A pull-out faucet has a hollow faucet body with open top and bottom ends and a cylindrical (laterally extending) side opening. A hollow, cane-shaped spout mounts to the top end and seats a spray head at one end. A separate valve block mounts in the housing through the side opening and connects to a mixing valve cartridge lying adjacent thereto on a lateral side. Water supply hoses snap into inlet passages of the valve. One end of a counterweighted spray hose assembly snaps into an outlet passage of the valve block and the other end connects to the spray head. The spray head can be extended from the spout and then retracted. A method of assembling the hoses and valve assembly into the hollow faucet body through the side opening is also disclosed.

Not applicable.
Not applicable.
The present invention relates to faucets, and in particular to faucets with pull-out type spray heads.
Conventional faucets have a faucet body, one or more flow control/mixing valves, one or more control handles, and a spout. The spout acts a conduit for expelling water that has passed through the valve(s), in which case the outflow is either fixed to begin at a single point, or in the case of a pivotal spout is limited to begin over a range of a prescribed horizontal arc.
Thus, faucets have conventionally been provided with separate stand-alone hand-held sprayers to provide the user with more flexibility with regard to the direction and point that outflow begins, particularly to facilitate spraying down dishware. These sprayers have a flexible hose attached to the spray head allowing the spray head to be pulled from a mount and moved about as needed. However, these faucets require extra room on the counter top for the sprayer mounting, as well as a separate hole through the counter top.
As an alternative, faucets with pull-out spray heads projecting from the main faucet body have been developed. See generally U.S. Pat. Nos. 5,213,268; 5,546,978; 5,758,690 and 6,370,713. The first two of these references have the sprayer unit extend from the side of the faucet body, and the latter two have the sprayer unit extend from the upper end of the faucet body.
Assembly of such pull-out faucets is usually more complicated then conventional faucets due to the added spray hose and its coupling to the water supply lines. The spray hose must run through the body of the faucet near the valve assembly, which typically includes a large number of components. Also, separate fasteners are ordinarily needed to install the valve assembly in the faucet body.
This can significantly increase the cost of production of the faucet, and in some cases the shipping weight of the product.
A need therefore exists for an improved pullout type faucet, particularly one that is easier to assemble and is relative lightweight.
In one aspect the invention provides a pull-out faucet. It has a hollow body defining a longitudinal cavity opening at a bottom end, at a top end and at an internally threaded side; a spout having proximal and distal ends and defining a passageway there between, the proximal end being mounted to the top end of the body; and a spray head having discharge orifices and being positioned adjacent the distal end of the spout when in a retracted position.
There is also a valve block that is not integral with the hollow body, is disposed in the cavity, has two inlet passages, has an outlet passage, and has a side face; a mixing valve cartridge having an end that is positioned adjacent the side face of the valve block and having an opposite end; and a control stem projecting from the opposite end of the cartridge.
Preferably, the side opening of the body is defined by a laterally extending cylindrical section having an inner end inside the cavity and an outer end outside the cavity. The mixing valve cartridge and valve block are secured to the body by tightening an externally threaded valve bonnet into the side opening so as to press them together and force a peripheral flange on the valve block to seat against an inwardly directed lip of the body.
Further, water supply hoses are coupled to the valve block inlet passages, an outlet hose has a first end coupled to the valve block outlet passage and a second end coupled to the spray head, and the outlet hose is of a suitable size to slide within the spout passageway to permit the spray head to be pulled from the spout to an extended position. There is also a handle coupled to the control stem for operating the valve.
In preferred forms there is a handle bonnet mounted about the control stem to the outer end of the cylindrical section to rotate with the control stem, and the valve block inlet passages open in the direction of the bottom opening in the body. One or more of the hoses can be coupled to the valve block by a push-in connection via a washer projection, the spray head can be coupled to the spray hose by a ball and socket connection, and there can also be a counterweight mounted to the spray hose to bias the spray head toward the distal end of the spout.
In another aspect the invention provides a method of assembling a pull-out faucet. One provides a faucet body defining a longitudinal cavity opening at bottom and top ends and at an internally threaded side; assembles to a valve block hot and cold water supply hoses so that they extend from inlet passages of the valve block; and assembles to the valve block an outlet hose so that it extends from an outlet passage of the valve block. One then inserts the hoses through the body side opening, then feeding them down through the bottom opening, and inserts the valve block into the side opening.
One then positions a mixing valve cartridge against a side face of the valve block so that corresponding ports of the mixing valve cartridge align with respective inlet and outlet passages of the valve block. Then one threads a valve bonnet into the side opening to secures the valve block and cartridge in the body. One then feeds a first end of the outlet hose up through the body bottom opening, through the cavity, through the top opening of the body, and into a spout attachable to the top end of the body. Then, one connects a spray head to a second end of the outlet hose.
In preferred forms the method includes mounting a handle bonnet about an end of the mixing valve cartridge, and mounting a counterweight to the outlet hose to bias the spray head towards a distal end of the spout.
The invention thus provides a faucet that is particularly suitable for kitchen sinks (albeit also useful for other plumbing applications such as bathtubs), where the spray head is connected to water supply lines by a flexible hose disposed inside the faucet. This allows the faucet to look and operate like a conventional solid body faucet and also allow the spray head to be pulled out from the faucet to change the location and reach of the spray head.
The faucet preferably has a hollow body with a cylindrical opening in which is disposed a valve block and a one-piece mixing valve cartridge lying laterally so that its valve stem extends out from one side of the faucet for attaching a handle. The threaded side opening and valve bonnet permit easy installation of the valve assembly (and hoses), while minimizing components and the weight of the faucet.
These and still other advantages of the invention will be apparent from the detailed description and drawings. What follows is a preferred embodiment of the present invention. To assess the full scope of the invention the claims should be looked to as the preferred embodiment is not intended as the only embodiment within the scope of the invention.


An audio caller identification system and method are provided. A caller identification device of a called party's telephone, whether integrated with the telephone or stand-alone, includes a speaker for audibly alerting the called party to the nature of an incoming call. A speech synthesizer in concert with an audio caller ID program may audibly identify a name and/or number of the calling party displayed on the called party's caller ID device, including descriptive terms for calling parties such as “private,” “unlisted,” or “out of the area.” When the called party's telephone begins to ring, the called party may listen to the audio identification of the calling party for a quick screening without having to go to the telephone to read the caller ID.

In recent years a growing number of telephone services have become available to users of telephone services. Such services include, for example, call forwarding, call waiting, conferencing, and caller identification.
Caller identification, or Caller ID, has become particularly popular as it allows called parties a certain degree of call screening prior to answering a call. In a typical case, the called party's telephone has a caller ID screen or a stand-alone attached caller ID device. When the called party receives a call, caller identification information on the calling party, including the date and time of the call, and often the name and number of the calling party, is displayed on the screen of the called party's caller ID device.
Typically, the called party receives the call, and the called party must rush to the telephone to determine who is calling by reading the caller ID screen on the called party's caller ID device. Most often, one of three caller identifications is provided to the called party. One, the identification is a name and/or number known to the caller, for example, a friend, family member, or associate. Two, the identification is a name and/or number unknown to the called party, or three, no name or number is provided, and the screen reads "private," "unlisted," "out of area," or the like. For called parties who are seeing impaired, the problem is greater because they are unable to read the caller ID information from a standard caller ID equipped telephone or standalone caller ID device.
It is with respect to these considerations and others that the present invention has been made.

BellSouth Intellectual Property Corporation


The invention relates to a hard metal or cermet body with a hard material phase consisting of WC and/or at least one carbide, nitride, carbonitride and/or oxicarbonitride of at least one of the elements from group IVa, Va, or VIa of the periodic table and a binding metal phase consisting of Fe, Co and/or Ni, said binding metal phase making up 3 to 25 mass %. In particular, WC crystallites should protrude beyond the hard metal or cermet surface of the by 2 to 20 xcexcm in order to improve the adhesion of surface layers that are applied.

