WO2006068486A2

WO2006068486A2 - Detergent or fabric softening composition comprising a controlled fragrance releasing means

Info

Publication number: WO2006068486A2
Application number: PCT/NL2005/050096
Authority: WO
Inventors: Johanne Theodorus Faustinus Keurentjes; Maria Francisca Kemmere
Original assignee: Dolphys Medical B.V.
Priority date: 2004-12-23
Filing date: 2005-12-23
Publication date: 2006-06-29
Also published as: WO2006068486A3

Abstract

The present invention relates to a detergent or fabric softening composition comprising a controlled fragrance releasing means, said controlled fragrance releasing means comprising: (a) a polymeric material having a glass transition temperature within the range of about 20° to about 80°C; and (b) a fragrance, wherein the fragrance substance can be released from the fragrance releasing means by reversible modification of the release characteristics of the polymeric material by supplying energy from an external energy source.

Description

Detergent or fabric softening composition comprising a controlled fragrance releasing means

Field of the invention

The present invention relates to a detergent or fabric softening composition comprising a controlled fragrance releasing means and a method for releasing a fragrance from a detergent or fabric softening composition.

Background of the invention

Fragrances are frequently incorporated in detergents and fabric softeners including tumble dryer sheets and dish washing compositions to give a pleasant odour during use of the detergent or fabric softener and to mask the inherent smell of soap or other surfactant or residues thereof present in the product or fabric after washing. The fragrances are generally complex mixtures of fragrant compounds of varying volatility. Upon storage of detergents and fabric softeners, perfumes and fragrances can be altered through interactions and/or reactions with the other components of the composition thereby possibly giving rise to less pleasant odours. Due to their volatile nature, fragrances tend to dissipated with time, in particular the most volatile compounds which are often associated with perceived freshness. Moreover, when used, such as during washing of fabrics with a laundry detergent or during drying the fabric in a tumble dryer, most of the perfume is also lost in the aqueous phase during the washing or drying cycle. It has been recognised as desirable that the fragrance should survive storage in the detergent composition and also survive the cleaning and drying processes and should be deposited on the fabric, so that fabrics laundered with a detergent and a fabric softener containing the fragrance should have the pleasant odour of the fragrance. Likewise, it has been recognised as desirable that fabric that is being dried in a tumble dryer wherein e.g. tumble dryer sheets comprising the fragrance are employed that the fragrance is deposited on the fabric.

Additionally, once adsorbed onto fabrics, the fragrance tends to dissipate very quickly. There is thus a need to improve the storage stability of fragrances, their delivery in the application and their long-lasting effect through sustained delayed release once applied on fabrics.

Summary of the invention

It is an object of the invention to provide a detergent or fabric softening composition that releases its fragrances in a controlled manner during use in a wash or drying cycle and not during storage.

The present invention therefore relates to a detergent or fabric softening composition comprising a controlled fragrance releasing means, said controlled fragrance releasing means comprising:

(a) a polymeric material having a glass transition temperature within the range of about 20° to about 80°C; and

(b) a fragrance, wherein the fragrance can be released from the fragrance releasing means by reversible modification of the release characteristics of the polymeric material by supplying energy from an external energy source.

The present invention also relates to a method for releasing a fragrance substance from a detergent or fabric softening composition, the detergent or fabric softening composition comprising a controlled fragrance releasing means, said controlled fragrance releasing means comprising a polymeric material and a fragrance, wherein the fragrance is released from the controlled fragrance releasing means by reversible modification of the release characteristics of the polymeric material by supplying energy from an external energy source, and wherein the polymeric material has a glass transition temperature within the range of about 20° to about 80°C.

Detailed description of the invention

The present invention is based on the discovery that the temperature increase is induced rapidly when the polymeric material is exposed to energy, e.g. supplied by an external heat source such as the warm water in a washing machine or the hot air provided in a tumble dryer. This fast temperature increase is utilised to change the glassy state of the polymeric material into the rubbery state by heating the polymeric material from a temperature below the T_g of the polymeric material to a temperature above the T_g of the polymeric material. If the temperature of the polymeric material is below the T_g, release of the fragrance is extremely low whereas as the temperature of the polymeric material is above the T_g, flexible polymer chains allow for fast diffusion of the fragrance.

An advantage of the detergent or fabric softening composition to the present invention is that the release characteristics of the controlled fragrance releasing means can be reversibly modified in such a way that the diffusion of the fragrance substance occurs repeatedly and reproducibly. For example, a wash cycle is characterised by various time cycles that run at different temperatures and the present invention allows for control of the release of the fragrance as a iunction of time and temperature. Another advantage of the present invention is that a fragrance can be delivered on demand. Consequently, the present invention enables that the release of a fragrance practically only occurs at the use stage of a detergent or fabric softening composition and that release of any fragrance does essentially not occur prior to this stage.

