GB1562560A - Hairsprays - Google Patents

Description

(54) HAIRSPRAYS (71) We, UNILEVER LIMITED, a British company, of Unilever House, Blackfriars, London EC4, England, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to hairsprays and in particular to an aerosol hairspray composition in which a hairspray resin is dissolved in a liquid vehicle comprising a mixture of an organic solvent and a propellant liquid, which composition is packaged within a container fitted with a discharge spray valve comprising a mechanical break-up actuator. When the actuator of the valve is operated the composition is discharged in aerosol form through the outlet or terminal orifice in the actuator, by the pressure within the container. Many marketed aerosol hairsprays are of the above type at the present time.

When a composition is discharged as an aerosol from a pressurised pack, some of the aerosol particles may be inhaled by the user or by other persons in the vicinity. The proportion of the product discharged which is capable of reaching and being deposited in the lung and is called herein the "respirable fraction" of the product. Industry is concerned that the user should not be exposed unnecessarily to respirable particles (see the article "Health related hazards of aerosols" by J.J. Sciarra published in Aerosol Age, December 1977, page 44).

This invention is concerned with providing an improved aerosol hairspray package.

According to the present invention there is provided a package for dispensing a hairspray resin, including in combination a container having a spray valve provided with a mechanical break-up actuator for dispensing a liquid in aerosol form and a composition within the container comprising a solution of a hairspray resin in a liquid vehicle comprising a mixture of an organic solvent and a liquefied propellant, wherein (A) the visocity of the composition is 0.80 to 4.00 centistokes, preferably 0.85 to 2.00 centistokes, at 25"C; (B) the pressure within the container is from 20 to 42 psig at 25"C; and (C) the mechanical break-up actuator is such that z/D1D2 has a value up to ie i- tp 0.80 such as from 0.15 to 0.80 (eg 0.50 to 0.80) where Z is the sum of the cross-sectional areas of the swirl channels of the actuator; Dl is the diameter of the spray (terminal) orifice of the actuator; and D2 is the diameter of the swirl chamber of the actuator.

Preferred features of the package of the invention are (D) the diameter of the housing orifice (also known as the body orifice or tail piece orifice) of the valve or, in the case where the dip tube of the valve is fitted within the housing orifice, the internal diameter of the dip tube is at least 25 x 10-3ins, eg 25 to 150 x 10-3 ins; and (E) the valve does not have a vapour phase tarp.

Preferably both of the latter features (D) and (E) are part of the package of the invention.

For a discussion of the construction of aerosol valves reference is made to chapter 6 of "Principles of Aerosol Technology" by Paul A. Sanders (1970). A typical mechanical break-up actuator is described in British Patent Specification No.799,468 (The Risdon Manufacturing Company) the drawings of which illustrate a spray valve having four swirl channels 58 leading to a swirl chamber 52 from which liquid emerges through the spray orifice 68. Commercially available mechanical break-up actuators usually have two, three or four swirl channels and in some forms the channels taper towards the swirl chamber. The value of Z for an actuator with tapering swirl channels is the sum of the mean values of the cross-sectional areas of the channels.

The hairspray resin is preferably included in the composition in an amount of from 0.1 to 7.5% by weight.

The hairspray resin may be any of those known to be suitable for holding the hair in a desired style. Amongst those that have found wide- commercial application are polyvinylpyrrolidone; copolymers of from 92.5 to 87.5% by weight vinyl acetate and from 7.5 to 12.5% by weight crotonic acid as described in US Patent No.2,996,471, eg National Starch Resyn 281310; terpolymers of from 7 to 89% by weight vinyl acetate, 6 to 13% by weight crotonic acid and from 5 to 80% by weight of a vinyl ester of an alpha-branched saturated aliphatic monocarboxylic acid having a minimum of five carbon atoms in the carboxylic moiety, said acid having the formula R3C(R1)(R2)COOHwhere R1 amd R2 are alkyl radicals and R3 is selected from hydrogen, alkyl, alkaryl, aralkyl and aryl radicals, such terpolymers being described in British Specification No.1,169,862 and US Application Serial No.625,328, and similar terpolymers being described in US Patent No.3,579,629, a commercially available terpolymer of this type being that sold under the name National Starch Resyn 282930; copolymers of from 20 to 60%by weight of N-vinylpyrrolidone and from 40to 80% by weight of vinyl acetate such as those described in US Patent No.3,171,784, and which copolymers are commercially available under the designations Luviskol 37E and Luviskol 28I (the word "Luviskol" is a trade mark); copolymers of maleic anhydride (1 mole) and an olefin (1 mole) containing 2 to 4 carbon atoms, particularly ethylene, said copolymer having a molecular weight of about 25,000 to 70,000, preferably being esterified to the extent of 50 to 70% with a saturated aliphatic alcohol containing from 1 to 4 carbon atoms, such as are described in US Patent No.2,957,838; amphoteric acrylic resins as described in US Patent No.3,726,288 and available commercially under the trade mark "Amphomer"; and copolymers of methyl vinyl ether and maleic anhydride (molar ratio about 1:1) and such copolymers esterified with a saturated aliphatic alcohol containing from 1 to 4 carbon atoms, an example thereof being the resin available commercially under the trade name Gantrez ES 435 (the word "Gantrez is a trade mark). However, those skilled in the art will appreciate that other resins are suitable for use in hairsprays, see for example the section entitled "Hair Lacquers or Hair Sprays", commencing on page 352 of Volume 2 of "Cosmetics Science and Technology" edited by M.S. Balsam and Edward Sagarin (1972).