The invention relates to a hard metal or cermet body with a hard material phase of WC and/or at least one carbide, nitride, carbonitride and/or oxycarbonitride of at least one of the elements of Group IVa, Va or VIa of the classification of elements and a metal binder phase of Fe, Co and/or Ni, whose proportion amounts to 3 to 25% by mass.
The invention relates further to a method for producing such a hard metal or cermet body through mixing, grinding, granulation and pressing of an initial mixture containing the corresponding components and subsequent sintering thereof.
In EP 0 344 421 A1 a cermet is proposed which should have either an average grain size of the hard material phase in the surface layer as compared to a core with a penetration depth of 0.05 mm, ranging between 0.8-1.2 times of the average grain size of the hard material phase in the cermet body core, or at the same penetration depth has a binder phase which ranges between 0.7 to 1.2 times of the corresponding average binder content of the cermet core, or wherein the hardness in the aforementioned penetration depth ranges between 0.95 and 1.1 times the average hardness of the cermet core. For the production of this cermet, the initial mixture is sintered after grinding, mixing and preliminary pressing. In a first step it is sintered under vacuum or in an inert gas atmosphere at up to 1300xc2x0 C. or below, while in a second step it is sintered at over 1330xc2x0 C. at a nitrogen pressure of 0.1 to 20 Torr (13.3 Pa to 2.66 Paxc3x97103 Pa). The nitrogen pressure is increased with increasing temperature.
The EP 0 368 336 B1 describes a cermet substrate with a hard surface layer, wherein the region with the maximal hardness lies at a depth between 5 xcexcm and 50 xcexcm from the substrate surface and the substrate surface has a hardness of 20 to 90% of the maximal hardness. For the production of this cermet the prepressed mixture is subjected to an initial temperature increase up to 1100xc2x0 C. in vacuum and to a subsequent temperature increase from 1100xc2x0 to a temperature range between 1400xc2x0 C. and 1500xc2x0 C. in a nitrogen atmosphere. It is subsequently sintered in vacuum.
The EP 0 374 358 B1 describes a method for producing a cermet with 7 to 30% by weight of a binder phase and a hard phase of titanium carbide, titanium nitride and/or titanium carbonitride with 35 to 59% by weight Ti, 9 to 29% by weight W, 0.4 to 3.5% by weight Mo, 4 to 24% by weight of at least one metal from the group of Ta, Nb, V and Zr, 5.5 to 9.5% by weight N and 4.5 to 12% by weight C. The formulated, mixed, dried and prepressed mass is sintered in such a manner that the temperature is increased in vacuum to 1350xc2x0 C., whereby the nitrogen atmosphere is set at 1 Torr (133 Pa) at 1350xc2x0 C., the partial nitrogen pressure together with the temperature of 1350xc2x0 C. are gradually increased up to the sintering temperature, whereby the nitrogen atmosphere is set at 5 Torr (665 Pa) at the sintering temperature.
The EP 0 492 059 A2 describes a cermet body, whose hardness at a penetration depth of no less than 1 mm is higher than in the cermet interior, whereby the binder content can be reduced in a layer thickness of 0.5 to 3 xcexcm with respect to the core substrate. The cermet should have a hard material coating whose thickness ranges between 0.5 to 20 xcexcm of carbides, nitrides, oxides and borides of titanium and Al2O3. For the production of this body a green compact is at first heated under vacuum to a temperature between 1100xc2x0 C. and 1400xc2x0 C., then nitrogen gas is introduced up to a pressure level at which the partial nitrogen pressure ranges between 5 and 10 Torr (665 and 1330 Pa), so that the nitrogen is removed from the substrate surface. The sintering and the subsequent cooling are performed in a non-oxidizing atmosphere, such as a vacuum or an inert gas atmosphere. After that the body is coated by CVD or PVD.
The production of a super tough cermet is proposed in EP 0 499 223, wherein the relative binder concentration in a 10 xcexcm thick layer close to the surface is 5 to 50% of the average medium content of binder in the cermet core, and in the underlying layer of 10 xcexcm to 100 xcexcm penetration depth the binder content at 70 to 100% in relation to the cermet core. In the method used therefore the sintering is performed under nitrogen gas with a constant pressure of 5 to 30 Torr (665 to 3.99xc3x97103 Pa) and the cooling is performed under vacuum with a cooling rate of 10 to 20xc2x0 C./min.
The EP 0 519 895 A1 discloses a cermet with a triple-layer border zone, wherein a first layer reaches to a depth of 50 xcexcm TiN, the next layer to a depth of 50 to 150 xcexcm penetration depth with a binder enrichment and the next layer of 150 xcexcm to 400 xcexcm is conceived with a binder reduction relative to the inner cermet core. For this purpose the sinter body is treated in an atmosphere of N2 and or NH3, optionally in combination with CH4, CO, CO2 at 1100xc2x0 to 1350xc2x0 C., for 1 to 25 hours at atmospheric pressure or at a pressure above 1.1 bar (1.1xc3x97105 Pa).
The cermets known to the state of the art have at their surface either different binder contents, which can be recognized by their spotted appearance, or tend to adherence of the binder to the sinter substrate, which due to the thereto related reaction, leads to changes in the composition of the contact zone. A further disadvantage of the cermets known to the state of the art is that, at increased contents of metal binder in the surface, the adhesion of thereto applied wear-resistant layers is poor. To the extent that the nickel proportion increases in the surface, CVD coating becomes impossible. Therefore the DE 44 23 451 A1 proposes a cermet which has a hard material content of 95 to 75% mass and 5 to 25% by mass Co and/or Ni binder, whereby the hard material phase consists of carbonitrides with cubic B1 crystal structure and 30 to 60% by mass Ti, 5 to 25% by mass W, 5 to 15% by mass Ta, up to 70% by mass of which can be replaced by Nb, 0 to 12% by mass Mo, 0 to 5% by mass V, 0 to 2% by mass Cr, and 0 to 1% by mass Hf and/or Zr. The (C+N) content in the carbonitride phase should be  greater than 80% by mol, whereby the nitrogen content ratio N/(C+N) ranges between 0.15 and 0.7. In a certain surface depth of 0.01 to 3 xcexcm, the proportion of the binder phase with respect to the underlying cermet core area is lower than 30% by mass. In this zone the titanium content is 1.1 to 1.3 times higher than in the underlying cermet core area, while the contents of tungsten, tantalum, as well as any content of molybdenum, niobium, vanadium and/or chromium are present only in an amount of 0.7 to 1 times in relation to the underlying cermet core areas. In an alternative embodiment of this cermet in the same surface border zone the relative content of binder phase is 90% by mass, the relative Ti content 100% to 120% and the sum of contents of tungsten, tantalum and optionally molybdenum, niobium, vanadium, chromium ranges between 80% by mass and 110% by mass, each in relation to the inner cermet core.
This border structure according to the aforementioned reference is produced through a process of cermet manufacturing, according to which the green compact produced through mixing, grinding, granulation and pressing is at first heated under vacuum up to the melting point of the binder phase at a pressure of 10xe2x88x921 mbar (10 Pa). During the further heating from the melting temperature of the binder phase to the sintering temperature, which is maintained from 0.2 to 2 hours, and a subsequent cooling to 1200xc2x0 C. a gas mixture of N2 and Co is introduced into the oven atmosphere, with a N2/(N2+CO) ratio between 0.1 and 0.9 which fluctuates within a period of time between 40 to 240 sec around a pressure on the average of 10% to 80% of an average pressure. The average pressure as well as the aforementioned ratio are selected depending on the binder content.
The EP 0 687 744 A2 also describes a nitrogen-containing sintered hard metal alloy with at least 75% by weight and a maximum of 95% by weight of hard phase content, containing titanium, an element of the Group VIa of the classification of elements and WC, the balance being a binder phase of nickel and cobalt. The alloy has 5% by weight to 60% by weight titanium in the form TiC and 30% by weight up to 70% by weight of a metal in the form of a metal carbide. The sintered hard metal alloy should have a soft outermost surface layer, consisting of a binder phase and WC. Below this outermost layer lies a layer with a thickness of 3 xcexcm to 30 xcexcm, which should consist substantially of WC with low metal binder contents.
A sintered hard metal alloy of the aforementioned composition is also described in EP 0 822 265 A2. The sintered body produced accordingly should have a border area subdivided into three layers, of which the outermost layer has a WC-content between 0 and 30% by volume, the balance being binder phase, the middle layer has 50% by volume to 100% by volume WC, the balance being binder phase and a third innermost layer has a WC content by volume between 0 and 30%, the balance being binder.
It is the object of the present invention to create a hard metal or cermet body suitable for CVD or PVD coating, whose surface insures an improved adhesion capability for the layers of hard materials deposited from the gas phase, such as diamond, cubic boron nitride, carbon nitrides, fuller""s earth, as well as metallic hard materials (carbides, nitrides, carbonitrides or oxycarbonitrides of the elements of Groups IVa-VIa of the classification of elements), as well as other layers which contain at least one of the elements B, C, N or O.
This object is achieved in a hard metal or cermet body which, according to the invention, is characterized in that WC crystallites project from the body""s surface by 2 to 20 xcexcm, preferably by 5 to 10 xcexcm. By means of these crystals a coarse-grained surface morphology is produced, which insures the adhesion of the applied surface layers due the interlocking of the crystallites with the deposited phases. These WC crystallites are embedded in the border zone adjacent the surface in such manner that even while grinding test work is performed they are not dislodged. The created surface roughness provides an ideal xe2x80x9canchoringxe2x80x9d for the application of surface coatings.
The WC content in the total hard material phase of the hard metal or cermet body ranges between a minimum of 50% by mass and a maximum of 96% by mass. Preferably the WC crystallites at the body border zone or surface, form a composition with up to 50% by volume of a cubic phase of a further hard material of a different composition and binder metal parts. This cubic phase can consist substantially of carbides, nitrides, carbonitrides and/or oxycarbonitrides of at least one element (with the exception of W) of the Groups IVa, Va and/or VIa of the classification of elements. The cubic phase can be conceived as single-phased or multi-phased. It can consist for instance of Ti(C,N) and (Ti,W)C. Also metals of Groups IVa, Va and/or VIa of the classification of elements, preferably W, Ta, Nb, Mo and Cr can be incorporated in the structure of the hard metal or cermet body, particularly in border zones close to the surface of the body. The cubic phases in the border zone can have either a homogeneous structure or a local grain border structure, as is basically known in cermets.
The present invention comprises especially cermet bodies whose phases with cubic crystalline structure contain 30 to 60% by mass titanium, 5 to 15% by mass tantalum and/or niobium, 0 to 12% by mass molybdenum, 0 to 5% by mass vanadium, 0 to 2% by mass chromium, 0 to 1% by mass hafnium and/or zirconium, whereby in the binder phase up to 2% aluminum and/or metallic tungsten, titanium, molybdenum, vanadium and/or chromium are dissolved.
The border zones close to the surface can be substantially homogeneous or have a gradient in their composition. They can have surface-close border zones of different compositions, whereby in a first outer layer at the body surface and reaching to a depths between 2 xcexcm and 3 xcexcm there is a carbonitride phase substantially free of binder phase, which borders an underlying middle layer with a thickness of 5 xcexcm to 150 xcexcm of a substantially pure WC-Co-composition, and which is followed by a third innermost layer with a thickness of at least 10 xcexcm and a maximum of 650 xcexcm, wherein the content of the binder phase and of the IVa and/or Va elements increase to the corresponding values which in the body interior are substantially constant, while the tungsten content decreases to the substantially constant value thereof in the inner body. The different layers of the aforedescribed sintered body blend continuously into one another, whereby preferably titanium is used as the metal of the carbonitride phase. The content of titanium and/or of a further element of the Groups IVa to VIa of the classification of elements, with the exception of tungsten, is at a maximal level in the outer layer, decreases steeply to a minimal value in the transition to the middle layer, and increases gradually in the transition to the third innermost layer, to a penetration depth of approximately 800 xcexcm measured from the surface, reaching an average value corresponding to the content in the total composition in the body interior, which however is below the level of the titanium or other metallic parts in the outer layer. Correspondingly the nitrogen content in the middle layer is minimal and increases in the transition to the outermost layer to proportions above the average nitrogen content of the alloy present in the inner core. By contrast, in the transition from the outermost layer to the middle layer the contents of tungsten and cobalt increase clearly. Optionally the hard material phase WC can be formed already during sintering from (Ti,W)C or (Ti,W) (C,N). Preferably the binder phase content in the middle layer amounts to maximum 0.9 times the binder phase content in the body interior, while the tungsten content in this middle layer amounts to at least 1.1 times the tungsten content existing in the body interior.
Alternatively it is also possible to have such border zones wherein the individual layers are not strictly separated from each other, but wherein the respective contents of metallic and non-metallic components of the alloy change gradually over wide transition areas. A body according to the invention can fulfill the following conditions in three layers forming the border zone:
In an outer layer, which closely follows the body surface or the border zone with a penetration depth of 1 to maximum 3 xcexcm and reaching down to a depth between 10 xcexcm and 200 xcexcm, the tungsten and the binder phase content amount to a maximum of 0.8 times the content resulting from the general composition. In this layer the tungsten and the binder phase content increase substantially continuously towards the body interior, while the nitrogen content decreases continuously towards the body interior. In an underlying middle layer of a thickness between 20 xcexcm and 400 xcexcm, with the advancing penetration depth the tungsten and binder phase contents pass through a maximal level, while the contents of elements of the Groups IVa and/or Va of the classification of elements pass through a minimal level. In a third innermost layer, which reaches to a penetration depth measured from the body surface of maximum 1 mm. the tungsten and binder phase contents decrease to the substantially constant values in the body interior, which correspond to the content in the general composition, and the contents of elements of the Groups IVa and Va of the classification of elements, particularly titanium, increase to the substantially constant values. The nitrogen content remains substantially constant in the transition from the middle layer to the innermost layer towards the body interior.
The alloys of the body of the invention can contain up to 2% by mass chromium and/or molybdenum, as well as between 3 to 40% by mass TiCN or up to 40% by mass TiC and/or TiN in the hard material phase TiCN.
Advantageously the hard metal or cermet body of the invention is coated with at least one hard material layer and/or a ceramic layer (Al2O3) or diamond, cubic boron nitride or similar layers.
In the case of nitrogen-free mixtures of hard materials and binder metals, the same are pressed into a green compact and at first are heated in vacuum to approximately 1200xc2x0 C., and subsequently in an inert gas atmosphere to a temperature between 1200xc2x0 C. and the sintering temperature, whereafter at the latest when the sintering temperature is reached, an atmosphere containing nitrogen and optionally carbon is set at a pressure between 103 and 107 Pa, preferably between 5xc3x97103 Pa and 5xc3x97104 Pa. To the extent that the sintering temperature may not yet have been reached, the heating up to this temperature continues and the same is maintained over a period of at least 20 minutes, or in this interval of at least 20 minutes only a slight cooling of maximum 2xc2x0 C./min is performed. In the subsequent cooling of the sintered body, the set nitrogen and optionally carbon atmosphere is maintained until at least 1000xc2x0 C. are reached.
If the initial mixture contains nitrogen proportions of at least 0.2% by mass in relation to the total hard material mass, the nitrogen-containing gas can be introduced later into the oven atmosphere, however at the latest when the sintering temperature is reached and, corresponding to the nitrogen content in the initial mixtures, it can be introduced also at a lesser partial pressure. In any case it has to be insured through the process and/or the initial mixture that there is a sufficiently high carbon content and tungsten content for the formation of the WC crystallites at the surface. In certain cases the sintering time has to be correspondingly extended.
In a variant of the process it is also possible to set the nitrogen-containing and optionally the carbon-containing atmosphere by introducing precursors, i.e. nitrogen-containing and optionally carbon-containing crucible materials, so that under the existing temperature and pressure nitrogen and carbon are formed in situ.
The size and frequency of the WC crystallites can be influenced by the time period and by the gas composition while the sinter body is at eutectic temperatures. Thereby longer treatment times and a higher content of carbon lead to larger and/or more frequently occurring WC-crystallites.
In an embodiment of the invention, the sinter body is heated up to 1200xc2x0 C. during the heating phase and this temperature is maintained for at least 20 minutes, preferably more than an hour, before continuing the further heating up to the sintering temperature.
Within the framework of the present invention there is also a process technology wherein, at first, in the heating phase up to approximately 1200xc2x0 C., the body is exposed to a vacuum, which is then replaced by an inert-gas atmosphere (e.g. a noble gas atmosphere).
The inert-gas pressure of 103 to 104 Pa is maintained until the sintering temperature is reached, after which a nitrogen-containing and optionally carbon-containing atmosphere is established at a higher pressure of more than 104 Pa above 1450xc2x0 C., preferably close to 1500xc2x0 C.
According to a further embodiment of the invention, after a holding period of at least 0.5 hours, the sintered body of hard metal or a cermet can be subjected to a xe2x80x9cpendular annealingxe2x80x9d, i.e. to a temperature setting wherein at least once, preferably several times, the temperature surpasses or falls below the eutectic melting point by at least 20xc2x0 C., preferably at least 50xc2x0 C. in an oscillating manner. Preferably the heating and cooling rates, as well as the speed with which the heating and cooling rates surpass or fall below the eutectic melting point are at maximum 10xc2x0 C./min. However cooling and/or heating speeds between 2xc2x0 C./min and 5xc2x0 C./min are preferred.
In a further embodiment of the invention, the gas mixture atmosphere of N2 and CO established after the sintering temperature was reached, can be selected with a ratio of N2/(N2+CO) between 0.1 and 0.9.
Finally within the framework of the present invention, it is possible, after reaching the sintering temperature, to set pressures oscillating around an average of the atmosphere containing nitrogen and optionally carbon, whereby the pressures deviate by 10 to 80% from an average value selected depending on the binder material. A corresponding process technology is explained for instance in DE 44 23 451 A1 to which reference is made.
According to a further embodiment of the invention, the surface of the finished sintered compact can be subjected to an etching treatment by means of gases or liquids, through which the WC crystallites are more clearly defined due to relief formation. This step can be particularly useful for the removal of binder metal parts from the substrate body surface, since these are particularly undesirable in the case of a diamond coating.

