Embodiments of the invention describe an illuminator having a light source to originate an illumination beam, wherein the light source further comprises a set of vertical-cavity surface emitting lasers (VCSELs), including a first VCSEL having a first laser emission wavelength, and a second VCSEL having a second laser emission wavelength different than the first laser emission wavelength. Thus, by varying laser emission wavelengths of VCSELs in a VCSEL array, embodiments of the invention produce low-contrast speckle, and do not limit the imaging capabilities of the host illumination system. In some embodiments of the invention, vertical external cavity surface emitting lasers (VECSELs) are utilized to produce the above described varying laser emission wavelengths.

Illumination systems include a light source and illumination optics for transferring light from the light source to a desired destination. Light from the light source is projected to a target, and the light reflected back is collected to form an image. The light source in an illumination system may be, for example, a light emitting diode (LED) or a laser. Laser light is inherently narrow band and gives rise to the perception of fully-saturated colors and unfortunately, narrow band light incident on random surfaces introduces an unacceptable image artifact known as "speckle."
Speckle (or speckle noise) may exist when one or more coherent light sources, such as laser light sources, are used in an illumination system. Speckle is typically randomized interference and a characteristic of coherent imaging.
The visual effects of speckle detract from the aesthetic quality of an image and also result in a reduction of image resolution. A variety of "de-speckling" techniques known in the art can be used to reduce this artifact to "acceptable levels," but only at the expense of system efficiency, which negatively impacts cost, reliability, package size, and power consumption.
Semiconductor lasers can be used to emit light in the near infrared wavelength range for illumination applications such as night-vision, covert surveillance, or industrial illumination. One particular structure of a semiconductor laser is a vertical-cavity surface emitting laser (VCSEL), where light emits perpendicular to the surface of the wafer plane. This vertical structure of the VCSEL lends itself easily towards building 2D arrays with high output power and low beam divergence, and the light from each VCSEL emitter element in the array can be easily collimated and used to build an efficient laser illuminator.
In the prior art, each VCSEL in an array tends to have very close to the same wavelength. This is due to the close proximity of the emitter elements within the array and the uniform wafer characteristics of the epitaxially grown laser structure. Therefore the individual VCSELs in the 2D array form speckle patterns that are nearly identical. These patterns combine to form high contrast speckle. High contrast speckle results in high levels of noise in the image, and limits the ability of an imaging system to resolve fine spatial detail. At worst, without some form of correction, speckle can make coherent illumination unsuitable for display purposes.
When operating near the noise floor of the system, such speckle noise can have a pronounced impact. Current techniques used to break speckle noise, such as utilizing vibrating diffusers and fiber stretchers, can actually introduce additional artifacts that reduce the image quality.
Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the inventive concepts presented herein. An overview of embodiments of the invention is provided below, followed by a more detailed description with reference to the drawings.
Description
Embodiments of the invention describe an illuminator having a light source to originate an illumination beam, wherein the light source further comprises a set of vertical-cavity surface emitting lasers (VCSELs) having varying laser emission wavelengths. It is to be understood in view of the description below that, by varying laser emission wavelengths of VCSELs in a VCSEL array, embodiments of the invention produce low-contrast speckle without limiting the imaging capabilities of the host illumination system. In some embodiments of the invention, vertical external cavity surface emitting lasers (VECSELs) (which, as referred to herein, are to be understood as type of VCSEL), are utilized to produce the above described varying laser emission wavelengths.
The VCSEL-based illuminators described by embodiments of the invention may use robust single-chip spectral interleaving approaches as described below. While each VCSEL in the array has a narrow bandwidth, each VCSEL in embodiments of the invention may be engineered to have a different wavelength based on various fabrication processes. Thus the individual speckle patterns generated by said VCSEL arrays have a low correlation, and the large number of VCSELS in an array average out to a uniform background.
Throughout this specification, several terms of art are used. These terms are to take on their ordinary meaning in the art from which they come, unless specifically defined herein or the context of their use would clearly suggest otherwise. In the following description numerous specific details are set forth to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.
FIG. 1 is a block diagram of an illumination and imaging system according to an embodiment of the invention. Illumination is used in order to provide photons necessary for a person or a camera to see a scene, for example, imaging a scene with a near-infrared (700 nm to 1.1 um) or short-wave infrared (800 nm to 1.7 um) camera. Illumination is also used to provide hyper-spectral illumination for hyper-spectral imaging.
In this embodiment, system 100 may be used for illumination applications such as night-vision, covert surveillance, or industrial illumination. System 100 includes laser light source 102, which includes a 2D VCSEL array. It is understood that the vertical structure of a VCSEL lends itself easily towards building 2D arrays with high output power and low beam divergence. Furthermore, the arrangement of the VCSELs in the 2D array creates light that may be easily collimated and used to build an efficient laser illuminator.
System 100 further includes microlens array 104, aligned with each VCSEL of light source 102, to collimate the generated light. The resultant collimated light is directed towards object 190 within in field of view 106 to illuminate said object.
System 100 may further include imaging optics configured to receive light from the illumination beam reflected from a surface of object 190. In this embodiment, said imaging optics are shown to include lens assembly 108 for focusing light on photosensitive or photodiode ("PD") region 110 to produce an image.
Determining speckle noise in the produced image is a complex assessment that includes the laser illuminator parameters, the imager parameters, and details related to the target surface depth within a resolved pixel of the sensor. At its most basic characterization, speckle is influenced by the relative spatial coherence of laser light source 102, the spectral coherence of said light source with respect to the depth of target 190, and details related to unintentional coherent interactions within the VCSEL array of laser light source 102. Objective speckle is formed by the reflection of coherent light from a rough surface onto a second surface. The second surface contains speckle whose properties are not a function of the viewing optics. Subjective speckle is formed when the first illuminated surface is viewed by an optical system (e.g., an eye or camera lens). The subjective speckle is formed on the image plane and is a function of the lens position, focal length, aperture size, and detailed design.
Prior art VCSEL arrays tend to include VCSELs having the same lasing emission wavelength, due to the close proximity of the emitter elements within the array and the uniform wafer characteristics of the epitaxially grown laser structure. Therefore the individual VCSELs in the 2D array may form speckle patterns in the produced image that are nearly identical, thereby forming high contrast speckle. It is understood that high contrast speckle results in high levels of noise in the image, and limits the ability of an imaging system to resolve fine spatial detail. Thus, laser light source 102 is designed to include an array of VCSELs having differing lasing emission wavelengths as described below. It is to be understood that such VCSEL arrays according to embodiments of the invention produce low-contrast speckle, and do not limit the imaging capabilities of system 100.
FIG. 2 is a block diagram of a laser light source and an image pixel according to an embodiment of the invention. In this embodiment, imager subsystem 200 is shown to include VCSEL array 202 and imager pixel 204 used to capture imaging information for target 290. In this figure, VCSEL array 202 is shown to include three VCSELs (211, 212 and 213). It is to be understood that in other embodiments of the invention, said VCSEL array may include many more VCSELs.
Imager pixel 204 as illustrated may be one of a plurality of imager pixels, or may be included in a single pixel device (e.g., an infrared distance measuring device such as a range finder). It is understood that in, for example, short-wave infrared (SWIR) target recognition and identification applications at long ranges, a user is typically dealing with situations where the imager resolution limited sampling distance on target 290 is on the order of 2-4 cm (w in FIG. 2). In such a situation, prior art VCSEL arrays operating at a long range will essentially illuminate each width of the target w from what appears to be the same location. It is understood that such real-world targets likely have depth that varies by on the order of a millimeter (d in FIG. 2) across the width of the resolved area w.
For SWIR imaging systems designed to work over broad spectral ranges, one may be operating with a lens design that has the size of the Airy disk nearly the same as the pixel pitch in the imager. This is especially true as SWIR imagers move toward 10 micron and smaller pixels. Thus with laser illuminators in general, when illuminating targets at long ranges (e.g., hundreds of meters), the small laser exit aperture leads to a situation where the laser has a large amount of spatial coherence and this spatial coherence generates a speckle structure that is the size of, or just larger than, the Airy pattern on the imager (although speckle structures may have a wide range of sizes—it may be as small as the Airy disk or several times larger; significant amounts of speckle will be seen for pixel sizes significantly larger than the Airy disk).
Hence, it is very probable that under some situations laser illumination can be expected to produce speckle that will be resolved by the imager and hence will degrade the image. Thus spatial coherence is a problem with illuminators in general; this problem is addressed by embodiments of the invention described below, which further address and reduce speckle interference.
Due to the spatial coherence of VCSEL arrays, embodiments of the invention may vary the optical path length for the ensemble of VCSEL array 202 such that VCSELs 211-213 vary by at least one wavelength in order to for the interference pattern on the imager to average out within pixel 204 to avoid pixel-to-pixel intensity artifacts. In one embodiment, the optimal wavelength difference is determined by the equation:
            d      λ        -          d              λ        +                  Δ                                                              λ                      ≈            d      ·      Δλ              λ      2        ≥  1
