Drug – bio-affecting and body treating compositions – Effervescent or pressurized fluid containing – Organic pressurized fluid
Reexamination Certificate
2002-02-21
2003-08-05
Dodson, Shelley A. (Department: 1616)
Drug, bio-affecting and body treating compositions
Effervescent or pressurized fluid containing
Organic pressurized fluid
C424S070110, C424S078020, C424SDIG001, C424SDIG002, C514S957000
Reexamination Certificate
active
06602489
ABSTRACT:
BACKGROUND OF THE INVENTION
The object of the invention is a compact hair spray product comprising a hair spray concentrate, a pressure-tight and diffusion-proof container and a fine-spray pump with pilot pressure buildup.
Hair spray products are usually sold either as aerosol sprays packed in aerosol containers and containing propellants or as propellant-free pump sprays which are sprayed by means of a mechanical spray pump, the pump lift volume usually being 120-190 &mgr;L. Because of their better performance and better application properties, aerosol sprays are substantially more important. The conventional aerosol hair sprays, however, have the drawback that such products require relatively large and unwieldy containers. This, in turn, leads to unattractive and difficult-to-configure packaging forms. Commonly used, for example, are 250-mL cans made of tinplate or aluminum in conventional cylindrical shape. The relatively large size is due to the comparatively large gas space which is devoid of active substances and which is needed for the propellant. Although pump sprays use no propellant and, hence, can be sold in less voluminous packages compared to aerosol cans, one has to put up with a definite loss in application properties. Consumers feel that, compared to aerosol sprays, the common, known pump sprays are for the most part wetter and coarser and that they have a longer drying time and a coarser drop spectrum. Their market share is correspondingly small. Moreover, because of the relatively low attainable concentration of the hair-strengthening polymer in aerosol sprays and the need for a large headspace, it has thus far not been possible to produce compact aerosol hair spray products which in terms of both application properties and economy in use match the aerosol sprays in the usual 250-mL package sizes.
Hair sprays are usually used in the form of polymer solutions in an alcoholic medium. The polymer concentration is relatively limited. According to Schrader, “Grundlagen und Rezepturen der Kosmetika” [Fundamentals and Formulations of Cosmetics], 2nd edition, 1989, page 772, the typical polymer content of a hair spray is 2-4%. Higher polymer contents lead to many problems which are due primarily to a marked increase in viscosity of the composition. For example, when the polymer concentration is increased, the droplet size of the sprayed composition based on the usual alcoholic solvent increases unacceptably to more than 100 &mgr;m. Good pump hair sprays have an average droplet size of about 80 &mgr;m, the smaller the better (for example 50 &mgr;m). The drawbacks of excessively large drops are the wetness effect, the pearl chain effect involving the formation of pearl-like droplets which on the hair are visible, poorly flowing and poorly drying, moreover long drying times, poor distribution on the hair, deterioration of the spray pattern etc. Besides the average droplet size, the droplet size distribution is determining for the quality of a hair spray, because even a relatively small number of very large drops brings about major drawbacks. The dv(50) and dv(90) values provide a measure of the droplet size distribution. These values give the maximum diameter of 50% or 90% of all droplets. For typical aerosol hair sprays, the average dv(50) value is about 40 &mgr;m and the average dv(90) value about 75 &mgr;m. For typical pump hair sprays, the average dv(50) value is about 75 &mgr;m and the average dv(90) value about 120 &mgr;m. The dv(90) value, in particular, should not exceed 140 &mgr;m and preferably not 130 &mgr;m. The sprays will otherwise be perceived as being very wet.
European Patent EP 0 460 123 A discloses a one-phase solvent mixture of C
2
-C
4
alcohols, water and a lower alkane, selected from among n-pentane, n-hexane and isohexane. This solvent mixture can be used in non-aerosol hair sprays. Hair spray concentrates and compact hair sprays are not described.
Desirable therefore are small, compact hair spray products which compared to the usual aerosol sprays and the usual pump hair sprays present a comparable economy of use at a fraction of the container volume, while at the same time presenting application properties, for example a strengthening efficacy and spray performance, that do not have the drawbacks of common pump hair sprays, but approximate those of aerosol sprays and, from the standpoint of environmental protection, also present a desirable, improved volatile organic compound [VOC] balance.
SUMMARY OF THE INVENTION
We have now found that this objective can be reached by use of a compact hair spray product comprising a special hair spray concentrate, a pressure-tight and diffusion-proof container and a special fine-spray pump with pilot pressure buildup.
The object of the invention therefore is a compact hair spray product comprising
(A) a hair spray concentrate having a viscosity permitting good sprayability and containing
(a1) at least one hair-strengthening polymer,
(a2) an alcoholic solvent for polymer (a1),
(a3) at least one organic solvent additive capable of reducing the viscosity of the concentrate and increasing the vapor pressure of the concentrate, and
(B) a pressure-tight and, for concentrate (A), diffusion-proof container and
(C) a fine-spray pump with
(c1) a cylindrical region made of a material that resists swelling by the organic solvent additive (a3),
(c2) a maximum lift of 0.12 mL and
(c3) pilot pressure buildup.
The hair spray concentrate preferably also contains a drying-retarding solvent additive (a4).
The object of the present invention is eminently suited for the production of hair spray products of compact design, for example with a volume of 40 to 60 mL, presenting an economy of use approximating that of typical 250-300 mL aerosol hair spray cans.
For purposes of the invention, by compact hair spray product is meant a hair spray product of more compact design than that of a typical aerosol hair spray, namely a product with a filling volume of less than 250 mL and particularly of at the most 150 mL. Preferred are filling volumes from 10 to 100 mL, particularly from 20 to 80 mL and especially from 40 to 60 mL. For purposes of the invention, by hair spray concentrate is meant a composition comprising at least one hair-strengthening polymer at a concentration that is higher than that of common hair sprays which typically is 4 wt. % and for hair lacquers 6 wt. %. The polymer concentration is preferably higher than 8% wt. % and particularly higher than 10 wt. %, based on the total composition. The maximum polymer concentration is preferably 20 wt. %.
For purposes of the invention, by viscosity permitting good sprayability is meant a viscosity at which the average droplet size obtained with a Seaquist-Perfect PZ1/100 HVT fine-spray pump is less than 100 &mgr;m and preferably less than 80 &mgr;m or for which the dv(90) value is at the most 140 &mgr;m and preferably at the most 130 &mgr;m. The average droplet size and droplet size distribution can be determined, for example, with the aid of a particle-sizing instrument based on laser radiation diffraction, for example a Malvern Particle Sizer instrument. The preferred kinematic viscosity is at the most 10 mm
2
.s, and preferably at the most 5 mm
2
.s, determined with a RheoStress 100 rotational viscometer, supplied by Haake, at a temperature of 25° C. and a shear gradient from 0.5 to 1400 s
−1
.
Suitable hair-strengthening polymers are selected from the group consisting of synthetic or natural or modified natural polymers, which in each case can have a nonionic, cationic, anionic or amphoteric character. A mixture of several of these polymers can also be used. According to the invention, by hair-strengthening polymer is meant a polymer which when used in the form of a 0.01 to 5% aqueous, alcoholic or aqueous-alcoholic solution is capable of depositing a polymer film on the hair thus strengthening the hair.
Suitable synthetic, nonionic, film-forming, hair-strengthening polymers are, for example, the homopolymers of vinylpyrrolidone, vinylcaprolactam or N
Starke Thomas
Steigerwald Franz
Steinmetz Uwe
Dodson Shelley A.
Striker Michael J.
Wella AG
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