quaternary ammonium salt. The resultant organophyllic clay was milled together with a fluoroelastomer to form either (1) an intercalated clay in which the fluoroelastomer penetrated the treated clay layers and spread them apart or (2) a randomly distributed exfoliated clay in the, fluoroelastomer wherein the intercalated clay was submitted to additional mill mixing at an elevated temperature in which X-ray diffraction analysis was said to provide no evidence of layer spacing or crystal ordering, thereby providing evidence that exfoliation had taken place.
U.S. Pat. No. 4,431,755, for example, describes the blending of an adduct of a phyllosilicate mineral filler (e.g. a smectite clay composed of expandable three-layer structures such as, for example, a Montmorillonite clay) and a quaternary ammonium salt with at least one rubber and an organosilane. Various quaternary ammonium salts are disclosed.
Historically, an intercalated clay is conventionally prepared by
(A) obtaining a smectite clay, other than a koalin type clay, namely a clay such as for example a Montmorillonite clay, which is comprised of a plurality of stacked layers, or platelets and which is swellable upon dispersion in water,
(B) dispersing the clay in an aqueous solution of a surfactant (e.g. a quaternary ammonium salt) which causes the clay to swell so that the average spacing between the platelets expands from about 4 Angstroms to an average spacing in a range of about 10 to about 30 Angstroms, followed by
(C) drying the treated, or intercalated, clay.
The smectite clay (e.g. a Montmorillonite clay) for use in this invention contains sodium ions between its layered platelets and the larger surfactant molecules contained in the water solution in which the clay is immersed position themselves between the layered platelets by an ion exchange with the sodium ions to cause or otherwise enhance the separation of the platelets to make the platelets more amenable to subsequent exfoliation.
Upon blending of the intercalated clay with a thermoplastic or thermosetting polymer, a portion of the platelets exfoliate, or delaminate, from the clay composite into a multiplicity of planar platelet-like particles, and possibly fractions of the platelets, within the polymer. For example, see U.S. Pat. Nos. 4,739,007; 4,810,734; 5,385,776 and 5,578,672.
While, as discussed above, particulate carbon black and amorphous silica, and sometimes clay, have heretofore been used for reinforcing rubber compositions for various tire components, a tire with certain component(s) comprised of a rubber composition which contains an intercalated organoclay which is at least partially exfoliated in situ within the elastomer host is considered herein to be novel and inventive.
For the description of this invention, the term “elastomer exfoliated nanoclay composite” means, unless otherwise indicated herein, an elastomer composition which contains an intercalated clay, in which the intercalated clay is at least partially exfoliated in situ within the elastomer host, particularly a smectite clay as a sodium Montmorillonite clay, in which the particles are primarily organoclay platelets, and fragments of such platelets, wherein the platelets are somewhat circular and possibly elliptical in shape having an average, somewhat irregular, diameter, or width, in a range of, for example, about 10 to about 1000 nanometers.
For the description of this invention, the term “organoclay”, or “intercalated clay” means, unless otherwise indicated, a clay, particularly a smectite clay such as a Montmorillonite clay, which has been treated with a surfactant, particularly a quaternary ammonium salt in an aqueous solution, so that the surfactant molecules penetrate the region between the; individual clay platelets (the process of intercalation) to thereby modify the surface properties of the individual platelets to have a greater affinity for a diene-based elastomer.
For the description of this invention, the term “clay platelet” means, unless otherwise indicated, an individual, thin, relatively flat, layer contained in a plurality of stacked layers of the above referenced organoclay.
For the description of this invention, the term “exfoliation” means, unless otherwise indicated, the process in which at least a portion of platelets of an intercalated clay, particularly an intercalated smectite clay such as an intercalated Montmorillonite clay, are delaminated in situ within an elastomer host as the intercalated clay is mixed with an elastomer composition at an elevated temperature in a range of about 100° C. to about 175° C.
The smectite clay, preferably the Montmorillonite clay, for use in this invention, might be described as a naturally occurring clay of a structure which is composed of a plurality of stacked, thin and relatively flat, layers, where such individual layers may be of a structure viewed as being composed of very thin octahedral shaped alumina layer sandwiched between two very thin tetrahedrally shaped silica layers to form an aluminosilicate structure. Generally, for such aluminosilicate structure in the naturally occurring Montmorillonite clay, some of the aluminum cations (Al
+3
) are viewed as having been replaced by magnesium cations (Mg
+2
) which results in a net negative charge to the platelet layers of the clay structure. Such negative charge is viewed as being balanced in the naturally occurring clay with hydrated sodium, lithium, magnesium, calcium and/or potassium cations within the spacing (sometimes referred to as “galleries”) between the aforesaid aluminosilicate layers, or platelets. The average spacing, between the layers, or platelets, typically in a range of about 1 to about 5 Angstroms, is largely determined by the nature of such aforesaid cation residues contained with the spacing and by the degree of hydration and which may be measured by x-ray diffraction method.
In the description of this invention, the term “phr” is used to designate parts by weight of a material per 100 parts by weight of elastomer. The ter
Ball Michael W.
Fischer Justin
The Goodyear Tire & Rubber Company
Young, Jr. Henry C.
LandOfFree
Tire with at least one of rubber/cord laminate, sidewall... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tire with at least one of rubber/cord laminate, sidewall..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tire with at least one of rubber/cord laminate, sidewall... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3081831