The above equation shows the relationship for the coherent interference is to just average out across pixel 204. For a wavelength of 1 micron and a depth, d, of 1 mm (i.e., this depth equating to the total path length variation of the reflected light from object 290 to pixel 204 of the imager subsystem 200), the Δλ utilized may be about 1 nm. In this example, this may be the minimum condition, and also the condition for 1 mm of depth across pixel 204. In other embodiments, it is understood that for uniform cancelation of speckle noise, even from an array of VCSELs, a spectral bandwidth value several times 1 nm may be desirable.
FIG. 3 is a graph comparing noise generated based on speckle for systems utilizing the prior art and embodiments of the invention. Graph 300 includes curve 302 illustrating prior art illuminator speckle/artifacts, curve 304 illustrating speckle/artifacts generated by an embodiment of the invention, and curve 306 shows camera noise generated by the host illumination system itself.
The small size and narrow spectral bandwidth of the lasers can cause speckle to be seen when viewing the illuminated object, as is common in laser illumination. Speckle is caused by the interaction of the laser energy with the optical surfaces that the laser energy encounters on its path from the laser aperture to the target and back to the eye or camera photon collection surface (i.e., retina or the camera focal plane array, respectively). Optical interference between the photons causes the appearance of bright and dark spots in the laser illuminated scene to be perceived by the camera or the eye. In low light levels, this optical interference, or speckle noise, reduces the clarity of the image and hence reduces the utility of the laser illumination for providing better visibility in low light or for providing optical energy for hyper-spectral imaging.
As can be seen in curve 302, speckle is highly undesirable because its high contrast masks the detection of elements in the scene being illuminated Curve 302 further shows how speckle can lead to the appearance of large amounts of additional noise when the light level in a scene is low and hence the noise due to the speckle moves the perceived pixels of the image in and out of the noise floor (i.e., curve 306) of the image.
Thus, curve 302 shows how the intensity noise detected in a row of pixels can dominate when operating near the noise floor of the imager, as is typical in low-light situations at long ranges. Curve 304 shows that by reducing the illuminator artifacts utilizing any of the embodiments of the invention described herein, the dominant signal can be restored to the scene that is being illuminated away from the noise of the illuminator itself (i.e., curve 306).
FIG. 4 is a cross-section schematic of a VCSEL array where the emission wavelength of each element within the array is different in accordance with an embodiment of the invention. In this embodiment, VCSEL array 400 is shown to include VCSELs 401, 402, 403 and 404. Said VCSELs each have varying lasing emission wavelengths 405, 406, 407 and 408, respectively. In this illustration, each of said VCSELs are top-emitting VCSELs. Other embodiments of the invention may utilize bottom emitting VCSELs.
FIG. 4 further includes a magnified illustration of VCSEL 401 to show its components, including complementary electrodes 411, semiconductor substrate 412, 1st and 2nd reflectors 413, gain region 414, and aperture formation regions 415. In this illustrated embodiments, VCSEL 401 is shown to further include isolation layer 416 disposed between an electrode and a reflector. It is to be understood that VCSELs 402-404 as illustrated include similar components.
In some embodiments of the invention, each of VCSELs 401-404 may include structural variations in any of the above described components to produce varying lasing emission wavelengths. For example, in some embodiments of the invention, each of VCSELs 401-404 may have different cavity lengths. It is to be understood that varying said laser cavity lengths varies the respective VCSELs' laser oscillator lengths. This may be accomplished, for example, by mirror deposition variation, material thickness trimming, the use of unique gratings, or any combination of these processes.
In other embodiments, each of VCSELs 401-404 may utilize a set of mirrors to define different resonant cavities, which will result in varying lasing emission wavelengths 405-408. In other embodiments, each of the reflectors of VCSELs 401-404 (such as reflectors 413 of VCSEL 401) may comprise one or more distributed Bragg reflectors (DBRs), wherein said DBRs are used to form a different effective optical path length for each VCSEL. In these embodiments of the invention, said reflectors may comprise any DBR configuration to form varying effective optical path lengths—e.g., a 1st DBR paired with an opposing dielectric DBR, a semiconductor DBR, an optical grating, etc. In other embodiments, each of VCSELs 401-404 may include variable sets of gratings to produce varying lasing emission wavelengths 405-408.
In some embodiments of the invention, each of VCSELs 401-404 may be processed to include designed structural variations (for example, varying aperture formation regions such as regions 415 of VCSEL 401 to vary their emitter diameters) such that they possess a different and unique mode structure and/or volume, thereby generating differing wavelengths 405-408.
In other embodiments of the invention, each of VCSELs 401-404 may include active cavity regions (such as gain region 414 and aperture formation region 415 of VCSEL 401) comprising different refractive indexes. Index of refraction variation within VCSEL array 400 may be accomplished by using tapered oxidation layers or other tapered or modulated dielectric or semiconductor layers.
In other embodiments of the invention, thermal approaches may be used to spectrally broaden VCSEL array 400 for low-speckle. It is to be understood that temperature variations across VCSELs 401-404 will induce changes in lasing wavelengths 405-408 due to wavelength drift. This may be accomplished by patterned heat spreaders, solders, or current injection gradient techniques.
FIG. 5 is a diagram of an array of VCSELs with varying optical cavity lengths according to an embodiment of the invention. In this embodiment, each of VCSELs 501, 502 503 and 504 include variations to the same intra-cavity structure component to produce varying laser emission wavelengths 505, 506, 507 and 508, respectively.
In this embodiment, layers 511, 512, 513 and 514 are shown to be progressively thinner in order to change the optical cavity length of VCSELs 501, 502, 503 and 504, respectively, thereby allowing for variations in laser emission wavelengths 505-508. For example, in embodiments where the reflectors of VCSELs 501-504 comprise DBRs formed from gallium arsenide (GaAs) and aluminum gallium arsenide (AlGaAs), each of layers 511-514 may be thinning layers of GaAs used in conjunction with dielectric DBRs above each device, 521, 522, 523 and 524, thereby allowing for variations in laser emission wavelengths 505-508 respectively.
Thus in the above described embodiments of the invention, because VCSELs 501-504 oscillate in a single longitudinal mode (with a narrow spectrum bandwidth and thereby emit a beam having a small angle of divergence), differing structural characteristics between each VCSEL changes the wavelength (i.e., wavelengths 505-508) of the longitudinal mode of each respective VCSEL. In other embodiments of the invention implemented in an array of VCSELs wherein each VCSEL has multiple selectable longitudinal modes, mechanisms are utilized so that VCSELs within the array select different longitudinal modes.
FIG. 6 is a diagram of an array of VESCELs where the emission wavelength of each element within the array is different in accordance with an embodiment of the invention. In this embodiment, VECSELs 601, 602, 603 and 604 of array 600 are structurally similar to VCSELs 401-404 of array 400, except each of said VECSELs separates one (or both) mirrors from the semiconductor substrate by replacing an upper mirror of the structure formed on a corresponding substrate (such as top reflector 413 of VCSEL 401) with a reflective material external to the cavity—shown here as external cavity reflector 610 formed along with microlens 611. Said external cavity reflector is formed to be separate from the remaining structure of VECSELs 601-604, and thus obtains a high output power and supports multiple longitudinal modes.
Embodiments of the invention may utilize various mechanisms to select different supported longitudinal modes for each of VECSELs 601-604. For example, the regions of external cavity reflector corresponding to each respective VECSEL may be configured to define different resonant cavities, thereby producing different laser emission wavelengths 605-608. In some embodiments, external cavity reflector 610 may comprise optical reflective gratings with varying pitch lengths, thereby producing different laser emission wavelengths for each of VECSELs 601-604.
Thus, as seen from the above examples illustrated in FIG. 5 and FIG. 6, embodiments of the invention may be utilized by VCSELs including a single or multiple longitudinal modes.
FIG. 7A is an illustration of a 2D VCSEL array emission format according to an embodiment of the invention. In this embodiment, a VCSEL-based laser low-speckle illuminator includes 2D array of VCSEL emitter elements 700. Said VCSEL emitter elements comprise varying laser emission wavelengths, thereby providing a broad spectral emission range. In this example, wavelengths λ1-λ10 are shown to vary, wherein the full width at half-maximum value (FWHM) of λ is ˜10 nm.
The number of pixels and the number of unique spectral elements within array 700 is dependent on the power and spectral bandwidth specification of the illuminator. The spectral gradient (i.e., laser emission wavelength variations) within array 700 may be limited to specific orientations. For example, the gradient may span from left to right (or any direction) from short to long wavelengths; radially outward, or a completely random pattern. The array may also be divided into groupings or sections across the array with unique wavelengths. It is also to be understood that the shape of array 700 is arbitrary, and may comprise other shapes in other embodiments (e.g., circular, square, etc).
In some embodiments of the invention, techniques to engineer a certain wavelength gradient or pattern into VCSEL array 700 for low-speckle using growth approaches include using non-rotation growth techniques, thermal gradient growth control, patterned or selective area growth, or combinations of the aforementioned growth techniques.
FIG. 7B is an intensity/wavelength spectra diagram for the VCSEL array described above with respect to FIG. 7A. Diagram 750 is an illustration of a 10 nm spectrum from a low-speckle VCSEL illuminator array at one temperature. As shown in this diagram, each of varying laser emission wavelengths (shown as curves 751, 752, 753, 754, 755, 756 and 757) combine to provide a wide light source of increased intensity, represented by curve 760.
Reference throughout the foregoing specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In addition, it is appreciated that the figures provided are for explanation purposes to persons ordinarily skilled in the art and that the drawings are not necessarily drawn to scale. It is to be understood that the various regions, layers and structures of figures may vary in size and dimensions.
In the foregoing detailed description, the method and apparatus of the present invention have been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention. The present specification and figures are accordingly to be regarded as illustrative rather than restrictive.