Hard metal or cermet body and method for producing the same


A flash EEPROM cell array is erased by applying a relatively high positive voltage to the source region of the cell and a ground potential to the control gate of the cell while allowing the voltage of the drain region and the substrate region of the cell to float. By floating the substrate, the source current during erase is greatly reduced since the only DC current path is between the control gate and the source region. Since the source current is small, a double-diffused junction is not required so that the cell can occupy a minimum area for a given design rule and the cell fabrication process is simplified. In addition, the generation of high energy holes is suppressed and improved performance may be obtained. Because the source current is small during the erase operation, the high positive voltage at the source region can be generated by an on chip charge pump from a supply voltage as low as +3 V. This simplifies the design of memory boards on which many flash EEPROM chips are to be placed. Moreover, the after erase Vt distribution of the memory cell is tightened since a relatively high positive voltage is applied to the source region during erasure. Finally, there is no issue of yield sensitivity to defects in the channel, since during the erasure operation, electrons trapped in the floating gate pass through the overlap region between the source region and the control gate, instead of through the channel.

There is a class of nonvolatile memory devices known as "flash EEPROMs" (electrical erasable programmable read only memory devices). The operation and structure of such devices is discussed in U.S. Pat. No. 4,698,787 issued Oct. 6, 1987, to Mukherjee et al., the disclosure of said patent being incorporated herein by reference. Another discussion respecting the operation and structure of flash EEPROM devices may be found in IEEE Journal of Solid State Circuits, Vol. SC-22, No. 5, October, 1987, pages 676-683 in an article entitled, "A 128K flash EEPROM Using Double-Polysilicon Technology" by Gheorghe Samachisa et al., the disclosure of said article being incorporated herein also by reference. A key feature of "flash" EEPROM's which distinguishes them from standard EEPROM's is that a select transistor is not included on a one-for-one basis with each floating gate transistor to select one memory cell for erasing. Instead, the memory cells of a flash EEPROM chip are erased in bulk, i.e., either the entire chip or by paged groups, commonly known as sectors. Each sector has a large number of floating gate transistors. For example, a 4 million bits (4 Mbit) flash EEPROM chip may have 8 equal size sectors of 64 thousand (64K) bytes each (each byte is equal to 8 bits and each bit is represented by one floating gate transistor). Typically, any combination of sectors, including all the sectors (i.e., the entire chip), can be concurrently erased. Elimination of the select transistor allows for smaller cell size and this gives the flash EEPROM an advantage in terms of manufacturing yield over a comparably sized (in terms of memory capacity) standard EEPROM.
A plurality of flash EEPROM cells may be formed on a semiconductor substrate (i.e., a silicon die) to each comprise a N-type source region integrally formed within a P portion of the substrate, a N-type drain region integrally formed within the P substrate portion and spaced apart from the source region, a P-type channel region interposed between the source and drain regions, a floating gate electrode insulatively spaced by a short distance (for example, 100 angstroms) above at least one of the source and drain regions, and a control gate electrode insulatively disposed above the floating gate electrode.
According to conventional operation, a flash EEPROM memory cell is "programmed" by inducing hot electron injection from a portion of the substrate (for example, a channel section near the drain region) to the floating gate. Electron injection carries negative charge into the floating gate. This injection mechanism is normally induced by grounding the source region and a bulk portion of the substrate, applying a relatively high positive voltage to the control electrode, for example, +12 Volts (V), to create an electron attracting field and applying a positive voltage of moderate magnitude (i.e., approximately +6 V to +9 V) to the drain region in order to generate "hot" (high energy) electrons. After sufficient negative charge accumulates on the floating gate, the negative potential of the floating gate raises the threshold voltage of its field effect transistor (FET) and inhibits current flow through the channel during a subsequent "read" mode. The magnitude of the read current is used to determine whether an EEPROM cell is programmed or not. Typically, in the read mode, a relatively low positive voltage, for example, +1.5 V, is applied to the drain, +5 V is applied to the control electrode and 0 V is applied to the source region of the memory cell.
The act of discharging the floating gate is called the erase function for a flash EEPROM cell. This erasure function is typically carried out by a Fowler-Nordheim tunneling mechanism between the floating gate and the source region of the transistor (source erase or negative gate erase) or between the floating gate and the substrate (channel erase).
A source erase operation is induced by applying a high positive voltage to the source region and a 0 V to the control gate and the substrate, while floating the drain of the respective memory cell. This positive voltage may be approximately +12 V.
While the source erase operation have the advantages of providing a tight after erase Vt distribution due to the use +12 V at the source for the erasure (a discussion of the control of after erase Vt distribution using high voltage source erase may be found in IEDM, 1992, pages 595-598 in an article entitled "Comparison of Current flash EEPROM Erasing Method: Stability and How to Control" by K. Yoshikawa et al., the disclosure of said article being incorporated herein by reference) and being insensitive to defects in the channel because all tunneling are through the small area of source to gate overlap, a number of drawbacks exist. First, an external power source of approximately +12 V is needed. Since different voltages, i.e., +4 V to +9 V, +5 V and +12 V, need to be applied to the drain and source regions of the device during programming, reading and erasure, it is often necessary to provide two off-chip power supplies for operating integrated circuit chips having such flash EEPROM's cells. There is a long-felt desire within the industry to develop a flash EEPROM integrated circuit chip which may be operated from only one power supply, i.e., +5 V or less. Unfortunately, the magnitude of source to substrate current tends to be relatively high during erasure, on the order of approximately 1 microamp per cell, and as a result, the power requirement of a memory chip having one million or more memory cells (a 1 megabit chip) can be as high as one ampere. Self-limiting techniques are often used for reducing this source to substrate current to levels of approximately 20 to 30 milliamps, but even at these levels, it is difficult to provide enough current from an on-chip charge pump circuit. An external power source of approximately +12 V or higher is needed.
A second drawback of the source erase technique is the difficulty in providing high density flash EEPROM cell arrays due to the requirement of a double-diffused source structure. When source erase technique is used, a relatively high reverse voltage is generated between the source and substrate during erasure. (The P-type substrate is at 0 V and the N+ type source region is at +12 V). A double-diffused source structure is normally employed (such as disclosed in Mukherjee, U.S. Pat. No. 4,698,787) to protect against undesirable reverse voltage breakdown of the source to substrate PN junction. The fabrication of a double-diffused structure requires an additional implantation step and a critical masking step which demands very precise alignment of the mask relative to the floating gate and the control gate of each cell within the flash EEPROM cell arrays. These additional steps, specifically the critical masking step, increase the cost and complexity of the fabrication process and reduce production yields. In addition, the double-diffused source structure occupies more substrate area than would otherwise be occupied by a single-diffused source structure and accordingly it is difficult to provide high density flash EEPROM cell arrays on relatively small dies in a cost-effective manner.
A third drawback associated with the source erasure of flash EEPROMs wherein a relatively high positive voltage (i.e., +12 V) is developed at the source region, is that there is a substantial probability that high energy holes ("hot" holes generated by a so called "avalanche effect") might be formed at a surface portion of the source to substrate junction and that these holes will become trapped in the thin dielectric underlying the floating gate. To a similar extent, there is a further danger that additional high energy holes will be generated by a so called "band to band tunneling conduction" mechanism and these will also be trapped in the gate dielectric. The distinction between avalanche generated holes and band to band generated is discussed in an IEEE paper entitled, "Drain-Avalanche and Hole-Trapping Induced Gate Leakage in Thin-Oxide MOS Devices" by Chi Chang, et al., IEEE Electron Device Letters, Vol. 9, No. 11, November, 1988, pages 588-590. This article is incorporated herein by reference.
The production or avalanche generated holes at the surface of the dielectric below the floating gate is undesirable because it can interfere with reliable programming, reading and erasure of randomly located memory cells (i.e., the gate disturb phenomenon), because it tends to decrease the charge retention time of the floating gate (holes trapped in the gate dielectric can migrate upwardly into the floating gate to neutralize the negative program charges in the floating gate). Specifically, during erasure, some memory cells may produce more hot holes than others and consequently their floating gates will be discharged at a faster rate. This creates a non-uniform erasure throughout the memory chip. Those holes which do not migrate to the floating gate during erasure can remain in the dielectric for random periods of time and then migrate to the floating gate, where they neutralize charge that is to be retained. Furthermore, during programming, trapped holes in the dielectric can cause undesirable programming of nonselected cells. These undesirable phenomena are further described in an article entitled, "Degradations Due to Hole Trapping in Flash Memory Cells" by Sameer Haddad et al., IEEE Electron Device Letters, Vol. 10, No. 3, March, 1989, pages 117-119; said article being incorporated herein by reference. A further disadvantage of operation in the avalanche breakdown region is that it increases the magnitude of source current during erasure.
A fourth drawback of the source erase technique is due to electron and hole injection into the source region, causing mobility degradation on the source region. This degradation may impair the performance of the flash EEPROM cell.
A negative gate erase operation is induced by applying +5 V to the source region, a negative voltage to the control gate and 0 V to the substrate, while floating the drain of the respective memory cell. This negative voltage may be as much as -10 V. One of the advantages of the negative gate erase technique is the reduction in the source voltage to +5 V during erasure which substantially reduce the probability of high energy holes resulting in improved reliability. The other advantages of the negative gate erase technique is that it only requires a single +5 V power supply (instead of a +12 V power supply as in the case of the source erase technique) and it is insensitive to defects in the channel because all tunneling are through the small area of source to gate overlap. However, a number of drawbacks may be associated with the negative gate erase operation.
First, a negative charge pump is needed to provide the -10 V required at the control gate for erasure. Also, in case of a +3 V supply voltage operation, a positive charge pump may also be needed to provide the +5 V required for the source region during erasure. A second drawback is that the negative gate erase technique fails to provide high density EEPROM cell arrays because a double-diffused source structure is found to be necessary in many instances. Third, the after erase threshold voltage (Vt) distribution of the flash EEPROM cells is wider, which is undesirable. A tight after erase V.sub.t distribution is desirable because designed safety margins accounting for the distribution of the threshold voltages, especially sense amplifiers', can be reduced.
A channel erase operation is induced by applying a high positive voltage to the substrate and a 0 V to the control gate, while floating both the source and the drain regions of the respective memory cell. This positive voltage may be as high as +12 V. One of the advantages of the channel erase technique is that a single-diffused source structure can be used, which allows a reduction in the size of the memory cells, resulting in a flash EEPROM array with higher density. The other advantage is that a separate +12 V power supply is not needed since the substrate high voltage can be pumped from a +3 V power supply. Furthermore, since the source is floating, there is generally no high energy holes related reliability problem.
Again, a number of drawbacks may be associated with the channel erase operation. First, since the erase involved tunneling through the whole channel, the channel erase operation is very sensitive to defects found in the channel. This could lead to potential yield problems. Second, the after erase Vt distribution of the flash EEPROM cells is widest among the three conventional erase techniques, which is very undesirable.
Hence, there is a need to have a method and a flash EEPROM memory cell structure that allows erasure operation with the advantages of the conventional erasure techniques in combination, while minimizing the drawbacks associated with such conventional techniques. The present invention addresses such a need.

