The rapid decrease in viscosity of liquids with increasing temperature is well-known. Ideally, for many applications (automobile lubricants, etc.) it would be desirable to solve this problem so that liquid viscosity would be insensitive to temperature. Alternatively, it might be desirable to provide liquid systems whose viscosities actually increase with temperature. It is true that with selected polymeric additives, it has been possible to reduce substantially the viscosity change with temperature which does occur with most oils and similar systems. These polymer additives, known as viscosity index improvers (or V.I. Improvers), are generally high molecular weight polymers.
The way in which these additives function can be summarized very briefly. In effect, they perform two functions, i.e., thickening, which merely increases fluid viscosity; and Viscosity Index (V.I.) improvement, which corresponds to limited thickening at ambient temperatures and a corresponding greater thickening at elevated temperatures. This can be accomplished by utilizing a polymeric additive which is poorly solvated by the liquid at ambient temperatures; however, at elevated temperatures, the polymer is more highly solvated such that the polymer expands and is a relatively more effective thickener.
While these V.I. Improvers have proven successful commercially, it is important to note that their effect at reducing viscosity changes with temperatures is rather mild. For a typical base oil containing a suitable V.I. Improver, the kinematic viscosity will still decrease by a factor of from 5 to 10 as the temperature increases from 30.degree. to 100.degree. C. Obviously, if it is desired to hold the viscosity roughly constant with such temperature changes, current technology has not offered an appropriate additive system.
U.S. Pat. No. 3,396,136 describes how copolymers of alkenylaromatic sulfonic acids, when properly neutralized, can be employed as thickeners for nonpolar solvents. Those metal sulfonate systems have been shown to be very effective; however, when employed as 2 component systems (i.e., ionic polymer plus nonpolar solvent), the variation of viscosity with increased temperature is very conventional and predictable. That is, the solution viscosity decreases markedly as temperature is increased.
U.S. Pat. No. 3,396,136 further teaches "in situ" neutralization of the sulfonic acid polymer which, under some conditions, can result in the availability of a small amount of polar cosolvent, i.e., a solvent for the sulfonate groups about equal in amount to the amount of sulfonate groups which are present. This amount of polar cosolvent is not within the critical limits of the instant invention, which require amounts of the third component (which interacts with the ionomeric groups of the ionomer copolymer) at levels which range from 10 to 600 times the molar equivalence of ionic groups. This level of cosolvent is about one to two orders of magnitude or more higher than employed in the cited art. This amount of such cosolvent is required to obtain the unusual and unexpected viscosity-temperature behavior which is observed. In addition, the cited patent is restricted to aromatic sulfonate polymers. The instant invention describes other polymers such as co- or terpolymers of acrylates or methacrylates with a sulfonate-containing monomer.
U.S. Pat. No. 3,666,430 teaches the gelling of organic liquids by the interaction of polar "associative bonds" which includes hydrogen bonding and "ionic crosslinking." Again this patent specifies that two components are necessary--the associating polymer (or polymers in some cases) and the nonpolar organic liquid. There is no mention of a third polar cosolvent except to point out that such polar liquids should not be present. Specifically, this patent states (column 2, line 7) that the hydrocarbon liquids to which this invention is to be applied should not contain a substantial portion of a miscible protolytic liquid such as methanol. It is clear that the language of this patent limits this invention to gels and further, that any amount of polar liquids which are present to an extent where they disrupt those gels are undesirable. The instant invention is distinct from that cited in that amounts of such polar compounds, as will break up gel at ambient conditions are required, and in fact, the most preferred state is free of any said gel at ambient temperatures.
U.S. Pat. No. 3,679,382 teaches the thickening of aliphatic hydrocarbons with synthetic organic polymers which contain olefinically unsaturated copolymerizable acids, amides, hydroxyacrylic esters, sulfonic acids, etc. It is emphasized in this patent (column 3, line 72) that it is critical in the preparation of such polymers that no surface active agent, catalyst or other additive be employed which introduces a metallic ion into the system. Therefore, it is preferred to employ ammonium or amine salts. It is clear that this invention (U.S. Pat. No. 3,679,382) specifically precludes the use of metallic counterions and is directed towards amine or ammonium derivatives. Only metallic counterions are effective in the instant invention and, in fact, attempts to employ amine derivatives have not resulted in the products which are the objective of this invention. Finally, this cited patent does describe (column 7, lines 13-19) that the addition of alcohols will reduce the viscosity of the thickened hydrocarbon and alter flow characteristics thereof.
One class of oil soluble polymers known to possess good low temperature viscometrics and to be practically of great interest in the V.I. additive area is that of the acrylate or methacrylate polymers. These long chain acrylate systems (alkyl groups of about 10 to 12 carbons or so) are sold commercially and have been very successful in achieving a suitable balance of thickening behavior and a combination of good low temperature fluidity and high temperature viscosity at reasonable polymer levels. This invention proposes a class of materials that will have comparable or superior viscometrics as compared to the acrylate or methacrylate family of materials. This preferred class of polymers is based on combining sulfonate containing monomers with acrylates and methacrylates of suitable chain length by appropriate polymerization techniques.
The instant invention represents an improvement over the process as described in U.S. Pat. No. 3,931,021, wherein the class of co- or terpolymers, as described in the instant invention, show improved low temperature viscometric properties. The co- and terpolymers of the instant invention are restricted to a class of polymers comprising copolymers and terpolymers derived from a metal sulfonate monomer and an alkyl acrylate or alkyl methacrylate, wherein the alkyl group has at least eight carbon atoms.


1. Field of the Invention
This invention relates to a superconducting energy stabilizer having multiple load connections employing DC-DC conversion. In particular, the invention relates to an energy stabilizer which utilizes energy stored in a superconducting inductive energy storage device to stabilize the delivery of energy to a DC or AC load or to retrieve and store regenerated energy supplied by the load. Additionally, the invention can supply stored energy to a utility or to an industrial electrical DC or AC distribution system to maintain the level of energy supplied to the consumers.
2. Background of the Prior Art
Prior art superconducting energy storage systems have been directed to the storage of energy derived from an alternating current power system and to the return of the stored energy to the alternating current (AC) power system. Typically, energy is stored during periods of low energy demand when surplus energy exists and is returned to the power system when energy demand is high.
One such system appears in Peterson et al., U.S. Pat. No. 4,122,512. Peterson et. al. uses a reversible alternating to direct current converter to convert the alternating current obtained from the AC power system into direct current for storage in a superconducting magnet and for converting the stored direct current into alternating current for return to the AC power system. This type of system, while providing for the efficient storage and return of energy to the AC power system, cannot perform the simultaneous storage and release of energy.
Another superconducting energy storage system described in Higashino, U.S. Pat. No. 4,695,932, discloses an energy storage circuit which converts three-phase alternating current to direct current for storage in a superconducting energy storage coil. A DC capacitor and chopper circuit are used to control the amount of direct current in the superconducting energy storage coil. According to Higashino, this configuration allows the current capacity of the converter to be scaled down in accordance with service power established by the current rating of the coil, and also allows a reduction of operation losses.
Known superconducting energy storage systems provide for the efficient storage and return of energy but cannot perform the simultaneous storage and release of energy. In addition, Higashino has a practical problem of charging the superconductive energy storage coil with a capacitor whose voltage must correspond to the voltage of the AC power system. For a 480 Volt AC system this would be around 650 volts DC. This voltage is too high to charge the superconducting energy storage coil near its maximum rated current, unless the coil is significantly oversized to accommodate the higher voltage value. Normally, a voltage of ten to twenty volts would be more appropriate for charging the coil. Even if Higashino's system used a step down transformer at the AC line in order to drop the capacitor bank voltage, the capacitor bank would need to provide a higher current which results in higher losses and costs due to a bigger magnet current and size.
In addition, these systems do not provide a means to boost the current delivered by the superconducting energy storage coil. If a utility or industrial electrical distribution system needs higher current than the magnet current, the known system using a chopper and a capacitor can not provide such a function.
Visser et al., U.S. Pat. No. 4,962,354, issued to Superconductivity, Inc. on Oct. 9, 1990 describes a superconducting voltage stabilizer. The superconducting voltage stabilizer comprises an AC/DC converter, a voltage regulator, an energy storage cell and a superconducting energy storage coil. Alternating current is converted to direct current and is stored in a superconducting energy storage coil. The stored direct current is released to an energy storage cell which in turn delivers the energy to a load. Energy is released in a controlled fashion according to the energy requirements of the load to thereby stabilize the load's operation. This patent, U.S. Pat. No. 4,962,354, is incorporated herein by reference.


The present invention relates to a support pad for a long hole drill for metal machining with improved properties specially for STS (Single Tube System) system and for drilling tools based on the Ejector® system. The invention also relates to a tool head equipped with a support pad, as well as a method of fabricating such a support pad.
Drilling in metals is divided generally in two types: long hole drilling and short hole drilling. By short hole drilling is meant generally drilling to a depth of up to 3-5 times the drill diameter.
In short hole drilling, the demands are not great, enabling the use of simple helix drills formed either of solid cemented carbide or as solid tool steel or of tool steel provided with cemented carbide inserts.
Long hole drilling, however, puts large demands on good chip formation, lubrication, cooling and chip transport. This is achieved through specially developed drilling systems with specially designed drilling heads fastened to a drill rod and fulfilling the above mentioned demands. The drill head may be of solid cemented carbide but is generally of tool steel provided with a number of cutting inserts of cemented carbide placed in such a way that they together form the necessary cutting edge. In the center of the head, a tough grade of insert is generally used and on the periphery a more wear resistant one. The cutting inserts are brazed or mechanically clamped. Generally the cutting inserts are brazed on small-diameter drills and mechanically secured on larger-diameter drills. In addition, the head is provided with support pads.
