Embodiments of the application describe a method and system for discovering and authenticating communication devices and establishing a secure communication link within a wireless home network without requiring a secure channel. According to an embodiment, communication devices exchange public keys using multiple messages each including at least a portion of the public key of the sending device. The devices authenticate the receipt of the public key and establish a shared master key. The shared master key is used to further derive a session key for securing the application data between the communicating devices for a current session.

1. Field
The invention relates to security association using authentication and verification of communication devices via public key cryptography in a wireless network.
2. Description of the Related Art
Generally in wireless networks such as Local Area Network (LAN) or Personal Area Network (PAN), devices communicate using secure means such as encrypted data. In a home network, a user may play videos using a DVD player, camcorder, or the like, and transmit the video to a TV via a wireless network. It is possible that the transmitted video may also be played on a TV in a neighbor's home. Another possibility is that a third party within the communication range of the home network may intercept the transmission, alter it, and re-send the altered data to the user's PC. Similarly, a receiving device such as neighbor's PDA makes sure that it receives data only from an intended sender.
To avoid such interruptions and hacking, the transmitted data is usually encrypted and checked so only the intended receiving device can decrypt and validate the data using a predetermined security protocol. To this end, the communicating devices need to share a session key that is not known to other devices. The section key will then be used to secure the user traffic for the current session. The devices use another shared session key for their data communications in the next session to reduce the chance of the session key being compromised or minimize the damage in case the session key is compromised.
To derive a session key, the two communicating devices need to establish a shared master key first. Good security practice does not use the master key to directly encrypt the user application data. Public key (PK) cryptography allows two devices to establish a shared secret, i.e., a shared master key, in broad light—in the presence of eavesdroppers. That is, PK cryptography is not vulnerable to passive attack. Unfortunately, existing techniques of PK cryptography is subject to active attack. An attacker can impersonate itself as one of the intended communication partners and transmit its public key under the disguise of an intended device, thereby tricking the other device to exchange data with the attacker without the device knowing that its communication is being hijacked by an unwanted third party. This is known as man-in-the-middle attack.
Since PK cryptography provides a friendly use model, especially in a wireless environment, there is a need for a method and system for applying PK cryptography to establish a security association, i.e., to establish a shared master key, between two communicating devices without the setback of man-in-the-middle attack.
The description that follows presents a series of systems, apparatuses, methods, and techniques that facilitate additional local register storage through the use of a virtual register set in a processor. While much of the description herein assumes a single processor, process or thread context, some realizations in accordance with the present invention provide expanded internal register capability customizable for each processor of a multiprocessor, each process and/or each thread of execution. Accordingly, in view of the above, and without limitation, certain exemplary exploitations are now described.
FIG. 1 illustrates an exemplary embodiment of a wireless home network 100. The home network 100 includes various devices configured for wireless communication with each other such as an entertainment rack 110, a TV 120, various speakers 130, a camcorder 140, a PDA 150, and a PC 160. The wireless network can be based on any standard wireless network protocols such as IEEE 802.11 or similar other wireless protocols known in the art. The entertainment rack 110 includes individual devices 110(1)-(n) capable of wireless communication. For illustration purpose, only few devices are shown; however, home network 100 can include other devices such as a server, an access point, and the like devices capable of wireless communication with other devices in the home network 100.
When a device wants to communicate with another device in the home network, for example, when a user wants to play a home video recorded on camcorder 140 on the TV 120, a secure wireless communication link needs to be established between the two devices. The communication link needs to be secure because the user may not want the video to be played on a wireless capable TV in his/her neighbor's bedroom. Thus, to establish a secure communication link, the user may initiate a link establishing process on both the devices. The process can be initiated by manually pressing a corresponding button on each device, by using a remote control to simultaneously initiate the link establishment process on each device, or by any other means known for controlling the operations of these devices. When the process is initiated, each device exchanges data packets using a PK distribution protocol. The PK distribution protocol may allow a time window within which each device performs the PK exchange. In case when devices are unable to complete the PK exchange within the allocated time window, the user will be alerted by a user-device interface such as the display of a blinking red LED, and the user may choose to abort or resume establishment of the secure communication link process.
The device can indicate the initiation and execution of the secure link establishment process by activating an indicator (e.g., displaying a stable red LED or similar indicator) on the device. The device can indicate the successful completion of the process by activating a different indicator, for example, by displaying a stable green LED on the device. If devices fail to establish a secure link, then they can indicate the failure by any determined means, for example, by displaying a flashing red light, playing a distinct sound (e.g., a beep or the like), displaying an error message on the TV or on a display capable remote control, or on the display of a corresponding network controller, or the like means. If devices succeed to establish the secure link, then the user can play and enjoy the video on the TV or initiate a secure data communication between the devices.
Similarly, other secure links can be established between various other devices in the wireless network, for example, between a tuner and speakers, a DVD player and a TV, a camcorder and a VCR, a digital camera and a computer, a projector and a digital screen, and the like and combinations thereof Further, a secure link can be established in a broadcast manner also; for example, a user may want to play a movie on his/her DVD player located in a family room but everyone in the house may want to watch the movie in the comfort of their bedroom. Thus, the user can establish a secure broadcast link between the DVD player and TVs in each room. Similarly, various other combinations can be formed to communicate data on a secure link between two or more devices without having to worry about an intruder who may intercept the communication and use it or alter it before retransmitting it.
FIG. 2 is a flowchart illustrating a method of exchanging public keys for secure association of two devices in a wireless network according to an embodiment. The process begins by initiating the link establishment on each device; for example, a user may press an activation button on each of the two devices (e.g., manually, via Infra Red remote control, or the like) (210). A device then sends the first message of the PK distribution protocol (220). The PK distribution protocol can be defined such that each message includes a portion of the PK of the sending device and the entire PK is exchanged using 'N' messages. The number of messages the PK is divided depends upon the level of security desired between the communication devices. The larger the number of messages, the stronger the lever of security. The device may retransmit the same message if it does not receive a positive acknowledgment to the last transmission of the message.
Before proceeding to send the next message, the device checks to see if it has received the message of the same sequence number containing a corresponding portion of the PK of the intended partner (230). The device will determine whether it has received the said message within the time window specified for the PK distribution protocol, i.e., whether a timeout has occurred (240). If a timeout has not occurred, then the device continues to wait for that message from the other device. If a timeout occurs, then the device issues a warning (e.g., via red flashing indicator, error message display, or similar other means) to indicate an error and terminate the security association process (250). It is up to the user to decide whether to reinitiate the process.
The device checks to see whether it has received the message that has the same sequence number as the one it last transmitted within the specified timeout (255). If the message has the same sequence number, then the device also checks whether the message that appears to carry the same sequence number is also a retransmission of the last message received by comparing the contents of the message with the contents of the last received message (260). Such an event could occur if an imposter sent a message with the same sequence number but with part of its own PK. If the event does happen, the device also issues a similar warning as described earlier to indicate a potential security attack and terminates the security association process (250). Otherwise, the device further checks if it has received any message that is out-of-sequence order (270). An imposter might attempt to send messages containing its own PK and mislead the device to treat it as the intended partner. If the device does find a received message that is out-of-order in sequence with earlier received messages, it also issues a warning to indicate a potential security attack and terminates the security association process (250).
After the device determines that it has received an acknowledgment to its last transmitted message containing part of its PK, it has received a message of the same sequence number containing part of another device's PK, it has not received a message with the same sequence number as previously received message but with different PK contents, and it has not received any out-of-order messages, it determines if all messages containing its PK and the intended device's PK have also been transferred to each other (280). If not, the device proceeds to transmit the message containing the next portion of its PK (290), repeating the procedures described above until the PK exchange completes.
As stated above, the number of messages exchanged between devices for PK transfer may depend on a desired level of security required for the communication link between the two devices. For example, a user wanting to play an entertainment video may not care for a high level of security between a DVD player and a digital TV and may wish to complete the link establishment process as soon as possible. However, on the other hand, a surveillance video being played in a conference room of a law enforcement agency's office may require the highest level of data security. After the PK transfer is successfully completed, the device continues to a mutual challenge stage as described below with reference to FIG. 3.
After the successful transfer of the PKs, the device begins a mutual challenge stage with the intended partner (300). This stage allows the two devices to verify that they have indeed received each other's PK in entirety. It also enables both devices to derive a shared master key based on the parameters used in the challenge process. The two devices then proceed to derive a shared session key that is used to secure the application traffic for the current session. The devices may reuse the shared master key to derive a new session key for the current or a new session, thus saving the steps of the security association process for a continued or a new session.
FIG. 3 is a flowchart illustrating a method of verifying the correct reception of PK from each other and deriving a shared master key for secure association of the two devices in a wireless network according to an embodiment. The mutual challenge stage is initiated on both devices A & B (e.g., a camcorder and a TV) using various means described herein above (300). After the initiation f the stage, device A chooses a random number Ra and encrypts it using device B's public key to generate an encrypted data Eb(Ra) (305). The public key of device B can be obtained as described herein above. Each device may send a message to the other device only after a previous message has been received from the other device. Each device may send a given message one or more times, but may not send messages out of sequence order.
Device A then sends the encrypted data Eb(Ra) to device B (310). When device B receives the encrypted data Eb(Ra) from device A, it decrypts the data using its private key to generate a decrypted data Ra′=Db(Eb(Ra)) (315). If device A had correctly received the public key of device B, then Ra′=Ra. Device B now chooses a new random number Rb. Device B combines Ra′ and Rb into a concatenated data, and encrypts the data using device A's public key to generate an encrypted data Ea(Ra′, Rb) (320). Device B then sends the encrypted data Ea(Ra′, Rb) to device A (325).