In this patent application, the term "external energy source" is to be understood as a means for warming the detergent or fabric softening composition to a temperature at which it is desired that the detergent or fabric softening composition releases the fragrance. Hence, such a means includes in general the warm water used in the washing machine during certain wash cycles and the hot air provided in a tumble dryer. As will be appreciated by the person skilled in the art, other sources for transferring heat that are within the scope of this invention comprise irons and ironing machines as often used in e.g. hotel accommodations, hospitals and the like and cupboards that can be used to freshen up clothing by providing heated air. According to the invention, it is preferred that the polymeric material has a glass transition temperature within the range of about 25° to about 60°C.

According to the invention, the detergent or fabric softening composition may be in a liquid form or a solid form. If the composition is in a liquid form, it is preferred that the composition is an encapsulated liquid composition, wherein the core of the composition comprises the detergents or fabric softening formulation whereas the encapsulating material, e.g. the shell of the encapsulated liquid formulation, comprises the polymeric material in which the fragrance is dispersed. Obviously, encapsulated liquid formulations that are known from the prior art may be provided with a film or layer comprising the controlled fragrance releasing means according to the invention, wherein said film or layer comprising the controlled fragrance releasing means may be further coated with other layers or films of e.g. polymeric materials, provided that said other layers or films are suitable for the intended applications. Encapsulated liquid formulations containing a fragrance and detergent compositions comprising said encapsulated liquid formulations are for example disclosed in US 2003125222 and US 2004209793, both incorporated by reference herein.

If the composition is in a solid form, preferably a granulated solid form, the granules preferably comprise a core comprising the detergent or fabric softening composition and an outer layer comprising the controlled fragrance releasing means. Obviously, granulated solid detergent or fabric softener compositions that are known from the prior art may be provided with a film or layer comprising the controlled fragrance releasing means according to the invention, wherein said film or layer comprising the controlled fragrance releasing means may be further coated with other layers or films of e.g. polymeric materials, provided that said other layers or films are suitable for the intended applications. In such compositions the controlled fragrance releasing means is essentially applied on the exterior or the outside of the detergent or fabric softening composition.

As will be apparent to the person skilled in the art, there has recently been considerable interest within the detergent industry for detergent compositions which have the convenience, aesthetics and solubility of liquid detergent products, but retain the cleaning performance and cost of granular detergent products. In particular, "compact" or low dosage granular detergent products are currently in high demand as they conserve resources and can be sold in small packages which are more convenient for consumers prior to use. Although granulated detergent compositions may show e.g. dissolution problems, especially at lower temperatures, improved methods are disclosed in the prior art that provide granular detergent compositions that do not suffer from such disadvantages. Reference is for example made to US 6.784.151, incorporated by reference herein. Alternatively, a liquid detergent or fabric softening composition may occur in liquid form and which comprises solid particles comprising the controlled fragrance releasing means according to the invention, wherein the solid particles are coated with a layer or film of a polymeric material comprising the fragrance and optionally with a subsequent layer or polymeric material Obviously, the subsequent layer of polymeric material does not dissolve in the liquid detergent or fabric softening composition but are soluble in the wash water of a washing machine or dishwashing machine. Processes for the manufacture of such liquid compositions are for example disclosed in US 6.767.880, incorporated by reference herein.

Any solid composition comprising the controlled fragrance releasing means according to the present invention may be an effervescent composition which has an improved dispersability or dissolvability compared to non- effervescent compositions. Such compositions are for example disclosed in US 6.300.302, incorporated by reference herein.

According to the invention, the detergent or fabric softening composition may be selected from the group consisting of detergent compositions for laundry applications, dish washing compositions and tumble dryer compositions which may both be in the solid or liquid form. According to a particular preferred embodiment of the present invention, the composition may be in the form of a flexible tumble dryer substrate such as a tumble dryer sheet that is provided with the controlled fragrance releasing means. For example, the sheet may be provided with a coating comprising the controlled fragrance releasing means, e.g. by laminating, or the sheet may be impregnated with a liquid comprising the polymeric material and the fragrance. In this patent application, the term "polymeric material" is to be understood as a polymer or a polymer composition that can be coated on detergent or fabric softening compositions as a layer or film by techniques well known in the art. The polymeric material may be of synthetic or natural origin or may comprise a blend of materials of synthetic or natural origin. As a consequence, the glass transition temperature as defined in this patent application should be understood as the glass transition temperature of the polymer composition and not necessarily of the polymer per se. For instance, the polymer composition may comprise a polymer per se as well as a fragrance, wherein the latter causes a decrease of the glass transition temperature of the pure polymer within the claimed range of about 20° to about 80°C. According to a first preferred embodiment of the invention, the fragrance to be released from the polymeric material is preferably homogeneously dispersed in the polymeric material. The present invention encompasses various preferred embodiments. According to a first, more preferred embodiment, the fragrance is mixed with the polymeric material so that the fragrance substance is homogeneously dispersed in the polymeric material. According to a second, more preferred embodiment of the present invention, the detergent or fabric softening composition comprises a controlled fragrance release means comprising: (a) a core comprising the polymeric material and the fragrance; and