Cutting inserts and support pads are made of cemented carbide with various contents of WC, Co and cubic carbides TiC, TaC, NbC depending on the application. Cutting inserts as well support pads are in addition coated with one or more wear resistant layers. Generally, the support pads are coated with a yellow layer of TiN. A long hole drill head with a geometrical configuration of inserts and support pads as outlined above is disclosed in U.S. Pat. No. 6,682,275 the disclosure of which is hereby incorporated by reference.
It is a primary purpose of the invention to provide a support pad and a long hole drill head in combination with such a support pad wherein the useful life and strength is substantially increased, especially when drilling in a titanium-based workpiece.
A second object of the invention is to provide an improved support head and long hole drill head having improved properties for the machining of heat resistant material, titanium based material and cast iron, as well as in the machining of nickel based alloys.


This application claims the benefit of priority under 35 U.S.C. xc2xa7119 to Japanese Patent Application No. 2001-74236 filed on Mar. 15, 2001, the entire contents of which are incorporated by reference herein.
1. Field of the Invention
The present invention relates to a semiconductor memory device which dynamically stores data with using a channel body of a transistor as a storage node.
2. Related Background Art
In a related DRAM, a memory cell is composed of an MOS transistor and a capacitor. The scale-down of the DRAM has been remarkably advanced by the adoption of a trench capacitor structure and a stacked capacitor structure. At present, the cell size of a unit memory cell is scaled down to an area of 2Fxc3x974F=8F2, where F is a minimum feature size. Namely, the minimum feature size F decreases with the advance of generation, and when the cell size is generally taken to be xcex1F2, xcex1 coefficient a also decreases with the advance of generation. Thus, at the present of F=0.18 xcexcm, xcex1=8 is realized.
In order to hereafter secure the trend of cell size or chip size which is the same as before, it is demanded to satisfy xcex1 less than 8 in F less than 0.18 xcexcm and further satisfy xcex1 less than 6 in F less than 0.13 xcexcm, and together with microfabrication, the formation of cell size of the possible small area becomes a large problem. Accordingly, various proposals for decreasing the size of the one memory cell with the one transistor and one capacitor to 6F2 or 4F2 are made. However, practical use is not easy since there are a technical difficulty that the transistor has to be a vertical type, a problem that electric interference between adjacent memory cells increases, and in addition difficulties in terms of manufacturing technology including fabrication, film formation, and the like.
It is therefore an object of the present invention to provide a semiconductor memory device which includes memory cells with simple transistor structure and which can store data dynamically.
According to one aspect of the present invention, a semiconductor memory device including MIS transistors to constitute memory cells, each of the MIS transistors comprising:
a semiconductor layer;
a source region formed in the semiconductor layer;
a drain region formed apart from the source region in the semiconductor layer, the semiconductor layer between the source region and the drain region serving as a channel body in a floating state;
a first gate which forms a channel in the channel body;
a second gate formed so as to control a potential of the channel body by a capacitive coupling; and
a high concentration region formed in the channel body on the second gate side, impurity concentration of the high concentration region being higher than that of the channel body,
wherein the MIS transistor has a first data state in which the channel body has a first potential and a second data state in which the channel body has a second potential.
According to another aspect of the present invention, a semiconductor memory device including MIS transistors to constitute memory cells, each of the MIS transistors comprising:
a semiconductor layer;
a source region formed in the semiconductor layer;
a drain region formed apart from the source region in the semiconductor layer, the semiconductor layer between the source region and the drain region serving as a channel body in a floating state; and
a first gate which forms a channel in the channel body,
wherein characteristics of the MIS transistor in the case where a channel current flows from the source region to the drain region is different from characteristics of the MIS transistor in the case where a channel current flows from the drain region to the source region, even when the same potential is applied to the first gate, and
wherein the MIS transistor has a first data state in which the channel body has a first potential and a second data state in which the channel body has a second potential, the first data state being set by the impact ionization generated near a drain junction or by a drain leakage current caused by the first gate, the second data state being set by sending a forward bias current between the drain region and the channel body.
According to a further aspect of the present invention, a semiconductor memory device including MIS transistors to constitute memory cells, each of the MIS transistors comprising:
a semiconductor layer;
a source region formed in the semiconductor layer;
a drain region formed apart from the source region in the semiconductor layer, the semiconductor layer between the source region and the drain region serving as a channel body in a floating state; and
a gate which forms a channel in the channel body,
wherein the MIS transistor has a first data state in which the channel body has a first potential and a second data state in which the channel body has a second potential, the first data state being set by a drain leakage current caused by the gate to which a negative potential is applied, the second data state being set by sending a forward bias current between the drain region and the channel body.


1. Field of the Invention
The present invention relates to an optical signal transmission system, and more particularly, to an optical signal transmission system in analog data service such as a bidirectional cable television (CATV) in which high carrier to noise ratio (CNR) characteristic is requested.
2. Description of the Related Art
In the next generation CATV systems discussed recently from various viewpoints, a digital video signal needs to be transmitted for broad band bidirectional communication services by video on demand (VOD) signals from subscribers services, as well as conventional broadcasting image signals (vestigial sideband--analog modulation (VSB-AM) signals). Further, it is importance to implement such a transmission system with low cost.
As a transmission system which satisfy the needs, there is a subcarrier multiplexed (SCM) system which is described by Robert Olshansky et al. in "Subcarrier Multiplexed Lightwave Systems for Broad-Band Distribution", (Journal of Lightwave Technology, Vol. 7, No. 9, September 1989, pp. 1329-1341) as reference 1 and by Winston I. Way in "Subcarrier Multiplexed Lightwave System Design Considerrations For Subscriber Loop applications", (Journal of Lightwave Technology, Vol. 7, No. 11, November 1989, pp. 1806-1818) as reference 2.
This SCM system is an optical signal transmission system using a single mode optical fiber as a transmission medium. Base band analog or digital signals for a plurality of channels, e.g., 60 channels are first high-frequency converted or up-converted using local oscillation circuits (LOs) having different frequencies and then frequency-division-multiplexed. These up-converted signals are synthesized or combined and a laser unit is modulated in accordance with the synthesized high-frequency signal or a combined signal. The frequency of an oscillation signal from the local oscillation circuit is a subcarrier for an optical carrier frequency. In the receiving unit, one of the frequency-division-multiplexing (FDM) channels is selected by a subscriber through a tuning operation of a local oscillation circuit, like the usual tuning operation in a television receiver and radio. A high frequency/microwave signal of the selected FDM channel is low-frequency-converted or down-converted to restore an original base band analog or digital signal.
In the above SCM system, in a case where analog image signal for 60 channels and a VOD signal as a digital video signal are simultaneously transmitted, there is a problem in that noise is generated due to clipping distortion so that a bit error rate of the VOD signal is increased because an effective optical modulation exceeds 20% for the image signals for 60 channels.
In order to solve the problem, an optical SCM transmission system is proposed in the proceedings of the 1994 spring Conference of IEICE (B-1128) (reference 3). In the reference 3, there is discussed an optimal method in which the bit error rate due to the clipping distortion can be reduced in the transmission of the combined signal composed of a VSB-AM signal as analog image signals and multivalue digital carrier signal (16QAM) as the digital video signal (to be referred to as a VOD signal) and it is concluded that it is effective to separate an image signal transmission system and a VOD signal transmission system from each other such that the VSB-AM signal and the 16QAM signal are transmitted in parallel.
FIG. 1 is a block diagram showing a conventional optical signal transmission system described in the reference 3. Referring to FIG. 1, the conventional optical signal transmission system includes an optical signal transmitting unit 101 for outputting an optical signal LF60 corresponding to image signals 60VA for 60 channels and an optical signal LV corresponding to a VOD signal VD independently, optical fibers 102 and 104 for transferring the optical signals LF60 and LV, respectively, and an optical signal receiving unit 103 for receiving the optical signals LF60 and LV and detecting a reception combined signal.
The optical signal transmitting unit 101 includes frequency division multiplexing (FDM) circuits 111 for frequency-division-multiplexing the image signals 60VA for 60 channels to produce an FDM signal F60, a semiconductor laser (LD) 112 which is subjected to analog-modulation based on the FDM signal F60 and outputs an optical signal LF60 on the optical fiber 102 via an optical isolator 113, the optical isolator 113 for preventing reflected light of the optical signal LF60 from being inputted into the semiconductor laser 112, an FDM circuit 114 for frequency-division-multiplexing the VOD signal VD to produce an FDM signal FV, and a semiconductor laser (LD) 115 which is subjected to analog-modulation based on the FDM signal FV and outputs an optical signal LV on the optical fiber 104. The receiving unit 103 includes an optical signal detector (PD) 121 coupled to the optical fiber 102, for receiving and photoelectrically converting the optical signal LF60 into a reception signal R60 and an optical signal detector (PD) 122 coupled to the optical fiber 104, for receiving and photoelectrically converting the optical signal LV into a reception signal RV.
Next, the operation of the conventional optical signal transmission system will be described with reference to FIGS. 2A and 2B which indicate the examples of analog-modulation of a semiconductor laser (LD). As shown in FIG. 2A, the analog-modulation of the semiconductor laser is a so-called small amplitude modulating operation in which the semiconductor laser is supplied with a current which satisfies the oscillation condition of the semiconductor laser, i.e., a constant bias current higher than a threshold current and a modulation current is superposed on the bias current. If the amplitude of the modulation current becomes greater so that the negative peak of the modulation current is decreased lower than the threshold current as shown in FIG. 2B, a part of the modulated light output signal, the negative peak in the example is cut so that the clipping distortion is caused. Also, when the output of the semiconductor laser is saturated at the positive peak, the clipping distortion is caused. Thus, the clipping distortion is caused when the optical modulation of the semiconductor laser is more than 100%.