Device A decrypts the received encrypted data using its own private key and generates a decrypted data (Ra″, Rb′)=Da(Ea(Ra′, Rb)), which produces decrypted portions of the random numbers as Ra″ and Rb′ (330). If device A had correctly received the public key of device B and device B had correctly received the public key of device A, then Ra″=Ra′=Ra and Rb′=Rb. Device A determines whether it had correctly received the public key of device B by comparing the random number Ra that it sent to device B with the random number Ra″ that it recovered from device B's returned encrypted data (335). If Ra and Ra″ are not equal, then device A did not correctly receive the public key of device B or/and vice versa, and the mutual challenge stage fails (340). Device A issues a warning to indicate an error and terminates the security association process.
If Ra″=Ra, device A combines Ra and Rb′ into a concatenated data (Ra, Rb′) and encrypts the data using device B's public key to generate an encrypted data Eb(Ra, Rb′) (345). Device A then sends the encrypted data Eb(Ra, Rb′) to device B (350). When device B receives the encrypted data, it decrypts it using its private key to extract (Ra′″, Rb″)=Db(Eb(Ra, Rb′)) (355). Device B determines whether device A correctly received its public key and it correctly received device A's public key by comparing the random number Ra′ it received earlier from device A with the random number Ra′″ it last recovered from device A, and the random number Rb it sent to device A with the random number Rb″ it recovered from device A (360). If Ra′ and Ra′″ are not equal, or if Rb and Rb″ are not equal, then device B determines that the PK exchange process did not succeed and the secure link establishment fails (340).
Otherwise, the mutual challenge has succeeded, that is, devices A and B have correctly obtained each other's public key (365). Once mutual challenge succeeds, each device can employ a predetermined PK cryptography method to derive a shared symmetric master key based on their public and private keys and some other information exchanged during the mutual challenge procedure such as Ra and Rb′ or Ra′ and Rb. Each device then can indicate the success of security association using appropriate means, e.g., by displaying a stable green light or the like. The user can then signal to the two devices to start their application data transmission and reception, e.g., by pressing the activation button again on each device or via similar other means.
The security association process ensures that an imposter cannot post as an authorized party to steal the data from the intended source device, or manipulate the intercepted data and then transmit it to the intended recipient. The process fails when a device receives messages with the same sequence number but different key contents (one sent from an imposter with its own key contents), receives messages out of sequence order (some sent from an imposter earlier or later than the true messages of the same sequence number from the intended device), or detects a failure in the final challenge stage (the entire key contents were assembled from messages sent by both the intended device and the imposter). By breaking the PK exchange protocol information into a large number of messages, it becomes more difficult for an imposter to stage an active attack on the intended communications. Thus, the number of the protocol messages to complete the PK exchange may be used as a parameter in achieving differing degrees of security association robustness. This method requires minimal user interaction/interface and no third party certificate.
The link indicator of a device indicates a successful establishment of the link only after the device has sent and received all messages of the PK distribution protocol as well as gone through the mutual challenge stage for authentication. The indicator may indicate a failure in the link establishment process when the device receives messages with the same sequence number but different key contents such as a message sent from an imposter with its own key contents, receives messages out of sequence order such as some messages sent from an imposter earlier or later than the true messages of the same sequence number from the intended device, or detects a failure in the final challenge stage such as the entire PK contents were assembled from messages sent by both the intended device and the imposter, and the like other errors as determined by the device or protocol designer. After a secure link has been established (as indicated by the indicator), the user may proceed with the application data exchanges (e.g., play video or the like). The devices each stop transmitting and receiving PK distribution protocol messages after a timeout following the initiation of the process.
For some user cases, it may be desirable or convenient to require the communicating devices to go through PK distribution procedure for each session (e.g., every time a user wants to play a movie or the like). The same procedure may be used for symmetric key distribution, but it will increase the chance of passive attack. Thus, symmetric key distribution is more vulnerable than public key distribution. If the symmetric key is overhead, then everything on the current and future sessions can be compromised. Each new session may be required to start with the symmetric key distribution, which is nevertheless weaker than public key distribution.
Realizations in accordance with the present invention have been described in the context of particular embodiments. These embodiments are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Boundaries between various components, operations and data stores are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of claims that follow. Finally, structures and functionality presented as discrete components in the exemplary configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of the invention as defined in the claims that follow.

This patent is subject to a terminal disclaimer.

System and method for security association between communication devices within a wireless home network


The device consists of a mechanism to place netwrap over the edge of a cylindrical bale that is created in a variable/fixed baling chamber of an agricultural round baler. The invention consists of a netwrap delivery system having of a pair of arms pivotally affixed to the outside of the baling chamber sidewalls. Also attached to the arms is an assembly frame. An actuator controls the pivoting motion of the delivery system inserting the netwrap between the stationary dimple roll and the pivot roll of the sledge assembly. Positioned outside the sidewall and between the outer frame member is a transition area. The netwrap is inserted between the stationary dimple roll and the pivot roll as well as into the transition area. Because the width of the delivery assembly is wider than that of the cylindrical bale, a portion of the netwrap is inserted over the edge by use of the transition area.

This invention relates to the improvement of an agricultural round baler. More specifically it relates to an improvement to the net wrap dispensing system that allows net wrap to be placed over the edge of a round bale.
Agricultural round balers have been used for several decades to collect and bind crop material so as to facilitate the storage of crop material for later use. Generally, a mower or mower-conditioner cuts the crop and arranges it in a windrow for drying. A general example of a disc mower-conditioner is the New Holland Discbine(copyright) disc mower conditioner model 1431 manufactured by New Holland North America, Inc. Later, an agricultural tractor pulls a baler over the windrow to collect the crop material. The baler""s windrow pickup gathers the cut and windrowed crop and lifts it into the baling chamber. The baling chamber consists of a pair of opposing sidewalls with a series of belts that rotate and compress the crop material into a cylindrically shaped bale. When the bale has achieved a desired size and density, the operator wraps the bale to ensure that the cylindrical and compact nature of the bale is maintained. There are many wrapping materials and methods of wrapping the bale depending on a variety of factors. Initially, twine was used to wrap the bale. Later netwrap and silage sheets were introduced. Generally, these methods focused on covering the cylindrical portion of the bale and not the ends. After the bale is bound or wrapped, it is ejected from the baler for later pickup by the farmer.
As previously mentioned, there are a variety of agricultural round balers. A general example of this device is illustrated by the New Holland Roll-Belt(trademark) Round Baler model number 678 manufactured by New Holland North America, Inc. Generally, round balers are pulled by an agricultural tractor and receive rotational power from the tractor""s power-take-off shaft positioned at the rear of the tractor. The energy is transmitted to a gearbox positioned on the baler. Some balers also use a hydraulic motor and pump arrangement to provide energy to the various baler elements such as the various rollers and belts. As previously discussed, a variety of methods are used to wrap the bale. Relatively recently, the use of netting or netwrap has been introduced. It is desirable for bales to maintain a cylindrical shape, however this has been especially difficult near the edge of the cylindrical bale. It is difficult for twine to remain on the edge of the bale as well as mechanically placing the twine in that position. Recently attempts have been made to extend a portion of the netwrap around the edge of the round bale. By allowing a slight portion of the netwrap to extend over the edge of the bale, the appearance of the round bale is improved. Furthermore, the bale is afforded additional protection. These methods have not been entirely successful as the prior art illustrates various deficiencies.
U.S. Pat. Nos. 5,230,193 and 5,243,806 illustrate a conventional fixed/variable hybrid baling chamber. To ensure that the core of the round bale is well defined, a sledge assembly is initially used to compress the crop material. As more crop material is introduced into the baling chamber, the apron of belts is loosened allowing more material to enter the baling chamber. The crop material remains compressed and in a cylindrical shape because of the interaction between the sledge assembly and belt apron. While this approach allows for the creation of a superior shaped and dense round bale, there are greater complications when encircling the bale with the netwrap material. Specially, the netwrap needs to be timed to enter the confines of the baling chamber through the sledge assembly and without interfering with operation of the apron of belts.
U.S. Pat. Nos. 4,366,665, 4,709,125, 4,969,315, 5,090,182 and 5,103,621 and 5,311,729 illustrate various designs for wrapping round bales with either netwrap or silage wrap. Typically, the wrap only covers the cylindrical portion of the of the round bale and not the ends. Usually, the wrap is spread to cover the length of the cylindrical portion of the round bale by a series of idler and spreader rolls. The wrapping material is kept on a roll at a single location for dispensing.
U.S. Pat. Nos. 4,917,008, and 6,006,504 illustrate attempts to extend netwrap over the edge of the cylindrical bale, but on variable sized bale chambers. The baling chambers on these balers are less complex and do not form crop material into cylindrical bale as effectively as a variable/fixed hybrid baling chamber. This is reflected in the simplistic design of the netwrap delivery assemblies. U.S. Pat. No. 6,006,504 uses a pair of guide plates to compress the ends of the bale so as to be able to insert netwrap around the edge of the bale from the rear tailgate. The addition of the guide plates to compress the bale causes additional stresses to the sides of the baling chamber and could also distort the appearance and shape of the bale. U.S. Pat. No. 4,917,008 uses a netwrap that contains an elastic material to wrap around the edge of the cylindrical bale.
Consequently, the need exists for an improved netwrap delivery assembly for use on an variable/fixed baling chamber that permits the netwrap to extend around the edge of the cylindrical bale.
It is an object of the present invention to provide a netwrap delivery system which can insert netwrap over the edge of a cylindrical bale.
It is a further object of the present invention to provide a netwrap delivery system that can operate on a fixed/variable hybrid baling chamber.
It is a further object of the present invention to provide a netwrap delivery system that can insert netwrap over the edge of the cylindrical bale without compressing the sides of the cylindrical bale.
It is a further object of the present invention to provide a netwrap delivery system that can insert netwrap onto the edge of the cylindrical bale through the sledge assembly of a fixed/variable hybrid baling chamber.