Flash EEPROM array with floating substrate erase operation


Digital video contrast enhancement and skin tone correction by conversion to CIECAM02 color space with lightness transformation and a skin tone probability density function of hue and saturation.

The present invention relates to digital signal processing, and more particularly to architectures and methods for digital color video processing.
Imaging and video capabilities have become the trend in consumer electronics. Digital cameras, digital camcorders, and video-capable cellular phones are common, and many other new gadgets are evolving in the marketplace. Advances in large resolution CCD/CMOS sensors, LCD displays, and high bandwidth wireless communication coupled with the availability of low-power digital signal processors (DSPs) has led to the development of portable digital devices with both high resolution imaging and display capabilities. Indeed, various cellphone models can display digital television signals. And digital television allows for more accurate color processing than with traditional analog video, and thus capabilities such as contrast enhancement to provide the high contrast images that are appealing to human eyes. Many contrast enhancement methods have been proposed for image processing applications; but they are either too complex to be used for consumer video or still cameras, or specific for different imaging applications such as biomedical imaging.
Furthermore, digital televisions have to support traditional television systems, such as NTSC and PAL. NTSC video systems are particularly susceptible to flesh tone (skin tone, skin color) errors, because the color subcarrier in NTSC may have phase errors that cause these errors. Some tint on the flesh color due to the actual display processing requires correction, as the human eye is sensitive to flesh tones as one of the important memory colors.
CIECAM02 is a color appearance model put out by the CIE. Moroney et al., "The CIECAM02 Color Appearance Model", IS&T/SID Tenth Color Imagining Conference, p 23 (2002) describes the conversion from usual color components (i.e., tristimulus pixel values) to the perceptual attribute correlates J, h, s of the CIECAM02 model. The model takes into account the viewing conditions to compute pixel J,h,s values.


A stable and high-solids aqueous dispersion of blocked isocyanates, containing auxiliary solvent, is prepared by (1) preparing a solution of a polyisocyanate mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A) and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B) in an auxiliary solvent (G) and (2) adding water to this solution, with intensive mixing, in an amount which is such as to give a two-phase system comprising a disperse polyisocyanate phase and a continuous, aqueous phase containing auxiliary solvent. In a preferred embodiment of the invention dispersions are prepared which are virtually free from auxiliary solvent, by first adding a portion of water to the solution (1), substantially removing the auxiliary solvent with intensive mixing and then adding a second portion of water with intensive mixing to the mixture comprising the polyisocyanates (A) and (B) and the first portion of water.

