Appeal No. 1997-1281
Application No. 08/317,830
be in a soluble form, or in a dispersed form such as in a
suspension . . . .
. . . .
By the wording “gelling agent”, it is meant a material
corresponding to the active ingredient in such a way that,
when mixed, at 50/50 w/w and 25 C, with (and optionallyo
ground with) an organic solvent wherein the active
ingredient is soluble, a gel is obtainable. According to
the present invention, a gel is essentially a material which
has a phase difference phi between the controlled shear
stress and the resulting shear strain such that tg(phi) is
less than or equal to 1.5, preferably less than or equal to
1.2. Tg(phi) is the tangent of the angle phi (or phase
difference). The measurement of phi is made by means of a
rheometer having a flat fixed plate and a rotating cone
above this plate such as the angle between them is less than
o o
10 , preferably 4 . The cone is caused to rotate by means
of a controlled speed motor; the rotation is a sinusoidal
one, i.e., the torque and the angular displacement change as
a sine function with time. This angular displacement
corresponds to the hereabove mentioned shear strain; the
torque of the controlled speed motor (which causes the
angular displacement corresponds to the hereabove mentioned
controlled shear stress.
Gelling agents which may be used in the invention are
tetramethyl decyne diol, ethoxylated dialkylphenol,
methylated clay, propylene carbonate, hydrogenated castor
oil, ethoxylated vegetable oil, diatomaceous earth, mixture
of dioctyl sodium sulfosuccinate and sodium benzoate, and
mixtures of hexanediol and hexynediol.
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