It is a further object of the present invention to provide a netwrap delivery system that may be affixed to the sides of the baling chamber instead of the sledge assembly.
It is a further object of the present invention to provide a netwrap delivery system that will allow net wrap material to be place over the edge of a cylindrical bale permitting good bale appearance.
The invention overcomes the deficiencies of the prior art. The invention is an improvement to the mechanism to place netwrap over the edge of a cylindrical bale that is created in a variable/fixed baling chamber of an agricultural round baler. The invention consists of a netwrap delivery system having of a pair of arms pivotally affixed to the outside of the baling chamber sidewalls. Also attached to the arms is an assembly frame. An actuator controls the pivoting motion of the delivery system inserting the netwrap between the stationary dimple roll and the pivot roll of the sledge assembly. Positioned outside the sidewall and between the outer frame member is a transition area. The netwrap is inserted between the stationary dimple roll and the pivot roll as well as into the transition area. Because the width of the delivery assembly is wider than that of the cylindrical bale, a portion of the netwrap is inserted over the edge of the cylindrical bale by use of the transition area.

Over the edge net wrap dispensing system for a round baler


Disclosed are stabilized electrostatically-sprayable topical compositions and methods of treating the skin by electrostatic application of such compositions. The compositions comprise:

The present invention relates to stable electrostatically-sprayable topical compositions, and methods of treating the skin by electrostatic application of such compositions. Examples of electrostatically-sprayable compositions include color cosmetics and skin care compositions.
A variety of topically-applied skin treatment products are known. Typically, such products are applied by massaging or rubbing into the skin with the fingers or a sponge-type applicator. Other methods of application are also known, including aerosol spraying, non-aerosol pump spraying, and electrostatic spraying. For example, electrostatic spraying of skin treatment agents is disclosed in U.S. Pat. No. 5,494,674, issued to Barnett et al. on Feb. 27, 1996.
Electrostatic spraying of topical materials has been proposed as a means for more efficient consumption and product activity, control over application, ease and cleanliness/hygiene of application, and even coverage.
In particular, the art has described electrostatically-sprayable formulations which involve modifying the conductivity of typically insulating fluids by blending with conductive fluids like ethanol. The insulating and conductive fluids in such systems comprise a single, semi-conductive phase which contributes to the electrostatic sprayability of the composition.
The formulation of more complex, electrostatically sprayable topical compositions, for example, those containing particulates such as pigments, is not straightforward. Pigmented color cosmetics typically contain multiple components such as oils, resins, solvents, pigments, oil absorbers, polymers, emollients and the like. A mixture of hydrophobic and hydrophilic components is often used. These systems can tend to separate due, for example, to chemical incompatibility and/or gravity effects, e.g., particulate materials may settle out. In electrostatic processes, prevention of such separation is a particular challenge, since charging of the fluid during the spray process tends to exacerbate separation or instability. Any unsprayed product tends to show separation due to polarization of components. In either case, the resultant non-homogeneous fluid exhibits poor spray quality when sprayed electrostatically.
As a result of identifying and appreciating the limitations of the known art, and through much experimentation, the present inventors have now discovered improved electrostatically-sprayable compositions and improved methods of applying topical compositions to the skin by electrostatically spraying. In particular, the present inventors have discovered electrostatically sprayable topical compositions which exhibit improved stability, and particularly improved stability upon exposure to electric fields necessary for electrostatic spraying. The compositions contain defined amounts of liquid insulating material, conductive material, insoluble particulates and thickener, wherein the liquid insulating materials and conductive materials are sufficiently miscible or soluble in the composition such that they are in substantially, preferably essentially, one phase.
The present compositions tend to provide good spray quality under conditions of electrostatic spraying.
The present invention relates to electrostatically sprayable topical compositions which exhibit improved stability, and particularly improved stability upon exposure to electric fields necessary for electrostatic spraying.
In one aspect the present invention relates to a topical composition which is electrostatically sprayable, the composition comprising
(a) from about 2% to about 90% of a liquid insulating material;
(b) from about 2% to about 90% of a conductive material;
(c) from about 0.1% to about 35% of a particulate material which is insoluble and immiscible in the composition; and
(d) from about 0.5% to about 30% of a thickener for stabilizing the composition.
The liquid insulating materials and conductive materials present in the composition are sufficiently miscible or soluble in the composition such that they are in substantially, preferably essentially, one phase. The compositions comprise a component for providing some esthetic or functional benefit to the skin, which may be the insulating, conductive, particulate or other material.
Another aspect of the invention provides a method of treating the skin by electrostatically spraying such compositions.
When electrostatically sprayed, compositions of the invention may provide one or more skin care benefits, including one or more of improved color integration with bare skin (enabling broader useable shade palettes for a given skin color as well as a very natural look), reduced potential for local irritation, improved evenness of particle (e.g., pigment) deposition, and improved skin feel (e.g., in long-wear topical formulas).
The essential elements of the present invention are herein described below. Also included are non-limiting descriptions of various optional and preferred elements useful in the compositions of the present invention.
The present invention can comprise, consist of, or consist essentially of any of the required or optional components and/or limitations described herein.
In the description of the invention various embodiments and/or individual features are disclosed. As will be apparent for the skilled practitioner all combinations of such embodiments and features are possible and can result in preferred executions of the invention.
All percentages and ratios are calculated by weight unless otherwise indicated. All percentages are calculated based on the total composition unless otherwise indicated.
All component or composition levels are in reference to the active level of that component or composition, and are exclusive of impurities, for example, residual solvents or by-products, which may be present in commercially available sources.
Referred to herein are trade names for materials. The inventors herein do not intend to be limited by materials under a certain trade name. Equivalent materials (e.g., those obtained from a different source under a different name or catalog (reference) number) to those referenced by trade name may be substituted and utilized in the compositions herein.
The compositions and components thereof herein described are suitable for topical applications, that is suitable for use in contact with human skin without undue toxicity, incompatibility, instability, allergic response, and the like within the scope of sound medical judgment.
Active and other ingredients useful herein may be categorized or described herein by their cosmetic, prophylactic and/or therapeutic benefit or their postulated mode of action. It is to be understood that the active and other ingredients useful herein can in some instances provide more than one cosmetic, prophylactic and/or therapeutic benefit or operate via more than one mode of action. Therefore, classifications herein are made for the sake of convenience and are not intended to limit an ingredient to the particularly stated application or applications listed.
Compositions of the present invention are electrostatically sprayable, topical compositions comprising:
(a) from about 2% to about 90% of a liquid insulating material;
(b) from about 2% to about 90% of a conductive material;
(c) from about 0.1% to about 35% of a particulate material which is insoluble and immiscible in the composition; and
(d) from about 0.5% to about 30% of a thickener for stabilizing the composition.
The liquid insulating materials and conductive materials present in the composition are sufficiently miscible or soluble in the composition such that they are in substantially, preferably essentially, one phase.
The compositions hereof are electrostatically sprayable and are suitably directly applied to the skin by electrostatic spray techniques. In general, this method involves raising the composition to be sprayed to a high electric potential in a spray nozzle to cause the composition to atomize as a spray of electrically charged droplets. The electrically charged droplets seek the closest earthed object to discharge their electric charge, which can be arranged to be the desired spray target.
In order to be electrostatically sprayable, a composition must have a resistivity which enables atomization as a spray of the charged droplets. In preferred compositions, the components of the composition are selected or adjusted such that the composition has a resistivity of from about 0.01 to about 5000 Mega-ohm-cm, more preferably from about 0.01 to about 2000 Mega-ohm-cm, most preferably from about 0.1 to about 500 Mega-ohm-cm. Resistivity is measured using standard, conventional apparatus and methods, generally at 25 degree C. Resistivity can be adjusted as necessary by varying the relative levels of insulating materials and conductive materials. In general, resistivity decreases with increasing percentage of conductive materials and decreasing percentage of insulating materials.
The compositions must also have a viscosity which permits electrostatically spraying. Materials of a wide range of viscosities may be suitable for use in the present invention, however the viscosity is preferably sufficiently high to minimize wicking of the composition droplets as they are applied. The tendency to wick depends on the surface tension of the composition and tends to increase with decreasing surface tension of the liquid diluent system. In compositions based on liquid diluents having a relatively low surface tension (i.e., which have a tendency to wet the substrate). The thickeners of the present invention can be utilized, optionally in combination with other viscosity control agents, to control viscosity and to minimize wicking. Preferably the viscosity is in the range of from about 0.1 to about 50,000 mPas, more preferably from about 0.5 to about 20,000 mPas, most preferably from about 5 to about 10,000 mPas (at 25 degree C., using 60 mm parallel plate with 0.5 mm gap at rate of 10 secxe2x88x921).
Liquid Insulating Material
Compositions of the invention comprise one or more liquid insulating materials in a total amount of from about 2% to about 90%, preferably about 5% to about 85%, more preferably about 10% to about 80%. By xe2x80x9cinsulatingxe2x80x9d it is meant that a material would not itself be suitable for electrostatic spraying (that is, it would not be able to cause sufficient alignment of the dipole molecules in the field to result in the subsequent, necessary net force), typically having a resistivity of greater than about 2000 Mega-ohm-cm, more typically greater than about 5000 Mega-ohm-cm. Preferred liquid insulating materials are volatile. As used herein, xe2x80x9cvolatilexe2x80x9d means that the material has a measurable vapor pressure at 1 atm. The present compositions may further include non-liquid or non- volatile insulating materials.
Preferred insulating materials have a viscosity of about 10,000 mPas or less. Suitable insulating materials are selected from non-polar substances, e.g., oils and other hydrophobic materials. Preferred insulating materials are selected from the group consisting of volatile silicones, volatile hydrocarbons, and mixtures thereof.