(b) an enveloping material being permeable for the fragrance or being soluble or disintegrating in water.

As will be apparent for the person skilled in the art, detergent or fabric softening compositions provided with the core layer and the enveloping material wherein the latter is water soluble may be impermeable for the fragrance, since upon use of said composition said enveloping material will dissolve during the washing process thereby releasing the fragrance. Furthermore, compositions having an enveloping material that is impermeable for the fragrance but which are water soluble may have the additional advantage that they are more stable during storage, i.e. that despite the volatility of the fragrance it cannot diffuse through the enveloping material.

The enveloping material may obviously be different in nature than the polymeric material. The enveloping material may also have a different colour than the core. The detergent or fabric softening composition is preferably coated with a core layer or film comprising the polymeric material upon which a layer or film of the enveloping material is applied.

Even more preferably, the detergent or fabric softening composition according to the second more preferred embodiment of the invention comprises a controlled fragrance release means comprising a core comprising a polymeric material in which the fragrance is homogeneously dispersed. According to a second preferred embodiment of this invention, the fragrance to be released is surrounded by the polymeric material. Optionally, the fragrance may be comprised by an inert filler material, said inert filler material being surrounded by the polymeric material. For example, the fragrance may be absorbed by or mixed with the inert filler material wherein the latter is encapsulated by the polymeric material. Consequently, this invention also provides a fragrance releasing means comprising:

(a) a core comprising the fragrance, optionally comprised by an inert filler material;

(b) the polymeric material; and (c) optionally an enveloping material being permeable for the fragrance or being soluble or disintegrating in water.

Experiments have further shown that it is preferred that the polymeric material is subjected to one or more, more preferably two or more, reversible glass transitions between a glassy state and a rubbery state. It has been found that such transitions, which as such require relatively little energy, can lead to very appreciable modifications in the release characteristics, which, in turn, can lead to a very appreciable increase in the diffusion of a fragrance present in the polymeric material.

In addition, instead of a fragrance, other components may be used in certain application, e.g. functional salts and enzymes.

Examples

Example 1

In dichloromethane (DCM) 0.49 g of p(BMA-MMA) was dissolved together with vanillin. The weight percentages vanillin used were 10, 15, 20, 25, 30 and 50. The mixture was stirred for 2 hours. Then these solutions were poured into aluminium cups and stored for at least two days in the fume hood until most DCM had evaporated. Then they are placed in the vacuum oven (0 ⁰C) for 24 hours. After this treatment the thin disks are dry and can be taken out of the aluminium cup. To get disks of the same size a round piece with a diameter of 2.8 cm was cut out.

To measure the on/off release system of the disk a jar, containing the disk and 50 ml water, was placed in the freezer (-18 ⁰C, below Tg) for 2 hours and then in the shaking bath (20 ⁰C, above Tg) for 2 hours and then back again to the freezer. In the freezer a sample of 1 ml was taken every 30 minutes and in the shaking bath every 15 minutes. The solution was directly completed with water (cf. Figure 1).

Example 2

Release system prepared by solvent casting/dip coating Used materials: poly (methyl methacrylate) Mw 120k (PMMA) polyφuthyl-methacrylate-co-methyl-methacrylate) Mw 100 (p(BMA-

MMA) poly ethylene vinylacetate (pEVAc; 40% VA) Vanillin DCM Acetone

a) Solvent casting with PMMA 120

A fragrance-releasing layer was prepared by solvent casting of 0.511 g PMMA and 0.059 g (10 wt%) vanillin with 4 mL DCM as a solvent. The T_g of pure PMMA is much higher (± 100 ⁰C) than the desired switch temperature, but solvent casting with 10% vanillin appeared to significantly decrease the T_g of the polymer from ± 100 °C to ± 45 °C.