Multi-wavelength VCSEL array to reduce speckle


An aqueous shear-thinning personal care composition comprising:

This invention relates to a personal care composition, for example a liquid or gel body wash, shower gel, handwash, skin cream, hair conditioner or moisturiser.
U.S. Pat. No. 5,612,307 discloses an aqueous liquid cleansing and moisturising composition comprising: a) a surface active agent selected from anionic, nonionic, zwitterionic and cationic, surface active agents, soap and mixtures thereof; and b) a benefit agent;
wherein the benefit agent and surface active agent are separate but combinedly dispensable from a single packaging means in a predetermined ratio as discrete domains, the domains having one dimension of at least about 1000 microns.
An advantage of the invention of U.S. Pat. No. 5,612,307 is said to be that it leads to improved deposition of benefit agents from a surface active agent containing aqueous liquid composition during use. The surface active agent and benefit agent are separated in the composition, i.e. they do not directly contact one another in the composition. This avoids adverse interactions which may occur between these two components and which may result in ineffective deposition of the benefit agent.
The composition of U.S. Pat. No. 5,612,307 is said to be suitable for cleansing and "moisturising", "conditioning" or "protection" of the skin. The benefit agent is included in the composition to moisturise, condition and/or protect the skin. By "benefit agent" is meant a substance that softens the skin (stratum corneum) and keeps it soft by retarding the decrease of its water content and/or protects the skin.
Preferred benefit agents of U.S. Pat. No. 5,612,307 include: silicones and siloxanes; fats and oils; waxes; hydrocarbons; higher fatty acids; higher alcohols; esters; essential oils; lipids; vitamins; sunscreens; and phospholipids.
Where adverse interactions between the benefit agent and surface active are likely to be particularly acute, U.S. Pat. No. 5,612,307 states that the benefit agent may be incorporated in the compositions in a carrier.
The surface active agent of U.S. Pat. No. 5,612,307 is preferably present at a level of from 1 to 35 wt %, preferably 3 to 30 wt %.
One preferred anionic detergent for use in the invention of U.S. Pat. No. 5,612,307 is a fatty acyl ethane sulfonate of formula RCO2CH2CH2SO3M, where R is an alkyl or alkenyl group of 7 to 21 carbon atoms and M is a solubilising cation such as sodium, potassium, ammonium or substituted ammonium. Preferably at least three quarters of the RCO groups have 12 to 18 carbon atoms and may be derived from coconut, palm or a coconut/palm blend.
It is also preferable in U.S. Pat. No. 5,612,307 that the composition includes from 0.5 to 15 wt % of a cosurfactant agent with skin-mildness benefits. Suitable materials are zwitterionic detergents identified in U.S. Pat. No. 5,612,307.
A favoured fatty acyl ethane sulfonate is "SCI" (sodium cocyl isethionate). SCI is commercially available and is a successful product but the scope it offers formulators is limited by its low solubility in water; its low hydrolytic stability, and the lack of stability in its pH value, over time.
The present invention is based on the use of a different fatty acyl sulfonate salt, and its advantageous co-formulation with amphoteric or zwitterionic surfactants, in aqueous environments.
In accordance with a first aspect of the present invention there is provided an aqueous shear-thinning personal care composition comprising:
(a) at least 3 wt % of a sulfonate compound of general formula