Suitable volatile silicones include cyclic polyalkylsiloxanes represented by the chemical formula [SiR2xe2x80x94O]n wherein R is an alkyl group (preferably R is methyl or ethyl, more preferably methyl) and n is an integer from about 3 to about 8, more preferably n is an integer from about 3 to about 7, and most preferably n is an integer from about 4 to about 6. When R is methyl, these materials are typically referred to as cyclomethicones. Commercially available cyclomethicones include Dow Corning(copyright) 244 fluid having a viscosity of 2.5 centistokes, and a boiling point of 172xc2x0 C., which primarily contains the cyclomethicone tetramer (i.e. n=4), Dow Corning(copyright) 344 fluid having a viscosity of 2.5 centistokes and a boiling point of 178xc2x0 C., which primarily contains the cyclomethicone pentamer (i.e. n=5), Dow Corning(copyright) 245 fluid having a viscosity of 4.2 centistokes and a boiling point of 205xc2x0 C., which primarily contains a mixture of the cyclomethicone tetramer and pentamer (i.e. n=4 and 5), and Dow Corning(copyright) 345 fluid having a viscosity of 4.5 centistokes and a boiling point of 217xc2x0, which primarily contains a mixture of the cyclomethicone tetramer, pentamer, and hexamer (i.e. n=4, 5, and 6). Dow Corning(copyright) 244 fluid and Dow Corning(copyright) 344 fluid are preferred cyclomethicones.
Other suitable volatile silicones are linear polydimethyl siloxanes having from about 3 to about 9 silicon atoms and the general formula (CH3)3Sixe2x80x94Oxe2x80x94[xe2x80x94Si(CH3)2xe2x80x94Oxe2x80x94]xe2x80x94nxe2x80x94Si(CH3)3 where n=0-7. These silicones are available from various sources including Dow Corning Corporation and General Electric.
Suitable volatile hydrocarbons include those having boiling points in the range of 60-260xc2x0 C., more preferably hydrocarbons having from about C8 to about C20 chain lengths, most preferably C8 to C20 isoparaffins. Preferred isoparaffins are isododecane, isohexadecane, isoeocosane, 2,2,4-trimethylpentane, 2,3-dimethylhexane and mixtures thereof. Most preferred is isododecane, for example available as Permethyl 99A from Permethyl Corporation. Additionally, nonvolatile insulating materials can include nonvolatile oils, silicone, or hydrocarbon based materials. These materials can be naturally or synthetically derived, such as mineral oil and isoeicosane. Nonvolatile hydrocarbons may have a chain length ranging from C20 to C200. When used in the phase, nonvolatile insulting solvents typically range from 0.01% to 80% in the formulation.
Examples of other insulating materials suitable for use herein include non-volatile oils such as disclosed in U.S. Pat. Nos. 5,800,816 and 5,505,937.
Conductive Material
Compositions of the invention comprise one or more conductive materials in a total amount of from about 2% to about 90%, preferably about 5% to about 80%, more preferably about 7% to about 70%. The conductive material ensures that the composition as a whole can, when in the presence of a non-uniform electric field, generate dielectrophoretic forces great enough to pull the composition toward the region of highest field intensity (hence creating an electrostatic spray). The conductive material preferably has a resistivity of less than 5000 Mega-ohm-cm, more preferably less than about 2000 Mega-ohm-cm, most preferably less than about 500 Mega-ohm-cm. This material preferably also has a relaxation time which is sufficiently long to enable a spray wherein all of the droplets have a particle size of less than 300 microns according to standard light microscopy techniques. The conductive material preferably has a relaxation time of from about 1E-7 to 1 seconds, more preferably from about 1E-6 to 1E-2 seconds, most preferably from about 1E-5 to 1E-3 seconds.
Preferred conductive materials are those which are sufficiently miscible or soluble with the liquid insulating materials such that they are in substantially, preferably essentially, one phase in the composition, as can be readily determined by ordinary light microscopy techniques. The conductive materials are preferably liquids which may be volatile or non-volatile and are preferably volatile.
Suitable liquid conductive materials include polar solvents, polar aprotic solvents, glycols, polyols, and mixtures thereof. Preferred liquid conductive materials are selected from the group consisting of water, alcohols, glycols, polyols, ketones and mixtures thereof, more preferably alcohols, glycols, polyols (typically comprising about 16 or less carbon atoms) and mixtures thereof. More preferred conductive materials are propylene glycol, butylene glycol, dipropylene glycol, phenyl ethyl alcohol, ethanol, isopropyl alcohol, glycerin, 1,3-butanediol, 1,2-propane diol, isoprene glycol, water, acetone, or a mixture thereof. Particularly preferred conductive materials are propylene glycol, butylene glycol, ethanol, glycerin, water, or a mixture thereof. The conductive material is more preferably selected from propylene glycol, ethanol, and mixtures thereof, and is most preferably propylene glycol.
The electrostatically sprayable compositions hereof are more preferably non-aqueous or contain only a small amount of water, e.g. less than about 10% by weight, preferably less than about 5% by weight, even more preferably less than about 1% by weight water. This is because, due to its short relaxation time (about 7E-6 seconds) and low resistivity, compositions containing large amounts of water generally create sprays which are difficult to control in terms of droplet size and spacing when electrostatic means are used.
The present compositions may include non-liquid or non-volatile conductive materials. Other conductive materials include solid particles such as metal powders, particles coated with metal or other conductive material, charged species (e.g., salts such as NaCl, or salts used conventionally in buffers in personal care products), and hydrophilic coated polymeric particles.
The relative total levels of the insulating and conductive materials may vary, provided that sufficient conductive material is present such that the composition realizes the electrical potential during spraying. The compositions preferably comprise a total of from about 5% to about 85%, more preferably from about 10% to about 80%, of insulating material and from about 5% to about 80%, more preferably from about 7% to about 70% of conductive material. In general, sprayability improves with the level of conductive material such that it will normally be advantageous to maximize the level of conductive materials. Preferred compositions comprise a weight ratio of insulating material to conductive material (disregarding any non-conductive particulate materials) of about 10:1 to 1:12.
Powder component
The compositions also comprise a total of from about 0.1% to about 35% of one or more powder materials, which are generally defined as dry, particulate matter having a particle size of from 0.001 to 150 microns, preferably 0.01 to 100 microns. The powder materials may be colored or non-colored (e.g., white or essentially clear), and may provide one or more benefits to the composition or skin such as coloration, light diffraction, oil absorption, translucency, opacification, pearlescence, matte appearance, lubricious feel, skin coverage and the like. These materials are well known in the art and are commercially available. Selection of the particular type and level of a given powder material for a particular purpose in a given product is within the skill of the artisan.
Suitable powders include various organic and inorganic pigments which color the composition or skin. Organic pigments are generally various types including azo, indigoid, triphenylmethane, anthraquinone, and xanthine dyes which are designated as DandC and FDandC blues, browns, greens, oranges, reds, yellows, etc. Inorganic pigments are generally insoluble metallic salts of certified color additives, referred to as lakes or iron oxides. Suitable pigments include those generally recognized as safe, and listed in C.T.F.A. Cosmetic Ingredient Handbook, First Edition, Washington D.C. (1988). Specific examples are red iron oxide, yellow iron oxide, black iron oxide, brown iron oxide, ultramarine FDandC Red, Nos. 2, 5, 6, 7, 10, 11, 12, 13, 30 and 34; FDandC Yellow No. 5, Red 3, 21, 27, 28 and 33 Aluminum Lakes, Yellow 5, 6, and 10 Aluminum Lakes, Orange 5 Aluminum Lake, Blue 1 Aluminum Lake, Red 6 Barium Lake, Red 7 Calcium Lake, and the like.
Other useful powder materials include talc, mica, titanated mica (mica coated with titanium dioxide), iron oxide titanated mica, magnesium carbonate, calcium carbonate, magnesium silicate, silica (including spherical silica, hydrated silica and silica beads), titanium dioxide, zinc oxide, nylon powder, polyethylene powder, ethylene acrylates copolymer powder, methacrylate powder, polystyrene powder, silk powder, crystalline cellulose, starch, bismuth oxychloride, guanine, kaolin, chalk, diatomaceous earth, microsponges, boron nitride and the like. Additional powders useful herein are described in U.S. Pat. No. 5,505,937 issued to Castrogiovanni et al. Apr. 9, 1996.
Of the components useful as a matte finishing agents, low luster pigment, talc, polyethylene, hydrated silica, kaolin, titanium dioxide, titanated mica and mixtures thereof are preferred.
Micas, boron nitride and ethylene acrylates copolymer (e.g., EA-209 from Kobo) are preferred for imparting optical blurring effects through light diffraction and improving skin feel, e.g., by providing a lubricious feel. Another particulate material for improving skin feel is SPCAT 12 (a mixture of talc, polyvinylidene copolymer, and isopropyl titanium triisostearate).
Preferred powders for absorbing oil are spherical, nonporous particles, more preferably having a particle size less than 25 microns. Examples of some preferred oil absorbing powders are Coslin C-100 (a spherical oil absorber commercially available from Englehard), Tospearl (spherical silica commercially available Kobo Industries), ethylene acrylates copolymer such as noted above, and SPCAT 12.
The powders may be surface treated with one or more agents, e.g., with lecithin, amino acids, mineral oil, silicone oil, or various other agents, which coat the powder surface, for example, to render the particles hydrophobic or hydrophilic. Such treatment may be preferred to improve ease of formulation and stability.
Thickening agents
Compositions hereof also comprise a total of from about 0.5% to about 50% of one or more thickening agents to enhance the stability of the composition, especially upon exposure to the electric field applied during spraying. Suitable thickening agents can be selected from the group consisting of silicones, waxes, clays, silicas, salts, natural and synthetic esters, fatty alcohols, and mixtures thereof. Nonlimiting examples of these thickening agents are described below.