In this conventional optical signal transmission system, since an FDM signal F60 corresponding to the image signals for 60 channels needs to be transmitted, the optical signal outputted from the single semiconductor laser 112 is modulated in accordance with the FDM signal F60. In this case, an effective optical modulation .mu.e is represented by the following equation for the FDM signal F60. ##EQU1## where N is the number of image signals which constitute the FDM signal F60 and .mu.i is the optical modulation index for the image signal VAi, A relation between the effective modulation index .mu.e and the clipping distortion is experimentally obtained. For instance, when an optical modulation index is 5% for an image signal for one channel and image signals for 60 channels are supplied to the semiconductor laser 112 as the FDM signal F60, the effective optical modulation index .mu.e of the semiconductor laser 112 is about 27%.
FIG. 3 is a graph showing a relation of a bit error rate (BER) to a carrier to noise ratio (CNR) when image signals of a plurality of channels and a VOD signal of one channel are simultaneously transmitted through modulation by a single semiconductor laser. It can be seen that a bit error is abruptly increased if the effective optical modulation index exceeds 20%. This is because the impulse noise due to the clipping distortion adversely influences to the modulated signal.


Many different polymers and materials have been added to polymer compositions in attempting to enhance the composition's impact strength or maintain the impact strength while enhancing other properties. For example, U.S. Pat. No. 5,118,753 (Hikasa et al.), incorporated herein by reference, discloses thermoplastic elastomer compositions said to have low hardness and excellent flexibility and mechanical properties consisting essentially of a mixture of an oil-extended olefinic copolymer rubber and an olefinic plastic. The olefinic plastic is polypropylene or a copolymer of polypropylene and an .alpha.-olefin of 2 or more carbon atoms. Modern Plastics Encyclopedia/89, mid October 1988 Issue, Volume 65, Number 11, pp. 110-117, the disclosure of which is incorporated herein by reference, also discusses the use of various thermoplastic elastomers (TPEs) useful for impact modification. These include: elastomeric alloys TPEs, engineering TPEs, olefinic TPEs (also known as thermoplastic olefins or TPOs), polyurethane TPEs and styrenic TPEs.
Thermoplastic olefins (TPOs) are often produced from blends of an elastomeric material such as ethylene/propylene rubber (EPM) or ethylene/propylene diene monomer terpolymer (EPDM) and a more rigid material such as isotactic polypropylene. Other materials or components can be added into the formulation depending upon the application, including oil, fillers, and cross-linking agents. TPOs are often characterized by a balance of stiffness (modulus) and low temperature impact, good chemical resistance and broad use temperatures. Because of features such as these, TPOs are used in many applications, including automotive facia and wire and cable operations, rigid packaging, molded articles, instrument panels, and the like.
Union Carbide Chemicals and Plastics Inc. announced in 1990 that they have developed a new cost effective class of polyolefins trademarked Flexomer™ Polyolefins that could replace expensive EPM or EPDM rubbers. These new polyolefins are said to have bridged the gap between rubbers and polyethylene, having moduli between the two ranges. Modulus of the rubber and of the formulation is not, however, the only criteria for evaluating a TPO formulation. Low temperature impact performance, sometimes measured by Gardner Impact at −30° C. also is sometimes important to a TPO composition's performance. According to the data contained in FIG. 4 of the paper “Flexomer™ Polyolefins: A Bridge Between Polyethylene and Rubbers” by M. R. Rifi, H. K. Ficker and M. A. Corwin, more of the Flexomer™ Polyolefin needs to be added into the TPO formulation in order to reach the same levels of low temperature Gardner Impact performance as the standard EPM rubber, thus somewhat negating the benefits of the lower cost EPM/EPDM replacement. For example, using the data of FIG. 4 of the Rifi et al paper, about 20% (by weight) of the EPM in polypropylene gives a Gardner Impact of about 22 J. at −30.degree. C., while the same amount of Flexomer™ Polyolefin gives a −30° C. Gardner Impact of about 13 J.
In a paper presented on Sep. 24, 1991 at the 1991 Specialty Polyolefins Conference (SPO '91) (pp. 43-55) in Houston, Tex., Michael P. Jeffries (Exxpol Ethylene Polymers Venture Manager of Exxon Chemical Company) also reports that Exxon's Exact™ polymers and Plastomers can be blended into polypropylene for impact modification. Exxon Chemical Company, in the Preprints of Polyolefins VII International Conference, page 45-66, Feb. 24-27 1991, also disclose that the narrow molecular weight distribution (NMWD) resins produced by their EXXPOL™ technology have higher melt viscosity and lower melt strength than conventional Ziegler resins at the same melt index. In another recent publication, Exxon Chemical Company has also taught that NMWD polymers made using a single site catalyst create the potential for melt fracture (“New Specialty Linear Polymers (SLP) For Power Cables,” by Monica Hendewerk and Lawrence Spenadel, presented at IEEE meeting in Dallas, Tex., September, 1991).
It is well known that narrow molecular weight distribution linear polymers disadvantageously have low shear sensitivity or low I10/I2 value, which limits the extrudability of such polymers. Additionally, such polymers possessed low melt elasticity, causing problems in melt fabrication such as film forming processes or blow molding processes (e.g., sustaining a bubble in the blown film process, or sag in the blow molding process etc.). Finally, such resins also experienced surface melt fracture properties at relatively low extrusion rates thereby processing unacceptably and causing surface irregularities in the finished product.
Thus, while the development of new lower modulus polymers such as Flexomer™ Polyolefins by Union Carbide or Exact™ polymers by Exxon has aided the TPO marketplace, there continues to be a need for other more advanced, cost-effective polymers for compounding with thermoplastics (e.g., polyolefins such as polypropylene or HDPE) to improve or maintain modulus and/or impact performance at room temperature or below.
Formulated compositions have now been discovered to have this combination of good low temperature impact performance and modulus. The compositions comprise:
A) a thermoplastic selected from the group consisting of thermoplastic polyurethanes, polyvinyl chlorides, styrenics, engineering thermoplastics, and polyolefins, and
B) an impact-modifying amount of at least one ethylene/α-olefin interpolymer.


Broadband communications have become an increasingly prevalent form of electromagnetic information exchange and coaxial cables are common conduits for transmission of broadband communications. Coaxial cables are typically designed so that an electromagnetic field carrying communications signals exists only in the space between inner and outer coaxial conductors of the cables. This allows coaxial cable runs to be installed next to metal objects without the power losses that occur in other transmission lines, and provides protection of the communications signals from external electromagnetic interference. Connectors for coaxial cables are typically connected onto complementary interface ports to electrically integrate coaxial cables to various electronic devices and cable communication equipment. Connection is often made through rotatable operation of an internally threaded nut of the connector about a corresponding externally threaded interface port. Fully tightening the threaded connection of the coaxial cable connector to the interface port helps to ensure a ground connection between the connector and the corresponding interface port. However, often connectors are not properly tightened or otherwise installed to the interface port and proper electrical mating of the connector with the interface port does not occur. Moreover, structure of common connectors may permit loss of ground and discontinuity of the electromagnetic shielding that is intended to be extended from the cable, through the connector, and to the corresponding coaxial cable interface port. Hence a need exists for an improved connector for ensuring ground continuity between the coaxial cable, the connector structure, and the coaxial cable connector interface port.


The invention relates to defined tetrakisazo dyes and mixtures thereof with defined trisazo dyes, their production and their use, especially for the dyeing of leather.
In U.S. Pat. No. 4,479,906 there are described trisazo dyes of the formula
in which
AO is the radical of an aromatic-carbocyclic diazo component,
BO is the radical of a coupling component which contains hydroxyl and/or amino groups,
n is the integer 1 or 2,
one XO is hydroxyl and the other XO is amino,
ZO is
TO is hydrogen, methyl, ethyl, benzyl, xcex2-hydroxyethyl, xcex2-hydroxypropyl, xcex2-cyanoethyl, xcex2-carboxyethyl or xcex2-carbalkoxyethyl of a total of two to five carbon atoms,
RO is hydrogen, hydroxyl, chloro, bromo, nitro, methyl, ethyl or carboxyl and
R1O is hydrogen, methyl, ethyl, chloro, bromo, cyano, nitro, hydroxysulphonyl, carboxyl or alkoxycarbonyl,
there being described in particular also some tetrakisazo dyes in which in the above formula n is 2, the two sulpho groups are in the positions meta to each XO (as corresponds to H-acid), ZO is a radical of formula (2). AO is the radical of an aminoazobenzene diazocomponent and BO is the radical of certain aminobenzene coupling components. These dyes are described also for the dyeing of leather in green to black shades.
It has now been found that tetrakisazo dyes of the below indicated structure of formula (I) are particularly valuable anionic dyes for obtaining dyeings of intensive dark shades, in particular for the penetration dyeing of leather in dark shades of high fastnesses, especially when combined with the below defined trisazo dyes of formula (X).
The invention relates to the defined dyes and dye mixtures, their production and their use.