Those copolymers which contain acidic groups and are water-insoluble are usually used in their neutralised water-soluble form. Suitable neutralising agents which may be included in the hairspray composition are amines, especially aminoalcohols, preferably 2 amino-2-methyl-1,3-propanediol and 2-amino-2-methyl- 1-propanol. Other suitable neutralising agents are also given in US Patent No.2,996,471.

Organic solvents for the hairspray resin which are commonly used in formulating hairspray compositions are ethanol, isopropanol, methylene chloride, methoxyethanol and 2ethoxy-ethanol, and mixtures thereof with water.

The propellant gases used in formulating aerosol hairsprays are well known to those skilled in the art. The propellant is usually a halogenated hydrocarbon, the fluorochlorohydrocarbons of the C1 and C2 alkanes being the most well known, or a liquefiable hydrocarbon.

Commonly used propellants are trichlorofluoromethane (propellant 11), dichlorodifluoromethane (propellant 12), butane and propane, and mixtures thereof. Other suitable propellants are referred to in US Patents Nos. 3,026,250, 3,145,147 and 2,957,838, and more generally in the section entitled "Propellants" commencing on page 443 of Volume 2 of "Cosmetics Science and Technology" referred to previously.

The hairspray compositions of this invention may contain adjuvants conventionally used in compositions of this type for example plasticisers, perfumes, dyestuffs and anti-seborrhoeic agents. Suitable anti-seborrhoeic agents are described in British Specifications Nos. 1,296,102 and 1,305,358. Polydimethylsiloxane-polyoxyalkylene copolymers as described in British Specification No. 1,424,002 may also be included.

The respirable fraction of the particles produced by an aerosol pack was determined in the following experiments using an Hexhlet elutriator (Brit. J. industr. Med., 1954, 11, 284) which separates particles according to their falling velocities in the air. The aerosol is drawn at a controlled horizontal velocity through a parallel plate elutriator; the vertical spacing of the plates is such that particles settling on them during the transit of the aerosol through the elutriator correspond to those which would separate aerodynamically in the upper respiratory tract of man. Thus the particles passing through the elutriator and collected on a filter represent those which would penetrate to the human lungs. The upper aerodynamic size limit for respirable particles collected in the Hexhlet is about 7 microns.

The procedure was as follows. A filter, dried and weighed, was loaded into the Hexhlet sampler and the pressurised pack to be tested was weighed. The vacuum was adjusted so that the gauge on the Hexhlet showed about 300 mm Hg. After thorough shaking the aerosol was sprayed into a cabinet fitted to the front of the Hexhlet sampler, each spray was of 2 second duration, the sprays being repeated with shaking every 20 second for a total of 20 sprays.

Sampling was continued for 5 minutes after the last spray. The pack was re-weighed to give the weight of product discharged. The weight collected is expressed in milligrams per 100 g of product discharged. This weight is a measure of the respirable material in an aerosol cloud. In order to be able to compare respirable fractions obtained from products containing different amounts of resin, it is necessary to allow for the evaporation of the solvents from the droplets in the aerosol cloud during sampling, and this is effected by dividing the respirable fraction (mg/ 100 g) by the percentage weight of the resin in the product, the quotient being referred to herein as the Corrected Respirable Fraction.

The measurement of respirable fraction was carried out at a relative humidity of 50% and a temperature of 20"C.

Experiments will now be described illustrating the effect of the above parameters on the corrected respirable fraction of an aerosol spray. Measurements of viscosity and pressure were carried out at 250C unless stated otherwise. In all cases, prior to filling with propellant all aerosol cans were purged of air. Percentages are by weight.