where R1 represents a C8-22 alkyl group;
R2 represents a C1-4 alkyl group;
each of R3, R4 and R5 independently represents a hydrogen atom or a C1-4 alkyl group; and
M+ represents a cation;
(b) at least 3 wt % of an amphoteric or zwitterionic surfactant;
(c) at least 10 wt % of water; and
(d) at least 0.5 wt % of an additional component in the form of particles or droplets suspended in the composition.
There may be further components present in the composition. Percentages given herein are percentages on total weight of the composition, including any such further components, for example when there is a plurality of compounds (a); and/or a plurality of surfactants (b).
Many additional components are described hereafter, some of which may go into solution and some of which remain in the composition as particles or droplets. The stipulation of the definition of the invention is that there must be at least one additional component which is in the form of particles or droplets suspended in the composition. The compositions of the present invention have an exceptional ability to be formulated with further components and in particular to suspend particles or droplets and we regard this as an essential element of the invention.
Preferably R1 represents a C10-20 alkyl group, most preferably a C12-18 alkyl group.
Preferably R2 represents a C1-4 alkyl group in which a propyl or butyl group is straight-chain. Preferably R2 represents an n-propyl, ethyl or, most preferably, a methyl group.
Preferably R3 represents a hydrogen atom.
Preferably one of R4 and R5 represents a hydrogen atom and the other represents a hydrogen atom or a C1-4 alkyl group, Preferably one of R4 and R5 represents a hydrogen atom or a C1-4 alkyl group in which a propyl or butyl group is straight-chain. Preferably one of R4 and R5 represents an n-propyl, ethyl or methyl group or, most preferably, a hydrogen atom. Most preferably both R4 and R5 represent hydrogen atoms.
Preferably M+ represents an ammonium cation or, most preferably, a metal cation. Suitable metal cations include alkali metal cations, for example sodium and potassium cations, and alkaline earth metal cations, for example calcium and magnesium cations. Preferably M+ represents a potassium cation, or, especially, a sodium cation.
Of course, a plurality of compounds (a) may be present.
Component (b) may include amphoteric or zwitterionic surfactants selected from betaines, for example alkyl betaines, alkylamidopropyl betaines, alkyamidopropyl hydroxysultaines, alkylampho acetates, alkylamphodi-acetates, alkylamphopropionates, alkylamphodipropionates, alkyliminodipropionates and alkyliminodiacetate.
Of course, a plurality of surfactants (b) may be present.
Amphoteric or zwitterionic surfactants may include those which have an alkyl or alkenyl group of 7 to 22 carbon atoms and comply with an overall structural formula:

where R1 is alkyl or alkenyl of 7 to 22 carbon atoms; R2 and R3 are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 6 carbon atoms; m is 2 to 4; n is 0 or 1; X is alkylene of 1 to 6 carbon atoms optionally substituted with hydroxyl; and Y is —CO2 or —SO3.
Amphoteric or zwitterionic surfactants may include simple betaines of formula:

and amido betaines of formula:

where m is 2 or 3.
In both formulae R1, R2 and R3 are as defined previously. R1 may, in particular, be a mixture of C12 and C14 alkyl groups derived from coconut so that at least half, preferably at least three quarters, of the groups R1 has 10 to 14 carbon atoms. R2 and R3 are preferably methyl.
Amphoteric or zwitterionic surfactants may include sulphobetaines of formula:

where m is 2 or 3, or variants of these in which —(CH2)3SO3− is replaced by

where R1, R2 and R3 in these formulae are as defined previously.
Amphoteric or zwitterionic surfactants may include amphoacetates and diamphoacetates. Amphoacetates generally conform to the following formula:

Diamphoacetates generally conform to the following formula:

where R is an aliphatic group of 8 to 22 carbon atoms and M is a cation such as sodium, potassium, ammonium, or substituted ammonium.
Compounds such as oleylbetaine and cocoamidopropylhydroxy-sultaine are regarded as very safe for the human body and for the eyes. Also preferred in some embodiments are sodium lauroamphoacetate, sodium cocoamphoactetate, disodium lauroamphoacetate, and disodium cocoampho-diacetate.
Preferably, in a composition in accordance with the present invention, component (a) is present in an amount of up to 30% by total composition weight.
Preferably in a composition in accordance with the present invention, component (b) is present in an amount of up to 30% by total composition weight.
Preferably in a composition in accordance with the present invention, component (c) is present in an amount of from 20% to 95% by total composition weight, preferably from 50 to 90%.
In one embodiment the composition of the present invention is a free-flowing liquid.
In one embodiment a composition in accordance with the invention is a shear thinning composition.
A composition in accordance with the present invention may suitably have a viscosity of from 250 to 300,000 mPa·s, measured at 25° C. using a Brookfield rotational viscometer equipped with an appropriate spindle at a rotation speed of from 0.1 revolutions per minute (rpm) to about 60 rpm. Examples of appropriate spindles include the Brookfield RVT Viscometer Helipath T-Bar Spindles B and C (used in the examples which follow). At low shear rates (rotation speeds) the viscosity as measured may be up to 300,000 mPa·s. At high shear rates (rotation speeds) the viscosity as measured may be as low as 250 mPa·s.
The compositions of the invention may be pourable liquids or semi-liquids e.g.
The compositions of the invention may be soft gels and may suitably be of viscosity in the range 800 to 20,000 mPa·s, measured under the conditions stated above.
The compositions of the invention may be firmer gels and may be of viscosity in the range 3000 to 100,000 mPa·s, measured under the conditions stated above.
Surprisingly, the aqueous compositions of the invention have desirable non-Newtonian properties and excellent suspending properties, being capable of maintaining solid or non-solid water-insoluble particles or droplets in suspension. Under the conditions of testing which have been applied in relation to the invention, no sedimentation or separation whatsoever of the water-insoluble particles or droplets has developed over time. Furthermore the compositions of the invention produce an excellent rich creamy foam which is stable, and is mild to the skin and eyes.
Without being bound by theory, it is believed possible that the following microstructural conditions are achieved in the present invention.
The compositions of the present invention are believed to exhibit a so-called lamellar phase structure comprising spherulites in suspension.
By "lamellar phase" is intended a hydrated solid phase or a liquid crystal phase in which several double layers are arranged in a parallel network, separated by layers of water or of an aqueous solution. In respect of the spherulites, these are multilamellar vesicles comprising several layers of surface-active agents arranged concentrically and generally ranging from 0.1 to 50 microns in size.
More specifically, the corresponding phase structure may, we believe, be a birefringent solution, optically characteristic of a non-isotropic mesomorphic phase. By the term "water-insoluble particles" are intended solid or non-solid entities which are not solubilized in the aqueous medium of the subject composition. These, more particularly, are solid particles or suspended droplets.
However the more significant point is not the microstructure per se but the fact that the components together produce a composition with excellent overall or macroscopic properties.
Important advantages of the compositions of the invention over many other compositions, and in over particular over compositions containing fatty acyl ethane sulfonates, such as SCI, is that they are hydrolytically stable and pH-stable, and that they can be formulated with many further ingredients, including particulates and droplets, without adverse interactions being found.
The composition may contain an electrolyte. An electrolyte is suitably present in an amount of from 0.5% to 25%, preferably 1% to 15%, preferably 2 to 10%, by total composition weight. The concentration thereof may be adjusted to produce the desired formulation.
Suitable as an electrolyte are ionic compounds, for example metal salts selected from sodium chloride, sodium sulfate, potassium chloride, potassium sulfate, sodium phosphate, disodium phosphate, potassium phosphate, dipotassium phosphate, sodium isethionate, sodium methyl isethionate and sodium lactate; and non-metallic salts, for example sodium citrate, ammonium chloride, ammonium citrate and ammonium lactate.
Preferred electrolytes include sodium and ammonium chloride.
Said additional component (d) is suitably one or more benefit agents in the form of particles or droplets. By "benefit agent" we can adopt the definition of US 2003/0180246A, that is, a "benefit agent" is any active ingredient that is to be delivered into the skin or hair, or onto the skin or hair, or both, at a desired location. For example, a benefit agent may be a substance that softens the skin (stratum corneum) and keeps it soft by retarding the decrease of its water content; and/or a substance which protects the skin; and/or an exfoliating material, for example a water insoluble particulate or suspended abrasive.
Preferred benefit agents include:                a) silicone oils, gums and modifications thereof such as linear and cyclic polydimethylsiloxanes, amino, alkyl alkylaryl and aryl silicone oils;        b) fats and oils including natural fats and oils such as jojoba, soyabean, rice bran, avocado, almond, olive, sesame, persic, castor, coconut, mink oils; cacao fat, beef tallow, lard; hardened oils obtained by hydrogenating the aforementioned oils; and synthetic mono, di and triglycerides such as myristic acid glyceride and 2-ethylhexanoic acid glyceride;        c) waxes such as carnauba, spermaceti, beeswax, lanolin and derivatives thereof;        d) hydrophobic plant extracts;        e) hydrocarbons such as liquid paraffins, petroleum jelly, microcrystalline wax, ceresin, squalene, squalane, and mineral oil;        f) higher fatty acids such as lauric, myristic, palmitic, stearic, behenic, oleic, linoleic linolenic, lanolic, isostearic and poly unsaturated fatty acids (PUPA) acids;        g) higher alcohols such as lauryl, cetyl, steryl, oleyl, behenyl, cholesterol and 2-hexadecanol alcohol;        h) esters (fatty acid esters, fatty alcohol esters) including cetyl octanoate, myristyl lactate, cetyl lactate, isopropyl myristate, myristyl myristate, isopropyl palmitate, isopropyl adipate, butyl stearate, decyl oleate, cholesterol isostearate, glycerol monostearate, glycerol distearate, glycerol tristearate, alkyl lactate for example lauryl lactate, alkyl citrate and alkyl tartrate;        i) essential oils such as fish oils, fragrance oils, mentha, jasmine, camphor, white cedar, bitter orange peel, ryu, turpentine, cinnamon, bergamont, citrus unshiu, calamus, pine, lavender, bay, clove, hiba, eucalyptus, lemon, starflower, thyme, peppermint, rose, sage, menthol, cineole, eugenol, citral, citronelle, borneol, linalool, geraniol, evening primrose, camphor, thymol, spirantol, pinene, limonene and terpenoid oils;        j) lipids such as cholesterol, ceramides, sucrose esters and pseudo-ceramides as described in European Patent Specification No. 556 957;        k) vitamins such as vitamin A and E, and vitamin alkyl esters, including those vitamin C alkyl esters;        l) sunscreens such as octyl methoxyl cinnamate (Parsol MCX) and butyl methoxy benzoylmethane (Parsol 1789);        m) phospholipids; and        n) one or more of scrubbing beads, anti-dandruff agents, anti-UV actives, mica, silica, pigments, natural and synthetic waxes, zinc oxide, titanium dioxide.
Other examples of suitable benefit agents include: depigmentation agents; reflectants; UV absorbers, thickening agents; detangling/wet combing agents; film forming polymers; humectants; amino acids and their derivatives; antimicrobial agents; anti-acne agents; anti-aging agents; antiseptics; analgesics; local anesthetics; anti-hair loss agents; hair growth inhibitor agents; inflammation inhibitors; proteins; deodorants and anti-perspirants; agents for treatment of dandruff, seborreheic dermatitis and psoriasis; skin emollients and skin moisturizers; hair conditioners; hair softeners; hair moisturizers; vitamins; tanning agents; skin lightening agents; antifungals such as antifungals for foot preparations; depilating agents; counterirritants; hemorrhoidals; insecticides; pigments or opacifying agents, moisturizing beads, natural abrasives, synthetic abrasives such as polyoxyethylene beads, mineral oils, petrolatum, silicone oils, polyalkylsiloxanes, polyalkyarylsiloxanes, sunscreens, reflectants and the like; and mixtures thereof.
Examples of suitable reflectants include mica, alumina, calcium silicate, glycol dioleate, glycol distearate, silica, sodium magnesium fluorosilicate, and mixtures thereof.
Examples of suitable UV absorbers include benzophenone, bornelone, PABA (Para Amino Benzoic Acid), butyl PABA, cinnamidopropyl trimethyl ammonium chloride, disodium distyrylbiphenyl disulfonate, potassium methoxycinnamate, and mixtures thereof.
The benefit agent (or benefit agents, in total) is preferably present in amount of from 0.1 to 50%, preferably from 1 to 40%, preferably from 1.5 to 30%, and most preferably from 2 to 20% by weight based on the composition weight.
A structurant may be added to the phase comprising the surface active agent, suitably in an amount of from 0.01%, preferably from 0.1%, more preferably from 1%, by weight based on the composition weight.
A structurant may be added to the phase comprising the surface active agent, suitably in an amount of up to 15%, preferably up to 12%, more preferably up to 10%, and most preferably up to 5%, by weight based on the composition weight.
The primary purpose of a structurant is to assist in the formation of a lamellar phase. It is believed that a lamellar phase, if achieved, may enable the compositions to suspend particles more readily while still maintaining good shear thinning properties. The lamellar phase also provides consumers with desired rheology ("heaping").
Suitable structurants include swelling clays, for example laponite; fatty acids and derivatives thereof, in particular, fatty acid esters; cross-linked polyacrylates such as Carbopol™ (polymers available from Goodrich); acrylates and copolymers thereof; polyvinylpyrrolidone and copolymers thereof; polyethylene imines; salts such as sodium chloride and ammonium sulphate; sucrose esters; gellants; and mixtures thereof. Examples of fatty acids which may be used are C10-C22 acid (e.g. lauric, oleic etc.), isostearic acid, linoleic acid, linolenic acid, ricinoleic acid, elaidic acid, arichidonic acid, myristoleic acid and palmitoleic acid. Ester derivatives include propylene glycol isostearate, propylene glycol oleate, glyceryl isostearate, glyceryl oleate and polyglyceryl diisostearate. Monoglyceride polyglycol ethers are suitable structurants.
Of the clays, particularly preferred are synthetic hectorite (laponite) clay used in conjunction with an electrolyte salt capable of causing the clay to thicken. Suitable electrolytes include alkali and alkaline earth salts such as halides, ammonium salts and sulphates.