The invention, thus, provides a tetrakisazo dye of formula
wherein
one of the two symbols X and Y signifies xe2x80x94OH and the other signifies xe2x80x94NH2,
Z signifies a radical of formula
xe2x80x94W1xe2x80x94Nxe2x95x90Nxe2x80x94B2 xe2x80x83xe2x80x83(xcex1)
or, if Y signifies xe2x80x94OH, also a radical of formula
xe2x80x94W2xe2x80x94Nxe2x95x90Nxe2x80x94D xe2x80x83xe2x80x83(xcex2),
Q1 signifies xe2x80x94SO2xe2x80x94 or xe2x80x94COxe2x80x94,
Q2 signifies the direct bond or, if Q1 is xe2x80x94SO2xe2x80x94, also a group xe2x80x94SO2xe2x80x94,
B1 signifies the radical of a coupling component Hxe2x80x94B1,
B2 signifies the radical of a coupling component Hxe2x80x94B2,
D signifies the radical of a diazo component Dxe2x80x94NH2,
W1 signifies the radical of a bicyclic bisdiazo component,
W2 signifies the radical of a bicyclic middle component and
M signifies hydrogen or a cation,
or a mixture of two or more tetrakisazo dyes of formula (I).
Formula (I) comprises in particular the following formulae
Thus, the invention provides in particular a dye of formula (Ia), (Ib) or (Ic) or a mixture of two or more thereof.
A particular further feature of the invention is represented by a mixture of at least one dye of the above formula (I) and at least one trisazo dye of formula
in which B1, D, Q1, Q2 and M have the significances indicated above for formula (I).
The dyes of the invention may be produced by means of diazotization and coupling reactions, in order to form the azo groups, in a manner conventional per se. In particular, a process for the production of the tetrakisazo dyes of the invention is characterized in that for the production of a dye of formula (Ia) the bisdiazocompound of a diamine of formula
is coupled at one side to the 3-position of a bis-coupling component of formula
the obtained azodiazocompound is either first coupled to a coupling component Hxe2x80x94B1, to give an intermediate of formula
and the diazocompound of an amine of formula
Dxe2x80x94Nxe2x95x90Nxe2x80x94W2xe2x80x94NH2 xe2x80x83xe2x80x83(V)
is coupled to the 6-position of the intermediate of formula (IV), or the azodiazocompound is first coupled in the 6-position with the diazocompound of an amine of formula (V) and then coupled to a coupling component Hxe2x80x94B1, for the production of a dye of formula (Ib) the bisdiazocompound of a diamine of formula (II) is coupled at one side to the 3-position of a bis-coupling component of formula (III) and the obtained azodiazocompound is either first coupled to a coupling component Hxe2x80x94B1, to give an intermediate of formula (IV), and then the bisdiazocompound of a diamine of formula
H2Nxe2x80x94W1xe2x80x94NH2 xe2x80x83xe2x80x83(VI)
is coupled at one side to the 6-position of the intermediate of formula (IV) and the obtained trisazodiazocompound is coupled to a coupling component Hxe2x80x94B2, or the azodiazocompound is first coupled in the 6-position with the bisdiazocompound of a diamine of formula (VI) and then the obtained disazobisdiazocompound is coupled to coupling components Hxe2x80x94B1, and Hxe2x80x94B2 or for the production of a dye of formula (Ic) the bisdiazocompound of a diamine of formula (VI) is coupled at one side to the 3-position of a bis-coupling component of formula (III) and the obtained azodiazocompound is either first coupled to a coupling component Hxe2x80x94B2 to give an intermediate of formula
and then the bisdiazocompound of a diamine of formula (II) is coupled at one side to the 6-position of the intermediate of formula (VII) and the obtained trisazodiazocompound is coupled to a coupling component Hxe2x80x94B1, or it is first coupled in the 6-position with the bisdiazocompound of a diamine of formula (II) and then the obtained disazobisdiazocompound is coupled to Hxe2x80x94B1, and Hxe2x80x94B2.
The compounds of formula (V) may be produced by coupling the diazocompound of a diazocomponent of formula
Dxe2x80x94NH2 xe2x80x83xe2x80x83(VIII)
to a middle component of formula (IX)
Hxe2x80x94W2xe2x80x94NH2 xe2x80x83xe2x80x83(IX).
The trisazo dyes of formula (X) may be synthetized by coupling the diazocompound of a diazocomponent of formula (VIII) to a compound of formula (IV) or to its precursor azodiazocompound, before coupling of the diazoazocompound to Hxe2x80x94B1. If the starting compounds are the same as the corresponding ones employed for the production of the dyes of formula (I), this reaction sequence may be carried out together with the production of the tetrakisazo dye or dye mixture, choosing the molar ratios in a suitable way.
In the mixtures of tetrakisazo dyes of formula (I) and trisazodyes of formula (X) the molar ratio of tetrakisazo dye or tetrakisazo dye mixture to trisazo dye or trisazo dye mixture is e.g. in the range of 95/5 to 20/80, prferably 80/20 to 30/70, more preferably 75/25 to 40/60.
As diazocomponents of formula (VIII) there may be employed any known diazotizable amines, in particular of the benzene of naphthalene series, preferably containing at least one solubilizing substituent, which preferably is a sulpho group, a carboxy group, a carbamoyl group and/or a sulphamoyl group.
As diazo components of formula (VIII) come, in particular, into consideration those of the following formulae
wherein
R1 signifies hydrogen, nitril, trifluoromethyl, nitro, xe2x80x94SO3M, xe2x80x94SO2NR4R5, xe2x80x94COOM or xe2x80x94CONR4R5,
R2 signifies hydrogen, nitro, xe2x80x94SO3M, xe2x80x94SO2NR4R5, trifluoromethyl, nitril, xe2x80x94COOM, xe2x80x94CONR4R5, C1-4-alkyl, C1-4-alkoxy, halogen or C1-2-mercaptoalkyl,
R3 signifies hydrogen, C1-4-alkyl, C1-4-alkoxy, halogen, C1-2-mercaptoalkyl, xe2x80x94NHxe2x80x94Ac, xe2x80x94NHxe2x80x94COxe2x80x94Oxe2x80x94CH3 or a radical of formula
R4 signifies hydrogen, C1-4-alkyl, C1-3-alkylene-Rxe2x80x2 or C2-3-3-hydroxyalkyl,
R5 signifies hydrogen, C1-4-alkyl, C1-3-alkylene-Rxe2x80x2, C2-3-hydroxyalkyl, benzyl or a radical of formula
Rxe2x80x2 signifies nitril, carbamoyl or xe2x80x94COOM,
R6 signifies hydrogen, nitro or xe2x80x94SO3M,
R7 signifies hydrogen, methyl, chlorine, nitro, xe2x80x94COOM or xe2x80x94SO3M,
R8 signifies hydrogen, halogen, nitro, xe2x80x94SO3M, xe2x80x94SO2NR4R5, methylsulphonyl, C1-4-alkyl or xe2x80x94NHxe2x80x94Ac,
R9 signifies hydrogen, halogen, nitro, xe2x80x94SO3M, xe2x80x94SO2NR4R5, methylsulphonyl, C1-4-alkyl or xe2x80x94NHxe2x80x94Ac,
R10 signifies nitro, xe2x80x94SO3M or xe2x80x94SO2NR4R5,
Ac signifies an aliphatic acyl group,
p signifies 0 or 1 and
r signifies 0 or 1,
R1 preferably signifies hydrogen or xe2x80x94COOM.
Of the alkyl and alkoxy groups with 1 to 4 carbon atoms, the lower molecular ones are preferred, in particular ethyl, methyl, ethoxy and methoxy. Halogen may in particular be fluorine, chlorine or bromine of which fluorine and, before all, chlorine are preferred.
Where in formula (a1) R3 signifies a radical of formula (axe2x80x2) this is preferably in para-position to the amino group, R1 preferably signifies hydrogen, R2 preferably signifies hydrogen or a sulpho group and, if R2 signifies a sulpho group, this is preferably in meta-position to the azo group and R6 and R7 preferably signify both hydrogen or, if R2 signifies hydrogen, R6 signifies preferably a nitro group and R7 signifies preferably a carboxy group or a sulpho group, the two substituents R6 and R7 being placed in the para-position to the imino group and in one of the two ortho-positions to the imino group.
Where the symbol R3 does not signify a radical (axe2x80x2), R3 preferably signifies hydrogen and R1 preferably signifies hydrogen or xe2x80x94COOM. According to a preferred feature, in this case in formula (a1) one or both of the positions ortho to the primary amino group and, more preferably, also one or both of the positions meta to the primary amino group are unsubstituted. According to a further preferred feature, if R1 signifies xe2x80x94COOM, this is in position ortho or para to the diazotizable primary amino group.
R4 preferably signifies hydrogen.
R5 advantageously signifies hydrogen, methyl, ethyl, hydroxyethyl or a radical of formula (axe2x80x3), in which R7 preferably signifies hydrogen or carboxy.
The aliphatic acyl group Ac advantageously signifies the radical of a low molecular aliphatic carboxylic acid, preferably of an alkanoic acid with 2 to 4 carbon atoms, more preferably acetyl or propionyl, of which acetyl is preferred.
Most preferably the diazo component of formula (a1) is an aminobenzoic acid, in particular anthranilic or p-aminobenzoic acid.
In formula (a2 ) preferably at least one of R8 and R9 has a significance other than hydrogen, more preferably R9 has a significance other than hydrogen and R8 signifies hydrogen, a nitro group or a sulpho group.
The primary amino group in formula (a4) may be in any of the positions xcex1 and xcex2 of the naphthalene ring and, if p signifies 1, the sulpho group may be in any of the other available positions, preferably so that at least one vicinal position to the amino group is unsubstituted; e.g. if the amino group is in position 1, the sulpho group is preferably in any of the positions 3 to 8, more preferably 4 to 8, and if the amino group is in the position 2, the sulpho group is e.g. in position 1 or in any of the positions 4 to 8, more preferably 5, 6 r 7. A preferred diazocomponent of formula (a4) is naphthionic acid.