The effect of can pressure, formulation viscosity and mechanical break-up actuator on the corrected respirable fraction is illustrated in Table I.

TABLE I Can Pressure Formulation Value of Z Corrected (psig) Viscosity for D1D2 Respirable (centistokes) Actuator Fraction 0.66 10 0.82 0.75 18 32 0.66 0.7 1.7 0.75 6 0.66 24 0.82 0.75 33 40 0.66 6 1.7 0.75 18 The compositions employed in the experiments summarised in Table I had a product to propellant weight ratio of 40:60. The product consisted of a solution of National Starch Resyn 28-1310 (a copolymer of vinyl acetate (90%) and crotonic acid (10%)) in ethanol. The lower viscosity composition contained 0.8% resin and the higher viscosity one 3% resin. The products also contained 10% based on the weight of the resin of amino methyl propanol as a neutralising agent. In each case a blend of Propellants 11 and 12 were used, the weight ratios being 70:30 and 50:50 in the case of the lower and higher pressure compositions, respectively.

In these experiments the same valve was used. The housing orifice of the valve had a diameter of 80 x 10-3 ins.

The effect of formulation viscosity on the corrected respirable fraction is also shown by the data given in Table II below. In this case the can pressure (46 psig) was constant and the same valve and actuator were used, the latter having a Z/ D 1D2 value of 0.18. The housing orifice of the valve had a diameter of 80 x 10-3 ins.

TABLE II Amount of Resin Formulation Viscosity Corrected Respirable in Formulation (centistokes) Fraction (%) 0.2 0.20 400 0.5 0.25 265 1.0 0.30 200 1.8 0.45 170 3.0 0.80 75 4.0 1.35 30 In the experiments whose results are reported in Table II, the resin employed was National Starch Resyn 282930 (a terpolymer of vinyl acetate (75%), crotonic acid (10%) and a vinyl ester of a branched chain fatty acid (15%)). Amino methyl propanol in an amount of 10% based on the weight of the resin as a neutralising agent was also present. The formulations had the following composition: Product Resin as specified in Table II Neutralising agent 10% of resin Ethanol to 15 Propellant Propellant 11 51 Propellant 12 34 The effect of variation in the value of the ratio Z/DlD2 for the actuator of the valve is also shown by the data given in Table III.

TABLE III ZID1 D2 Corrected Respirable Fraction 0.36 14 0.66 28 0.75 38 0.85 46 1.10 52 The data in Table III were obtained employing a hairspray having the following composition: National Starch Resyn 28-1310 2.0 Amino methyl propanol 0.2 Ethanol 37.8 Propellants 11/12(65 : 35) 60.0 This composition had a viscosity of 0.94 centistokes and the pressure within the aerosol container was 36 psig. The housing orifice of the valve had a diameter of 80 x 10-3 ins.

The results of experiments showing the effect of the diameter of the housing orifice on the corrected respirable fraction are summarised in Table IV.

TABLE IV Housing Orifice Corrected Respirable (thousandths of an inch) Fraction 13 52 18 41 25 27 80 22 In the experiments on which the results of Table IV are based there was used a formulation containing 2% of National Starch Resyn 281310. The remainder of the composition consisted of amino methyl propanol (0.2%), ethanol (37.8 v7o) and a 65:35 blend (60 }7o) of propellants 11 and 12. The composition had a viscosity of 0.94 centistokes and the pressure within the aerosol container was 36 psig. The same actuator was used throughout this experiment and it had a Z/DID2 value of 0.43.

In all the above experiments the valve employed had no vapour phase tap. Use of a vapour phase tap leads to an increase in the respirable fraction. This can be seen from the following Table V which gives values for the corrected respirable fractions for two pairs of packages the individual packages of each pair differing only in that the spray valve of one had a vapour phase tap whereas the other did not. For the second pair a spray valve with a larger housing orifice was employed.

TABLE V Corrected Respirable Fraction Housing Orifice Housing Orifice Diameter of Diameter of 25 x 10-3 ins 80 x 10-3 ins No vapour phase tap 136 64 Vapour phase tap of 204 83 13 x 10-3 ins The formulation of the aerosol composition was as follows: National Starch Resyn 28-2930 1.10 Amino methyl propanol 0.11 Ethanol 13.79 Propellant 11 51.00 Propellant 12 34.00 This composition had a viscosity of 0.32 centistokes and the pressure within the aerosol container was 46 psig. The value of the ratio Z/DtD2 for the mechanical break-up actuator was 0.43.

The following Examples illustrate the use of hydrocarbon propellants.

