Perfume compositions – Perfume compositions – Nonliquid or encapsulated
Reexamination Certificate
1997-12-23
2001-02-27
Warden, Jill (Department: 1743)
Perfume compositions
Perfume compositions
Nonliquid or encapsulated
C512S002000, C424S070100, C424S070110, C424S451000, C510S108000, C510S119000, C510S349000, C510S515000, C510S519000
Reexamination Certificate
active
06194375
ABSTRACT:
This invention relates to detergent compositions and other fabric treatment compositions, including personal washing and hair-conditioning compositions, laundry detergent compositions and rinse conditioner compositions for fabric softening.
SUMMARY OF THE PRIOR ART
There have been a number of proposals for absorbing perfume onto a solid carrier material, and various reasons for doing so. In a number of instances, the objective of such proposals has been merely to convert liquid perfume into a solid form which can more readily be incorporated into another product. It has been asserted that such carrier substances may serve to protect the perfume from loss during storage or protect it from contact with other constituents of a composition.
Examples of disclosures of such carriers for perfume are GB-A-1306924, U.S. Pat. No. 3,449,266U.S. Pat. No. 3,909,461U.S. Pat. No. 4,536,315, U.S. Pat. No. 4,539,135, U.S. Pat. No. 4,713,193, GB-A-2066839, EP-A-332259, EP-A-332260 and JP-A-63/79662. In many of these documents the carriers are inorganic materials.
EP-A-535942 and EP-A-536942 are concerned with inorganic carrier materials which serve to reduce the vapour pressure of absorbed perfume.
As pointed out in those documents, a carrier material which reduces the perfume vapour pressure over the solid carrier but releases the perfume on contact with water can be useful to avoid giving excessive perfume odour to a concentrated product, yet provide the required concentration of perfume in a wash or rinse liquor.
EP-A-285694 is one of a series of documents concerned with porous cross linked polymers obtained by polymerisation around droplets of a liquid substance which may subsequently be removed. These porous polymers can act as carriers for a variety of liquids. They are used in products for application to the skin, and give controlled release of the liquid to the skin.
U.S. Pat. No. 4,842,761 discloses composite particles in which one polymer is embedded within another. These particles are used as perfume carriers in laundry detergents and provide controlled release of perfume.
THE INVENTION
We have now found that the deposition of perfume from a composition having an active ingredient can be improved by incorporating the perfume into particles containing organic polymer, and providing at the surface of the particles a further polymer with free hydroxyl groups. Such polymer enhances deposition of the particles and by doing so also enhances deposition of the perfume. The use of such particles can enhance deposition of perfume, or components thereof; it can retard the evaporation of deposited perfume and can also enhance the extent to which deposited perfume survives a subsequent drying step.
Accordingly, the present invention provides a product which is an article or composition containing an active ingredient which is a detergent active, a fabric softening agent or a hair conditioning agent, and particles containing organic polymer which are insoluble in water and carry perfume, carried by a core of the particle, and at the exterior of the core a further polymer attached to the core so as not to be removed therefrom in water, which further polymer incorporates free hydroxy groups and is present in a quantity which is no more than 25% of the weight of the particles. This further polymer will be referred to below as a “hydroxy functional polymer”.
The quantity of the particles in the products will depend on the nature of the product but will generally provide perfume in an amount within the broad range 0.1 to 10% by weight. In particular such products may be personal washing compositions, fabric detergent compositions, other cleaning compositions and fabric or hair conditioner compositions incorporating such perfume-containing particles.
As will be explained in greater detail below, the organic polymer particles may be polymer capsules which enclose perfume or may be solid (but possibly porous solid) particles into which perfume is absorbed. Polymer capsules may enclose liquid perfume or a solid core into which perfume is absorbed.
The particles themselves are insoluble in water, so that they can be deposited from an aqueous wash or rinse liquor.
The hydroxy functional polymer at the exterior of these particles may form, or be included within a coating or incomplete coating on these individual particles. The hydroxy functional polymer is preferably nonionic or cationic. It will be explained below that it generally constitutes between 1 and 25% of the weight of the perfume-containing particles, usually between 1 and 10%. Cationic functionalities may additionally be present at the exterior of the particles, and may be provided by the hydroxy functional polymer or otherwise. Presence of cationic monomers has a tendency to increase particle size.
Particle Size
Polymer particles used in this invention desirably have an average particle size of at least 1 &mgr;m, better at least 20 &mgr;m or 30 &mgr;m, for ease of handling. Also, we have observed that the rate of release of fragrance may be faster than desired if the particles are of very small size such as average size of 1 &mgr;m. The polymer particles desirably have an average size not larger than 150 &mgr;m, better not over 125 &mgr;m so that the particles are not easily visible after deposition.
For particles intended to be used in fabric washing or conditioning, it is especially preferred to use particles with a mean size of at least 40 &mgr;m, e.g. 40 to 100 &mgr;m to retain perfume in the particles and provide slow perfume release.
For particles intended for other products, e.g. personal washing products, a faster rate of release may be desired than with fabrics products, although retention of perfume and delay in release for some hours is still desirable, consequently a smaller particle size may be advantageous, such as a mean size in the range from 10 to 50 &mgr;m.
Polymerisation techniques generally produce a range of particle sizes. For this invention it is desirable that a high proportion of the particles lie between the above limits on particle size. Thus, when particles are intended for fabric treatment, preferably 90% or more of the particles are larger than 30 &mgr;m. Preferably also 90% or more of the particles are not larger than 150 or even 125&mgr;. Better, 95% or more are not larger than 125 or even 100 &mgr;m.
To achieve these criteria, it may be necessary to sieve the particles and thereby separate oversized and/or undersized particles. An important aspect of reducing the amount of emulsion polymer formed (broadly speaking, polymer beads of a size below 10 &mgr;m) is to use an initiator system that is substantially insoluble in the aqueous phase, so as to prevent initiation of monomer molecules held in micelles. Suitable water insoluble initiators include azo compounds such as azobisisobutyronitrile (AIBN) and higher alkyl peroxides.
Hydroxy Functional Polymer
This polymer bearing hydroxy groups and located at the exterior of the particles serves to enhance deposition onto (or retention on) skin, hair, hard surfaces especially vitreous surfaces and fabric.
This polymer is desirably such that at least 80% of the monomer residues in the polymer contain at least one free hydroxy group able to participate in hydrogen bonding. The polymer is preferably nonionic and such that, in its pure state, it is water-soluble. However, when attached to the exterior of the particles, it does not render them water soluble. The attachment is such that the polymer is not completely removed upon contact with water. It may be chemically bonded with the core polymer.
The preferred polymer is polyvinyl alcohol.
As is well known, polyvinyl alcohol cannot be prepared directly by polymerisation, and is obtained by the hydrolysis of polyvinyl acetate. This hydrolysis generally stops before completion, and polymers with varying amounts of hydrolysis are commercially available.
We have found that deposition of particles, especially onto fabric, is better when the polyvinyl alcohol exhibits a substantial level of hydrolysis.
We may therefore prefer to u
Goodall Marcus James
Irving Pamela Virginia
Ness Jeremy Nicholas
Cole Monique T.
Pillsbury Madison & Sutro LLP
Quest International B.V.
Warden Jill
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