The compounds (a5) are indicated in the free amino form, as diazo components they are however usually employed directly in the form of the respective commercially available diazonium compounds 1-diazonium-2-naphthol-4-sulphonic acid (in which r=0) and 1-diazonium-6-nitro-2-naphthol-4-sulphonic acid (in which r=1).
Among the above diazo components are preferred those, which do not contain a hydroxy group in ortho position to the diazotizable amino group, in particular the compounds of formula (a1) and (a4).
Preferably Dxe2x80x94NH2 contains at least one hydrophilic substituent, preferably a substituent selected from the group consisting of xe2x80x94SO3M, xe2x80x94SO2NR4R5, xe2x80x94COOM and xe2x80x94CONR4R5, more preferably not more than one hydrophilic substituent per homocyclic aromatic nucleus.
As a middle component there is understood a compound that acts as a coupling component and that contains a diazotizable primary amino group or a group convertible to a diazotizable primary amino group and which compound, upon having been coupled with a diazo compound, if required after having converted a substituent convertible to a primary amino group to this primary amino group, is diazotized and the obtained azodiazocompound is then coupled to a further coupling component. As middle components, from which W1 derives, come preferably into consideration middle components containing a primary amino group.
The radical W2 and respectively the middle component of formula (IX), from which the radical W2 derives, contains two rings of aromatic character, of which one is a benzene ring and the other may be an optionally condensed second benzene ring (to give a naphthalene radical) or a benzene ring linked over a bridging group or a heterocyclic ring linked to the benzene ring, optionally over a heteroatomic bridging group. The diazotizable primary amino group is suitably a substituent of a benzene ring and the coupling position is suitably activated by at least one electron donor substituent, in particular by an amino group or preferably a hydroxy group. The middle component of formula (IX) preferably is a compound of the aminonaphthalene series (more preferably of the aminonaphthole series), of the 1-(aminophenyl)-5-pyrazolone or -5-aminopyrazol series or of the sulphanilylamino-phenol or -pyrimidone series. Where the middle component is of the pyrazole series, it is preferably a pyrazolone in which the 3-position may be substituted with carboxy or C1-4-alkyl, preferably methyl, and where the primary amino group at the 1-positioned phenyl radical is in meta- or para-position to the pyrazole radical. Where the middle component is of the sulphanilylaminophenol series, the phenolic hydroxy group is preferably in meta-position and the two benzene rings preferably do not contain any further substituents. Where the middle component is of the sulphanilylaminopyrimidine series, this is e.g. a middle component as described in GB-A 2 276 174, among which 6-amino-2-sulphanilylamino-3-H-pyrimidin-4-one and 2-sulphanilylamino-3-H-pyrimidine-4,6-dione are preferred. Among the aminonaphthols are preferred those containing two or preferably only one sulpho group, more particularly H-acid, J-acid and xcex3-acid (the latter being particularly preferred).
B1 or B2 may be the radical of any coupling component Hxe2x80x94B1 or Hxe2x80x94B2 which may, in particular, be of the benzene, naphthalene, heterocyclic or open-chain methylene-active series, and suitably contains at least one substituent that activates the compound Hxe2x80x94B1 or Hxe2x80x94B2 or coupling, in particular an aromatically bound or enolic, optionally etherified hydroxy group or an optionally substituted amino group, so that the coupling reaction may take place in the corresponding activated position of the molecule Hxe2x80x94B1 or Hxe2x80x94B2.
Suitable coupling components Hxe2x80x94B1 or Hxe2x80x94B2 are, in particular, those of the following formulae
wherein
R13 signifies hydrogen, xe2x80x94OR17 or NHR17,
R14 signifies xe2x80x94OR17 or xe2x80x94NHR17,
R15 signifies hydrogen, xe2x80x94SO3M, xe2x80x94SO2NR4R5, xe2x80x94COOM or xe2x80x94CONR4R5.
R16 signifies hydrogen, xe2x80x94SO3M, xe2x80x94SO2NR4R5, xe2x80x94COOM or xe2x80x94CONR4R5,
R17 signifies hydrogen, C1-4-hydrogen, C1-4-alkyl, Acxe2x80x2 or a radical of formula
Acxe2x80x2 signifies the acyl radical of an aliphatic carboxylic acid,
Q3 signifies xe2x80x94COxe2x80x94, xe2x80x94SO2xe2x80x94 or the direct bond,
R18 signifies hydrogen, methyl, xe2x80x94NHxe2x80x94Ac, xe2x80x94COOM or xe2x80x94NO2 or, if in formula (bxe2x80x2) Q3 signifies xe2x80x94COxe2x80x94 or xe2x80x94SO2xe2x80x94, also xe2x80x94NH2,
R19 signifies xe2x80x94OH or xe2x80x94NH2,
R20 signifies hydrogen, C1-4-alkyl, C1-4-alkoxy, xe2x80x94OH, xe2x80x94NRxe2x80x3Rxe2x80x3xe2x80x2 or xe2x80x94NHxe2x80x94Ac,
R21 signifies hydrogen, C1-4-alkyl or C1-4-alkoxy,
Rxe2x80x3 and Rxe2x80x2xe2x80x3 independently, signify hydrogen, C1-2-alkyl or C2-3-hydroxy-alkyl,
R22 signifies hydrogen, sulphonaphthyl or a radical of formula
G1 signifies hydrogen, halogen, methyl, methoxy or xe2x80x94COOM,
G2 signifies hydrogen, halogen, trifluoromethyl, nitril, nitro, xe2x80x94COOM, xe2x80x94SO3M or xe2x80x94SO2NR4R5,
R23 signifies C1-4-alkyl, phenyl, xe2x80x94COOM, xe2x80x94CONR4R5, xe2x80x94COOCH3 or xe2x80x94COOC2H5,
R24 signifies xe2x95x90O or xe2x95x90NH,
R25 signifies hydrogen, unsubstituted amino, phenylamino, sulphonaphthyl, open-chain C1-8-alkyl, C6-9-cycloalkyl, carboxy-(C1-4-alkyl), C2-4-alkyl substituted with hydroxy, methoxy, ethoxy or a sulpho group in one of the positions xcex2 to xcfx89, or a radical of formula (bxe2x80x3),
R26 signifies hydrogen, nitril, acetyl, xe2x80x94COOM, carbamoyl, xe2x80x94SO3M, pyridinio or 2-methyl-pyridinio,
R27 signifies hydrogen, hydroxy, methyl, carboxy, phenyl, sulphomethyl or carbamoyl,
R28 signifies hydroxy, primary amino, nitrilamino, thiol or a radical of formula
R29 signifies hydroxy or primary amino,
R30 signifies hydroxy or primary amino,
R31 signifies hydrogen, methyl, chlorine, chloromethyl or chloroacetyl,
T signifies xe2x80x94Oxe2x80x94, xe2x80x94NHxe2x80x94 or the direct bond,
R32 signifies naphthyl, sulphonaphthyl, disulphonaphthyl or a radical of formula (bxe2x80x3),
R33 signifies C1-4-alkyl,
G3 signifies hydrogen, hydroxy, C1-4-alkoxy, xe2x80x94NHAc, xe2x80x94NH2, di-(C1-4-alkyl)-amino or carboxy-methylamino, and
G4 signifies hydrogen or methyl,
and, where in formula (b4) R26 stands for pyridinio or orthomethylpyridinio, any carboxy or sulpho group present in the molecule may be in the form of the anion xe2x80x94SO3xe2x80x94 or xe2x80x94COOxe2x80x94 to form the counter ion in the form of the inner salt.
The aliphatic acyl radical Acxe2x80x2 in the significance of R17 may be the radical of any aliphatic carboxylic acid as can be introduced by acylation, in particular of a C2-12-alkanoic primary monocarboxylic acid, preferably such as stated above for Ac, especially C2-4-alkanoyl, most preferably acetyl.
If R18 signifies xe2x80x94COOM, Q3 in formula (bxe2x80x2) signifies in particular xe2x80x94COxe2x80x94. If in formula (bxe2x80x2) Q3 signifies the direct bond, R18 preferably signifies hydrogen. If in formula (bxe2x80x2) Q3 signifies xe2x80x94SO2xe2x80x94, R18 preferably signifies methyl, acetylamino or xe2x80x94NH2. If in formula (bxe2x80x2) Q3 signifies xe2x80x94COxe2x80x94, R18 preferably signifies hydrogen or xe2x80x94NO2.
In formula (b1) xe2x80x94OR17 preferably signifies hydroxy and xe2x80x94NHR17 preferably signifies xe2x80x94NHR17xe2x80x2, where R17xe2x80x2 signifies hydrogen, methyl, acetyl or a radical of formula (bxe2x80x2). Preferably R14 signifies hydroxy or xe2x80x94NHR17xe2x80x2 and R13 signifies hydrogen or, where R14 signifies xe2x80x94OH, also a group xe2x80x94NHR17xe2x80x2. More preferably either R14 signifies hydroxy and R13 signifies hydrogen or xe2x80x94NHR17 or R14 signifies xe2x80x94NHR17xe2x80x2 and R13 signifies hydrogen, R15 preferably signifies hydrogen, xe2x80x94SO3M, xe2x80x94COOM or xe2x80x94CONH2. R16 preferably signifies hydrogen or xe2x80x94SO3M, more preferably hydrogen. Preferred coupling components of formula (b1) are those in which R13, R15 and R16 signify hydrogen and, in particular, R14 signifies hydroxy. Most preferably (b1) is xcex2-naphthol.