1. Field of the Invention
The present invention relates to stable and high-solids aqueous dispersions of blocked polyisocyanates, either containing auxiliary solvent or being virtually free from auxiliary solvent, to a process for preparing such dispersions and the use of such dispersions as cross-linkers for film-forming resins.
2. Description of the Background
Blocked (or capped) polyisocyanates are known and widely used as cross-linking agents for film-forming resins in solvent-borne coating systems. For reasons of environmental protection and, of course, of cost as well, numerous technical developments of the recent past have been directed to reducing the amount of solvent or, as is particularly desirable, at providing solvent-free or virtually solvent-free systems.
Aqueous dispersions of blocked polyisocyanates are suitable for use in single-component waterborne (or water-thinnable) coating materials, i.e. in aqueous, solvent-free or virtually solvent-free coating systems, which, in addition to the blocked polyisocyanates, which function as cross-linking agents, comprise a water-dissolved or -dispersed film-forming resin having functional groups that are able to react with isocyanate groups. Since blocked isocyanates are, in the majority of cases, solids or highly viscous substances, they can be dispersed in water only with the addition of solvents or, without solvent, only above their melting point. The disadvantages of the two processes are that, in the first case, the solvent used for dilution must be removed again after dispersion, at considerable expense, while in the case of melt emulsification, some of the blocking agent is cleaved off early at the high temperatures required, and the isocyanate groups that have been released react with water in the course of dispersion and are no longer available for cross-linking with the functional groups of the film-forming resin.
The aqueous dispersions of the blocked polyisocyanates (and, of course, those of the film-forming resins as well) should, where possible, be of high solids content. The principal advantage of high-solids content dispersions is that, with only one application, it is possible to produce thick coats having excellent properties (fullness, resistance, hiding power). Relative to multicoat applications, this means not only a saving in time and (because of the multiple stoving procedures) in energy, but also in optimizing quality, since each additional coat increases the risk of production errors. In addition, high-solids dispersions also lessen the costs of transportation and storage. The dispersions should, moreover, be stable, i.e. storable for long periods without sedimenting or coagulating to any marked extent. Should coagulation or sedimentation nevertheless occur, the deposits should be readily and durably redispersible.
Known processes for preparing stable aqueous dispersions of blocked polyisocyanates make use of external emulsifiers and protective colloids (JP 4 216 815, JP 4 216 816, JP 4 216 817 and WO 94/22935). A disadvantage of these processes is the permanent hydrophilicity of the emulsifiers and of the protective colloids, which is retained in the coatings which result on stoving by reaction of the polyisocyanates with the isocyanate-reactive groups of the film-forming resins. Consequently, these coatings have a tendency, under the effect of water, to become cloudy, to soften and/or to swell up, ruling out the use of such dispersions at least for coating materials that are to be employed outdoors.
The process that DE 24 56 469 describes for preparing aqueous dispersions starts with partially blocked polyisocyanates, which are reacted with a hydrophilicizing agent, which contains an NCO-reactive group and also a hydrophilic or potentially hydrophilic group, for example, a sulfo acid or carboxyl group. Both types of groups can be converted by neutralization into hydrophilic ionic groups, for example sulfonate or carboxylate groups. The hydrophilicizing agents used in the examples are the sodium salts of N-methylaminoethanesulfonic acid. The reaction product is then dispersed in water. A similar process is described in EP 0 012 348, where the blocked hydrophilicized polyisocyanates are not only self-dispersible, but also promote the dispersion of hydrophobic film-forming resins. In the case of these processes, however, which are not used industrially, the linking of the compound having a (potentially) hydrophilic group takes place, because of the partial blocking beforehand, at low NCO contents, which firstly requires an uneconomically long reaction time and secondly has the consequence either that not all of the free NCO groups are hydrophilically linked or, in the case of excess hydrophilicizing agent, that unreacted hydrophilicizing agent remains in the polyisocyanate dispersion.
DE 27 08 611 describes a process for preparing polyurethane prepolymers, in which polyisocyanates are first of all reacted with an excess of hydroxycarboxylic acids such as dimethylolpropionic acid, and then the free isocyanate groups that remain are blocked. These polyurethane prepolymers must have high acid numbers of  greater than 30 mg of KOH/g, since at lower acid numbers, stable dispersions or solutions can be prepared only with additional organic solvents. A disadvantage of this process is that a very considerable proportion of the original isocyanate groups is lost for cross-linking with the film-forming resin as a result of the reaction with the hydroxycarboxylic acid hydrophilicizing reagent. A further disadvantage of this process is the high viscosity of dispersions with a solids content  greater than 35% by weight, which makes processing more difficult if not virtually impossible.
EP 0 312 836 describes a process in which isocyanate groups are capped by reaction with a cyanourea salt. The hydrophilic groups thereby created participate in the cross-linking reaction in the course of stoving, and thus do not impair the density of cross-linking. A disadvantage, however, is that amines are given off during stoving, which only with difficulty leave the paint film, and, in the case of light-colored coatings, cause disruptive yellowing of the coatings.
EP 0 133 223 describes blocked polyisocyanates which are hydrophilicized by means of cyclic malonates. Curing in these systems takes place likewise through the cyclic malonate groups, with the result that the hydrophilic modification again does not cause any reduction in the cross-linking density. Detrimental to this process, however, are the considerable amounts of water-soluble organic solvent required.
EP 0 524 511 discloses a process in which nonionically modified polyisocyanates having free isocyanate groups are first of all dispersed in water and then the isocyanate groups are blocked. In the course of this reaction, however, some of the isocyanate groups react with water and are lost for the cross-linking reaction. Moreover, it is difficult to establish reproducibly the particular stoichiometric proportions that are desired.
Furthermore, EP 0 537 578 discloses a process in which blocked polyisocyanates, for textile finishing (crease-resistant finishing), are hydrophilicized with, inter alia, polyalkylene oxide units incorporated therein and are dispersed. EP 0 424 697 and DE 28 14 815 also describe dispersions of blocked, nonionically hydrophilicized polyisocyanates. These dispersions, however, are in turn permanently hydrophilic, so that coatings produced with them may turn cloudy, soften and/or swell under the action of moisture and are, therefore, unsuitable for exterior applications.
EP 0 022 452 describes a one-component polyurethane system whose hardener is a polyurethane prepolymer in which each molecule is linked with a hydrophilic modifying reagent. In addition to the loss of cross-linkable isocyanate groups, a disadvantage here is that a solvent mixture of water and alcohol is required and, in particular, that dispersions with a solids content of  greater than 40% by weight have such a high viscosity that they are difficult to process.
Finally, EP 0 566 953 and EP 0 576 952 describe specific polylsocyanate mixtures, hydrophilicized by means of hydroxycarboxylic acids, which are suitable for the curing of film-forming resins in aqueous systems. A need, therefore, continues to exist for an aqueous dispersed polyurethane system of improved stability and high solids content.
Accordingly, one object of the present invention is to provide an aqueous dispersion of a blocked polyisocyanate which is stable and has a high solids content.
Briefly, this object and other objects of the present invention as hereinafter will become more readily apparent can be attained by a process for preparing stable and high-solids aqueous dispersions of blocked polyisocyanates, containing auxiliary solvent, comprising:
(1) preparing a solution of a polyisocyanate mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A) and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B) in an auxiliary solvent (G), and
(2) adding to this solution, with intensive mixing, an amount of water which is sufficient to give a two-phase system comprising a dispersed polyisocyanate phase and a continuous, aqueous phase containing auxiliary solvent.
In an advantageous embodiment of this process, corresponding dispersions which are, however, virtually free from auxiliary solvent (G) are prepared by
(3) adding a first portion of the total amount of water used to the solution of stage (1),
(4) substantially removing the auxiliary solvent (G) from the aqueous mixture that is formed, containing auxiliary solvent, with intensive mixing, and
(5) adding a second portion of water to the remaining mixture comprising the blocked polyisocyanates (A) and (B) and the first portion of water, with the provisos that (i) the first portion of water is of a size such that the polyisocyanates (A) and (B) form the continuous phase in the mixture which remains after the substantial removal of the auxiliary solvent (G), and (ii) the addition of the second portion of water takes place with intensive mixing, at least up until the point of phase inversion.
Another aspect of the invention are stable and high-solids aqueous dispersions of blocked polyisocyanates, both containing auxiliary solvent and, in particular, dispersions which are virtually free of auxiliary solvent, which dispersions comprise, as a disperse phase, a polyisocyanate mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A) and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B), which dispersions are prepared by the process of the invention. The stable and high-solids dispersions of the blocked polylsocyanates (A) and (B) function as cross-linkers for film-forming resins.
Properties and Advantages of the Dispersions of the Invention
The process of the invention provides, surprisingly, dispersions which have an optimum combination of the following advantageous properties:
(i) The solids content is high. In the case of the systems containing auxiliary solvent, the solids content is generally at least 35 and up to 80% by weight, preferably from 35-60% by weight. In the case of the systems which are virtually free from auxiliary solvent, the solids content is generally in the range from at least 35% by weight up to 60% by weight, advantageously from 40-50% by weight.
(ii) The viscosities of the high-solids dispersions at 25xc2x0 C., despite the high solids content, are generally  less than 1000 mpaxc2x7s, with the result that they can be processed without problems.
(iii) The latent isocyanate content, i.e. the amount by weight of isocyanate groups, calculated in unblocked form, in the blocked polyisocyanate mixture comprising (A) and (B), is sufficiently high despite the hydrophilicization. It is in general  greater than 8% by weight and can be up to 15% by weight. The mean latent NCO functionality, depending on the poiyisocyanate employed, is generally in the range from 2.5-4.5 and to can be up to 6.0 or more, so that the particular requirement of high cross-linking density in the stoved coatings is ensured. The high latent isocyanate content and the high cross-linking density provide outstanding mechanical properties such as hardness and chemical resistance of product cross-linked coatings. To this extent, the coatings prepared with the dispersions of the invention are at least equal to the coatings prepared from the prior art.