Suitable silicones include alkyl siloxane gellants, high molecular weight dimethicones (fluids greater than 1000 mPas), and high molecular weight alkyl, hydroxyl, carboxyl, amino, and/or fluoro-substituted dimethicones (fluids greater than 1000 mPas). Preferred silicone gellants are described in U.S. Pat. No. 5,654,362 and 5,880,210, and include cyclomethicone and dimethicone crosspolymers (e.g., Dow Corning 9040).
Waxes can be defined as lower-melting organic mixtures or compounds of high molecular weight, solid at room temperature and generally similar in composition to fats and oils except that they contain no glycerides. Some are hydrocarbons, others are esters of fatty acids and alcohols. Suitable waxes may be selected from the group consisting of natural waxes including animal waxes, vegetable waxes, and mineral waxes, and synthetic waxes including petroleum waxes, ethylenic polymers, hydrocarbon waxes (e.g., Fischer-Tropsch waxes), ester waxes, silicone waxes, and mixtures thereof. Synthetic waxes include those disclosed in Warth, Chemistry and Technology of Waxes, Part 2, Reinhold Publishing (1956).
Specific examples of waxes include beeswax, lanolin wax, shellac wax, carnauba, candelilla, bayberry, jojoba esters, behenic acid waxes (e.g., glyceryl behenate which is available from Gattifosse as Compritol(copyright)), ozokerite, ceresin, paraffin, microcrystalline waxes, polyethylene homopolymers, polymers comprising ethylene oxide or ethylene (e.g., long chained polymers of ethylene oxide combined with a dihydric alcohol, namely polyoxyethylene glycol, such as Carbowax available from Carbide and Carbon Chemicals company; long-chained polymers of ethylene with OH or another stop length grouping at end of chain, including Fischer-Tropsch waxes as disclosed in Warth, supra, at pages 465-469 and specifically including Rosswax available from Ross Company and PT-0602 available from Astor Wax Company), C24-45 alkyl methicones, C8 to C50 hydrocarbon waxes, alkylated polyvinyl pyrrolidones (e.g., xe2x80x9cGanexxe2x80x9d alkylated polyvinylpyrrolidines available from the ISP Company) , fatty alcohols from C20 to C60 (e.g., xe2x80x9cUnilinsxe2x80x9d, available from Petrolite Corporation), and mixtures thereof.
Preferred structuring or thickening agents are those which are substantially inert to distribution of charge through a fluide, e.g., waxes and high molecular weight silicones and hydrocarbons. For example, Versagel from Penreco can be used and is a high molecular weight material.
Water dispersible and oil dispersible clays may be useful to provide thickening. Suitable clays can be selected, e.g., from montmorillonites, bentonites, hectorites, attapulgites, sepiolites, laponites, silicates and mixtures thereof.
Suitable water dispersible clays include bentonite and hectorite (such as Bentone EW, LT from Rheox); magnesium aluminum silicate (such as Veegum from Vanderbilt Co.); attapulgite (such as Attasorb or Pharamasorb from Engelhard, Inc.); laponite and montmorillonite (such as Gelwhite from ECC America); and mixtures thereof.
Suitable oil dispersible clays include organophilically modified bentonites, hectorites and attapulgites. Specific commercially available examples of these clays include Bentone 34 (Rheox Corp.)xe2x80x94Quaternium-18 Bentonite; Tixogel VP (United Catalysts)xe2x80x94Quaternium-18 Bentonite; Bentone 38 (Rheox Corp.)xe2x80x94Quaternium-18 Hectorite; Bentone SD-3 (Rheox Corp.)xe2x80x94Dihydrogenated Tallow Benzylmonium Hectorite; Bentone 27 (Rheox Corp.)xe2x80x94Stearalkonium Hectorite; Tixogel LG (United Catalysts)xe2x80x94Stearalkonium Bentonite; Claytone 34 (Southern Clay) Quaternium-18 Bentonite; Claytone 40 (Southern Clay) Quaternium-18 Bentonite; Claytone AF (Southern Clay) Stearalkonium Bentonite; Claytone APA (Southern Clay) Stearalkonium Bentonite; Claytone GR (Southern Clay) Quaternium-18/Benzalkonium Bentonite; Claytone HT (Southern Clay) Quaternium-18/Benzalkonium Bentonite; Claytone PS (Southern Clay) Quaternium-18/Benzalkonium Bentonite; Claytone XL (Southern Clay) Quaternium-18 Bentonite; and Vistrol 1265 (Cimbar)xe2x80x94Organophilic Attapulgite. These organophilic clays can be purchased as pre-dispersed organophilic clay in either an oil or an organic solvent. The materials are in the form of a heavy paste that can be readily dispersed into the formulation. Such materials include Mastergels by Rheox, United Catalysts, and Southern Clay.
Other thickening agents include fumed silicas and alkali metal or ammonium halides. Examples of fumed silicas include Aerosil 200, Aerosil 300, and the alkyl-substituted fumed silicas such as Aerosil R-100, 200, 800, and 900 series of materials, all available from the DeGussa Corporation.
Optional components
The compositions hereof optionally comprise additional components such as are conventionally used in topical products, e.g., for providing some esthetic or functional benefit to the composition or skin, such as sensory benefits relating to appearance, smell, or feel, therapeutic benefits, or prophylactic benefits (it is to be understood that the abovedescribed required materials may themselves provide such benefits).
The CTFA Cosmetic Ingredient Handbook, Second Edition (1992) describes a wide variety of nonlimiting cosmetic and pharmaceutical ingredients commonly used in the skin care industry, which are suitable for use in the topical compositions of the present invention. Such other materials may be dissolved or dispersed in the composition, depending on the relative solubilities of the components of the composition.
Compositions to be delivered using the present invention are preferably generally liquid in form. Any adjunct materials which are present may be liquid, solid or semi-solid at room temperature, though they should be selected so as to permit electrostatic spraying of the composition. For enhancing electrostatic spraying, preferred compositions have a solids content of about 35 weight % or less. In this regard, xe2x80x9csolidsxe2x80x9d refers to particulate materials which are not soluble or miscible in the composition, and includes particulate pigments and oil absorbers.
Examples of suitable topical ingredient classes include: anti-acne agents, anti-inflammatory agents, anti-cellulite agents, anti-microbial agents, anti-fungal actives, antioxidants, radical scavengers, chelating agents, desquamation actives, skin bleaching and lightening agents, shine providing agents, shine control agents, skin-conditioning agents (e.g., humectants, including miscellaneous and occlusive), other skin-feel agents, moisturizers, skin repair ingredients including agents for preventing, retarding, and/or reversing skin lines, wrinkles, or atrophy, skin soothing and/or healing agents, self-tanning actives, sunscreens, sunblocks, vitamins and derivatives thereof, abrasives, other oil absorbents, astringents, skin sensates, film formers or materials, e.g., polymers, for aiding the film-forming properties and/or substantivity of the composition, including materials which impart extended wear and/or transfer resistance to the composition, other colorants, pigments and dyes, essential oils, fragrance, structuring agents, emulsifiers, solubilizing agents, anti-caking agents, antifoaming agents, binders, buffering agents, bulking agents, denaturants, pH adjusters, propellants, reducing agents, sequestrants, cosmetic biocides, and preservatives.
Preferred compositions of the invention comprise one or more ingredients selected from the group consisting of materials which impart wear and/or transfer resistant properties, co-solubilizers and mixtures thereof. Nonlimiting examples of these components include the following:
Materials for enhancing wear or transfer resistance. One or more materials for imparting wear and/or transfer resistant properties, e.g., via film forming or substantive properties, may be used in the present compositions. Such materials are typically used in an amount of from about 0.5% to about 20%.
Such materials include film forming polymeric materials. While the level of film forming polymeric material may vary, typically the film forming polymeric material is present in levels of from about 0.5% to about 20% (e.g., from about 1% to about 15%), preferably from about 0.5% to about 10% by weight, more preferably from about 1% to about 8% by weight. Preferred polymers form a non-tacky film which is removable with water used with cleansers such as soap.
Examples of suitable film forming polymeric materials include:
a) sulfopolyester resins, such as AQ sulfopolyester resins, such as AQ29D, AQ35S, AQ38D, AQ38S, AQ48S, and AQ55S (available from Eastman Chemicals);
b) polyvinylacetate/polyvinyl alcohol polymers, such as Vinex resins available from Air Products, including Vinex 2034, Vinex 2144, and Vinex 2019;
c) acrylic resins, including water dispersible acrylic resins available from National Starch under the trade name xe2x80x9cDermacrylxe2x80x9d, including Dermacryl LT;
d) polyvinylpyrrolidones (PVP), including Luviskol K17, K30 and K90 (available from BASF), water soluble copolymers of PVP, including PVP/VA S-630 and W-735 and PVP/dimethylaminoethylmethacrylate Copolymers such as Copolymer 845 and Copolymer 937 available from ISP, as well as other PVP polymers disclosed by E. S. Barabas in the Encyclopedia of Polymer Science and Engineering, 2 Ed. Vol. 17 pp. 198-257;
e) high molecular weight silicones such as dimethicone and organic-substituted dimethicones, especially those with viscosities of greater than about 50,000 mPas;
f) high molecular weight hydrocarbon polymers with viscosities of greater than about 50,000 mPas;
g) organosiloxanes, including organosiloxane resins, fluid diorganopolysiloxane polymers and silicone ester waxes.