If in formula (b2) R20 signifies hydroxy, xe2x80x94NRxe2x80x3Rxe2x80x2xe2x80x3 or xe2x80x94NHxe2x80x94Ac, it is preferably in meta-position to R19 and R21 preferably signifies hydrogen. If R20 signifies C1-4-alkyl or C1-4-alkoxy it may be in any of the available positions ortho, meta and para to R19. More preferably R19 signifies hydroxy. Advantageously R21, signifies hydrogen.
Of the alkyl and alkoxy radicals with 1 to 4 carbon atoms, also in Hxe2x80x94B1 or Hxe2x80x94B2 the lower molecular ones are preferred (analogously as in Dxe2x80x94NH2), more specifically ethyl, methyl, ethoxy and methoxy. In the C2-3-hydroxyalkyl radicals the hydroxy group is preferably in xcex2position.
In formula (b3) R22 preferably signifies a radical of formula (bxe2x80x3). In formula (bxe2x80x3)xe2x80x94in the significance of R22xe2x80x94preferably at least one of G1 and G2 signifies hydrogen, more preferably G1. R23 preferably signifies C1-4-alkyl, more preferably methyl. R24 preferably signifies oxygen.
The open-chain C3-8-alkyl radicals in the significance of R25 may be linear or branched, if they contain 6 to 8 carbon atoms they are preferably branched; the cycloalkyl radicals in the significance of R25 are preferably cyclohexyl, which may be substituted with 1 to 3 methyl groups, more preferably it is unsubstituted cyclohexyl. The carboxy-substituted C1-4-alkyl group preferably is carboxymethyl or xcex2-carboxyethyl. The substituent (hydroxy, methoxy, ethoxy, sulpho) at the C2-4-alkyl, in the significance of R25, is preferably in xcex2-position. If R25 signifies a radical of formula (bxe2x80x3) G1 preferably signifies hydrogen and G2 preferably signifies carboxy, sulpho or trifluoromethyl. Preferred significances of R25 are hydrogen, a radical of formula (bxe2x80x3), C1-8-alkyl, C2-3-hydroxyalkyl and C6-9-cycloalkyl.
R26 preferably signifies hydrogen, a sulpho group or one of the stated nitrogen-containing substituents.
R27 preferably has a significance other than hydrogen, more preferably methyl.
In formula (b5) preferably at least one of R29 and R30 signifies hydroxy, more preferably both R29 and R30 signify hydroxy groups.
If in formula (b5) R28 signifies a radical of formula (bxe2x80x3xe2x80x2), xe2x80x94NHxe2x80x94Q3xe2x80x94 preferably signifies a group xe2x80x94NHxe2x80x94SO2xe2x80x94.
In formula (b6) the hydroxy group preferably is in position 8. If R31 is other than hydrogen it is preferably in position para to the 8-positioned hydroxy group. R31 preferably signifies hydrogen or methyl, more preferably hydrogen.
In formula (b7) T preferably signifies xe2x80x94NHxe2x80x94. More preferably R32 is unsubstituted phenyl and R33 is preferably methyl.
The coupling component radical xe2x80x94B1 or xe2x80x94B2 preferably contains up to three cycles (homocyclic rings, heterocyclic rings and optionally a cycloaliphatic ringxe2x80x94a naphthalene radical being calculated as two cycles), more preferably xe2x80x94B1 or xe2x80x94B2 contain each one or two of such cycles.
The coupling components Hxe2x80x94B1 and Hxe2x80x94B2 preferably correspond to formula (b1), (b2), (b3) and/or (b7) or are preferably mixtures of (b1) with one of (b2), (b3) or (b7), e.g. in the molar ratio of 1/9 to 9/1, preferably 3/7 to 7/3.
The bis-diazo component radicals W1 are bicyclic, in particular they contain two benzenic rings linked to each other over a heteroatomic bridge. They derive from corresponding bis-diazo components containing as a substituent at one of the two rings a primary diazotizable amino group and as a substituent at the other benzenic ring a primary diazotizable amino group or a substituent convertible into such a primary amino group, in particular a nitro group reducible to primary amino or an acylated amino group hydrolyzable to primary amino; more preferably this substituent is, however, primary amino. As bis-diazo components from which W1 derives come, in particular, into consideration those of the formula
wherein
T1 signifies a heteroatomic bridging member, in particular xe2x80x94SO2xe2x80x94, xe2x80x94COxe2x80x94, xe2x80x94SO2xe2x80x94NHxe2x80x94, xe2x80x94SO2xe2x80x94NHxe2x80x94SO2xe2x80x94, xe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94NHxe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94NHxe2x80x94, or a methylene bridge.
Rx signifies primary amino, acetylamino or nitro, and
z signifies 0 or 1.
In formula (Aa1) Rx preferably signifies primary amino.
T1 preferably signifies xe2x80x94SO2NHxe2x80x94, xe2x80x94COxe2x80x94NHxe2x80x94, xe2x80x94NHxe2x80x94 or xe2x80x94SO2NHxe2x80x94SO2xe2x80x94, among which xe2x80x94NHxe2x80x94 and especially xe2x80x94SO2xe2x80x94NHxe2x80x94 are particularly preferred.
R2 in formula (Aa1) preferably signifies hydrogen.
Where T1 signifies xe2x80x94NHxe2x80x94 z preferably signifies 1. Where T1 signifies xe2x80x94COxe2x80x94NHxe2x80x94 or xe2x80x94SO2xe2x80x94NHxe2x80x94 the xe2x80x94NHxe2x80x94 group thereof is preferably linked to the benzenic ring bearing the substituent Rx. Where T1 signifies a bridging group containing a xe2x80x94SO2xe2x80x94 or xe2x80x94COxe2x80x94 group z preferably signifies 0.
The substituent Rx, in particular the primary amino group, may be in position meta, or preferably, para to T1.
The compounds of formula (VI) preferably correspond to the above formula (Aa1) wherein Rx signifies primary amino, which is more preferably in para position to T1.
In formula (II) Q1 preferably signifies xe2x80x94SO2xe2x80x94; Q2 preferably signifies the direct bond.
Among the tetrakisazo dyes of the invention are preferred those in which Z signifies a radical of formula (xcex1), especially those of formula (Ib), and particularly preferred are also their mixures with trisazo dyes of formula (X).
The diazotization and coupling reactions may be carried out in a manner conventional per se. Diazotization may e.g. be carried out with a nitrite (preferably sodium nitrite) in acidic aqueous medium (preferably in the presence of hydrochloric acid) and at low temperatures, e.g. in the range of xe2x88x925xc2x0 C. to +10xc2x0 C., preferably 0 to 5xc2x0 C. The coupling reaction of the diazonium compounds to the respective coupling components is advantageously carried out at temperatures in the range of xe2x88x925xc2x0 C. to +30xc2x0 C., preferably below 25xc2x0 C., more preferably in the range of 0 to 10xc2x0 C. The coupling of the diazo compound of an amine of formula (VIII) to a middle component of formula (IX) may be carried out under distinctly acidic to strongly basic pH-conditions, e.g. at a pH in the range of 4 to 12, preferably 5 to 11. The selective coupling of a bisdiazo compound of a diamine of formula (II) or (VI) at one side to the 3-position of a compound of formula (III) is suitably carried out under distinctly acidic conditions, e.g. at a pH in the range of 1 to 5, preferably by adding an aqueous solution of a compound of formula (III) of a nearly neutral pH (e.g. pH in the range of 6 to 8, preferably 6.5 to 7.5) into the acidic solution, in which the diazotization has been carried out and that contains the diazonium compound.
The coupling of the monoazodiazo compound to a coupling component Hxe2x80x94B1 or Hxe2x80x94B2 may be carried out at any pH as suitable for coupling to the respective coupling component, preferably at pH values below 10, in particular in the range of 4 to 8.5, more preferably under nearly neutral conditions, in particular at pH-values in the range of 6 to 7.5 and at temperatures, e.g. in the range of xe2x88x925xc2x0 C. to +30xc2x0 C., preferably 0 to 25xc2x0 C. The coupling of a diazo compound of an amine of formula (V) to the 6-position of a compound of formula (IV) is preferably carried out under mildly basic to nearly neutral pH-conditions, e.g. at a pH in the range of 6 to 9, preferably 6.5 to 8 and under temperatures preferably in the range of 0 to 25xc2x0 C. These pH and temperature conditions are also suitable for the selective coupling of the bisdiazocompound of a bisamine of formula (II) or (VI) at one side to the 6-position of a disazo compound of formula (VII). The coupling of the trisazodiazocompound to a coupling component Hxe2x80x94B1 or Hxe2x80x94B2 may be carried under conditions as described above for the coupling of the monoazodiazo compound. By using a suitable base for pH-adjustment (preferably alkali metal hydroxide, e.g. sodium hydroxide or potassium hydroxide, more preferably sodium hydroxide), the dyes may be obtained in a suitable salt form of high hydrosolubility. If desired, they may be obtained in another salt form, e.g. by precipitation by means of acidification and then conversion to another salt form by addition of a suitable base.
The synthetized dyes may be purified, if desired, in any manner conventional per se, e.g. by precipitation (e.g. by salting out or by acidification with a strong mineral acid) and filtration and optionally re-precipitation and filtration, and/or by microfiltration and, optionally, ultra-filtration. Where desired, the dye solution may be further purified and/or concentrated by means of suitable membrane filtrations. The purified dye solutions may be dried to dye-powder or -granulate.