(iv) When low-boiling auxiliary solvents (G) are used, they can be substantially removed by distillation. In the case of the preferred embodiment of the invention, the solvent is removed following the addition of a first portion of the total amount of water used, as a result of which the content of residual auxiliary solvent (G) in the finished dispersion, as formed by adding the second portion of water, can be reduced without difficulty to  less than 2% by weight, in particular  less than 0.5% by weight. The dispersions are, therefore, virtually free from auxiliary solvent. Contents of residual auxiliary solvent (G) of  less than 0.5% by weight are advantageous since the dispersions do not give rise to any unpleasant odor in the course of the processing.
(v) The dispersions of the invention are storable for long periods both at room temperature and at slightly elevated temperature up to 60xc2x0 C. For example, dispersions virtually free from auxiliary solvent with solids contents of from 45-50% by weight produce  less than 1% by weight of solid sediment under optimum conditions at room temperature within 6 months or at 60xc2x0 C. within 4-8 weeks. The slight sedimentation is in general, moreover, readily and durably redispersible. This good to excellent long-term stability is achieved with a minimum of hydrophilicity, namely by hydrophilicizing only part of the polyisocyanate, without the addition of an external dispersant and/or protective colloid and without the incorporation of hydrophilicizing polyoxyalkylene units and also, at least in the case of the preferred dispersions, without the addition of solvent.
(vi) The minimal hydrophilicity has the desired consequence. moreover, that the cured coatings are not very sensitive to moisture and are, therefore, also well-suited to exterior applications.
An essential feature of the invention is that the blocked polylsocyanate is a mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A) and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B). The hydrophilically modified polyisocyanates (A) apparently facilitate the dispersion of the hydrophobic polyisocyanates (B) to give dispersions having optimum properties in terms of performance, such as viscosity, particle size and hardness of the subsequent coating films, and provide long-term stabilization of the dispersions. Advantageously, the proportion of the blocked, hydrophilically modified polyisocyanate (A) is from 35-60% by weight and, in particular, from 40-50% by weight. The proportion of the blocked, hydrophobic polyisocyanate (B), accordingly, is advantageously from 40-65% by weight and, in particular, from 50-60% by weight.
The Hydrophilically Modified Polyisocyanates (A) and the Hydrophobic Polvisocyanates (B)
Both the blocked, hydrophilically modified polyisocyanates (A) and the blocked, hydrophobic polyisocyanates (B) are derived from the customary hydrophobic polyisocyanates (C) employed in paint chemistry. Instead of using only one blocked, hydrophilically modified polyisocyanate (A) and/or only one blocked, hydrophobic polyisocyanate (B), it is not infrequently possible to employ, with advantage, polyisocyanates (A) and/or (B) which are based on mixtures of different hydrophobic polyisocyanates (C). The hydrophobic polyisocyanates (C) become hydrophilically modified polyisocyanates (D) by being reacted with a hydrophilicizing agent (E) and, if desired, with a neutralizing agent (H), as explained later on. By reaction with a blocking agent (F) the hydrophilically modified polyisocyanate (D) becomes the blocked, hydrophilically modified polyisocyanate (A) and the hydrophobic polyisocyanate (C) becomes the blocked, hydrophobic polyisocyanate (B).
In principle, suitable polyisocyanates for the invention include all aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic polyisocyanates, as are described, for example, by W. Siefken in Liebigs Annalen der Chemie, 562, pages 75-136. A detailed exposition of the polyisocyanates that can be employed is given in EP 0 537 578, page 3, lines 10-45. Preferred polyisocyanates, because of the high light stability and weathering resistance of the paint films produced therefrom, include aliphatic and/or cycloaliphatic polyisocyanates having a mean molecular weight of up to about 1000 g/mol, advantageously of about 800 g/mol, and with a mean isocyanate functionality of from 2-4. Examples of these include simple diisocyanates such as 1,6-diisocyanatohexane (HDI), bis(4-isocyanatocyclohexyl)methane (HMDI), 1,5diisocyanato-2-methylpentane (MPDI), 1,6-diisocyanato2,4,4-trimethylhexane and/or 1,6-diisocyanato-2,2,4-trimethylhexane (TMDI), and also, in particular, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI). They also include dimers of uretdione structure prepared by catalytic reaction of these simple diisocyanates, principally of IPDI, HDI and/or HMDI. Another preferred class of polyisocyanates are the compounds having more than two isocyanate groups per molecule, that are prepared by allophanatization, trimerization, biuretization or urethanization of the simple diisocyanates, for example the reaction products of these simple diisocyanates such as IPDI, HDI and/or HMDI, with polyhydric alcohols (for example glycerol, trimethylolpropane, pentaerythritol) or with polyfunctional polyamines, or the triisocyanurates prepared by trimerizing the simple diisocyanates such as IPDI, HDI and HMDI. Examples of the (less preferred) aromatic polyisocyanates that may be mentioned include 2,4 and/or 2,6-diisocyanatotoluene and also 4,4xe2x80x2- and/or 2,4xe2x80x2-diisocyanatodiphenylmethane.
The Hydrophilicizing Agent (E)
As mentioned, the hydrophobic polyisocyanates (C) can be converted by reaction with a hydrophilicizing agent (E) and, if desired, with a neutralizing agent (H), as set out below, into hydrophilically modified polyisocyanates (D). Suitable hydrophilicizing agents (E) include at least one NCO-reactive group having a hydrogen that is active in accordance with the Zerewitinoff test and at least one hydrophilic or potentially hydrophilic group. Suitable NCO reactive groups, in particular include hydroxyl groups and primary and secondary amino groups. Hydrophilic groups include, inter alia, again hydroxyl groups, which are present in the hydrophilicizing agent or may come about as a result of groups present in the hydrophilicizing agent. Examples of preferred hydrophilic groups are the sulfo acid group and the phosphonic acid group. These are comparatively strongly dissociated relative to the carboxyl group and are, therefore, regarded as hydrophilic. They can be converted by neutralization into the ionic hydrophilic sulfonate and phosphonate groups, respectively, thereby raising the pH of the dispersion into the neutral or basic range, which is generally advisable. The carboxyl group is an example of a potentially hydrophilic group, since it dissociates but weakly and is, therefore, hardly hydrophilic, but is converted by neutralization almost entirely into the strongly dissociated, ionic hydrophilic carboxylate group. Another example of a potentially hydrophilic group is the tertiary amino group, which is converted by reaction (or neutralization) with an acid into the ionic hydrophilic, quaternary ammonium group. The hydrophilicizing agent (E) must, of course, only be employed in an amount such that sufficient isocyanate groups for the cross-linking reaction with the film-forming resin are retained.
A detailed description of the hydrophilicizing agents is presented in EP 0 537 578. Examples of suitable hydrophilicizing agents (E) include hydroxycarboxylic, hydroxysulfonic, hydroxyphosphonic, aminocarboxylic and aminosulfonic acids and tertiary aminoalkanols. Specific examples include glycolic acid, betaaminopropionic acid, hydroxyethanesulfonic acid, hydroxyethanephosphonic acid and N,N-dimethylaminoethanol. A particularly suitable hydrophilicizing agent (E) is dimethylolpropionic acid (DMPA), each of whose hydroxyl groups reacts with one isocyanate group and which is, therefore, able to link two molecules of polyisooyanate with an increase in the molecular weight and, if appropriate, in the NCO functionality as well. Probably as a result of steric hindrance, the carboxyl group is virtually inert with respect to the isocyanate groups under the reaction conditions.
Instead of reacting a hydrophobic polyisocyanate (C) to form a hydrophilically modified polyisocyanate (D) and mixing the latter with further hydrophobic polyisocyanate (C) for conjoint blocking, the mixture of the polyisocyanates (A) and (B) can also be produced by only partially hydrophilicizing an amount of hydrophobic polyisocyanate (C) corresponding to this mixture by reacting it with an amount of hydrophilicizing agent (E) which is such that the proportions of resultant, hydrophilically modified polyisocyanate (D) and of remaining hydrophobic polyisocyanate (C) correspond to the desired ratio of blocked hydrophilically modified polyisocyanate (A) to blocked hydrophobic polyisocyanate (B) for the finished dispersion, by converting any potentially hydrophilic groups by neutralization into ionic hydrophilic groups and by blocking the unreacted isocyanate groups of the hydrophilicizing mixture.
The Blocking of the Hydrophilically Modified polvisocyanate (A) and of the Hydrophobic Polyisocyanate (B)
The isocyanate groups of the hydrophilically modified polyisocyanate (D) and of the hydrophobic polyisocyanate (C) are blocked in conventional manner, in each case individually or, preferably, together, by reaction with appropriate blocking agents (F). Blocking is described, for example, in Progress in Organic Coatings 3 (1975), pages 73-99 and in Progress in Organic Coatings 9 (1981), pages 3-28. Use is made of the known blocking agents (F), which at from 20-120xc2x0 C. enter with isocyanate groups into an addition reaction which is reversible at higher temperatures, so that the isocyanate groups that are then freed again are able to react with reactive groups of a film-forming resin. Examples of appropriate blocking agents (F) include secondary and tertiary alcohols, phenols, C-H-acidic compounds such as malonic acid derivatives, lactams, e.g., xcex5-caprolactam and oximes. Preferred blocking agents include oximes such as formaldoxime, acetaldoxime, cyclohexanone oxime, acetophenone oxime, benzophenone oxime and, in particular, methyl ethyl ketoxime. Other blocking agents which can be used are 3,5-dimethylpyrazole and 1,2,4-triazole.
The Neutralizing Agent (H)
If a potentially hydrophilic group, for example a carboxyl group or a tertiary amino group, is introduced into the polyisocyanate by the hydrophilicizing agent (E), it can be converted by the neutralizing agent (H) into an ionic hydrophilic group. The neutralizing agent is a base if the potentially hydrophilic group is an acidic group, for example the carboxyl group, and is an acid in the case of basic potentially hydrophilic groups, for example a tertiary amino group. The bases can be inorganic bases such as ammonia or hydrazine, or organic bases. Preference is given to ammonia and to primary, secondary or tertiary amines, such as ethylamine, n-propylamine, dimethylamine, di-n-butylamine, cyclohexylamine, benzylamine, morpholine, piperidine and triethanolamine. Particular preference, because of their inert behavior relative to the blocked NCO functions, is given to tertiary amines such as N,N-dimethylethanolamine, N,N-diethylaminoethanol, triethylamine, tri-n-propylamine and tri-n-butylamine. Suitable acids preferably include carboxylic acids such as formic acid, acetic acid and benzoic acid.
The Auxiliary Solvent (G)
Preferred auxiliary solvents (G) include low-boiling inert solvents, which do not exhibit a miscibility gap with water, at least over wide ranges. These solvents have a boiling point at atmospheric pressure of  less than 100xc2x0 C. and can, therefore, be removed easily, if desired, by distillation down to a residual content of  less than 2% by weight and, in particular, of  less than 0.5% by weight, based on the finished dispersion, and reused. Examples of suitable such solvents include acetone, methyl ethyl ketone and tetrahydrofuran. Also suitable in principle are higher-boiling solvents such as n-butylglycol, di-n-butylglycol and N-methylpyrrolidone, which remain in the water-thinnable dispersion. However, they are less preferred because a particular advantage of the invention is that it is possible to prepare aqueous dispersions which are high in solids and stable even without environmentally polluting organic solvents.
The Preparation Process