Examples of these polymers and cosmetic compositions containing them are found in PCT publication Nos. WO96/33689, published Oct. 31, 1996; WO97/17058, published May 15, 1997; and U.S. Pat. No. 5,505,937 issued to Castrogiovanni et al. Apr. 9, 1996, the U.S. patents incorporated herein by reference. Additional film forming polymers suitable for use herein include the water-insoluble polymer materials in aqueous emulsion and water soluble film forming polymers described in PCT publication No. WO98/18431, published May 7, 1998. Examples of high molecular weight hydrocarbon polymers with viscosities of greater than about 50,000 mPas include polybutene, polybutene terephthalate, polydecene, polycyclopentadiene, and similar linear and branched high molecular weight hydrocarbons.
Preferred film forming polymers include organosiloxane resins comprising combinations of R3SiO1/2 xe2x80x9cMxe2x80x9d units, R2SiO xe2x80x9cDxe2x80x9d units, RSiO3/2 xe2x80x9cTxe2x80x9d units, SiO2 xe2x80x9cQxe2x80x9d units in ratios to each other that satisfy the relationship RnSiO(4-n)/2 where n is a value between 1.0 and 1.50 and R is a methyl group. Note that a small amount, up to 5%, of silanol or alkoxy functionality may also be present in the resin structure as a result of processing. The organosiloxane resins must be solid at about 25xc2x0 C. and have a molecular weight range of from about 1,000 to about 10,000 grams/mole. The resin is soluble in organic solvents such as toluene, xylene, isoparaffins, and cyclosiloxanes or the volatile carrier, indicating that the resin is not sufficiently crosslinked such that the resin is insoluble in the volatile carrier. Particularly preferred are resins comprising repeating monofunctional or R3SiO1/2 xe2x80x9cMxe2x80x9d units and the quadrafunctional or SiO2 xe2x80x9cQxe2x80x9d units, otherwise known as xe2x80x9cMQxe2x80x9d resins as disclosed in U.S. Pat. No. 5,330,747, Krzysik, issued Jul. 19, 1994, incorporated herein by reference. In the present invention the ratio of the xe2x80x9cMxe2x80x9d to xe2x80x9cQxe2x80x9d functional units is preferably about 0.7 and the value of n is 1.2. Organosiloxane resins such as these are commercially available such as Wacker 803 and 804 available from Wacker Silicones Corporation of Adrian Michigan, and G. E. 1170-002 from the General Electric Company.
Other materials for enhancing wear or transfer resistance include trimethylated silica. Suitable silicas of this type and cosmetic compositions containing them are described in U.S. Pat. No. 5,800,816 issued to Brieva et al., incorporated herein by reference.
Co-solubilizers. The compositions hereof may contain one or more co-solubilizers, e.g., to enhance the formation and stability of the composition. The co-solubilizer is especially useful to bridge compatibility of two materials which are normally incompatible, resulting in the creation of a single, stable phase. Co-solubilizers may therefore be particularly preferred to enhance miscibility or solubility of the liquid insulating and conductive materials present in the composition. When used, compositions of the invention typically comprise from about 0.5% to about 10%, preferably from about 1% to about 5%, more preferably from about 1.5% to about 3% co-solubilizer.
Suitable co-solubilizers are best chosen using a solubility parameter scale as is described in xe2x80x9cSolubility: Effects in Product, Package, Penetration, and Preservation,xe2x80x9d by C. D. Vaughan, Cosmetics and Toiletries, Vol. 103, Ocober 1988. Based on the solubility parameter of two incompatible materials, a third material with a solubility parameter in between that of the two incompatible materials may sometimes be found which is independently compatible with the two incompatible materials. When all three materials are then combined, they may exhibit the properties of a single stable phase, as could be measured, visually for example, via a light microscope.
Co-solubilizers can be polar fluids, non-polar fluids, polar aprotic solvents, or amphiphilic materials and are chosen from these broad categories to fit the needs of the two incompatible materials to create a single phase.
Particularly useful co-solubilizers for the present compositions include polydiorganosiloxane-polyoxyalkylene copolymers. Such polymers are described in U.S. Pat. No. 4,268,499, incorporated herein by reference. Suitable copolymers of this type are known and many are available commercially. A preferred co-solubilizer of this type is known by its CTFA designation as dimethicone copolyol. Preferred co-solubilizers also include the surfactants disclosed in U.S. Pat. No. 5,143,722, incorporated herein by reference.
Product Forms and Particular Compositions The compositions of the invention can be adapted to a variety of product forms, including pigmented and non-pigmented skin care compositions, e.g., lotions, creams, moisturizers, foundations, blush, eye shadow, self-tanning products, touch-up products (e.g., for oil/shine control), and chemical peels. Such compositions may comprise a volatile insulating and conductive material, one or more powders and/or skin treatment actives, and optionally one or more of the above described additional materials. Lotions, creams and moisturizers will typically include one or more of humectant, nonvolatile oil, emulsifier, preservative, powder material, and structuring agent or thickener. Examples of nonvolatile oils are described in U.S. Pat. No. 5,800,816. Such compositions may also comprise an effective amount of a prophylactic or therapeutic skin ingredient care ingredient, e.g., selected from oil/shine control actives, desquamation actives, anti-acne actives, anti-inflammatory actives, skin bleaching or lightening actives, skin-feel agents, skin repair ingredients, sunscreens, sunblocks, and vitamins or derivatives thereof. Color cosmetics such as foundations, blush, and eye shadows may contain one or more ingredients as for lotions, creams and moisturizers, and will contain a powder for coloration.
In a preferred embodiment the composition is in the form of a cosmetic foundation. As used hereinafter, the term xe2x80x9cfoundationxe2x80x9d refers to a liquid or semi-liquid skin cosmetic which includes, but is not limited to lotions, creams, gels, pastes, and the like. Typically the foundation is used over a large area of the skin, such as over the face, to provide a particular look. Foundation compositions of the invention typically comprise:
(a) from about 2% to about 90% of a liquid insulating material;
(b) from about 2% to about 90% of a conductive material;
(c) from about 0.1% to about 35% of a particulate material which is insoluble and immiscible in the composition; and
(d) from about 0.5% to about 30% of a thickener for stabilizing the composition.
Foundation compositions of the invention typically comprise from about 2% to about 20% pigment for coloration, and from about 2% to about 15% of additional non-pigmented particulates.
Electrostatic spray techniques
The compositions hereof are suitably directly applied to the skin by electrostatic spray techniques. In general, this method involves raising the composition to be sprayed to a high electric potential in a spray nozzle to cause the composition to atomize as a spray of electrically charged droplets. The electrically charged droplets seek the closest earthed object to discharge their electric charge, which can be arranged to be the desired spray target.
For use in the present invention, the hardware and electrical componentry and circuitry may be of any suitable construction and design. The art of electrostatic spraying contains many examples of suitable apparatus which may be used in the present invention and such disclosures of such apparatus or particular features thereof may be applied either singly or in combination to the spray systems of the present invention. Examples of suitable electrostatic spraying hardware include those described in the following publications: U.S. Pat. Nos. 4,549,243; 4,561,037; 4,663,639; 4,854,506; 4,846,407; 5,121,884; 5,222,663; 5,222,664; 5,221,050; 5,290,600; 5,337,963; 5,292,067; 5,490,633; 5,184,778; 5,503,335; 5,684,666; and 4,776,515; Japanese patent No. 1,932,551; JP-A-56-97214; Canadian Patent Application No. 2018551-1; GB-A-1393333; GB-A-15697007; GB-A-2092025; GB-A-2061769; GB-A-2073052; Taiwanese Patent No. NI-64734; EPO Application No. 94924355.4 (Publication No. 716626); EPO Application No. 95915955.9 (Publication No. 748256); EPO Application No. 95916790.9 (Publication No. 748257); EPO Application No. 94931643.4 (Publication No. 789626); EPO Application No. 95932065.6 (Publication No. 776253); EPO Application No. 95932063.1 (Publication No. 785823); EP-A-029301; EP-A-253539; EP-A-224352; EP-A-031649; EP-A-132062; EP-A-163390; EP-A-171184; EP-A-234842; EP-A-243031; EP-A-368494; EP-A-441501; EP-A-468735; EP-A-468736; PCT Application No. GB96/01286 (Publication No. 096/40441); PCT Application No. GB97/00376 (Publication No. 097/31718); PCT Application No. GB97/02746; and WO-A-85/00761; of which the U.S. patents are incorporated herein by reference in their entirety. Preferred electrostatic spray devices are disclosed in copending, commonly assigned U.S. patent applications Attorney""s Docket No. 7711, U.S. Ser. No. 09/377,333, entitled xe2x80x9cHand-Held Electrostatic Sprayer Apparatusxe2x80x9d filed in the names of Chinto B. Gaw et al. on Aug. 18, 1999; and Attorney""s Docket No. 7712, U.S. Ser. No. 09/377,332 entitled xe2x80x9cDisposable Cartridge for Use in a Hand-Held Electrostatic Sprayer Apparatusxe2x80x9d filed in the name of Chinto B. Gaw et al. on Aug. 18, 1999, both incorporated herein by reference.
Preferred devices include an apparatus suitable for small-scale personal use which has a reservoir for containing the topical composition, at least one delivery means, e.g., a nozzle, in communication with the reservoir; a high voltage generator generating voltage in the range of 1 to 26 kilovolts (e.g., from 12 to 26 kilovolts) powered from a portable or non-portable (preferably portable) electricity source; and control means for selectively applying the high voltage from the generator to the at least one delivery means. In use, the control means is actuated to electrostatically spray the topical composition from the at least one delivery means directly onto the skin at an intended site.
As will be appreciated by persons skilled in the art, particular constructional features and design and electrical and other operating parameters of such apparatuses may be selected or adjusted as necessary, in the context of the present invention, in accordance with the desired functioning characteristics, as for example dictated by the composition to be sprayed and/or the needs or wishes of a user. Features of the apparatus of the present invention which may be so selected and/or adjusted include for example: voltage generated by the high voltage generator and power source, electric field strength in or in the region of the product delivery means, flow rate of the product to be sprayed from the reservoir to and out of the delivery means, size and configuration of the delivery means itself and construction and properties of any product feed mechanism utilized between the reservoir and the output of the delivery means.