The dye may, upon isolation or dialysis, be blended with suitable blending agents conventional per se, e.g. alkali metal salts (sodium carbonate, sodium sulphate) non-electrolyte blending agents (mainly oligosaccharides, e.g. dextrine) or/and with surfactants (e.g. as suitable as wetting agents), in particular non-ionic and/or anionic surfactants. There may e.g. be mentioned hydrocarbon sulphonates, sulphonated castor oil, sulphosuccinates, lignin sulphonate, hydrophilic polysaccharide derivatives, ethoxylated alkylphenols or fatty alcohols. If a surfactant is employed the weight ratio of the surfactant to the dye is advantageously in the range of 5:95 to 40:60. If desired, especially if the composition contains a surfactant, as indicated above, it may be formulated with water as a liquid concentrated dye-composition, preferably with a dry-substance content in the range of 10 to 70%, more preferably 20 to 50% by weight, referred to the weight of the composition.
The dyes of the invention are, in general, of dark hues, in particular ranging from green to red hues, e.g. bluish black, reddish black or greenish black, and/or deep black.
The tetrakisazo dyes of the invention are anionic dyes and are suitable for dyeing substrates dyeable with anionic dyes.
Any substrate that is dyeable with anionic dyes is suitable as a substrate that may be dyed with the azo dyes of the invention; these include natural and regenerated cellulose, polyurethanes, basically modified high polymers (e.g. basically modified polypropylene), natural or synthetic polyamides or anodized aluminium, in particular, however, leather substrates. The substrate to be dyed may be in any conventional form, e.g. in the form of loose fibers, filaments, yarns, woven or knitted goods, non-woven webs, carpets, half-ready-made and ready-made soft goods and tanned leather or pelts. The dyes may be employed in any desired concentration up to the saturation of the substrate. The dyeing may be carried out by any conventional methods that are suitable for the substrate to be dyed, e.g. by exhaustion or impregnation methods (e.g. padding, spraying, foam application or application with a roller, or printing), preferably from aqueous medium; for synthetic substrates, the dye may optionally also be incorporated into the synthetic mass. Paper may be dyed in the pulp, or after sheet formation.
The dyes of the invention are, however, mainly suitable for the dyeing of leather and pelts.
Any kinds of leather which are conventionally dyed from aqueous medium are suitable, particularly grain leather (e.g. nappa from sheep, goat or cow and box-leather from calf or cow), suede leather (e.g. velours from sheep, goat or calf and hunting leather), split velours (e.g. from cow or calf skin), buckskin and nubuk leather; further also woolen skins and furs (e.g. fur-bearing suede leather). The leather may have been tanned by any conventional tanning method, in particular vegetable, mineral, synthetic or combined tanned (e.g. chrome tanned, zirconyl tanned, aluminium tanned or semi-chrome tanned). If desired, the leather may also be re-tanned; for re-tanning there may be used any tanning agent conventionally employed for re-tanning, e.g. mineral, vegetable or synthetic tanning agents |e.g. chromium, zirconyl or aluminium derivatives, quebracho, chestnut or mimosa extracts, aromatic syntans, polyurethanes, (co) polymers of (meth)acrylic acid compounds or melamine/, dicyanodiamide/and/or urea/formaldehyde resins|. Thus leathers of very high to very low affinity for anionic dyes may be used.
The leathers may be of various thicknesses, thus, there may be used very thin leathers, such as book-binder""s leather or glove-leather (nappa), leather of medium thickness, such as shoe upper leather, garment leather and leather for handbags, or also thick leathers, such as shoe-sole leather, furniture leather, leather for suitcases, for belts and for sport articles; hear-bearing leathers and furs may also be used. After tanning (in particular after a re-tanning) and before dyeing, the pH of the leather is advantageously set to values in the range of 4 to 8 (the leather is xe2x80x9cneutralizedxe2x80x9d); depending on the kind of the leather, there may be chosen an optimum pH range, e.g. for grain leather pH values in the range of 4 to 6, for suede leather and split velours and for very thin leathers pH-values in the range of 4.5 to 8, for intermediately dried suede leathers and intermediately dried split velours the pH may range in the scope of 5 to 8. For the adjustment of the pH-value of the leather there may be employed conventional assistants; for tanned leather of acidic character the pH may be adjusted by addition of suitable bases, e.g. ammonia, ammonium bicarbonate or alkali metal salts of weak acids, e.g. sodium formate, sodium acetate, sodium bicarbonate, sodium carbonate or sodium sulphite, of which sodium formate and sodium bicarbonate are preferred. Sodium carbonate and sodium bicarbonate are usable in particular as second bases for the exact adjustment of the superficial pH-value of the leather. Mineral tanned leather may, if desired, also be masked, e.g. with alkali metal formate, oxalate or polyphosphate or e.g. with titanium/potassium oxalate.
The dyeing may be carried out in a manner known per se suitably in an aqueous medium and under conventional temperature and pH conditions, in particular in the temperature range of 20 to 80xc2x0 C., preferably 25 to 70xc2x0 C., milder temperature conditions, in particular in the range of 25 to 40xc2x0 C., being preferred for the achievement of deeper penetrations and for the dyeing of wool-bearing skins and furs. The pH-values of the dye-bath may, in general, range broadly, mainly from pH 8 to pH 3; in general the dyeing may be advantageously begun at higher pH-values and concluded at lower pH-values. Preferably the dyeing is carried out at pH-values xe2x89xa74, in particular in the pH-range of 8 to 4, and for the conclusion of the dyeing procedure the pH-value is lowered (e.g. by addition of an acid conventional in the leather dyeing technique such as acetic acid or formic acid) preferably to values in the range between 4 and 3. The dye concentration may range broadly, if desired, up to the saturation degree of the substrate, e.g. up to 5%, referred to the wet weight of the substrate. The dyeing may be carried out in one or more stages, e.g. in two stages, optionally with insertion of charge reversal of the substrate by means of conventional cationic assistants.
The dyes of the invention may, if desired, be employed in combination with conventional dyeing assistants, mainly non-ionic or anionic products (in particular surfactants, preferably hydrophilic polysaccharide derivatives, polyoxyethylated alkylphenols or alcohols, lignosulphonates or sulpho group-containing aromatic compounds).
A fatting may, if desired, be carried out before and/or after the dyeing process, in particular also in the same liquor. For fatting after the dyeing process the fatting agent is advantageously added before the pH of the liquor is lowered, preferably to values between 3 and 4.
For the fatting (in particular fat-liquoring) step there may be used any conventional natural animal, vegetable or mineral fat, fat oil or wax, or chemically modified animal or vegetable fat or oil, which include in particular tallow, fish oils, neats-foot oil, olive oil, castor oil, rapeseed oil, cottonseed oil, sesame oil, corn oil and Japanese tallow, and chemically modified products thereof (e.g. hydrolysis, transesterification, oxidation, hydrogenation or sulphonation products), bees-wax, Chinese wax, carnauba wax, montan wax, wool fat, birch oil, mineral oils with boiling range within 300 and 370xc2x0 C. (particularly the so-called xe2x80x9cheavy alkylatesxe2x80x9d), soft paraffin, medium paraffin, vaseline and methyl esters of C14-22-fatty acids; and synthetic leather fatting agents, including esters, in particular partial esters of polybasic acids (e.g. phosphoric acid) with optionally oxyethylated fatty alcohols. Of the above mentioned the methyl ester, the sulphonation products and the phosphoric acid partial esters are particularly preferred. By the term xe2x80x9csulphonationxe2x80x9d for the fatting agents, there is meant generally the introduction of the sulpho group including also the formation of a sulphato group (=xe2x80x9csulphatingxe2x80x9d) and the introduction of a sulpho group by reaction with a sulphite or SO2 (=xe2x80x9csulphitingxe2x80x9d).
A conventional leather softener, in particular a cationic leather softener may, if desired, be applied in a final step, particularly if fatting has been carried out with a sulphonated fat-liquoring agent.
The treated substrate may then be further treated in conventional manner, e.g. rinsed or washed, drained, dried and cured.
According to the invention there may be obtained azodyes that display, even with a relatively low number of hydro-solubilizing substituents in W1, W2, D, B1 or B2, a high solubility in water, especially where the anionic dyes are in alkali metal salt form; they are distinguished by their stability to electrolytes (in particular inorganic ions), specifically also to bases and acids, and are also distinguished, especially on leather, by their build-up and a high degree of insensitivity to variations of the affinity of the leather towards anionic dyes, very level dyeings of outstanding penetration and high colour-yield being obtainable. In these leather-dyeing properties the dyes of formulae (Ic) and especially (Ib) excel over those of formula (Ia) and are, thus, preferred. According to a particular feature of the invention and with a view to these properties, they may advantageously be employed also in a form substantially free of other elektrolytes, as obtainable by dialysis.
The dyeings, particularly on leather, have excellent fastness properties, for example wet-fastnesses, fastness to rubbing, light-fastness and stability to PVC-migration. They are readily combinable with other dyes, in particular such with similar tinctorial behavior. There may be obtained very level, intense, fine dyeings, grain side and velours side being very evenly dyed, the shade of the dyeings on different kinds of leather being equal or very similar; in admixture with corresponding compatible dyes with which the dyes of the invention are combinable, in particular with the above trisazo dyes of formula (X), there may also be obtained very intense and regular dyeings of high yield and optimum fastnesses. By the choice of the substituents some of the properties of the dyes (e.g. solubility, shade, build-up, penetration, levelness etc.) may be varied accordingly. The polyazodyes of the invention, especially the preferred ones, are also well combinable with trisazo or other tetrakisazo dyes, there being obtainable very homogeneous shades and penetrations and regular dyeings of optimum fastnesses, also light fastness.