Composition Example I Example 2 National Starch Resyn 28-2930 2.30 2.30 Amino methyl propanol 0.23 0.23 Sucrose octaacetate 0.10 0.08 Perfume 0.20 0.20 Water 10.00 Methylene chloride 25.00 Hydrocarbon propellant 16.00 18.00 Industrial methylated spirit to 100 00 to 100.00 Viscosity of composition 1.51 1.10 (centistokes) Pressure within the aerosol 36 25 container (psig) Actuator Z/D1D2 ratio 0.36 0.36 Diameter of housing orifice 80 80 (x 10-3 in) Corrected respirable fraction 8 10 The spray valves employed had no vapour phase tap.

The hydrocarbon propellant was Calor Aerosol Propellant Grade 30, a commercial hydrocarbon blend consisting mainly of a mixture of propane and butanes having a vapour pressure of about 30 psig at 21"C (the word "Calor" is a trade mark).

In all the aerosol products referred to above the aerosol valve was provided with a so-called standard dip tube, ie the dip tube was fitted over the end of the valve tail piece. The dip tubes employed had an internal diameter in the range from 80 to 120 x 10-" ins. However, it is possible to employ so-called capillary dip tubes which fit within the housing orifice. In this case it is required that the internal diameter of the dip tube is at least 25x 10 ins. Increasing the diameter of the capillary dip tube acts to reduce the value of the corrected respirable fraction. Capillary dip tubes usually have an internal diameter up to about 60 x 10-3 ins.

We make no claim herein to an aerosol hairspray package in which the viscosity of the composition is 0.82 to 0.98 centistokes at 25"C and Z/DlD2 has a value of 0.40 to 0.45.

SUBJECT TO THE FOREGOING DISCLAIMER WHAT WE CLAIM IS: 1. A package for dispensing a hairspray resin, including in combiantion a container having a spray valve provided with a mechanical break-up actuator for dispensing a liquid in aerosol form and a composition within the container comprising a solution of hairspray resin in a liquid vehicle comprising a mixture of an organic solvent and a liquefied propellant, wherein (A) the viscosity of the composition is 0.80 to 4.00 centistokes at 250C; (B) the pressure within the container is from 20 to 42 psig at 250 C; and (C) the mechanical break-up actuator is such that Z/DlD2 has a value up to 0.80 where Z is the sum of the cross-sectional areas of the swirl channels of the actuator; D1 is the diameter of the spray orifice of the actuator; and D2 is the diameter of the swirl chamber of the actuator.

2. A package as claimed in claim 1, wherein the diameter of the housing orifice of the valve or, in the case where the dip tube of the valve is fitted within the housing orifice, the internal diameter of the dip tube is at least 25 x 10-3 ins.

3. A package as claimed in claim 1 or claim 2, wherein the valve does not have a vapour phase tap.

4. A package as claimed in any of claims 1 to 3, wherein the viscosity of the composition is from 0.85 to 2.00 centistokes at 25"C.

5. A package as claimed in any of claims 1 to 4, wherein Z/D1D2 has a value of from 0.15 to 0.80.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. composition is 0.82 to 0.98 centistokes at 25"C and Z/DlD2 has a value of 0.40 to 0.45. SUBJECT TO THE FOREGOING DISCLAIMER WHAT WE CLAIM IS:

1. A package for dispensing a hairspray resin, including in combiantion a container having a spray valve provided with a mechanical break-up actuator for dispensing a liquid in aerosol form and a composition within the container comprising a solution of hairspray resin in a liquid vehicle comprising a mixture of an organic solvent and a liquefied propellant, wherein (A) the viscosity of the composition is 0.80 to 4.00 centistokes at 250C; (B) the pressure within the container is from 20 to 42 psig at 250 C; and (C) the mechanical break-up actuator is such that Z/DlD2 has a value up to 0.80 where Z is the sum of the cross-sectional areas of the swirl channels of the actuator; D1 is the diameter of the spray orifice of the actuator; and D2 is the diameter of the swirl chamber of the actuator.

2. A package as claimed in claim 1, wherein the diameter of the housing orifice of the valve or, in the case where the dip tube of the valve is fitted within the housing orifice, the internal diameter of the dip tube is at least 25 x 10-3 ins.

3. A package as claimed in claim 1 or claim 2, wherein the valve does not have a vapour phase tap.

4. A package as claimed in any of claims 1 to 3, wherein the viscosity of the composition is from 0.85 to 2.00 centistokes at 25"C.

5. A package as claimed in any of claims 1 to 4, wherein Z/D1D2 has a value of from 0.15 to 0.80.