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
2000-06-12
2002-09-03
Dawson, Robert (Department: 1712)
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...
C524S612000, C524S858000, C524S860000, C524S863000, C528S408000, C528S418000, C424S486000
Reexamination Certificate
active
06444745
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to silicone compositions, more particularly to compositions comprising a silicone polymer network.
BRIEF DESCRIPTION OF THE RELATED ART
The personal care industry thrives on being able to deliver multiple performance products based on mixture of several components, with each having performance characteristics important to or desirable in the final formulation. One desirable characteristic is the ability to provide a silky initial feel derived from low molecular weight silicones, such as for example, octamethylcyclotetrasilioxane or decamethylcyclopentasiloxane, in the formulation while maintaining a high, but shear-thinnable viscosity. While these low molecular weight silicones provide the desired feel characteristics, they are also low viscosity, highly flowable liquids. Thus they are not easily held in a formulation, preferring rather to separate and flow out of a given container or flow uncontrollably across the skin when used in a specific application. Further, it desirable to achieve an initial silky feel while providing a smooth, low-residue feel upon dry-down. Polymeric silicone gels prepared in volatile silicone been found to deliver desirable initial feel of volatile, low viscosity silicones to formulations while at the same time provide high viscosity and a smooth silky feel on dry-down, see for example, U.S. Pat. Nos.5,760,116, 5,493,041 and 4,987,169.
Such polymeric silicone gels have typically been made by the hydrosilylation reaction, which requires the use of both SiH functional groups and terminal olefinic groups to form crosslinked siloxane polymers. Thus only siloxane structures that can incorporate silylhydride groups and optionally, vinyl functional siloxane groups, can be utilized in making these materials. Further this method of generating crosslinked siloxane polymers limits the range of desirable organofunctional groups that may be incorporated into the polymeric structure to create additional performance advantages in complex formulations. Thus attempts to include organofunctional groups into the crosslinked siloxane polymer include unsaturated organic groups compatible with the hydrosilylaton reaction.
SUMMARY OF THE INVENTION
In a first aspect, the present invention relates to a silicone composition, comprising:
(a) a polyethersiloxane block copolymer network, comprising:
one or more polyether blocks, each comprising two or more structural units of the formula (I):
—R
1
O— (I)
wherein each R
1
is independently a divalent hydrocarbon radical or R
2
, wherein R
2
is a trivalent hydrocarbon radical, and
one or more polysiloxane blocks, each comprising two or more structural units of the formula (II):
—R
3
2
SiO
2/2
— (II)
wherein each R
3
is independently a monovalent hydrocarbon radical or R
2
, and
wherein at least one polyether block of the copolymer network is bonded to at least one polysiloxane block of the copolymer network by a link according to formula (III):
wherein the R
2
O unit of the structure of formula (III) is a unit of the at least one polyether block and the R
2
R
3
SiO
2/2
unit of the structure of formula (III) is a unit of the at least one polysiloxane unit, and
(b) a fluid within the network.
In a second aspect, the present invention is directed to a method for making a silicone composition, comprising polymerizing an epoxy functional organosiloxane compound in the presence of an acid catalyst and a fluid.
In a third aspect, the present invention is directed to a personal care composition comprising the polyethersiloxane block copolymer network of the present invention.
In a fourth aspect, the present invention is directed to a method for making a personal care composition, comprising combining one or more personal care ingredients with a polyethersiloxane block copolymer network of the present invention.
In a fifth aspect, the present invention is directed to a method for reversibly imparting characteristics of a solid to a fluid, comprising introducing the fluid into a polyethersiloxane block copolymer network of the present invention.
The copolymer network of the present invention exhibits, in its various embodiments, a high affinity for a wide variety of fluids, including emollient fluids. The silicone composition of the present invention exhibits good stability, that is a high resistance to separation of the fluid from the silicone composition. Personal care compositions containing the copolymer network and an emollient fluid, whether the copolymer network and fluid are added separately to the personal care composition or added to the personal care composition in the form of the silicone composition of the present invention, exhibit improved sensory feel, leave a smooth silky feeling in the skin upon dry down and exhibit good stability, that is, a high resistance to separation of the emollient fluid from the personal composition.
DETAILED DESCRIPTION OF THE INVENTION
As used here in, the terminology “network” means a three dimensionally extending structure comprising interconnected polyethersiloxane block copolymer chains. Preferably, fluid is contained within interstices of the network. The term “interstices” is used herein in reference to a network to denote sp aces within the network, that is, spaces between the polyethersiloxane block copolymer chains of the network.
In a preferred embodiment, the polyethersiloxane block copolymer network is a crosslinked network that is insoluble in the fluid component of the silicone composition of the present invention, but that is capable of being swollen by the fluid. The amount of crosslinking present in the crosslinked network may be characterized with respect to the degree of swelling exhibited by the network in the fluid. In a preferred embodiment, the crosslinked structure of the network is effective to allow the network to be swollen by a molecular weight silicone fluid, such as, for example, decamethylcyclopentasiloxane, from its original volume to a swollen volume that is a factor of from 1.01 to 5000, more preferably from 2 to 1000, and even more preferably from 5 to 500, times its original volume. The original volume of the network can be determined, for example, by extracting or evaporating all of the fluid component for the silicone composition of the present invention to leave the original volume, that is, the volume of the polyethersiloxane block copolymer network in the absence of the fluid.
As used herein the terminology “hydrocarbon radical” includes acyclic hydrocarbon radicals, alicyclic hydrocarbon radicals and aromatic hydrocarbon radicals.
As used herein in reference to a hydrocarbon radical, the term “monovalent” means that the radical is capable of forming one covalent bond per radical, the term “divalent” means that the radical is capable of forming two covalent bonds per radical and the term “trivalent” means that the radical is capable of forming three covalent bonds per radical. Generally, a monovalent radical can be represented as having been derived from a saturated hydrocarbon compound by conceptual removal of one hydrogen atom from the compound, a divalent radical can be represented as having been derived from a saturated hydrocarbon compound by conceptual removal of two hydrogen atoms from the compound and a trivalent radical can be represented as having been derived from a saturated hydrocarbon compound by conceptual removal of three hydrogen atoms from the compound. For example, an ethyl radical, that is, a
CH
2
CH
3
radical, is an a monovalent radical, a dimethylene radical, that is, a
(CH
2
)
2
— radical, is an a divalent radical and an ethanetriyl radical, that is, an
radical, is a trivalent radical, each of which can be represented as having been derived by conceptual removal of one or more hydrogen atoms from the saturated hydrocarbon ethane.
As used herein, the terminology “acyclic hydrocarbon radical” means a straight chain or branched hydrocarbon radical, preferably containing from 1 to 60 carbon atoms per radical, which may be saturated or unsaturated and which
Chaiyawat Atchara
Kilgour John A.
O'Brien Michael J.
Dawson Robert
Peng Kuo-Liang
Wheelock Kenneth S.
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