Release experiments

Two round PMMA films with a diameter of 22 mm were placed together in 20 mL deionized water at room temperature for 16 hours. Consecutively, the temperature was held at 40 °C for 45 minutes and at 70 °C for 15 minutes. This cycle was repeated three times. At regular intervals 1 mL samples were taken and the 20 mL was completed by refilling with deionized water. The vanillin release was measured by UV- spectroscopy at a wavelength of 229 nm and is shown in Figure 2. From Figure 2 can be concluded that the vanillin release is greatly enhanced at a temperature of 70°C. However, the amount of released vanillin decreases each time the temperature cycle is repeated. This is because the concentration of vanillin in the polymer matrix is below the maximum vanillin solubility in the polymer. Therefore the driving force for diffusion decreases every time the temperature cycle is repeated. b) Dip coating in a solution ofpβMA-MMA)

By dip coating a thin (approximately 200 μm) vanillin- saturated pEV Ac-film in a solution of 3,9 g p(BMA-MMA) 100 in 10 mL of DCM or acetone. The pEV Ac-layer was prepared by solvent-casting with DCM. This way, there is good attachment between the fragrance-containing layer and the rate-determining layer. Moreover, the concentration gradient of vanillin over the rate-determining layer can be considered constant; resulting in the same driving force each time the temperature cycle is repeated.

Release experiments

Release experiments were performed by placing a dip-coated disk in deionized water and exposing it to temperatures of 22° and 70 °C. The results are shown in Figure 3. It is clear from these data that the vanillin release is greatly enhanced when the temperature of the water bath is at 70°C and that the amount of released vanillin is approximately constant each time the temperature cycle is repeated. The average ratio of the release above and below the T_g is approximately 200.

Claims

1. A detergent or fabric softening composition comprising a controlled fragrance releasing means, said controlled fragrance releasing means comprising: (a) a polymeric material having a glass transition temperature within the range of about 20° to about 80°C; and (b) a fragrance, wherein the fragrance can be released from the fragrance releasing means by reversible modification of the release characteristics of the polymeric material by supplying energy from an external energy source.

2. The detergent or fabric softening composition according to Claim 1, wherein the polymeric material has a glass transition temperature within the range of about 25° to about 60°C.

3. The detergent or fabric softening composition according to Claim 1 or Claim 2, wherein the detergent or fabric softening composition is a solid or a liquid composition.

4. The detergent or fabric softening composition according to Claim 3, wherein the detergent of fabric softening composition is an encapsulated liquid composition.

5. The detergent of fabric softening composition according to Claim 4, wherein the encapsulating material comprises the controlled fragrance releasing means.

6. The detergent or fabric softening composition according to Claim 3, wherein the detergent or fabric softening composition is a granulated solid composition, the controlled fragrance releasing means being essentially applied on the exterior or the outside of the detergent or fabric softening composition.

7. The detergent or fabric softening composition according to any one of Claims 1 - 6, wherein the detergent or fabric softening composition is selected from the group consisting of laundry compositions, dish washing compositions, tumble dryer compositions and flexible tumble dryer substrates.

8. The detergent or fabric softening composition according to Claim 7, wherein the tumble dryer device is a tumble dryer sheet.

9. The detergent or fabric softening composition according to any one of Claims 1 - 8, wherein the fragrance is homogeneously dispersed in the polymeric material.

10. The detergent or fabric softening composition according to any one of Claims 1 - 9, wherein the fragrance releasing means comprises:

(a) a core comprising the polymeric material and the fragrance; and

11. The detergent or fabric softening composition according to Claim 10, wherein the fragrance is homogeneously dispersed in the polymeric material.

12. The detergent or fabric softening composition according to Claim 10, wherein the detergent or fabric softening composition is coated with a layer or film on a core comprising the polymeric material and the fragrance and the layer or film on the core is coated with a layer of the enveloping material.

13. The detergent or fabric softening composition according to any one of Claims 1 - 9, wherein the fragrance releasing means comprises:

(a) a core comprising the fragrance, optionally comprised by an inert filler material; (b) the polymeric material; and

(c) optionally an enveloping material being permeable for the fragrance or being soluble or disintegrating in water.

14. A method for releasing a fragrance substance from a detergent or fabric softening composition, the detergent or fabric softening composition comprising a controlled fragrance releasing means, said controlled fragrance releasing means comprising a polymeric material and a fragrance substance, wherein the fragrance substance is released from the controlled fragrance releasing means by reversible modification of the release characteristics of the polymeric material by supplying energy from an external energy source, and wherein the polymeric material has a glass transition temperature within the range of about 20° to about 80°C.