Hydrophobic polyisocyanate (C) is first of all reacted with the hydrophilicizing agent (E), alone or in the presence of a catalyst. The hydrophobic polyisocyanate (C) is judiciously employed as a solution in an auxiliary solvent (G) with a solids content of from about 40-80% by weight. Suitable catalysts include organic tin salts such as dibutyltin diacetate or dibutyltin dilaurate. The reaction is started, for example, at room temperature and then the temperature is raised to up to 120xc2x0 C. in order to complete the reaction. Such relatively high temperatures may in particular be necessary when blocking is conducted without solvent. When an auxiliary solvent (G) of appropriate boiling point is used as well, the reaction mixture can be heated at reflux for a time. It is preferable to operate at a temperature from 40-100xc2x0 C. At these temperatures, the potentially hydrophilic groups of the hydrophilicizing agent (E) are generally inert, or virtually inert, with respect to the isocyanate group.
The hydrophilicizing agent is advantageously employed in an amount such that on average there is not more than one NCO-reactive function in the hydrophilicizing agent, intended for linking, per polyisocyanate molecule. In the case of dimethylolpropionic acid, therefore, not more than 1 mol of the acid is employed for 2 mol of polyisocyanate. It is advantageous to use about 1 equivalent of the NCO-reactive function that is intended for linking per mole of polyisocyanate. In each case, a mixture is formed that has statistical distribution of the hydrophilicizing groups. This mixture is regarded as a hydrophilically modified polyisocyanate (D) in the context of the invention, even if it does not include hydrophilically modified components.
To block the isocyanate functions it is also possible to treat a mixture of the resultant, hydrophilically modified polyisocyanate (D) and hydrophobic polyisocyanate (C), the latter being in turn, if desired, in the form of a from 40-80 percent strength by weight solution in an auxiliary solvent (G), with the blocking agent (F) in the stated proportion. As mentioned, the mixture to be blocked can also be produced by reacting hydrophobic polyisocyanate (C) with a corresponding excess of hydrophilicizing agent (E) and, if desired, with neutralizing agent (H). Alternatively, but less practically, the hydrophilically modified polyisocyanate (D) and the hydrophobic polyisocyanate (C) can each be blocked separatelyand the blocked products mixed. To make the mixing procedures easier it is possible in any case to add a quantity (or possibly a further quantity) of auxiliary solvent (G). Blocking takes place, depending on the blocking agent, at room temperature or judiciously at an elevated temperature of from 40-100xc2x0 C. The blocking reaction leads to a temperature-dependent equilibrium. By means of guideline experiments it is possible without difficulty to determine the optimum temperature for a given polyisocyanate mixture (C) and (D) and a given blocking agent (F). The amount of blocking agent (F) depends on the number of isocyanate functions to be blocked. It is judicious to employ stoichiometric amounts, or a slight deficit, of blocking agent (F) in order to ensure complete reaction of the blocking agent, so that neither the product nor the auxiliary solvent (G) to be recycled is contaminated with blocking agent (F).
In principle it is also possible first of all to subject hydrophobic polyisocyanate (C) to partial blocking and then to react the remaining isocyanate groups with the hydrophilicizing agent (E), to convert any potentially hydrophilic groups into ionic hydrophilic groups, by neutralization, and to mix the resulting, blocked, hydrophilically modified polyisocyanate (A) with blocked, hydrophobic polyisocyanate (B). However, this is not advantageous, since the hydrophilicization reaction requires uneconomically long times because of the relatively low concentration of isocyanate groups.
If the hydrophilicizing agent (E) has initially introduced only potentially hydrophilic groups, the solution of the blocked polyisocyanates (A) and (B), as it is or following the addition of further auxiliary solvent (G), is neutralized in order to convert the potentially hydrophilic groups into ionic hydrophilic groups. As mentioned, it is generally advisable to neutralize more strongly acidic and, therefore, hydrophilic groups as well. In both cases, the neutralizing agent (H) is employed in stoichiometric amounts or else in deficient or excess amounts. In general, from 50-130 mol % of the amount required for complete neutralization is employed. By way of the amount of neutralizing agent it is possible to influence the viscosity of the dispersion. The greater the deficit, the less viscous the dispersion. On the other hand, the ionic hydrophilic groups formed as a result of neutralization promote the dispersion of the blocked polyisocyanates, so that not less than 50 mol % of neutralizing agent should be used. The optimum amount also depends on the proportion of blocked hydrophilically modified polyisocyanate (A) to blocked hydrophobic polyisocyanate (B) and for a particular dispersion can be determined by experiments without difficulty.
To prepare aqueous dispersions containing auxiliary solvent, water, which preferably has been deionized, is added to the neutralized solution, gradually or all at once. Alternatively, the neutralized solution is introduced, again gradually or all at once, into preferably deionized water. In both cases provision is made for intensive mixing, with or without the action of shear forces, thereby promoting the development of fine, stable dispersions. Intensive mixing is brought about, for example, with a propeller stirrer or with a dissolver. It is also possible to combine the operations of neutralization and dispersion, for example by adding the neutralizing agent (H) and the water simultaneously to the solution of the blocked polyisocyanates (A) and (B), it being possible for all or some of the neutralizing agent (H) to be dissolved in the water. The amount of water is preferably such that a dispersion with a solids content of from 35-80% by weight and a continuous phase containing aqueous auxiliary solvent is formed. It depends on the nature and the amount of the auxiliary solvent (G) and on the nature, proportion and degree of hydrophilicization of the polyisocyanates (A) and (B) and can be determined without difficulty by experiments. The amount of the auxiliary solvent in the dispersion is generally less than 25% by weight.
The auxiliary solvent-containing dispersions prepared in this way have the advantage over the conventional, water-free systems of a lower solvent content. In comparison with systems containing aqueous auxiliary solvent and external emulsifiers or protective colloids, they are advantageous because the ultimate coated film is markedly more resistant to moisture and the effects of weathering. In relation to systems containing aqueous auxiliary solvent and extensively or completely hydrophilicized polyisocyanates, the present dispersions have the same advantage; moreover, they are considerably less viscous, which facilitates their processing.
The dispersions virtually free from auxiliary solvent and having a solids content of from 35-60% by weight, advantageously from 40-50% by weight, that are prepared in the above-mentioned preferred embodiment of the process of the invention are particularly desirable. To obtain them, the overall amount of water is divided into two portions. First of all, a first portion is added to the neutralized solution of the blocked polyisocyanates (A) and (B). This first portion is such that when the auxiliary solvent (G) is removed there is no phase inversion, i.e. the water remains in dispersion or in solution in the continuous polyisocyanate phase. A sharp drop in viscosity is characteristic of the phase inversion. The maximum first portion of water which still does not lead to phase inversion depends essentially onthe desired solids content of the dispersion and on the nature of the polyisocyanates, their proportion and their degree of hydrophilicization, and can be determined without difficulty by experiments. In general it is not more than 75% of the overall amount of water. The optimum first portion of water is in general from 30-60% of the overall amount. The first portion of water can, like the solution of the polyisocyanates (A) and (B), be at room temperature at moderately elevated temperature such as 30-40xc2x0 C., or else at a high temperature.
Following the addition of the first portion of water the temperature is raised, rapidly or gradually, to from 50-110xc2x0 C. under atmospheric or reduced pressure, so that auxiliary solvent (G) is removed by distillation. During this procedure intensive mixing is again provided, as described above. This promotes the formation of a fine, stable dispersion and also brings about rapid and substantial removal of the auxiliary solvent (G). xe2x80x9cSubstantial removalxe2x80x9d means that the content of auxiliary solvent (G) in the finished dispersion after adding the second portion of water is not more than 5% by weight. Then, under reduced pressure, it is possible to remove further auxiliary solvent (G) so that its content in the ready-to-use dispersion is  less than 2% by weight, advantageously  less than 0.5% by weight. However, it is more practical to remove the auxiliary solvent (G) even before adding the second portion of water, to such a substantial extent that its content in the finished dispersion, i.e, simply after the addition of the second portion of water, is  less than 2% by weight, advantageously  less than 0.5% by weight. When the auxiliary solvent has been substantially removed, the second portion of water is added, gradually, at intervals or continuously. In this case intensive mixing as described above is provided, at least to the point of phase inversion, so that the resulting dispersion is sufficiently fine and stable. The temperature of the remaining water is advantageously in the range in which the temperature of the dispersion lies, while the auxiliary solvent (G) is removed, preferably at from 60-100xc2x0 C. If superatmospheric pressure is used when adding the second portion of water, the temperature of the water may exceed 100xc2x0 C. This makes the operation of dispersion easier, especially in the case of systems of relatively high viscosity. However, it is necessary in doing this to take note of the deblocking temperatures. Following the addition of the second portion of water, the dispersion is allowed to cool with stirring.
Stable and high-solids, aqueous dispersions are obtained that are virtually free from auxiliary solvent and which on storage at room temperature for 6 months or at 60xc2x0 C. for from 4-8 weeks generally deposit less than 1% by mass of the solids they contain. This amount of solids, and any greater amounts of solids which may occasionally be deposited under suboptimal conditions, can be redispersed rapidly and durably by the action of appropriately high shear forces. Compared with aqueous dispersions that are virtually free from auxiliary solvent and have been prepared using emulsifiers or protective colloids, the present dispersions have the advantage that the ultimate coated films are more resistant to moisture and the effects of weathering. The same applies in comparison to corresponding dispersions in which there are relatively highly, or completely, hydrophilicized polyisocyanates; the latter, moreover, have a considerably higher viscosity, hindering their processing.
Using the Dispersions
The stable and high-solids aqueous dispersions of the invention, containing auxiliary solvent or virtually free from auxiliary solvent, are suitable as cross-linking agents for heatcross-linking, storage-stable one-component coating systems, preferably for producing environmentally compatible, water-thinnable polyurethane coating systems by combination with aqueous film-forming resins, i.e. aqueous solutions, dispersions or emulsions and/or other water-thinnable systems comprising polymeric resins, having on average more than 1.5 NCO-reactive groups such as hydroxyl or amino groups, in each molecule. For this purpose the dispersions of the invention are combined with aqueous film-forming resins, preferably in amounts such that there is one NCO-reactive group of the film-forming resin per NCO group of the polyisocyanate. If desired, further cross-linkers known to those of skill in the art such as melamine resins, and/or known auxiliaries, for example, additives to enhance the leveling, the gloss and/or the adhesion of the coating, are mixed in, and the finished coating material is applied as it is or following dilution with water to adjust the viscosity, to the substrate in a usual manner. The coating is preferably first of all dried and then stoved at from 100-250xc2x0 C. with elimination of the blocking agent, thereby cross-linking the film-forming resin.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.