The surface active agent phase may also comprise a thickening agent, ie a material which maintains the viscosity of this phase as the shear rate thereof is increased during use. Suitable materials include cross-linked polyacrylates such as Carbopol™ (polymers available from Goodrich); natural gums including alginates, guar, xanthan and polysaccharide derivatives including carboxy methyl cellulose and hydroxypropyl guar; propylene glycols and propylene glycol oleates; salts such as sodium chloride and ammonium sulphate; glycerol tallowates; and mixtures thereof.
Thickeners may also be added to the benefit agent in order to achieve the required viscosity during use. Preferred thickeners for the benefit agent include fumed silica; polyethylene; alkyl silicone waxes; aluminium silicate; lanesterol; natural and synthetic waxes; fatty acids and derivatives thereof, in particular, fatty acid monoglyceride polyglycol ethers; higher fatty alcohols; petrolatum; narogel; polyammonium stearate; hydrotalcites; and mixtures thereof. Hydrotalcites are materials of general formula[MmNn(OH)2(m+n)]n+Xx−n/x.yH2O
where M is a divalent metal ion e.g. Mg2−; N is a trivalent metal ion e.g. Al2+; X is an exchangeable anion e.g CO3−, NO3−; stearate, cinnimate; m is the number of divalent metal ions; and n is the number of trivalent metal ions.
Furthermore, the benefit agent may also function as a carrier to deliver efficacy agents to skin treated with the compositions of the invention. This route is particularly useful for delivering efficacy agents which are difficult to deposit onto the skin or those which suffer detrimental interactions with other components in the composition. In such cases the carrier is often a silicone or hydrocarbon oil which is non solubilised/micellised by the surface active phase and in which the efficacy agent is relatively soluble. Examples of such efficacy agents include anti-viral agents; hydroxycaprylic acids; pyrrolidone; carboxylic acids; 3,4,4′-trichlorocarbanilide; benzoyl peroxide; perfumes; essential oils; germicides and insect repellants such as 2,4,4′-trichloro-2′-hydroxydiphenyl ether (Irgasan DP300); salicylic acid; willow extract, N,N-dimethyl m-toluamide (DEET); and mixtures thereof.
The composition may contain one or more additional anionic surface-active agents, in addition to the acyl sulphonate salt defined above; preferably selected from salts of fatty acids; alkali metal salts of mono- or dialkyl sulfates; mono- or dialkyl ether sulfates; lauryl ether sulfates; alkyl sulfonates; alkyl aryl sulfonates; primary alkane disulfonates; alkene sulfonates; hydroxyalkane sulfonates; alkyl glyceryl ether sulfonates; alpha-olefinsulfonates; alkyl phosphates; sulfonates of alkylphenolpolyglycol ethers; salts of alkyl sulfopolycarboxylic acid esters; alkyl sulfosuccinates and salts thereof, alkyl ether sulfosuccinates and salts thereof, non-acylated alkyl isethionates; fatty acid taurates; acyl taurates; products of condensation of fatty acids with oxy- and aminoalkanesulfonic acids; sulfated derivatives of fatty acids and polyglycols; alkyl and acyl sarcosinates; sulfoacetates; alkyl phosphates; alkyl phosphate esters; acyl lactates; alkanolamides of sulfated fatty acids and salts of lipoamino acids. Particularly exemplary salts of the above, where applicable, are the sodium, potassium, ammonium, magnesium and triethylamine salts.
In the case of sodium lauryl ether sulfate, LESNa, this is a surface-active agent widely used in shampoos by reason of its foaming properties. It is a cheap, conventional, washing base.
The composition may contain one or more non-ionic surface-active agents, preferably selected from the following: reaction products of compounds having a hydrophobic group and a reactive hydrogen atom, for example aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide (for example alkyl (C6-C22) phenol-ethylene oxide condensates, the condensation products of aliphatic (C8-C18) primary or secondary linear or branched alcohols with ethylene oxide, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylenediamine); long chain tertiary amine oxides, long chain tertiary phosphine oxides and dialkyl sulphoxides; alkyl amido amine oxides; alkyl tertiary phosphine oxides; alkoxyl alkyl amines; sorbitan; sorbitan esters; sucrose esters; sugar amides, such as a polysaccharide amide; lactobionamides; and alkyl polysaccharide nonionic surfactants, for example alkylpolyglycosides. Preferred non-ionic surfactants are sucroglycerides and ethyoxylated fatty alcohols, especially those derived from lauryl, cetylstearyl, stearyl, cetyl and oleocetyl alcohols.
A non-ionic surface active agent, when present, preferably comprises up to 15% wt of the composition, preferably up to 10% wt.
Representative solid particles include active materials or agents such as those used for hair treatments, e.g., zinc pyrithione, or any abrasive materials which may be of natural or synthetic origin. In particular, these are polycarbonates, polypropylenes, polyethylenes, alumina, calcite and clays. Such particles generally have a crystal size ranging from about 1 to 600 microns and preferably from about 10 to 400 microns.
In the case of the suspended droplets, these are preferably droplets of at least one vegetable oil, essential oil and/or, more particularly, silicone oil.
The silicone oils which are well suited according to the present invention include the polyalkylsiloxanes, polyalkylarylsiloxanes and mixtures thereof. The preferred polyalkylsiloxanes are, especially, polydimethylsiloxanes such as dimethicone whose viscosity may range from about 20 mPa·s to 50 Pa·s at 25° C., pure or mixed with cyclomethicone. Particularly exemplary of the polyalkylarylsiloxanes are the polyphenyldimethyl-siloxanes.
In particular, polydiorganosiloxanes such as polydimethylsiloxanes having a molecular weight of less than or equal to 3,000,000 and polydimethyl-diphenylsiloxanes of molecular weight of about 600,000 are especially well suited according to the invention. The size of the oil droplets within the compositions of the invention advantageously ranges from about 0.5 to 50 microns.
The formulations according to the invention may contain approximately 0.5% to 8% and, preferably, about 1.5% to 4.5% by weight of water-insoluble particles.
Specific formulations of the invention may include these:                (a) as additional anionic agent LESNa and as co-surface-active agent lauryl alcohol containing two moles of ethylene oxide per mole of lauric alcohol and as electrolyte NaCl in a lauryl alcohol 2EO/LESNa mole ratio of from 2.1 to 4.3,        (b) as additional anionic agent, a sodium lipoamino acid and the lipoproteol LC0® mixed with the same lauryl alcohol containing two moles of ethylene oxide per mole of lauric acid and having a lauryl alcohol 2EO/sodium lipoamino acid mole ratio ranging from about 1.2 to 6.7,        (c) as additional anionic agent LESNa, and as co-surface-active agent oleylbetaine and as electrolyte NaCl, in an oleylbetaine/LESNa mole ratio of from 1.1 to 3.7.
Generally, the compositions according to the invention contain an anionic surface-active agent mixed with at least one cosurface-active agent in a cosurface-active agent/anionic surface-active agent mole ratio equal to or greater than 1.
A benefit of the invention is the ability to suspend oil and/or emollient particles in a non-Newtonian composition. The following oil/emollients may optionally be suspended in the compositions of the invention. Various classes of oils are set forth below.
Vegetable oils: Arachis oil, castor oil, cocoa butter, coconut oil, corn oil, cotton seed oil, olive oil, palm kernel oil, rapeseed oil, safflower seed oil, sesame seed oil and soybean oil.
Esters: Butyl myristate, cetyl palmitate, decyloleate, glyceryl laurate, glyceryl ricinoleate, glyceryl stearate, glyceryl isostearate, hexyl laurate, isobutyl palmitate, isocetyl stearate, isopropyl isostearate, isopropyl laurate, isopropyl linoleate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, propylene glycol monolaurate, propylene glycol ricinoleate, propylene glycol stearate, and propylene glycol isostearate.
Animal Fats: acetylated lanolin alcohols, lanolin, lard, mink oil and tallow.
Other examples of oil/emollients include mineral oil, petrolatum, silicone oil such as dimethyl polysiloxane, lauryl and myristyl lactate.
The emollient/oil is generally used in an amount from about 0 to 20%, preferably 0 to 15% by wt. of the composition.
In addition, the compositions of the invention may include optional ingredients as follows:                Organic solvents, such as ethanol; auxiliary thickeners, sequestering agents, such as tetrasodium ethylenediaminetetraacetate (EDTA), EHDP or mixtures in an amount of 0.01 to 1%, preferably 0.01 to 0.05%; and coloring agents, opacifiers and pearlizers such as zinc stearate, magnesium stearate, TiO2, EGMS (ethylene glycol monostearate) or Lytron 621 (Styrene/Acrylate copolymer); all of which are useful in enhancing the appearance or cosmetic properties of the product.        Antimicrobials such as 2-hydroxy-4,2′4′ trichloro-diphenyl-ether (DP300); preservatives, for example dimethyloldimethyl-hydantoin (Glydant XL1000), parabens, sorbic acid etc.        Coconut acyl mono- or diethanol amides as suds boosters, and strongly ionizing salts such as sodium chloride and sodium sulfate may also be used to advantage.        Antioxidants such as, for example, butylated hydroxytoluene (BHT) may be used advantageously in amounts of about 0.01% or higher if appropriate.        Cationic conditioners which may be used include Quatrisoft LM-200 Polyquaternium-24, Merquat Plus 3330-Polyquaternium 39; Jellner Polyquaternium 10; Merquat 550; and Jaguar® type conditioners.        Deflocculating polymers.        Chelating agents including but not limited to EDTA, EDTA salts, NTA, methylenediamine disuccinate and salts of methylenediamine disucuccinate.
Compositions of the invention may be formulated as products for washing the skin, for example, bath or shower gels, hand washing compositions or facial washing liquids; pre- and post-shaving products; rinse-off, wipe-off and leave-on skin care products; products for washing the hair and for dental use.
In accordance with a second aspect of the present invention there is provided the use of a composition of the invention, as defined above, in the formulation of a personal care product with improved stability, in an aqueous environment.
In accordance with a third aspect of the present invention there is provided the use of a composition of the invention, as defined above, in the formulation of a personal care product which has improved stability in an aqueous environment compared with a corresponding compound in which each of R2 to R5 is a hydrogen atom.
Suitably the composition, and in particular the defined sulfonated compound, is resistant to breakdown in an aqueous environment. Preferably it has essentially no effect on the pH of the product, over time. It has excellent lathering properties and is very mild to skin and eyes.
Weight percentage values herein refer to the total complement of compounds of a named type, e.g. amphoteric or zwitterionic surfactants in total; or benefit agents in total.
Where a percentage value is given for a component it refers to the active content of that component.
The invention will now be further described, by way of example, with reference to the following examples.
Examples 1 to 5 were carried out to assess the suitability of certain isethionate salts for use in the present invention. Examples 6-14 relate to certain compositions which are within the scope of the present invention.
In the examples abbreviations used are as follows:
SCMI—sodium cocoylmethylisethionate
SCI—sodium cocoyl isethionate
SLS—sodium lauryl sulfate
SLMI—sodium lauroylmethylisethionate
SLES—sodium laureth sulfate
SCEI—sodium cocoyl ethyl isethionate
CAPB—cocamidopropyl betaine
CMEA—cocamide monoethanolamine.

