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
1998-01-15
2002-08-13
Mulcahy, Peter D. (Department: 1713)
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...
C524S047000, C524S420000, C524S430000, C524S431000, C524S432000, C524S445000, C524S449000, C524S451000, C424S059000
Reexamination Certificate
active
06433068
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to heterophase, thermally reversible hydrocarbon gels which are suitable for use as suspending and dispersing agents. The suspending and dispersing agents of the invention employ a hydrocarbon gel which contains block copolymers, the copolymers being preferably derived from styrene-rubber block units.
BACKGROUND OF THE INVENTION
Various types of gel products are known in the art. U.S. Pat. No. 5,221,534 of Applicants' Assignee, for example, discloses gel compositions which contain one or more health and beauty aid components wherein the gel comprises a hydrocarbon oil and a blend of at least two different polymers selected from the group consisting of diblock and triblock polymers. The hydrocarbon oils disclosed in this patent are indicated as having characteristics which would cause them to remain liquid at temperatures ranging from 0° C. up to about 200° C. for almost all applications.
U.S. Pat. No. 4,164,563 to Chang discloses compositions for topical application to the skin which are indicated as being greasy occlusive viscous bases comprising a mixture of from 40-90% of a greasy viscous base and from 10-60% of a solid non-irritating ointment forming powder. Other ingredients such as colorants can also be included in the composition. The composition can also contain a thickening agent which can be an unvulcanized elastomeric block polymer.
U.S. Pat. No. 5,221,534 discloses gels comprising a mineral oil and blends of copolymers and including health and beauty aid components.
PCT Patent Application No. W088/00603 of Francis et al. describes block copolymer compositions which are described as gels or gelloid liquid extended polymer compositions which comprise an intimate mixture of a block copolymer containing relatively hard blocks and relatively elastomeric blocks. A suitable block copolymer is Kraton 1651, a triblock copolymer. The copolymer additionally contains at least 500 parts by weight of extender liquid per 100 parts of the block copolymer, the liquid being present to extend and soften the elastomeric blocks of the block copolymer.
European Patent Application No. 224389 of Gamarra et al. discloses styrene-diene block copolymer compositions and in particular a mixture of triblock copolymers and a hydrocarbon oil. These compositions are useful as sealing materials.
U.S. Pat. No. 4,369,284 describes a transparent gel prepared from triblock copolymers and oils useful as molded products. The triblock copolymers used therein receive specific styrene end blocks to ethylene and butylene center blocks. The end block to center block ratio is given as being between 31:69 and 40:60.
SUMMARY OF THE INVENTION
It is accordingly one object of this invention to provide heterophase, thermally reversible hydrocarbon gel compositions that have advantageous properties when used as a vehicle to suspend or disperse solids and liquids therein.
A further object of the invention is to provide hydrocarbon gel compositions formed with certain diblock, triblock, radial block and/or multiblock copolymers which have advantageous properties when used as a suspension agent for various solids and non-hydrocarbon liquids.
Other objects and advantages of the present invention will become apparent as the description of the invention proceeds.
In satisfaction of the foregoing objects and advantages, the present invention provides in one embodiment, a thickened and gelled hydrocarbon having solids and/or liquids suspended therein. The thickened and gelled hydrocarbon composition comprises:
(a) from about 20 to about 95 weight percent of a hydrocarbon, and optionally one or more hydrocarbon-soluble substances;
(b) from about 0.1 to about 50 weight percent of a diblock, triblock, radial block and/or multiblock copolymers, or blends thereof comprising from about 0 to about 100 weight percent of one or more diblock copolymers and from about 100 to about 0 weight percent of one or more triblock, radial block and/or multiblock copolymer; and
(c) from about 0.01 to about 75 weight percent of one or more solids and/or non-hydrocarbon liquids suspended therein.
The hydrocarbon used in the composition preferably has a vapor pressure up to about 600 mm Hg at 20° C.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to new thickened and gelled hydrocarbon-containing, block copolymer gels having solids and/or non-hydrocarbon liquids suspended or dispersed therein. The gel compositions of the invention comprise a hydrocarbon, optionally one or more hydrocarbon-soluble substances, one or more diblock copolymers, one or more triblock, radial block and/or multiblock copolymers, or a mixture thereof, and one or more solids or liquids suspended or dispersed therein.
The invention may accordingly be described as a gelled and thickened hydrocarbon comprising:
(a) from about 20 to about 95 weight percent of a hydrocarbon, optionally containing one or more hydrocarbon-soluble substances, or mixtures thereof;
(b) from about 0.1 to about 50 weight percent of a diblock, triblock, radial block and/or multiblock copolymers, or a blend thereof comprising from about 0 to about 100 weight percent of one or more diblock copolymer and from about 100 to about 0 weight percent of one or more triblock, radial block and/or multiblock copolymer; and
(c) from about 0.01 to about 75 weight percent of one or more solids and/or non-hydrocarbon liquids suspended or dispersed therein.
In a preferred composition of the invention, the copolymers or blends thereof comprise from about 0.1 to about 25 weight percent, preferably from about 0.1 to about 10 weight percent, of one or more triblock, radial block and/or multiblock copolymers and from about 70 to about 99.9 weight percent of one or more diblock copolymers.
When formed into gels, the copolymers or blends thereof comprise from about 0.1 to about 50 weight percent of the total weight of the composition. Preferably the total weight of polymer contained in the hydrocarbon oil will range from about 0.5 to about 30 weight percent, more preferably 1 to 20 weight percent, though this preference may change depending upon the particulars of the application desired, as will be apparent to one skilled in the art.
The gel compositions of the invention are generally non-aqueous. However, water may be added to certain compositions to form emulsions, for example, for use as a spray, cream or lotion.
Each of the diblock, triblock, radial block and/or multiblock copolymers used in the invention contains at least two thermodynamically incompatible segments. By the expression thermodynamically incompatible with respect to the polymers, it is meant that the polymer contains at least two incompatible segments, for example, at least one hard and one soft segment. In general, in a triblock polymer, the ratio of segments is one hard, one soft, one hard or an A-B-A copolymer. Diblock copolymers, on the other hand, are of the A-B type and sequential with respect to hard and soft segments. The multiblock and radial block copolymers can contain any combination of hard and soft segments, provided that there are both hard and soft characteristics. These copolymers are fully disclosed in U.S. Pat. No. 5,221,534, the disclosure of which is incorporated herein by reference.
Commercially available thermoplastic rubber type polymers which are especially useful in forming the compositions of the present invention are sold under the trademark Kraton® by Shell Chemical Company. The Kraton® rubber polymers are described as elastomers which have an unusual combination of high strength and low viscosity and a unique molecular structure of linear diblock, triblock and radial copolymers. Each molecule of the Kraton® rubber is said to consist of block segments of styrene monomer units and rubber monomer and/or comonomer units. Each block segment may consist of 100 or more monomer or comonomer units. The most common structure for the triblock copolymer is the above-mentioned linear ABA block type; styrene-butadiene-styrene (SBS) and styrene-isoprene-styrene (SIS), whi
Lu Lin
Morrison David S.
Ray Robert H.
Dula Arthur M.
Mulcahy Peter D.
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