Stable and high solids aqueous dispersions of blocked polyisocyanates


A device for programming user-defined information into an electronic device is provided. The programmer allows a user to program customized information, such as user-selected audio, video, or Internet access information into his or her programmable device. Such electronic devices include wireless telephones, pagers, and personal digital assistants. The programmer allows a user to, among other things, customize the device to suit his or her particular taste.

This application relates to electronic devices, and more particularly to a programming apparatus that allows users to program user-defined information into their electronic device.
There are many types of electronic devices available to consumers today that have the ability to produce both audio sounds and video displays. Many of these devices provide users with the ability to select and play a particular piece of audio or video. A television viewer, for example, may tune to a TV channel and watch a particular program, or connect a VCR or DVD player to the television in order to view a specific program not currently being broadcast. Similarly, an audio system user may tune a receiver to a particular radio station to hear a certain genre of music, or connect a CD or tape player to the system in order to hear specific pieces of music. In both cases, the audio and video is user-selectable.
Currently, however, there are many electronic products that offer an audio/video playing capability that are not fully user-programmable. Users of such devices (e.g., wireless or cordless telephones, pagers, personal digital assistants (PDAs), hand-held computers and the like) have to choose from a limited selection of pre-programmed information (e.g., audio clips, video clips or frames, etc.) placed there by the manufacturer. This severely limits the user's ability to customize the device to suit his or her particular taste. Furthermore, most pre-programmed audio tends to be rather generic and can be confusing when a device of a nearby user generates a sound similar to or the same as that of another user's device. Although a programmable memory within many such electronic devices could support user-defined audio, currently, no system exists for programming such information into an electronic device.
The same is true for user-defined video. For example, certain types of user-defined video information, such as video clips, frames, and other digital or analog images could be programmed into an electronic device (e.g., PDA, wireless phone, or any portable display device) and displayed at a time of the user choosing. Although a programmable memory within such a device could support user-defined video, currently, no system exists for programming such information into the device.

Methods and apparatuses for programming user-defined information into electronic devices