This patent is subject to a terminal disclaimer.

Abstract: where R1 represents a C8-22 alkyl group alkyl group; R2 represents a C1-4 alkyl group; each of R3, R4 and R5 independently represents a hydrogen atom or a C1-4 alkyl group; and M+ represents a sodium or potassium cation;(b) at least 3 wt % of an amphoteric or zwitterionic surfactant;(c) at least 10 wt % of water; and(d) at least 0.5 wt % of an additional component in the form of particles or droplets suspended in the composition. The composition is stable in an aqueous environment and can be formulated with a wide range of additional components.


Various phenylamine derivatives are described as well as the use of compounds to inhibit BID protein for controlling apoptotic cascade.

1. Field of the Invention
The present invention relates generally to the use of compounds to treat a variety of disorders, diseases and pathologic conditions and more specifically to the use of phenylamine derivatives to treat various disorders.
2. Background Information
Currently, there is a need for compounds that are capable of selectively killing and/or reducing the viability of various cells. There is also a need for pharmacological tools for the further study of the physiological processes associated with apoptosis.
The apoptotic cascade in cells is known to lead to cell death. Uncontrolled cell death can be associated with several human pathologies, such as neurodegenerative diseases, ALS, liver inflammation, multiple sclerosis, and ischemic injuries. BH3 Interacting Domain Death Antagonist (BID) is a protein that is a member of the BCL-2 family proteins involved in the control of the apoptotic cascade. Therefore, BID represents a potential target for inhibition by various therapeutic agents. It is desirable that such therapeutic agents be capable of occupying a deep hydrophobic crevice on the surface of BID. Unfortunately, no such therapeutic agents have been developed.
Accordingly, a need exists to identify potent cell permeable compounds for targeting the BCL-2 family of receptors such as, for example, BCL-xL, BCL-2, MCL-1, or BCL-B. There exists a need for agonists that can inhibit the binding of BH3 to the BCL-2 receptors.
In addition a need exists for compounds useful as chemosensitizers in particular, where anti-apoptotic BCL-2 family proteins, such as BCL-xL, BCL-2, Mcl-1, BCL-W, or BCL-B, are overproduced by the cells.

Inhibition of bid-induced cell-death using small organic molecules


In a method for producing a monofilament with reduced secondary binding forces of at least two commonly extruded polymers for the production of bristles or interdental cleaners which are slittable substantially axially through the action of mechanical forces, the at least two polymers of the monofilament are disposed in a regular geometrical arrangement with substantially axially extending boundary layers in which the reduced secondary binding forces prevail for generation of defined slits of flags.