The size and configuration of the one or more delivery means in the apparatus of the invention may be of any suitable form and again may be selected in association with other parameters to give an optimized functioning electrostatic spray delivery system. Commonly the or each delivery means will be in the form of a nozzle, preferably of insulating or semi-insulating material such as plastics or various polymers, as is well known in the art. In one preferred form of nozzle, a conduit for carrying the product to be sprayed terminates in an orifice at the tip of the nozzle, from which orifice the product is ejected for example initially as a ligament but in any event eventually dispersing as a spray of charged droplets. The orifice preferably has a diameter of not greater than about 800 microns (e.g., from 508-762 microns or 0.020xe2x80x3-0.030xe2x80x3). Even more preferably the orifice has a diameter of from about 500 to about 750 microns.
The delivery means may advantageously include metering means to provide a dosing mechanism for delivering a predetermined fixed amount of material from the or each nozzle. Such an expedient may for example be useful in conjunction with a system having a controlled flow rate. In preferred embodiments of the apparatus of the invention, the or each delivery means is in communication, i.e. preferably fluid communication, with the reservoir or reservoirs (if for example more than one material or composition is to be desired to be sprayed from the same apparatus or even the same delivery means) by virtue of product feed means. In one preferred form, such feed means may comprise an insulator having a channel between the nozzle and the product reservoir, through which the product to be sprayed flows before reaching the point of high electric field strength where it is dispersed as a charged spray of droplets or particles. In another preferred form the feed means may comprise a hollow conduit through which the composition passes under the effect of capillary action.
As is well known in the art, the apparatus according to the invention preferably includes a trigger (i.e. a manual control means) or alternatively an automatic control means to selectively apply the high voltage from the generator to the or each delivery means to electrostatically spray the composition onto the skin. Any other suitable control means however, e.g. which automatically control actuation of the system, may be used, as will be appreciated by persons skilled in the art.
In preferred embodiments of the invention, voltages generated by the high voltage generator from the power source are in the range of from about 1 to about 26 kilovolts, more preferably from about 6 to about 20 kilovolts. The most suitable voltage for a given system may depend upon the product to be sprayed, as well as other parameters, all of which will generally be selected to give an overall optimized system. Voltage may be applied at constant positive or alternating polarity, however positive polarity is preferred.
Electric field strengths which are responsible for the spraying action of the electrostatic apparatus will be largely dependent upon the voltage applied. However, field strengths may be controlled or adjusted if necessary, for example by changes in nozzle configuration or geometry and/or the use of field intensifying electrodes, which are well known in the art cited above.
The deposition of the composition on the skin, including spray droplet size and spacing and skin coverage, is influenced by the product spray flow rate, the rate of product application to the skin, and the amount of product applied to the skin. In general, droplet size increases with increasing resistivity, decreasing voltage, and increasing flow rate, spacing increases with increasing voltage and decreasing deposition amount, and coverage increases with increasing flow rate and increasing deposition amount.
Optimum flow rates of material to be sprayed will generally depend upon the composition of the product itself, and may be selected appropriately on that basis preferably so as to avoid sensory negatives. Also, as already mentioned with respect to viscosity of the sprayable material, a suitable flow rate may be selected depending upon the particular delivery regime and/or habit or needs of a user. Generally it will be desired to utilize lower flow rates with concentrated materials in order to better control the deposition of the composition. By way of example, preferred flow rates of compositions for delivery in accordance with embodiments of the invention are in the range of from about 0.036 to about 1800 ml/hr (0.00001 to about 0.5 ml/sec), more preferably from about 0.1 to about 360 ml/hr (0.0001 to about 0.1 ml/sec), even more preferably from about 0.1 to 100 ml/hr, most preferably from about 1 to about 30 ml/hr per the delivery means. Particularly preferred applications utilize a higher speed flow rate of from about 4 to about 18 ml/hr (preferably about 9 ml/hr), and a lower speed flow rate of from about 2.4 to about 10.8 ml/hr (preferably about 7.2 ml/hr), where the low speed is about 0.2 to 0.8 times the high speed.
In general, as the flow rate increases it will be desired to utilize a higher voltage in order to provide optimal sprayability and small sprayed droplet sizes. In a preferred embodiment, the composition is sprayed at a flow rate of from about 0.1 to about 100 ml/hr, a voltage of from about 1 kV to about 26 kV (preferably about 1 kV to about 20 kV), and an application rate of from about 0.01 mg composition/cm2 of skin to about 12 mg composition/cm2 of skin. Relatively high solids compositions such as foundations are typically applied at a rate of about 1 mg/cm2 skin; relatively low solids compositions such as skin lotions are typically applied at a rate of about 5 to 6 mg/cm2 skin. Relatively low solids compositions such as skin lotions are typically delivered at a flow rate of from about 50 to about 60 ml/hr. Relatively high solids compositions such as foundations are preferably electrostatically sprayed at said application rate, at a flow rate of from about 1 to about 30 ml/hr and a voltage of from about 6 kV to about 20 kV. A voltage range of from about 3 kV to about 20 kV is preferred.
Total product application amounts, in terms of amount of product sprayed per cm2 skin, is typically less than about 6 mg/cm2. An exemplary application amount is about 0.8 mg/cm2, which tends to provide about 30-40% skin coverage.
The product is typically applied at a rate of 0.005 sec/cm2 skin area to 6 sec/cm2 skin area, more preferably rate of 0.01 sec/cm2 skin area to 3 sec/cm2 skin area, most preferably rate of 0.05 sec/cm2 skin area to 2 sec/cm2 skin area.
Preferred usage instructions for electrostatic application
Electrostatic compositions may be applied by a second party (including robotic means) or the end-user of the composition. The present invention also relates to instructions for using an electrostatic spray device to apply topical compositions to the face, especially foundation compositions, and especially second-party and self-application techniques, context, and methods of training self-application.
a) application techniques
It has been found that improved results are achieved by observing certain directions relating to distance of the device (particularly the nozzle) from the target application area (the face), the rate of application of product to the skin (including flow rate and device speed settings), and motion of the device during application (including the direction and character of the motion).
In use, the device is held or otherwise positioned so as to efficiently deliver the spray to the target facial area and to avoid obstruction of the spray.
In general, the device is held or positioned sufficiently distant from the target such that the spray pattern spreads sufficiently and does not tend to form lines or other undesirable concentrated effects on the target substrate, and close enough such that the spray adequately grounds to the target so as to deliver optimum coverage and even-ness of laydown. Typically, the device is held or positioned such that the nozzle is from about 3-4 inches (9-13 cm) from the target facial area.
During self-application, it is best to keep one or both eyes open when applying to areas of the face below the nose, and closed when applying to areas of the face above the nose. When self-applying while the eyes are closed, it can be helpful to appropriately judge the distance with which to hold the device from the face, by first stretching the arm all the way out straight (until the feel of the spray mist on the face can no longer be felt clearly) and then bending the elbow to bring the device closer, slowly, until the spray mist is first clearly felt. This typically leads to ensuring that the device stays about 3-4 inches from the applier""s face.
For improved even-ness of coverage, the device should be kept moving during application, preferably at a steady pace with a sweeping motion, without stopping in place while the device is operating. In general, the preferred pace is such that in one second one can usually transverse the forehead, or make two passes over a single cheek, depending on the facial size. The swath areas may be partially overlapped, such as occurs with a Zamboni smoothing ice. In a typical 60-90 second application, each facial area is typically passed over 2-8 times.
In a preferred technique, the composition is applied following the contours of the face and in four sections. First, smooth horizontal strokes are made across the forehead. Product is then applied to each side of the face utilizing back and forth sweeping, semi-circular motions following the natural contours of the cheekbone working down to the chin from the side of the face to the center of the face. While applying to the cheeks, it is important to avoid the fourth region, the nose, which is preferably sprayed last since its relative height tends to preferably attract spray. The nose is then sprayed, if needed, along with the area above the upper lip. Where the wearer has visible facial hair, it may be preferred to tilt the nozzle slightly downward to minimize accentuating the visibility of the hair. Also, when first self-applying it is preferred to begin with the jaw line and work xe2x80x9cupxe2x80x9d the face until one becomes more comfortable with the application process. This allows the wearer to keep her eyes open initially and see where the spray is going on the face, and helps for judging how far away from the face she may be with the device.
Improved results have also been found where the applicant utilizes two or more speeds such as described above for applying the product. The preferred use is typically to use a faster speed (higher flow rate) for all-over-face coverage and a slower speed for spot coverage. Preferred is a higher speed flow rate of from about 4 to about 18 ml/hr (preferably about 9 ml/hr), and a lower speed flow rate of from about 2.4 to about 10.8 ml/hr (preferably about 7.2 ml/hr), where the low speed is about 0.2 to 0.8 times the high speed The slow speed allows a more controlled build up of coverage in a specified area without unintentional overapplication. In general, the application process is designed so as to avoid overapplication, resulting in an unnatural look and/or uneven application, but to provide sufficient coverage. It can be helpful for a second party to first view the user with their typical facial makeup in order to identify likely coverage objectives. It is also helpful to utilize a stepwise application, involving at least one sequence of overall application and optionally spot coverage, so that the applicant or user can titrate to the desired appearance.
A typical application process involves the following steps:
1) Apply all over the face using a relatively fast speed/flow rate designed to apply product at a rate of about 9 milliliters/hour;
2) judge whether or not more coverage is needed, and if so where and how much more;
3a) If more product is desired in xe2x80x9cspotxe2x80x9d areas, e.g., age spots, acne, red areas, dark areas, apply additional spray to the specific areas defined using a slow speed/flow rate designed to apply about 5-7 milliliters/hour;
3b) If more product is desired xe2x80x9call-overxe2x80x9d, repeat step (1);
4) Iterate Steps 2 and 3 until the desired coverage is obtained.