“Digital goods” is a generic label for electronically stored or transmitted content. Examples of digital goods include images, audio clips, video, multimedia, software, and data. Digital goods may also be called a “digital signal,” “content signal,” “digital bitstream,” “media signal,” “digital object,” “object,” and the like.
Digital goods are often distributed to consumers over private and public networks—such as Intranets and the Internet. In addition, these goods are distributed to consumers via fixed computer readable media, such as a compact disc (CD-ROM), digital versatile disc (DVD), soft magnetic diskette, or hard magnetic disk (e.g., a preloaded hard drive).
Unfortunately, it is relatively easy for a person to pirate the pristine digital content of a digital good at the expense and harm of the content owners—which includes the content author, publisher, developer, distributor, etc. The content-based industries (e.g., entertainment, music, film, etc.) that produce and distribute content are plagued by lost revenues due to digital piracy.
Modern digital pirates effectively rob content owners of their lawful compensation. Unless technology provides a mechanism to protect the rights of content owners, the creative community and culture will be impoverished.
Watermarking
Watermarking is one of the most promising techniques for protecting the content owner's rights of a digital good. Generally, watermarking is a process of altering the digital good such that its perceptual characteristics are preserved. More specifically, a “watermark” is a pattern of bits inserted into a digital good that may be used to identify the content owners and/or the protected rights.
Generally, watermarks are designed to be completely invisible or, more precisely, to be imperceptible to humans and statistical analysis tools.
A watermark embedder (i.e., encoder) is used to embed a watermark into a digital good. A watermark detector is used to extract the watermark from the watermarked digital good. Watermark detection is performed in real-time even on small devices.
Those of ordinary skill in the art are familiar with conventional techniques and technology associated with watermarks, watermark embedding, and watermark detecting.
Watermarks have limitations. They may be used to designate a digital good as protected and, perhaps, to indicate that a license is necessary to legally use the digital good. However, since watermarks are identical in all copies of a digital good, a digital pirate can reproduce the original content of a marked copy by breaking the watermark at a single watermark detector, for example by extracting the detection key and using it to find the watermark and remove it or jam it.
Therefore, others may use the original content without the watermark; thus, without the content owner receiving the appropriate compensation. This is generally called “break once run everywhere” or BORE.
Furthermore, to individualize a particular copy of a digital good (or a particular system that will use that good) with watermarks, we need to augment it with a technology called “fingerprinting”.
Conventional Fingerprinting
Conventional fingerprinting (i.e., “classic fingerprinting”) refers to techniques that involve uniquely marking each copy of a particular digital good, and associating each uniquely marked copy with a “classic fingerprint.” That classic fingerprint is associated with or assigned to a particular entity (e.g., person, business, media player, or smart card) to which the copy is distributed.
If unauthorized copies of the uniquely marked copy are made, the fingerprint can be traced back to the original entity to which the copy was initially distributed. In other words, classic fingerprinting technology may be used to trace piracy to its origin.
As an example, consider a printed map. When a mapmaker produces a map, they may want to ensure that those individuals to whom the map is distributed do not make unauthorized copies of the map and distribute them to others. One way that the mapmaker might protect his maps is to introduce a different trivial error (e.g., a non-existent street) into each of the copies of the map that are distributed. Those different trivial errors are fingerprints. Each fingerprint is then associated with an individual to whom the map is distributed. By associating each different fingerprint with a different individual, if and when unauthorized copies of that individual's copy are uncovered, they can be traced back to the original individual by virtue of the unique fingerprint that the map contains.
Using embedding methods similar (but not identical) to watermarking, the fingerprint is embedded into a digital good. If we want to achieve both prevention and “after the fact” tracing, a combination of the fingerprint and watermark are embedded into a digital good.
Very powerful machines that can devote significant resources to the process of detecting a fingerprint typically perform fingerprint detection. If necessary, a fingerprint detector can have access to the original unmarked digital good, using it to improve the likelihood of success in detecting the fingerprints—even from content modified by malicious attacks.
Classic Fingerprint=Unique Entity Identifier (UEid)
Although the term “fingerprint” is commonly understood by those of ordinary skill in the art, the terms “classic fingerprint” or “unique entity identifier” (UEid) may be used hereinafter to refer to this conventional technology (and its unique marks). This is done to avoid confusion with the use, herein, of “fingerprinting” in the other sections of this document (i.e., sections other than the “Background” section). In those other sections, the term “fingerprinting” may refer to a similar, but distinctly different technology.
Collusion
One problem with fingerprinting can arise when two or more entities collude. Their purpose for doing this may be to discover, modify, or remove their fingerprints and/or the embedded watermark. Those that attempt to collude are called “colluders.” A group of colluders who attempt to collude are part of a “collusion clique.”
Returning to the map example for illustration, collusion occurs when two or more individuals get together and compare their maps. They can, given enough time, ascertain their unique fingerprints by simply looking for the differences between their maps. If they can ascertain their fingerprint, they can alter it and therefore possibly avoid detection.
With the advent of the Internet and electronic distribution, fingerprinting digital goods for purposes of detecting or deterring unauthorized copying has become particularly important. As in the above map example, collusion by different individuals in the digital context can pose challenges to the owners and distributors of digital goods.
Conventional Fingerprinting/Watermarking Systems with Collusion Resistance
Existing conventional fingerprinting/watermarking systems have some capability for collusion detection. However, the protection offered by these systems is limited.
For example, Ergun et al. have proved that no conventional fingerprinting system can have a better asymptotical collusion-resistance than: O((N/log(N))1/2)—where O indicates “order of magnitude” and N is the size of the marked digital good. For example, the best fingerprinting system today, “the Improved Boneh Shaw System” achieves for a typical two hour movie a collusion resistance of only 40 users. This system, just as the original “Boneh Shaw Fingeprinting System” has collusion resistance in the order of O(N1/4).
The derivation of the upper bound on fingerprinting mechanisms by Ergun et al. considers embedding distinct fingerprints per copy of a digital good and models collusion attacks as averaging of copies with additive noise. Aspects of their work are described in an article entitled “A Note on the Limits of Collusion-Resistant Watermarks,” authored by Ergun, Kilian, and Kumar, appearing in Proc. Eurocrypt, 1999.
For example, another conventional fingerprinting system (the “Boneh-Shaw, or B-S system”) defines a lower bound on collusion-resistant fingerprinting: O(N1/4). Assuming that the marked digital good is a typical music clip, the lower bound of the number of colluders necessary to thwart this conventional system is in the neighborhood of 4. The B-S system is a fingerprinting system that attempts to overcome the problem of collusion when fingerprinting digital goods. Aspects of the B-S system are described in an article entitled “Collusion-Secure Fingerprinting for Digital Data” authored by Boneh and Shaw, appearing in IEEE Transactions on Information Theory, Vol. 44, No. 5, Sep. 1998.
Those of ordinary skill in the art are familiar with conventional techniques and technology associated with classic fingerprinting, classic fingerprinting embedding, and classic fingerprinting detecting.
Although the conventional fingerprinting systems provide some protection against collusion, that protection is only effective when the number of colluders is relatively small. Consequently, the confidence level that a marked digital good is free from the effects of collusion is not high.
Accordingly, there is a need for a new watermarking/fingerprinting technology that is more collusion resistant. A new technology is needed that increases the protection that is provided by fingerprinting (and watermarking) to detect colluders even when their numbers are large. If that numbers is several orders of magnitude greater than the conventional, then the confidence level—that a marked digital good is free from the effects of collusion—would be very high indeed.
Moreover, there needs to be a more effective technique to identify that a digital good has had its mark removed and who removed that mark. That way, piracy crimes can be more effectively investigated.


In some types of partial middle ear implantable (P-MEI) or total middle ear implantable (T-MEI) hearing aid systems, sounds produce mechanical vibrations within the ear which are converted by an electromechanical input transducer into electrical signals. These electrical signals are in turn amplified and applied to an electromechanical output transducer. The electromechanical output transducer causes an ossicular bone to vibrate in response to the applied amplified electrical signals, thereby improving hearing.
An electromechanical transducer used for the purpose of vibrating or sensing from any or all elements of the ossicular chain may be mounted in or near the middle ear. The transducer is generally contained in a housing or enclosure, forming a driver or sensor assembly that facilitates the placement of the transducer within the middle ear.
In previous designs, applicant has noticed unwanted resonances within the audible frequency range, which can be disconcerting to the person having the implant.
What would be desirable are transducers which more accurately convert the electrical signal received into vibrations which can be coupled to the ossicular chain.


The present disclosure generally relates to information processing and, in particular, storing user data on servers.
Many service providers (e.g., cloud computing services, data sync services, file hosting services, etc.) enable user data to be stored at one or more servers. For example, an application synchronization service may allow a user to sync one or more applications so that user data associated with one application on one client system may be transferred and used on another application on another client system. Synchronization of the applications on the two systems may be achieved by storing user data on a data storage server.
In order to protect user data and the privacy of users, software on a first client system may generate an encryption key based on a passphrase (e.g., the user's password or another user supplied string) and encrypt the user data using the encryption key before it is transmitted to a data storage server to be stored. The user may download the encrypted data from the data storage server on a second client system. However, in order to access the encrypted data on the second client system, the second client system must have access to a key to decrypt the encrypted data. In some cases, the second client system may generate a key using the same user provided passphrase or password and decrypt the encrypted data using the key. However, the user may not be able to generate the key to decrypt the encrypted user data if the user forgets the passphrase (or if the user changes his password).