The invention relates to a monofilament with reduced secondary binding forces having at least two polymers commonly extruded in regular geometric relationship with substantially axially extending border surfaces for producing bristles or interdental cleaners, which are substantially axially slittable by the action of mechanical forces. The invention relates to a method for producing bristles or interdental cleaners from such monofilaments as well as to brush-ware with such bristles and to interdental cleaners.
Bristles for brushware of all types, e.g. personal hygiene and tooth-brushes, household brushes, industrial brushes, paint brushes, etc., are mainly produced from polymers, in that the polymer melt is extruded into continuous monofilaments, the monofilaments are stretched and optionally stabilized. The bristles are then produced from such monofilaments by cutting to the desired length. As a rule, the monofilaments, like the bristles, have a circular cylindrical cross-section. For special applications bristles with a different cross-section are known, e.g. an oval or polygonal cross-section. The monofilaments are then extruded with a corresponding profile.
In many cases it is desirable to use bristles having a fibrous and preferably fine fibrous structure at the use end. This e.g. applies for brushware intended for the application of media to surfaces or the like, e.g. paint brushes. Even if a fleecy structure is sought, the bristle must be of a fine fibrous nature. Of late in the dental sector it has been found that conventional bristles of toothbrushes have inadequate cleaning action, because they do not penetrate into the fine cracks of the tooth surface and instead slide over same. Much the same applies for the cleaning action in the interdental space.
In order to obtain a highly fibrous structure, proposals have already been made for extruding the monofilament from polymer blends. During the extrusion and subsequent stretching of the monofilament, the polymer molecules are oriented in the longitudinal direction of the monofilament. The primary binding forces acting in the longitudinal direction ensure high tensile strength. The longitudinal orientation of the molecules also effects the desired flexural elasticity. In monofilaments made from a single polymer, the so-called secondary binding forces, namely the forces transverse to the molecular extension, are adequate in order to prevent a unraveling or cleaving of the monofilament or bristle. In the case of monofilaments from two different, blended polymers, sliding zones, in which the secondary binding forces are reduced, occur between the molecular chains of the polymers during stretching. Such a monofilament or a bristle produced therefrom can be unraveled by the action of mechanical forces using knife-like tools. The resulting flags have a very irregular shape, irregular cross-sections and frayed peripheral surfaces. Although a larger bundle of such bristles is fleecy and of good absorbing structure, the flags have uncontrolled strength characteristics. They tear out, break off or wrap round. Such unraveled bristles are consequently unsatisfactory and are even unusable for many applications. For hygienic reasons their use in toothbrushes is risky.
The same disadvantages are encountered in a known bristle structure (WO97/14830) which has a core and an envelope, which are produced by the coextrusion of two different polymers. The core material is mechanically or chemically removed at the use-side end of the bristle in order to form a deep pocket, which is intended to receive a dentifrice or paint. In addition, flags can be obtained by unraveling the envelope material to the extent that it projects over the core. This unraveling takes place in a conventional manner by cutting with knives. The bristles obtained show the same irregular structure mentioned above.
Particularly for toothbrushes, bristles have already been proposed which comprise a plurality of such fibers, similar to textile fibers, and an envelope jacketing the fibers (DE 94 08 268 U1). The envelope and fibers can be coextruded as a filament. After cutting the bristle to length, the envelope is removed at the use-side end of the bristle by mechanical working or cutting, so that the fibers are free over a short length. Quite apart from the complicated production of such bristles, they can only be used to a limited extent. It is particularly disadvantageous that there is a sudden change in the bending behavior at the transition between the fibers and the envelope. If such bristles are used in applicators, there can be damage to the surface due to the hard transition. The same applies when such bristles are used in toothbrushes in connection with the action on the teeth and gums. In addition, the fibers are bending-limp, so that they do not or do not adequately penetrate into deeper cavities, intendental spaces etc. In case of permanent stressing, the fibers also easily break off at the edge of the envelope.
WO96/39117 discloses an intendental cleaner made from monofilaments which are co-extruded in defined geometric relationship. Each monofilament comprises at least two polymer components leading to reduced secondary binding forces at the borders between neighboring monofilaments. The secondary forces are reduced through the action of axial tensile forces to produce a multi-fibered fleecy structure similar to that of dental floss.
Conventional textile fibers (U.S. Pat. No. 3,117,362) are produced having glossy, sharp-cornered structures by co-extruding various polymers, each of which has a suitable cross sectional shape, which bond to each other at their bordering surfaces and which are separated through introduction of a solvent which dissolves one of the polymers.
The problem of the invention is to propose a monofilament of at least two commonly extruded polymers, which is suitable for producing slitted bristles or interdental cleaners with reproducible strength characteristics and flags or slits which are definable according to number, shape and dimension. The invention is directed to a method for the production of bristles or interdental cleaners from such monofilaments.
A monofilament solving this problem is characterized in accordance with the invention in that the border surfaces are border layers having reduced secondary binding forces, wherein the monofilament comprises a matrix of polymers whose physical and chemical properties define the properties of the bristle or interdental cleaner. A second polymer is imbedded as a thin layer into the matrix.
As a result of the geometry of the boundary layers it is possible to forecast in what way the monofilament for example for an interdental cleaner or the bristle produced from the monofilament by cutting to length will be disintegrated or split by the action of mechanical forces. The slits or flags occur precisely with the predetermined contour given by the extrudate geometry. As the boundary layers extend in the longitudinal direction of the monofilament, each flag has a constant shape and cross-section along its entire length. Thus, the flags have the same strength characteristics, in particular, identical bending behavior and identical tensile strength. By appropriately defining the geometry, flags can also be produced with different cross-sections. Since the monofilament or bristle, under the action of mechanical forces, splits exclusively and precisely at the boundary layers, the flags can have edges at their facing surfaces in dependence on the thin layer array to assist the cleaning action. A bristle split in this way is consequently more effective at its peripheral surface than conventional spreading of the bristle flags. The congruent shapes prevent excessive spreading of the bristles. In a densely packed bundle, each bristle once more acquires a monofilament-like shape and the full effect of the flags only results from the axial or radial pressure. Media can thereby be well absorbed and delivered on application by pressure action.
This makes it possible to produce bristles, whose flags have the desired characteristics of conventional bristles comprising the matrix polymer. Since splitting separates the thin layer into residual waste remnants which may or may not cling to the matrix material flags, no or few sharp structures are formed and there is no need for extensive cleaning of the split bristle. Accurately flagged and slit monofilaments for interdental cleaners are obtained, with which the propagation of splitting or slitting can be avoided.
The polymer of the matrix as well as of the thin layers can also be a copolymer or a polymer blend. These aforementioned advantages are achieved in a particularly optimum form if the thin layers at least partly comprise the polymer of the matrix. In this case the polymer or the bristle tears at the weakest point when force is exerted, namely roughly in the center of the thin layers, but the adhesiveness of the part of the matrix polymer in the thin layer at the resulting, neighboring flags is adequate to avoid the formation of sharp structures.
The thin layers preferably have a thickness of a few xcexcm. Since monofilaments for brushes have diameters typically ranging from 0.2 mm to 1.2 mm, the thin layers have a thickness which is small compared to the diameter of the monofilament. Practical extrusion tests have revealed that such thin layers can be coextruded together with the polymer of the matrix.
The two polymers can be present in roughly equal parts in the thin layers.
The specific definition of the geometry is determined by the desired characteristics of the bristle and interdental cleaner. Thus, the thin layers in the matrix can extend to the circumference of the monofilament, so that the monofilament can be split or slit with a relatively limited force action.
Alternatively, the thin layers can terminate in the matrix at a separation from the periphery of the monofilament. In this case a somewhat greater force action is required, but it is advantageous that the resulting flags, also in the edge region, comprise the matrix material, i.e. have the same wear characteristics as the envelope of the bristle or the flags.
Optionally the monofilament matrix can have a third polymer incorporated into said matrix and which is mainly used for influencing the strength characteristics of the resulting flags.
As is normally the case with bristles, the monofilament can be circular, but can also have a non-circular cross-section. Particular mention is made of polygonal cross-sections, which are more effective in their cleaning action than circular cross-sections.
In this case the thin layers can extend to the corners of the polygonal cross-section, so as to give relatively sharp edges with an edge angle of less than 90xc2x0.
Alternatively, the thin layers can also extend to the surfaces of the polygonal cross-section. It is then possible to obtain edges with an angle of approximately 90xc2x0.
According to a preferred development the matrix comprises a polyamide and the thin layers a polyolefine, particularly polypropylene or polyethylene. This material combination has secondary binding forces at the interfaces which are sufficient to prevent an untimely tearing or unraveling during processing and use of the bristles. However, the polymer union tears in the case of a strong, planned application of force.
The method according to the invention for producing bristles from the aforementioned monofilament comprises the following steps: coextruding the at least two polymers into a monofilament, stretching and optionally stabilizing the monofilament, cutting the monofilament to bristles of the desired length, splitting the bristles at their use ends along the boundary layers along a limited length by the action of mechanical forces acting transversely to the axis of the bristle.
Another method suitable for producing bristles as well as interdental cleaners from the aforementioned monofilament comprises the following steps: coextruding the at least two polymers into a monofilament, slitting, following extrusion, stretching and optically stabilizing, the monofilament along the boundary layers on a locally limited length for forming short slits by the action of mechanical forces acting transversely to the axis of the monofilament. With the method in accordance with the invention, crack-like slits can be formed in the monofilament envelope and these can be used for receiving media. In the case of toothbrushes or interdental cleaners these can be dentifrices or dental or antibacterial preparations. As a result of the slitting action, the monofilaments envelope has an increased roughness.
Interdental cleaners of any length can be manufactured from the monofilament described above. The same measure can naturally be carried out on the bristle cut to length from the monofilament. The location of slitting and the extension of the slits can be matched to the bristle length, in order to either prevent or encourage planned splitting of the bristle end. For example, only the bristle end may be split The slits made on the envelope can be used for the further splitting of the bristle following the wearing away of the flags. As a function of the nature and number of incorporated layers, a corresponding number of flags is formed at the use end of the bristle.
For processing monofilaments into interdental cleaners of any length, a variation of the method provides for compressing the monofilament in its axial direction during or after the action of the mechanical forces. The lengthwise slitted areas and the strips limiting the slits respectively are thereby bulged.
The mechanical forces are preferably applied to a greater part of the periphery of the monofilament or bristle to ensure that all the boundary layers of the polymers are effected.
The slitting of the monofilament or the splitting of the bristles preferably takes place by impact forces. Alternatively, squeezing or torsional forces can also be used. These forces can be applied to the cut to length bristle or also simultaneously to groups of bristles, e.g. bristle bundles, before or after the fixing thereof to the bristle carrier of the brush.
The bristles are preferably rounded at their use-side ends. This can take place before and/or after splitting. In accordance with a further preferred embodiment of the method, the several ends obtained after splitting are provided with a marking optically indicating the usable length. This indicates to the user that the bristle has become worn up to the marking, i.e. following the wearing of the split ends the use characteristics suddenly change, since the much stiffer cross-section of the entire bristle is then effective. The split ends also become ever shorter and consequently mechanically more aggressive. Such an indication is particularly appropriate in the case of toothbrushes, personal hygiene brushes, etc.
The invention is described in greater detail hereinafter relative to embodiments and the attached drawings, wherein: