Fast cure film forming formulation

Details Fast cure film forming formulation Fast cure film forming formulation

2000-06-12

2003-01-28

Moore, Margaret G. (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

C528S035000, C523S118000, C524S731000, C524S588000, C524S268000, C106S287140, C106S287160, C106S015050, C424S065000, C424S059000, C424S280100, C514S772300

Reexamination Certificate

active

06512072

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to one-part formulations which rapidly cure on exposure to moisture and are useful for forming films in personal and healthcare applications. The formulations comprise an alkylene trialkoxy terminated siloxane; a catalyst; a diluent; and, optionally, an alkoxysilane and/or a filler.
Many formulations for forming films are known in the pharmaceutical art. These include, for example, ointments, salves, creams, lotions, gels, elastomers and the like. Some of these formulations use silicone-based materials as key components. Silicone based materials are desirable in these formulations since they are generally inert to the body.
One example of silicon-based materials in film forming formulations is provided in European publication number 465,744. This publication teaches the use of a multi-part formulation including an active agent, a Si-H containing polymer, a polymer having unsaturated groups bound to silicon, a catalyst and a hydrophilic component. This formulation is mixed and applied to the body where it cures and forms a controlled release gel.
The prior art methods such as those described in EP 465,744, however, have several disadvantages. For instance, in such methods the person utilizing the formulation must be skilled so as to ensure adequate mixing of the appropriate amounts of component materials in the formulation and then applying the correct amount of the mixed formulation to the desired site before it gels. Similarly, such a method can be an inconvenience and messy for the user. Finally, these methods involve ingredients that may not be desirable for healthcare applications.
WO 90/03809 teaches a coating material for forming bandages comprising a siloxane containing bandage material diluted in a volatile polydimethylsiloxane. The materials described in this reference, however, are different than those described and claimed herein.
Finally, patent such as U.S. Pat. Nos. 3,175,993, 4,772,675, 4,871,827, 4,888,380, 4,898,910, and 4,906,719 teach silicone sealants comprising an alkylene trialkoxysilyl terminated polysiloxane; an alkoxysilane; and a catalyst. Such references, however, do not teach the compositions or the uses described and claimed herein.
We have now discovered a formulation for making a film which can avoid many of the above prior art problems.
SUMMARY OF THE INVENTION
The present invention relates to a formulation comprising 5 to 79.99 wt. % of an alkylene trialkoxysilyl terminated polysiloxane; 0 to 5 wt. % of an alkoxysilane; 0.01 to 5 wt. % of a catalyst; 0 to 25 wt % of a filler; and 20 to 94.99 wt % of a volatile diluent.
The present invention also relates to a method for forming a film on a substrate comprising mixing the above components and applying the formulation onto the desired site, wherein said formulation cures in situ on the desired site to form the film.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to formulations which are useful for forming films on substrates, preferably biological substrates, where they can serve, for example, as barrier films, cosmetic films, drug delivery mechanisms and the like.
The first component in the formulations of the present invention comprises alkylene alkoxy terminated polysiloxanes. The polymers may be linear or branched and may be homopolymers, copolymers, or terpolymers. Moreover, the polymers may be a single species or a mixture of different polymers. Typically, it is preferred that these polymers have, on average, at least 1.2 alkylene trialkoxysilyl chain terminations per molecule.
The monomeric units of these polymers may include organic units, such as ethylene, butylene, or oxyalkylene units, but preferably a majority of the monomeric units are siloxy units such as those described by the formula R
9
s
SiO
(4−s)/2
, where each R
9
is independently selected from the group consisting of alkyl groups comprising 1 to about 6 carbon atoms, phenyl, and fluorinated alkyl groups, and s is 0, 1, 2 or 3. Examples of the alkyl groups described by R
9
include methyl, ethyl, propyl, butyl and hexyl. An example of the fluorinated alkyl groups described by R
9
includes 3,3,3-trifluoropropyl. The preferred polymers comprise polydiorganosiloxanes having repeating units described by the formula —(R
9
2
SiO
2
)
f
—, wherein each R
9
is as described above, preferably methyl, and f is a value such that the polymer has a viscosity within a range of about 0.5 to 3000 Pa·s at 25° C. and preferably within a range of about 5 to 150 Pa·s at 25° C.
These polymers preferably comprise, on average, at least 1.2 alkylene trialkoxysilyl chain terminations per molecule described by formula —ZSiR
1
x
(OR)
3−x
, wherein each R is independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and isobutyl, R
1
is selected from the group consisting of methyl and ethyl, and x is 0 or 1. In preferred embodiments, each R is independently selected from the group consisting of methyl and ethyl, and x is zero. Z in the above formula is independently selected from the group consisting of divalent hydrocarbon radicals free of aliphatic unsaturation comprising about 2 to 18 carbon atoms and a combination of divalent hydrocarbon radicals and siloxane segments described by the formula
wherein R
9
is as defined above, each G is a divalent hydrocarbon radical free of aliphatic unsaturation comprising about 2 to 18 carbon atoms, and c is a whole number from 1 to about 6. Examples of the divalent hydrocarbon radicals describing Z and G include alkylene radicals such as ethylene, propylene, butylene, pentylene, and hexylene; and arylene radicals including phenylene. Preferably, Z is alkylene with ethylene being particularly preferred.
These polymers typically have, on average, at least 1.2 alkylene trialkoxysilyl chain terminations per molecule, and preferably, have, on average, at least 1.5 alkylene trialkoxysilyl chain terminations per molecule. Since these polymers may have on average at least 1.2 alkylene trialkoxysilyl chain terminations per molecule, some polymers may contain other types of chain terminations. Preferably, this other type of chain termination comprises organosilyl chain terminations selected from the group consisting of CH
2
═CH—SiR
9
2
— and R
6
3
—Si—, where R
9
is as defined above and each R
6
is independently selected from the group consisting of R
9
and vinyl. Examples of organosilyl chain terminations include trimethylsilyl, triethylsilyl, vinyldimethylsilyl, and vinylmethylphenylsilyl.
Polysiloxanes useful herein include those described in U.S. Pat. Nos. 3,175,993, 4,772,675, 4,871,827, 4,888,380, 4,898,910, 4,906,719, and 4,962,174, which are hereby incorporated by reference, and can be described, for example, by the formula
wherein R, R
1
, R
9
, Z, x, and f are as described above. These polymers can be made as described in the above patents.
Other polymers useful in this invention are mixtures of the polysiloxanes described by this formula (I) with trialkyl terminated siloxanes and/or the polysiloxanes described by Kamis et al., U.S. Pat. No. 4,898,910, which is hereby incorporated by reference, and described, for example, by the formula
wherein R, R
1
, R
9
, Z, x and f are as defined above.
When the polymer comprises mixtures of polysiloxanes described by the above formulas, typically the polysiloxanes will be present in an amount such that 40 percent or less of the chain terminations will be organosilyl chain terminations, and preferably in an amount such that less than 25 percent of the chain terminations are organosilyl chain terminations.
The most preferred polymers useful in this invention are those polymers described by the polysiloxane formula (I).
The polymers useful herein can also include organic units. One type of organic polymer useful in the invention is the polyoxyalkylene, described by Okawa et al., U.S. Pat. No. 5,403,881, and hereby incorporated by reference to show polyoxyalkylene polymers comprising on average at least 1.2 alkylene trialkoxysi

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