The overall time for application tends to be from about 0.5 to 3 minutes (generally from about 60 to about 90 seconds).
b) context
When instructing someone to apply product either to themselves or others, it has been found that the context with which the first application or demonstration is made is very important to help the end-user feel comfortable and positive about the application experience. The context is preferably designed to provide the user with visible and tactile expectations. It preferably includes the steps of reviewing safety, explaining how the spray works, and demonstrating how the spray works.
More particularly, the safety of the composition, device and method is reviewed, typically including a recommendation to keep eyes closed when spraying above the nostrils as an added safety level. Any eye, inhalation, grounding/electrical safety or other concerns which the user may have are addressed.
How the spray works is generally explained, for example, by explaining that the product is a fine mist of product droplets that are charged so that they stay separated during application and are uniquely attracted to the face versus non-target areas such as the hair, clothing, etc., yet needs no blending. Demonstrating how the spray works preferably includes showing how to hold the device (e.g., by resting it between the thumb and fore finger), and how to activate the device (e.g., by pressing the on/off button with your fore-finger, preferably instructing to keep fingers away from the nozzle. A useful demonstration before actual use involves providing a visible expectation (i.e., how the product comes out of the device), e.g., by spraying on a piece of paper, paper towel, non-target skin (e.g, hand or arm) or the like, and providing a tactile expectation, e.g., by spraying on non-target skin to show how the spray feels on the skin. The user should understand that the product is emitted as a fine, uniform spray or mist that needs no blending into the skin, which is very light in feel. The user should also preferably understand that the mist generally forms a circular, versus linear (jets) pattern and that the swath diameter is proportional to the distance of the device from the face.
Other means may be provided to enhance the user""s experience, e.g., music or other audio effects, flowers, aromatherapy, massage, or other known means of promoting relaxation.
c) self-application training
Where the user intends to self-apply the product, the learning curve for self-applying the composition is also important to user satisfaction. Preferred training involves at least a step of joint application by the user and a second party. More preferred training methods allow the user to gradually become familiar with the techniques, and involve a sequence of steps comprising application by a second party, joint application by the user and a second party, and full application by the user with optional assistance of a second party or instructional materials. The steps are preferably performed on different days, more preferably on consecutive days. However, the steps may be performed on the same day and optionally immediately following each other if it is practical and provided that cleansing of the user""s skin between steps does not cause negative effects.
One preferred method of training is a 3-5 day training period during which the user gradually becomes comfortable with self-application:
(1) On the first day, a second party applies the product to the end-user.
(2) On the second day, the second party applies product to half the end-user""s face and then the end-user completes the application with personalized guidance from the second party and/or instructional aids such as a usage pamphlet and/or a video of others self-applying the product. The second party or instructional aid preferably reminds the end user of the proper device distance, speed, the desirability of keeping the eyes closed as described above, and other helpful suggestions such as described above, e.g., such as beginning with the jaw line and working xe2x80x9cupxe2x80x9d the face until becoming more comfortable with the application process.
(3) On the third day, the end-user applies full face product with optional guidance from the second party and/or instructional materials.
(4) On optional fourth and fifth days, the third day procedure is repeated.
When it is desirable to demonstrate self-application with a single demonstration, the preferred method is to follow the above instructions for the second day.
The self-application learning curve preferably involves three elements of expectation or context, technique or application, and confidence. Expectation/context involves addressing any safety concerns and describing the product which comes out of the device. Technique/application involves application techniques, including how to hold/handle the device and instructions regarding proper distance from the face, amount of product to apply, how long to apply, hand motion, and application speeds. Confidence involves allowing the user to practice applying the product, optionally with assistance from a second party or other instructional aids. Preferred aspects of these elements is as described herein above.
Other topical application methods
The topical compositions can alternatively be applied to the skin to form the discontinuous films by silk screen techniques or the like, and additionally by using application techniques which provide product deposition via the use of normal forces (i.e., forces perpendicular to skin surface).
In the first method, a piece of plastic, metal, cloth or other mesh (preferably conformable to facial contours), with evenly spaced holes/pores of about 150 microns or less in diameter is placed against the skin. Then topical composition, e.g., a pigmented foundation, is pressed through the holes in the mesh to deposit the same pattern of droplets on the skin which exists in the pores of the mesh. One convenient way to press the fluid through the mesh is to first absorb it into a sponge, cloth or other absorbent material and then to press the soaked sponge or other material against the mesh. Another means of accomplishing this is to spread or draw the fluid across the mesh with a stiff-edged product such as a rubber squeegee, much like spackling a wall. After the product is pressed through the mesh, the mesh is removed, and cleaned if desired for re-use. The mesh is then moved to any bordering, uncovered areas and the process is repeated as many times as necessary to complete application of the target area. Once the fluid on the skin has dried, if applicable, the process may be repeated by placing the mesh back over the areas where product is already deposited, and orienting the mesh at a different angle to minimize the potential for overlapping droplets. This re-application process will allow for tighter particle spacing than inherently exists in the mesh, if desired.
Any type mesh which allows for a deposition with the desirable size and spacing pattern described herein may be used. Examples of such materials include microaperatured formed films as are described in U.S. Pat. No. 4,342,314, issued to Radel et al. on Aug. 3, 1982 and U.S. Pat. No. 4,629,643 issued to Curro et al. on Dec. 16, 1986, both of which are herein incorporated by reference in their entirety. As is described in these references, suitable materials for these formed films are preferably polyolefins, e.g., polyester. Preferable mesh hole size and spacing is equivalent to the desired end discontinuous film particle size and spacing. Alternatively, the discontinuous deposition pattern is achieved without the use of a mesh or screen, but rather is accomplished through the use of a porous material with pores which are less than about 150 microns in diameter. The porous structure may comprise open cells, closed cells, or some combination thereof. The term xe2x80x9ccellsxe2x80x9d, as used herein, refers to the 3-dimensional voids present in the material which may, or may not have interstitial openings which would connect the voids to one another. In one embodiment, the fluid topical skin product is absorbed into the porous material and then xe2x80x9cblottedxe2x80x9d onto the skin using forces perpendicular to the skin (as opposed to tangential, or shearing forces). This application technique uses the pore size and pore spacing of the material to create the discontinuous deposition pattern.
Such porous materials can be created by techniques which include, but are not limited to:
1) seeding mechanisms in which the pores are created by incorporating a physical material which is later extracted, destroyed, removed, or decays after the structure is formed, examples of such materials include elastomeric rubber structures manufactured by the Porelon and MicroFoam Companies such as Porlon and Microfoam brand materials which are described in U.S. Pat. Nos. 3,971,315 and 4,824,621, both of which are herein incorporated by reference in their entirety;
2) aerating (i.e., incorporating air or inert gases into) polymeric materials via mechanical shearing, high pressure (e.g., forced air), or the like, examples include foams of synthetic latex nitriles produced Latex Foam Products, Inc. (LFP) such as xe2x80x9cNBRxe2x80x9d, xe2x80x9cSBRxe2x80x9d, or xe2x80x9cSKxe2x80x9d type materials;
3) using emulsion chemistry and processing techniques to control the pore size and densityxe2x80x94examples of such materials include polyurethane foams produced by the Lendell corporation, or flexible microcellular foams such as those cited in U.S. Pat. Nos. 5,260,345 and 4,522,953, both of which are herein incorporated by reference in their entirety.
4) sintering powder particulates of various sizes to create the desired pore size and densityxe2x80x94examples of such materials which utilize particulates of high density polyethylene, polypropylene, or nylon and are produced by the Porex Technologies Corporation (e.g. Porex X4900 and X4800 series in coarse sheets or custom-molded parts).
In another variation on the use of porous materials to create a discontinuous pattern, a continuous or discontinuous film of fluid is applied to the skin and the porous material (as described above) is subsequently blotted onto the continuous film to remove fluid from the skin surface by absorbing the fluid into the pores of the material. The discontinuous pattern, in this case, is formed by and corresponds to the structural pattern of the polymeric material which separates the pores. In this example, the spacing of polymeric material which separates the pores should be less than 150 microns in effective diameter. The phrase xe2x80x9ceffective diameterxe2x80x9d, as used herein, refers to the diameter of a circle with an area equal to the area of the irregularly shaped region of interest.
In yet another execution, the discontinuous pattern is created by blotting non-porous materials with a relief texture in which the raised areas of the texture do not exceed 150 microns in effective diameter. In this execution the nonporous, textured material is blotted into a fluid reservoir (much like an ink pad), imparting the fluid product onto the raised textured areas of the non-porous substrate. The substrate is then blotted onto the skin (using forces normal to the skin) and the raised textured pattern of the nonporous material is transferred to the skin surface.
In still another execution, the discontinuous pattern is created by blotting non-porous materials with a relief texture where the reliefed areas of the texture do not exceed 150 microns in effective diameter. The phrase relief texture or reliefed areas, as used herein, refers to the depressed areas of the textured surface or textures formed by such depressed areas or regions. In this execution the nonporous, textured material is blotted into a fluid reservoir, imparting the fluid product onto all surfaces of the substrate (both raised and depressed). The fluid product on the raised areas is then removed through a secondary process such wiping, absorbing, evaporating, or the like. The substrate is then blotted onto the skin (using forces normal to the skin) and the depressed textured pattern of the nonporous material is transferred to the skin surface.

Stable, electrostatically sprayable topical compositions

Abstract: The liquid insulating materials and conductive materials present in the composition are sufficiently miscible or soluble in the composition such that they are in substantially one phase.