A method of using bias-dependent S-parameter measurements as a form of microscopy. The microscopy can be used to resolve the details of the internal charge and electric field structure of a semiconductor device. Like other forms of microscopy, the S-parameter microscopy focuses on pseudo xe2x80x9cimagesxe2x80x9d and provides a contrast in the xe2x80x9cimagesxe2x80x9d. Essentially, the images are gathered in raw form as S-parameter measurements and extracted as small signal models. The models are used to form charge control maps, through a selective method analogous to focusing. Focusing is provided by an algorithm for the unique determination of small signal parameters with contrasts provided by utilizing measured bias dependent activity to discriminate boundaries between the electrical charge and fields. As such, the system is able to accurately forecast semiconductor performance.

1. Field of the Invention
The present invention relates to a method for modeling semiconductor device technologies and more particularly to a method for modeling semiconductor device technologies, such as field effect transistors (FET), of which high electron mobility transistors (HEMT) are one type. The process of modeling a semiconductor device technology involves fully characterizing the way in which the devices operate internally. This particular method involves determining the electrical properties corresponding to the internal structure of the semiconductor device, such as magnitude, state and location of the internal electrical charges and fields using S-parameter microscopy to enable the performance of the device to be forecasted. Semiconductor device technology models enable the electrical performance of an arbitrary device fabricated with the particular technology to be projected based solely on physically-related parameters. This capability enables the performance of circuits that are built using these devices to be forecasted.
2. Description of the Prior Art
The capability to accurately forecast product yield of integrated circuits, such as microwave monolithic integrated circuits (MMIC), is an invaluable asset in semi-conductor manufacturing. Yield forecasting allows for better allocation of limited manufacturing resources; identification of yield problems; and reduced manufacturing costs. In GaAs MMIC manufacturing, the drive to produce products for new markets under reduced design costs and reduced time-to-market cycles have increased the probability for RF performance yield problems. These risks become even more acute when RF performance specifications are pushed to the limits of the semiconductor device technology in accordance with the current trend of an ever more competitive environment.
Addressing the cause of poor MMIC RF yield can be an insidious problem in that it may not be specific. In particular, RF yield problems may occur as a result of unrealized shortcomings distributed across the entire manufacturing process. The principle mechanisms which contribute to yield loss in an MMIC manufacturing process are illustrated in FIG. 1. As shown, four out of seven possible mechanisms relate strongly to RF yield loss. Factors, such as unrealistic performance specification; poor design-for-manufacturing; and process variability may individually or accumulatively reduce the RF yield, hence raising the long term manufacturing costs as well as the design to manufacturing cycle time.
Various methods are used for RF yield forecasting. For example, both statistical and empirical modeling methods are known. Statistical modeling employs device models and circuit simulation while empirical approaches uses measured data. Such statistical models include Monte Carlo statistical models, correlated statistical models, boundary models and database models. Monte Carlo statistical models allow device model parameters to vary independently of each other by Gausian statistics while correlated statistical models are known to represent more realistic statistics in which the variations are constrained with correlation between the model parameters. Long-term model databases are typically created for the purpose of process control monitoring but can also be used in yield forecasting, for example, as disclosed in xe2x80x9cA Product Engineering Exercise in 6-Sigma Manufacturability: Redesign of pHEMT Wideband LNA, by M. King et al., 1999 GaAs MANTECH Technical Digest, pp. 91-94, April 1999.
Boundary models are a set of models that represent the xe2x80x9cprocess corner performancexe2x80x9d. Boundary models are known to be ideal for quickly evaluating the robustness of a new design to an anticipated process variation. Some manufacturers are known to develop methods that directly evaluate robustness through xe2x80x9cprocess corner experimentationxe2x80x9d, for example as disclosed xe2x80x9cGaAs Fabs Approach to Design-for-Manufacturabilityxe2x80x9d, by R. Garcia, et al. 1999 GaAs MANTECH Technical Digest, pp. 99-102, April 1999. However, the boundary methods cannot be used to determine RF performance distributions that are fundamental to yield calculation. As such, this method is unsuitable for RF yield prediction.
Long-term model databases are a powerful tool for MMIC process control monitoring and typically consist of large samples of small signal equivalent circuit model extractions for single consistent device structures, measured under a standard set of bias conditions. Database models unambiguously capture true process variations through uniform sampling. Unfortunately, such models are limited to applications based closely around original measurements. For example, accurately extending a database model to represent a device with different bias conditions and layouts is problematic. Such determinations are labor intensive, as generally set forth in; xe2x80x9cA Product Engineering Exercise in 6-Sigma Manufacturability: Redesign of a pHEMT Wide-Band LNA,xe2x80x9d supra. In other circumstances, it is virtually impossible or unadvisable to apply database results, for example, to predict low noise or low signal results from a small signal model.
Monte Carlo statistics are simple to implement for RF yield simulations. However, forecasts produced by this method are relatively inaccurate and are normally used for worse case yield analysis. In particular, examples of inaccurate yield forecasts provided by Monte Carlo and correlated statistical models are shown in FIGS. 2A and 2B, which illustrate simulated versus actual noise and gain statistics for a 22-26 GHz GaAs pHEMT LNA. As illustrated, the squares and circles represent simulated data points by correlated statistical and Monte Carlo statistical models, respectively and the dashed line represents the measured data points.
Correlated statistical models provide a better method than the Monte Carlo method, however, the results from this method can also be inaccurate. Another drawback of correlated statistical models is that substantial model databases are also needed in order derive the correlation which subject method to restrictions that normally plague long-term model databases.
As mentioned above, empirical forecasting is also known to be used for forecasting RF yield. In such empirical forecasting methods, the long-term RF yield of one circuit is predicted by known process dependent RF yield characteristics of another circuit. This method can be thought of yield mapping which utilizes a linear mapping transformation between a critical RF performance parameter and the measured device process control monitor (PCM) data. This transform is known to be used to map PCM data into circuit performance space. Any distribution of PCM parameters are transformed into a distribution of RF performance. An example of such a transformation is shown in FIG. 3 which illustrates a transformation of a device PCM to MMIC RF performance space. To apply the yield map design to other circuits, an offset is included to account for differences associated with design. Such empirical methods are known to provide accurate forecasting of noise figure and small signal gain performance but not for power. An exemplary comparison of forecasted and measured noise figure performance for a 35 GHz GaAs pHEMT LNA is shown in FIG. 4 in which the forecasted data is shown with a line and measured data is shown by squares.
One drawback to yield mapping is that it cannot be used to accurately predict RF performance before the designs are produced. Instead its prediction must be refined as the design dependent offset becomes determined through feedback from the pre-production run.
Unfortunately, to accurately model the characteristics of a semiconductor device, phenomenon associated with the internal structure of the device, such as, the length of the linear conductance region; the magnitude of saturating electrical fields; the effective transit distance for saturated carriers; and the like need to be obtained. Finite element device simulations have been known to be used to calculate the internal electrical charge/electrical field structure of devices. Unfortunately, such device simulations are generally not accurate, thus providing results that are significantly different from measured device statistics. As such, there is a lack of analytical techniques that can resolve and measure electrical properties associated with the internal structure of a semiconductor device to accurately model semiconductor devices.
Briefly, the present invention relates to a method of using bias-dependent S-parameter measurements as a form of microscopy. The microscopy can be used to resolve the details of the internal charge and electric field structure of a semiconductor device. Like other forms of microscopy, the S-parameter microscopy focuses on pseudo xe2x80x9cimagesxe2x80x9d and provides a contrast in the xe2x80x9cimagesxe2x80x9d. Essentially, the images are gathered in raw form as S-parameter measurements and extracted as small signal models. The models are used to form charge control maps, through a selective method analogous to focusing. Focusing is provided by an algorithm for the unique determination of small signal parameters with contrasts provided by utilizing measured bias dependent activity to discriminate boundaries between the electrical charge and fields. As such, the system is able to provide models that accurately describe the internal electrical structure of semiconductor devices.

S-parameter microscopy for semiconductor devices


A clamping mechanism is provided for attaching an auxiliary apparatus to a weapon having a frame. The clamping mechanism has projections which are biased by a flexible member toward corresponding recessed portions formed in the frame of the weapon. A retaining member is also provided which may be moved between an open and a closed position. In the closed position, the flexibility of the flexible member is minimized, such that the projections of the clamping mechanism are locked against the corresponding recessed portions of the weapon. In the open position, the flexible member may bend away from the weapon thereby disengaging the projections of the clamping mechanism from the recessed portions of the weapon. A battery housing is also provided for receiving a battery casing which holds one or more batteries. The batteries are provided for energizing the auxiliary apparatus. The battery housing has a cavity formed therein. A recessed portion is provided in the surface of the cavity for receiving a projection formed in the battery casing. A spring member is provided for biasing the projection of the battery casing toward the recessed portion of the cavity to maintain the battery housing in a closed position.

1. Field of the Invention
The invention relates generally to an aiming assistance device and, more particularly, to attaching an aiming assistance device to a weapon.
2. Background of the Invention
The need to effectively direct weapon fire at a target is well recognized. To do this, it is helpful to be able to see the target and to be able to aim the weapon in the direction of the target. To facilitate seeing the target, numerous devices have been invented for mounting a flashlight or other illuminators on a weapon for illuminating the target area. To facilitate aiming a weapon, numerous devices have been invented for mounting a laser on a weapon, thereby creating an aim point for the weapon.
Numerous systems have been developed for attaching aiming assistance devices such as scopes, illuminators, lasers, or combined illuminator/laser units to weapons. For convenience, these devices may be referred to as auxiliary devices. These systems typically require separate brackets or other mechanical components, which necessitate tools, e.g. screwdrivers, coins, or bullets, for attaching and detaching the device itself or the mechanical component. Alternatively, attaching and detaching the devices or mechanical components requires partial disassembly or modification of the weapon. Further, such systems typically require use of two hands to mount the device on the weapon, both hands performing a function beyond merely gripping the weapon. This requirement presents several disadvantages. For instance, the user may be forced to remove his trigger hand from the trigger area of the weapon. Moreover, attachment and detachment of these devices is relatively time consuming.
As a result of these and other problems with conventional aiming assistance devices, the user typically leaves the auxiliary device mounted on the weapon or performs a time consuming operation to mount the device when needed. These alternatives are undesirable. For example, if the device is left mounted on the weapon, it cannot be used independently of the weapon despite the fact that many situations call for illuminating an area without pointing a weapon toward that area. Also, in the context of handguns, for example, holsters are not readily available to accommodate weapons having such devices mounted thereon. Thus, it is often difficult to carry a weapon having such a device attached to it. This presents special problems for law enforcement officers. Additionally, the user may not want to use the device during daylight hours, but may want to attach the device to a weapon at night. Further, the user may want to be able to readily remove the device when it is no longer needed. Moreover, depending on the configuration of the device, the user may need to replace its batteries. Preferably, the user should be able to perform this procedure quickly without the need for tools.
Another problem with conventional auxiliary devices is that the device is often much wider than the weapon or the device protrudes substantially beyond the front end of the weapon. These characteristics often result in subjecting the device to greater wear and tear because the device often contacts various obstructions in the environment where the weapon is being used. For instance, a device extending substantially beyond the end of a barrel of a weapon may catch on doorways, clothing, tree branches, or other objects tending to tear the device apart from the weapon and possibly damaging, or rendering inoperable, the device or the weapon itself. Another problem is that an assailant may more easily disarm a user by grabbing an aiming device which extends substantially beyond the weapon. The danger of these and other problems occurring would be particularly great at night or when ordinary vision is otherwise impaired.
Additionally, many prior auxiliary devices, especially illuminators, are bulky. This characteristic is undesirable.
These disadvantages are not intended to be exhaustive, and those with ordinary skill in the art will appreciate that other disadvantages of conventional auxiliary devices and systems for attaching those devices are readily apparent.


A sprinkler comprising a plurality of horizontally extending chambers each including a plurality of spray nozzles oriented at different angles, a drive for cyclically driving the sprinkler about its horizontal axis, and water-steering means for selectively steering the water to the plurality of chambers while the sprinkler is cyclically driven about its horizontal axis. In one described embodiment, the plurality of chambers are oscillated about the horizontal axis of the sprinkler; and in other described embodiments, the plurality of chambers are rotated about the horizontal axis of the sprinkler.

The present invention relates to sprinklers. It relates particularly to the oscillator type sprinkler which includes a water distributor tube carrying a plurality of spray nozzles along its length oriented at different angles in order to distribute the water over a wide area. While the invention is particularly useful in the above-described oscillator-type sprinkler, it can also advantageously be used in a rotary-type sprinkler, as will be apparent from the description below.
One of the advantages of oscillating sprinklers is that they produce a rectangular wetting pattern, as distinguished from the conventional rotatable sprinklers which produce a circular wetting pattern. However, because of the large number of spray nozzles fed by the oscillating water distributor tube, such oscillating sprinklers require a relatively high pressure in the water supply line in order to wet a given size area. Thus, if the water pressure of the supply line is not sufficiently high, the range of the sprinkler may be substantially restricted. In addition, because of the large number of nozzles fed from the oscillating water distributor, the nozzles must be of relatively small diameter, thereby producing small-diameter spray jets having not only a relatively short range, but also relatively high wind and evaportation losses. Moreover, at high pressure the jet streams become mist, which thereby shortens the spray range and reduces substantially the sprinkler coverage.
An object of the present invention is to provide a sprinkler having advantages in the above respects.


A receiving apparatus for SNR estimation of a signal such as the LTE PUCCH, transmitted over a channel of an OFDM wireless communication system.

In Long-Term Evolution (LTE) by the 3rd Generation Partnership Project, the Radio Access Network is optimized for packet-oriented applications with low latency and high-peak rates. In order to guarantee that the packets are correctly delivered to the upper layers, LTE employs a combination of Automatic Repeat Request and Forward Error Correction, also known as Hybrid-ARQ, which must be fed back to a base station. In the uplink, the uplink control channel called the physical uplink control channel (PUCCH) is associated with the transmission of Channel Quality Indicators, Hybrid-ARQ acknowledgements and scheduling requests. Within the PUCCH, multiple User Equipments can share the same time-frequency resources, the User Equipments being multiplexed via Code Division Multiplexing in the frequency domain and in the time domain, simultaneously. For Channel Quality Indicators information, for instance, Code Division Multiplexing is achieved by cyclically shifting a code exhibiting Constant Amplitude Zero Autocorrelation property. This is based on the fact that cross-correlation is null among cyclically shifted Constant Amplitude Zero Autocorrelation codes.
LTE PUCCH determines a signal to noise ratio (SNR) or Signal to Interference-plus-Noise Ratio (SINR) associated with each User Equipment. LTE PUCCH SNR or SINR may then be used as a reference value during power control procedure. Accurate estimation of the SNR/SINR ensures that each User Equipment can appropriately adjust its transmitting power so as not to unduly generate interference over other User Equipments and also avoids unduly wasting battery power. LTE specifications do not specify how LTE PUCCH SNR/SINR should be determined. Conventional methods usually determine separately the noise power level and the signal power level associated with each UE, each being derived based on estimates of the channel over which the LTE PUCCH signal was transmitted. Unfortunately, such methods tend to be inaccurate where timing errors are experienced due to the fact that orthogonality between CAZAC codes is often lost in Orthogonal Frequency Division Multiplexing (OFDM) systems such as LTE. In such cases, timing errors can cause a linearly growing phase error within OFDM symbols which ultimately impair the accuracy of the LTE PUCCH SNR.
This situation is problematic, mostly where several User Equipments are piggy-backed by the PUCCH, since the combination of a plurality of timing errors has the effect of limiting the capacity of the PUCCH carrying more User Equipments at the same time.
Therefore, it would be desirable to have a solution that would determine the PUCCH SNR/SINR without suffering from the negative impact of the timing errors.

Method and apparatus for SNR estimation apparatus in OFDM systems

Abstract: The proposed apparatus brings determines the noise power level in the frequency domain based on a noise covariance matrix where timing errors are back compensated in the equation since timing error is expressed a complex exponential therein. Contrary to the common methods used for determining the noise power level, in the present invention deriving the channel estimate components from the pilot symbol(s) comprised in the received signal is not required.

Abstract: Based on the present invention, user's transmit power is reduced thereby improving battery power longevity. Further, since interference is reduced, more users may be multiplexed together in the same resources.

Abstract: A method and a computer program product are also claimed.


A plate-link chain composed of a plurality of plates that form plate sets, which are connected to an adjacent plate set with a hinge joint. At least some of the plates have a stopping means that limits bending of the plate-link chain in a direction opposite to the bend direction the chain undergoes when it passes over and around a pulley or a gear with which the chain comes into contacting engagement when the pulley or gear rotates.

1. Field of the Invention
The present invention relates to a plate-link chain composed of a plurality of plates that form plate sets, which are connected to adjacent plate sets with a hinge joint.
2. Description of the Related Art
Plate-link chains are used in transmissions, for example those having continuously variable transmission ratio properties (a continuously variable transmission or CVT). The chain is positioned between pulleys in the form of pairs of conical disks having a variable spacing between the disks of a disk pair, or as a toothed plate-link chain in combination with gears. Chain strand vibrations arise through the effects of forces acting on the chain links as the chain runs onto or off of a sprocket in the toothed plate-link chain transmission, or onto or off a pulley in a CVT transmission. Strand vibrations here mean transverse vibrations of the chain between the pulleys or sprockets. The impacts of the tooth flanks in a toothed plate-link chain in combination with the polygon effect of the link chain excites the chain strand to vibration. A similar thing happens with plate-link chains in CVT transmissions between the rocker member faces and the pulleys. As a result of the entry impulses as the toothed plates enter as a toothed plate-link chain meshes with the gear, vibrations can occur which can reach various frequencies, depending upon the speed of the chain. Such vibrations can have a negative effect on the acoustic behavior of such a chain drive. To prevent those unwanted effects on the acoustic behavior of the transmission, it is possible to install within the transmission additional remedial measures, such as, for example, sliding rails or damping elements. Such measures require additional construction space, however, and also increase the production costs.
Reducing chain strand vibrations by applying measures to the chains is known. For example, U.S. Pat. No. 1,780,040 describes a toothed plate with a right-angle bend on the back. That arrangement blocks the vibration of the chain in one direction. The plate can also be designed as a guide plate. A disadvantage of that solution is the very stiff implementation of the plates, especially in the back region, which results in an increase in the plate rigidity and as a consequence an increase in the tensile stresses at the openings in the plate that receive the hinge pins. An additional disadvantage is the increased construction space required by the chain because of the offset bend, and expensive production costs for the individual plates.
One object of the present invention is to provide plate-link chains that are simple and inexpensive to produce, and that also reduce chain strand vibrations. Another object is to provide a plate-link chain that allows additional damping measures such as sliding rails or damping elements to be dispensed with, so that the requisite construction space and the costs of producing a transmission can be reduced.

LuK Lamellen und Kupplungsbau Beteiligungs KG


The present invention provides a low-cost MEMS functional device by improving air tightness of a jointed section by anode junction in wafer level packaging for MEMS based functional devices. The MEMS functional device comprises a function element section formed by processing a substrate mainly made of Si, a metallized film for sealing formed around the functional element, and a glass substrate jointed to the metallized film for sealing by anode junction. Formed on a surface of the metallized film for sealing is a metallized film containing at least one of Sn and Ti as a main component.

1. Field of the Invention
The present invention relates to a functional device based on the MEMS (Micro Electro Mechanical Systems). The MEMS is used for manufacturing high-frequency filters, various sensors, actuators, and the like by etching a substrate including Si as a main component.
2. Description of the Related Art
In the field of MEMS, functional devices such as high-frequency sensors, acceleration sensors, angular velocity sensors, and actuators are manufactured by processing a base material including Si as a main component using the etching technique. The base material may comprise a Si wafer or a wafer including an insulating layer (the wafer is called as SOI (Silicon on Insulator)).
A SAW (Surface Acoustic Wave) filter is typically used for a typical high-frequency filter used for cellular phone and the like. Recently, a FBAR (Film Bulk Acoustic Resonator) filter is also used. When the SAW filter is manufactured, a functional device is formed on a substrate of a piezoelectric element, while a functional device in the FBAR filter is manufactured by forming a piezoelectric membrane on a substrate including Si as a main component. To ensure property and reliability of the functional device in these high-frequency filters, the function element section needs to be sealed air-tight.
In sensors for acceleration based on the MEMS, a first method of forming a functional element is to measure acceleration loaded to an entire device from a change in movement of the functional device. In this case, a spindle-shaped or comb-like electrode is used through etching. In a second method, acceleration is read from a change in resistance generated because of distortion loaded to a resistor previously formed on a beam. In this case, a through-hole is provided by etching a substrate containing Si as a main component, and a spindle is held via a thin beam to form a resistor on the beam. Even in either method is adopted, because movement of an electrode or a spindle is influenced by an air pressure within a package, air-tight sealing for the package is required. Furthermore there has been developed, as a third method, a method for detecting acceleration by measuring temperature distribution within the functional device with a temperature sensor. In this case, a hollow structure is formed on a substrate containing Si as a main component, and a thin, net-like beam is formed on the hollow structure. A temperature sensor is formed at a prespecified position on the beam, while a heat source is formed on a portion of the beam. Thus, in the state where a gas inside the package is heated by the heat source, when acceleration is loaded, the gas flows in the package. By measuring the temperature distribution in such a state, the loaded acceleration is detected. Also in the functional device having the configuration as described above, air-tight sealing is required for the package.
In any case, air-tight sealing for the package is indispensable for maintaining the performance in sensors having a movable section like the MEMS or a high-frequency filter.
Examples of a conventional technique for providing air-tight sealing include a method in which a functional device is provided on a ceramic package and a cover made of metal, ceramics, glass or the like is connected to the functional device with solder or glass having a lower melting point. In the methods, however, the functional device is packaged discretely.
Recently, contemplation of completing air-tight sealing for the MEMS functional device in a wafer state has been made as a method of reducing the packaging cost for the MEMS-based functional device. To achieve the objective, it is necessary to joint another water to a substrate containing Si as a main component with a functional device formed thereon and seal the jointed portion air-tight. Such an example is described, for instance, in DIGEST OF TECHNICAL PAPERS 2002:IEEE International Solid-State Circuits Conference 0-7803-7335-9/02/2002 IEEE (Non-patent document 1)


A bi-phase shift keying signal demodulation circuit for an RDS receiver receives RDS modulation signal and reproduces RDS data from the RDS modulation signal. The RDS modulation signal is produced by modulating a sub-carrier by a signal modulated by a bi-phase shift keying modulation using the RDS data. The bi-phase shift keying signal demodulation circuit includes: a clock reproducing unit for reproducing an RDS clock signal from the RDS modulation signal; a multiplying unit for operating a logical product of the RDS modulation signal and the RDS clock signal; a phase comparison unit for comparing the phase of the output signal of the multiplying unit with a synchronizing signal of the sub-carrier and producing a phase comparison signal; a pulse converting unit for converting pulses in the phase comparison signal into pulses of higher frequency than that of the phase comparison signal; and an integration/reset unit for monitoring the converted phase comparison signal at every period of the RDS clock signal for phase judgement and producing a bi-phase shift keying demodulation signal from which the sub-carrier component is removed.

1. Field of the Invention
This invention relates to a bi-phase shift keying signal demodulation circuit for an RDS (Radio Data System) receiver which receives multiplexed data of RDS signals inclusive of digital messages such as information used for selection of broadcasting stations.
2. Description of the Prior Art
As a traffic information system for relieving a traffic snarl, there is known an ARI broadcasting system. In the ARI broadcasting system, a sub-carrier of 57 kHz is constantly multiplexed into an FM radio wave of a broadcasting station so as to identify the station which is broadcasting traffic information. In addition, in that system, a DK signal and a BK signal, obtained by amplitude-modulating the sub-carrier by predetermined frequencies, are multiplexed into the radio wave so as to provide information relating to a beginning or end of the traffic information, or a region in which traffic information is broadcasted.
As a similar system, there is known an RDS system in which digital data identifying broadcasting stations, etc., are multiplexed into an FM radio wave using a sub-carrier of 57 kHz. Data to be multiplexed in the RDS system is configured by a plurality of groups consisting of 104 bits data, and various messages mainly used for the selection of broadcasting station are standardized. The transmission rate of RDS data is 1.1875 kbit/sec, and RDS data is encoded by a differential encoding. Then, a clock signal of 1.1875 kHz is modulated by a bi-phase shift keying using the encoded data. Further, a sub-carrier of 57 kHz is modulated by a carrier suppressed amplitude modulation using modulated data of bi-phase shift keying. Double sideband (DSB) signals of the modulated data are multiplexed to audio data, and the multiplexed data is transmitted. A sub-carrier of RDS data is designed so as to be in phase or in orthogonal phase (shifted by 90 degrees) with the third harmonic of a pilot signal (19 kHz) indicating a stereo broadcasting. When it is required to maintain coexistence of the ARI signal and the RDS modulated signal, the two signals are multiplexed so that the frequencies thereof are equal to each other and the phase relation of them becomes orthogonal with each other (shifted by 90 degrees).
RDS data is obtained by demodulating the RDS modulation signal according to the following manner. Firstly, the RDS modulation signal is extracted from an FM modulation signal using a band pass filter, and a bi-phase shift keying signal is obtained from the extracted signal by a PLL (Phase Locked Loop) synchronization detection. Simultaneously, a synchronization signal of sub-carrier is also generated by the PLL synchronization detection. Then, an RDS clock signal is extracted from the bi-phase shift keying signal and the bi-phase shift keying signal is demodulated using the extracted RDS clock signal. Then, a synchronization detection circuit operates a logical product of the demodulated bi-phase shift keying signal and the synchronizing signal to produce a bi-phase shift keying signal. Then, the RDS data is decoded from the bi-phase shift keying signal by a differential decoding.
In the above described RDS receiver, when the phase relation between the synchronizing signal of the sub-carrier and the sub-carrier component of the bi-phase shift keying modulation signal is stable, the demodulation performance is kept stable. However, in the synchronizing detection, an error component due to jitter is produced when an intensity of the electric field in a received signal is weak. In addition, when an ARI signal is transmitted with an RDS signal, the PLL synchronizing detection circuit locks with the ARI signal whose degree of modulation is higher than that of the RDS signal. In this case, the error component due to jitter increases. As a result, the phase relation between the synchronizing signal and the sub-carrier component of the bi-phase shift keying modulation signal becomes unstable and the RDS data is reproduced erroneously.

Bi-phase shift keying signal demodulation circuit for RDS receiver


The invention concerns catheterization assemblies designed to reduce the risk of infection, transmission of bloodborne pathogens, loss of blood, and development of embolisms in a patient. Embodiments of the invention are directed to a catheterization assembly having a catheter hub with multiple access ports. In some embodiments, the catheter hub is permanently attached to a catheter and a valve. The catheter hub provides fluid communication between the valve and the catheter. The catheter hub may also be provided with a sealing member that provides access to a fluid passageway of the catheter hub but which prevents leakage of fluids from the catheter hub. In other embodiments, the catheter hub includes a passageway and an air vent for allowing air to pass out of the catheterization assembly.

1. Field of the Invention
The invention relates generally to vascular access devices such as catheter assemblies. The invention is particularly directed to a catheterization assembly designed to reduce the risk of infection, transmission of bloodborne pathogens, loss of blood, and development of embolisms in a patient. The catheterization assembly incorporates a catheter hub that has multiple access ports for allowing air to exit the catheterization assembly, providing fluid communication between a valve and a catheter, and enabling insertion and removal of a catheter introducer without leakage of body fluids from the catheterization assembly.
2. Description of the Related Art
In current medical practice, it is often necessary to have access to the venous system of a patient. For example, it is a common procedure to obtain diagnostic information about the heart or its vessels by inserting a tube (a "catheter") into a vein of the patient and withdrawing blood. Oftentimes, catheterization is necessary to deliver fluids such as medications into the patient's venous system. Additionally, it may be necessary to aspirate fluids from the catheter site to evaluate blood profiles, perform diagnostic assays, etc.
Typically catheterization is conducted by inserting a needle, or other introducer, directly into a patient's vein and pushing or threading a catheter through the entry site created by the needle. Conventional catheterization practice has been to introduce the catheter into the patient's vein and then to attach a secondary component, such as an injection port with a sealed septum, to the catheter to prevent blood leakage, minimize catheter clotting, and to facilitate the introduction of medications or aspirate fluids. In this case the introduction or aspiration of fluids is accomplished by utilizing a needle to penetrate the septum thereby accessing the patient's vasculature via the catheter. The needle is generally inserted into a sealed entry port.
Since the early 1990's, infection by bloodborne pathogens has become a serious concern to health care workers and patients alike. HIV/AIDS and various forms of hepatitis have caused a dramatic shift in the way medical devices are constructed. The elimination of needle sticks and blood contact have been the primary design changes. However, many devices currently marketed as "safety" devices fall short of the goal of preventing the transmission of bloodborne pathogens.
Any device connected to the patient's bloodstream should not have an exposed fluid reservoir due to the potential for bacterial infection from contact with a tainted object. If the fluid reservoir or cavity is not cleaned, then there is a potential for developing bacteria in the fluid reservoir. The bacteria could be introduced into a patient's bloodstream when the device is subsequently used to administer new medications to or aspirate fluids from the patient. Additionally, there is a risk of blood coagulating in the catheter and possibly in the injection apparatus; hence, these components must be frequently replaced thereby creating possible medical complications as well as additional discomfort, pain, and cost to the patient.
Turning in particular to the case of catheters, certain catheters such as Peripherally Inserted Central catheters ("PICCs"), Midline ("Mid") catheters, and Peripheral catheters can remain in a patient for hours or in some cases as long as 180 days. During the course of treatment with a catheter, a patient's venous system may be accessed a number of times to either remove or introduce fluids.
The traditional PICC, Mid, or peripheral catheter is constructed of a length of tubing terminating at the proximal end with a female luer hub (a "catheter hub"). The primary difference between these three catheters is the length of the tubing. The rationale for different lengths is based on the type and duration of the therapy a patient is to receive.
The insertion of these catheters into a patient's venous system can differ procedurally. The peripheral catheter, being the shortest of the three types and measuring about 3.5″ in length, is often inserted into a patient's vein through the use of a needle disposed within the catheter tube. These types of catheters are frequently referred to as "over-the-needle catheters." The peripheral catheter is percutaneously inserted into a peripheral vein and terminates in the same peripheral vein. After insertion, the needle is removed, leaving the catheter in the vein. Often, blood will flow out of the back of the luer hub and expose the health care worker to blood contact. Usually, a second component commonly referred to as a "J-loop" is attached to the catheter hub.
A J-loop is a tube approximately 6″ in length and is often configured with an injection cap, luer fitting, or needle free valve at its proximal end. Typically, the J-loop is also configured with a male luer fitting at its distal end for attachment to other devices. The J-loop primarily functions to allow handling of injection ports or fluid flow regulating devices away from the point of insertion of the catheter into the patient. Without the use of a J-loop, manipulation of an injection cap, for example, connected directly to the catheter hub would likely result in the inadvertent dislodging of the catheter from the patient. When the J-loop is not supplied with some terminal connector the health care worker must supply one in order to prevent leakage of bodily fluids from the J-loop, or to provide an access port to the catheter via the J-loop.
The PICC and Mid are inserted in a similar fashion. Typically, an introducer is placed into the vein first. The introducer is a thin splittable tube whose internal diameter (ID) is closely matched to the outside diameter (OD) of the internally disposed needle in much the same way as described with reference to the peripheral catheter. Once the introducer has been placed in the vein, the needle is removed and again, blood can be seen to come out of the proximal end of the introducer. The introducer will remain in place and acts as a conduit for threading the PICC or Mid catheter into the patient's vein. Once the PICC or Mid catheter is in the vein, the introducer is removed, and blood can often escape from the hub of the catheter.
Thus, to date, there is an absence of safety devices on the market which reduce or prevent the risk of exposure to bloodborne pathogens to health care workers during and after catheter insertion.
It has also been recognized that known catheterization devices contribute to the incidence of transmission of nosocomial infections to a patient undergoing catheterization. Since 1970, the Center for Disease Control (CDC)'s National Nosocomial Infection Surveillance System (NNIS) has been collecting data on the incidence and etiologies of hospital acquired infections. The majority of hospital-acquired bloodstream infections are associated with the use of a catheter, particularly central venous catheters.
Today, catheter maintenance requires many manipulations of the catheter. For example, every three days, injection caps, valves, and tubing must be replaced. In so doing, the health care worker can inadvertently expose the patient to nosocomial infections caused by bacteria, viruses, and/or fungi. Each and every manipulation that opens the catheter's closed system exposing it to airborne bacteria and touch contamination is a potential source of danger to the patient. Types of organisms that most commonly cause hospital-acquired bloodstream infections include, Staphylocooccus aureus, Candida spp., Escherichia coli, Pseudomonas aeruginosa, Acinetobacter calcoaceticus, and Klebsiella pneumoniae. These microorganisms can infect the patient's bloodstream and, in extreme cases, sepsis and death can result.
The known catheterization devices typically lack features to reduce the risk to the patient of an air embolism. The insertion of a central catheter exposes a patient to the possibility of "sucking" air through the catheter into the patient's bloodstream. This risk can result in death or serious injury to the patient.
Moreover, the known catheterization assemblies often increase the cost of medical care. In today's market, as stated earlier, PICCs can often be in a patient for periods of time up to 180 days. Valves are attached to these catheters to allow for the introduction of drugs, diagnostic agents, etc. Because the valves are detachable, the Center for Disease Control ("CDC") dictates that these valves must be replaced every 72 hours. Valves typically cost approximately $1.50/each (USD). Over a 180 day period, on average, sixty valves must be replaced at a cost of nearly $90.00 (USD). Accordingly, there is a need for catheterization assemblies having valves which prevent blood backflow and which are not required to be replaced periodically to reduce health care costs.
Consequently, there is a constant need in the relevant technology for improved safety devices which prevent or reduce the risk to the patient of transmission of bloodborne pathogens, loss blood, infection, or air embolism in the course of insertion and use of catheter devices. Additionally, affordable safety devices would be a great benefit to both the patient and medical community.

Closed system catheterization assembly and related methods


An operator control system for a self-propelled vehicle such as a lawn mower is provided wherein the control system includes two opposing and preferably upwardly extending and converging hand grips each having a corresponding drive control lever associated therewith. Each drive control lever may have at least a portion that is parallel to a grip axis of its respective hand grip. Further, each drive control lever may have a pivot axis that is substantially parallel to the corresponding grip axis such that the drive control lever remains substantially parallel to its respective hand grip throughout its travel. In some embodiments, a neutral lock is provided to permit locking of each drive control lever in at least one position, e.g., a neutral position. Secondary levers such as operator presence control (OPC) levers may also be included. In one embodiment, an OPC lever is associated with each hand grip.

Various types of lawn mowers are known. For example, small, walk-behind mowers are in general use by both homeowners and professionals alike. At the other end of the spectrum are large, riding mowers adept at mowing correspondingly large and typically unobstructed areas. Between these two categories lies what are commonly referred to as "mid-size" mowers.
Generally speaking, mid-size mowers are self-propelled units having a cutting width of approximately 36-60 inches. While they may be configured as either riding (including ride-on and ride-behind) or walk-behind units, walk-behind mowers potentially offer greater maneuverability. For example, walk-behind mowers are particularly efficient when mowing large lawns having numerous obstacles (e.g., trees, shrubs, flowerbeds, and the like) which necessitate intricate trimming, or when mowing lawns which may otherwise be ill-suited to high-speed riding mowers. Moreover, walk-behind mowers are often used in areas with steep slopes which may pose traction or tipping problems for riding mowers. Furthermore, mid-size, walk-behind mowers are also, in general, less expensive than riding mowers. While the present invention is directed to control systems for use with either riding or walk-behind vehicles, it will, for the sake of brevity, be described with respect to mid-size, walk-behind mowers.
One type of control system known for use with mid-size mowers uses two rearwardly extending handles each equipped with a scissors-type lever. Each lever operatively controls one of two drive wheels typically located at or near the rear corners of the cutting unit. Where the levers are configured as "normally engaged," actuating (e.g., squeezing) one of the drive levers causes disengagement and/or braking of the corresponding drive wheel, permitting the mower to turn about that wheel. Alternatively, the levers may be "normally disengaged" such that actuating (e.g., squeezing) one of the drive levers causes engagement of the corresponding drive wheel.
While scissors-type lever control systems are more than adequate for their intended purpose, drawbacks remain. For instance, scissors-type levers, in general, may provide limited mechanical advantage in overcoming lever tension. Accordingly, when cutting a lawn with many trees, shrubs, or other obstacles that necessitate numerous turns, discomfort in the hands, wrists, and arms may occur. Scissors-type lever control systems may also be susceptible to variation in lever tension over the lever travel. Furthermore, depending on the position of each lever within its throw, the operator may not be able to grasp the respective lever with all fingers.
Other systems are also known. For example, U.S. Pat. No. 5,511,367 to Powers et al. and U.S. Pat. No. 5,809,755 to Velke et al. disclose control systems having a generally transverse hand position. While addressing some of the above-identified problems, other issues with hand position and/or control actuation potentially remain.

Operator control system for self-propelled vehicles

Exmark Manufacturing Company, Incorporated


A nutrition infusion is provided for administration through a peripheral vein that contains a vitamin B group and vitamin C stably and includes two solutions of a sugar solution and an amino acid solution. In the nutrition infusion for administration through a peripheral vein, the sugar solution contains vitamin B1, vitamin B12, and pantothenic acid and has a pH of 4.7 to 5.5, and the amino acid solution contains vitamin B2, folic acid, vitamin C, and biotin and has a pH of 7.0 to 7.5.

In order to supply nutrients vital for sustaining life, such as carbohydrates, amino acids, and electrolytes, to a patient who cannot be supplied with nutrients orally or is insufficiently supplied with nutrients orally, intravenous nutrition therapy in which an infusion is administered through a vein is widely performed. The intravenous nutrition therapy is roughly classified into central venous nutrition therapy and peripheral venous nutrition therapy, by the route of administration.
In the central venous nutrition therapy, an infusion high in calories is administered through the central vein for a relatively long time. Accordingly, it is necessary to appropriately add vitamins and trace elements that could become deficient during the period of administration. In clinical practice, vitamin formulations and trace element formulations are added at the time of use by being mixed in the infusion. However, the mixing operation is cumbersome, and there is a concern that bacterial contamination or ingress of foreign substances will be caused by the mixing operation, which may be a cause of medical malpractice. Therefore, regarding a high-calorie infusion for administration through a central vein that is used for a long time, a formulation which contains reducing sugar, amino acids, electrolytes, and vitamins and in which solutions can be mixed in a sterile state is under development and has been commercialized. For example, PTLs 1 and 2 and NPLs 1 and 2 disclose an infusion formulation for central venous nutrition that is mixed with vitamins.
On the other hand, in the peripheral venous nutrition therapy, a nutrition infusion containing about 30% to 60% of the calories administered by the central venous nutrition therapy is administered through the peripheral vein. Duration of administration thereof is relatively short, such as 3 days to 2 weeks, and initially, mixing of vitamins was not particularly considered for the peripheral venous nutrition therapy. However, it is reported that the vitamin B1 concentration is reduced during the peripheral venous nutrition therapy (NPL 3). Vitamin B1 deficiency is highly likely to cause serious side-effects such as lactic acidosis, and accordingly, in order to improve safety, a nutrition infusion formulation for peripheral vein administration mixed with vitamin B1 in advance is reported (PTL 3). In addition, several formulations have been commercialized (NPLs 4, 5, and 6).
In recent years, it has been a reported that deficiency of vitamins other than vitamin B1 can be potentially caused in patients receiving infusion through a peripheral vein, and that it should be considered that the infusion for a peripheral vein should also be mixed with plural vitamins that are particularly necessary for the metabolism of sugar and amino acids (PTL 4).
However, each of the components including reducing sugar, amino acids, electrolytes, and vitamins shows sufficient stability or solubility in different pH regions. On the other hand, regarding the nutrition infusion for administration through a peripheral vein, if the pH of infusion is acidic at the time of administration, phlebitis or angialgia is easily caused, so it is desired that the pH be neutral. In addition, some of the respective components interact with each other. Therefore, in consideration of this point, a stable nutrition infusion for administration through a peripheral vein mixed in advance with vitamins is desired.
For example, folic acid causes turbidity in the acidic region of a sugar electrolyte solution, and even when mixed with an amino acid solution, folic acid causes incompatibility if vitamin B2, vitamin C, and the like coexist, so it is difficult to obtain a stable formulation. Therefore, for the infusion for administration through a central vein mixed with vitamins, which is used for the central venous nutrition therapy, a third chamber separated from the sugar electrolyte or amino acid solution is provided to separate the folic acid from the sugar electrolyte solution or vitamins B2 and C, so as to stabilize the infusion (PTL 2, NPLs 1 and 2). In addition, there is a disclosure regarding a method of mixing vitamins with an infusion for administration through a central vein that includes two solutions of a sugar solution and an amino acid solution. However, in this infusion, pH of the sugar solution and amino acid solution is 3.5 to 4.5 and 5.0 to 7.0, respectively, so the pH of the both solutions is acidic (PTLs 5 and 6). Moreover, regarding a nutrition infusion for administration through a peripheral vein, PTL 4 discloses an infusion for administration through a peripheral vein that is mixed with a vitamin B group, which is obtained by mixing vitamin B12 in an amino acid solution not containing sulfite, and mixing vitamin B1 in a sugar solution. However, PTL 4 discloses that since vitamin C, biotin, pantothenic acid, and the like sometimes decompose other vitamin B groups, it is preferable to add those components immediately before the administration.

Vitamin-containing nutrition infusion for administration through peripheral vein


The cylinders of a two-stroke cross-head marine diesel engine characterised by a power output of 4,000 kW per cylinder or greater are lubricated by a cylinder lubricant comprising a basestock of lubricating viscosity, on overbased metal detergent and an oil-soluble sulfur-containing compound or phosphorus-containing compound, thereby to raise the onset temperature of scuffing-type mechanical wear of the cylinder walls.

This invention relates to the lubrication of the cylinder or cylinders of a cross-head marine diesel (compression-ignited) engine for raising the temperature of the onset of scuffing-type mechanical wear of the cylinder walls of the engine during its operation.
One type of marine diesel propulsion engine is characterised as a slow speed, two-stroke engine which is frequently referred to as a cross-head engine because of its construction. The firing cylinder and crankcase are lubricated separately by cylinder and system oils respectively. The cylinder oil, sometimes referred to as a marine diesel cylinder lubricant (MDCL), is fed to the internal walls of the cylinder by injection and, unlike the system or crankcase oil, is consumed.
xe2x80x9cThe Motor Shipxe2x80x9d, May 1999 pages 27-33, reports the emergence of a new generation of large bore cross-head marine diesel engines, the cylinders of which are subjected to higher gas pressures and temperatures then hitherto in order to improve engine efficiency. The article states that this has given rise to xe2x80x98disastrousxe2x80x99 instance of scuffing, that is to say adhesive wear of the internal walls of the cylinder, for example defined by cylinder liners, due to thinning of the lubricant film between the piston and the wall under the above-mentioned conditions.
The phenomenon of xe2x80x9cscuffingxe2x80x9d is approached when the lubricant becomes so thin that its thickness is similar to the height of the microscopic roughness (or asperities) on the opposing surfaces to be lubricated. Further thinning of the lubricant gives rise to actual solid/solid contact between opposing surfaces. When solid/solid interactions occur between asperities, they tend to adhere and give rise to so-called xe2x80x9cadhesive frictionxe2x80x9d. The stresses on the asperities are sufficient to remove material, which material loss is called xe2x80x9cadhesive wearxe2x80x9d or xe2x80x9cscuffingxe2x80x9d.
The present invention ameliorates the above problem, as evidenced by test results described in this specification, by lubricating the cylinder with an MDCL that includes a specific auxiliary additive.
Thus, in a first aspect, the invention is a combination of a cylinder of a two-stroke cross-head marine diesel engine with a cylinder lubricant comprising, or made by admixing:
(A) a base stock of lubricating viscosity, in a major amount;
(B) at least one overbased metal detergent, in a minor amount; and
(B) at least one auxiliary, preferably ashless or non-metal-containing, additive component, in a minor amount, and that is different from (B), comprising:
(C1) an oil-soluble sulfur-containing compound, and/or
(C2) an oil-soluble phosphorus-containing compound,
wherein the cylinder is characterised by a power output of 4000 or greater, such as 4200 or greater, preferably 4500 or greater, more preferably in the range of 4500 to 6000, kW. The bore of the cylinder may, for example, be 850 or greater, such as 900 or greater, preferably in the range of 900 to 1000, cm.
A second aspect of the invention is a method of lubricating a cylinder of a two-stroke cross-head marine diesel engine which comprises supplying to the walls of the cylinder, a cylinder lubricant as defined in the first aspect of the invention, wherein the cylinder is defined as in the first aspect of the invention.
A third aspect of the invention is a method of raising the temperature of the onset of scuffing-type mechanical wear of the walls of a cylinder of a two-stroke cross-head marine diesel engine by lubricating the walls with a cylinder lubricant as defined in the first aspect of the invention, wherein the cylinder is as defined in the first aspect of the invention.
In this specification, the following words and expressions shall have the meanings ascribed below:
xe2x80x9cmajor amountxe2x80x9dxe2x80x94in excess of 50 mass % of the lubricant;
xe2x80x9cminor amountxe2x80x9dxe2x80x94less that 50 mass % of the lubricant, both in respect of the stated additive and in respect of the total mass % of all the additives present in the lubricant, reckoned as active ingredient of the additive or additives;
xe2x80x9cactive ingredient (a.i.)xe2x80x9d refers to additive material that is not diluent,
xe2x80x9ccomprises or comprising, or cognate wordsxe2x80x9dxe2x80x94specifies the presence of stated features, steps, integers or components, but does not preclude the presence or addition of one or more other features, steps, integers, components, or groups thereof;
xe2x80x9cTBNxe2x80x9dxe2x80x94Total Base Numbers as measured by ASTM D2896;
xe2x80x9coil-soluble or oil-dispersiblexe2x80x9dxe2x80x94do not necessarily indicate solubility, dissolvability, miscibility or capability of suppression in oil in all proportions. They do mean, however, solubility or stable dispersibility sufficient to exert the intended effect in the environment in which the oil is employed. Moreover, additional incorporation of other additives may permit incorporation of higher levels of a particular additive, if desired;
it will be understood that the various components of the lubricant, essential as well as optimal and customary, may react under the conditions of formulation, storage or use and that the invention also provides the product obtainable or obtained as a result of any such reaction.
The features of the invention will now be discussed in more detail as follows:
Two Stroke Cross-Head Marine Diesel Engine
Certain characteristics of the engines of this invention and their cylinders have been indicated above. Further, the engines may, for example, have from 6 to 12 cylinders and their engine speed may, for example, be in the range of from 40 to 200, preferably 60 to 120, rpm. Their total output may, for example, be in the range of 18,000 to 70,000 kW.
Cylinder Lubricant
The lubricant may, for example have a TBN of 15 or greater, preferably, 40 or greater, for example in the range of from 60 to 100. Preferably, the viscosity index of the lubricant is at least 80, such as at least 90, for example at least 100.
The lubricant may, for example, have a kinematic viscosity at 100xc2x0 C. (as measured by ASTM D445) of at least 14, preferably at least 15, more preferably in the range from 17 to 30, for example from 17 to 25, mm2sxe2x88x921.
(A) Base Stock of Lubricating Viscosity
The base stock is an oil of lubricating viscosity (sometimes referred to as base oil) and may be any oil suitable for the lubrication of a cross-head engine. The lubricating oil may suitably be an animal, vegetable or a mineral oil. Suitably the lubricating oil is a petroleum derived lubricating oil, such as a naphthenic base, paraffinic base or mixed base oil. Alternatively, the lubricating oil may be a synthetic lubricating oil. Suitable synthetic lubricating oils include synthetic ester lubricating oils, which oils include diesters such as di-octyl adipate, di-octyl sebacate and tri-decyl adipate, or polymeric hydrocarbon lubricating oils, for example liquid polyisobutene and poly-alpha olefins. Commonly, a mineral oil is employed. The lubricating oil may generally comprise greater that 60, typically greater than 70%, by mass of the lubricant and typically have a kinematic viscosity at 100xc2x0 C. of from 2 to 40, for example from 3 to 15, mm2sxe2x88x921, and a viscosity index from 80 to 100, for example from 90 to 95.
Another class of lubricating oil is hydrocracked oils, where the refining process further breaks down the middle and heavy distillate fractions in the presence of hydrogen at high temperatures and moderate pressures. Hydrocracked oils typically have kinematic viscosity at 100xc2x0 C. of from 2 to 40, for example from 3 to 15, mm2sxe2x88x921 and a viscosity index typically in the range of from 100 to 110, for example from 105 to 108.
The term xe2x80x98brightstockxe2x80x99 as used herein refers to base oils which are solvent-extracted, de-asphalted products from vacuum residuum generally having a kinematic viscosity at 100xc2x0 C. from 28 to 36 mm2sxe2x88x921 and are typically used in a proportion of less that 30, preferably less than 20, more preferably less than 15, most preferably less than 10, such as less than 5, mass %, based on the mass of the lubricant.
(B) Overbased Metal Detergent
Overbased metal compounds suitable for use in the lubricant of the present invention include alkali metal and alkaline earth metal additives such as overbased oil-soluble or oil-dispersible calcium, magnesium, sodium or barium salts of a surfactant selected from phenol, sulfonic acid, carboxylic acid, salicylic acid and naphthenic acid, wherein the overbasing is provided by an oil-insoluble salt of the metal, e.g. carbonate, basic carbonate, acetate, formate, hydroxide or oxalate, which is stabilised by the oil-soluble salt of the surfactant. The metal of the oil-soluble surfactant salt may be the same or different from that of the metal of the oil-insoluble salt. Preferably the metal, whether the metal of the oil-soluble or oil-insoluble salt, is calcium.
Preferably, the TBN of the or each of the overbased metal compounds is at least 250, such as up to 500.
Surfactants for the surfactant system of the overbased metal compounds preferably contain at least one hydrocarbyl group, for example, as a substituent on an aromatic ring. The term xe2x80x9chydrocarbylxe2x80x9d as used herein means that the group concerned is primarily composed of hydrogen and carbon atoms and is bonded to the remainder of the molecule via a carbon atom but does not exclude the presence of other atoms or groups in a proportion insufficient to detract from the substantially hydrocarbon characteristics of the group. Advantageously, hydrocarbyl groups in surfactants for use in accordance with the invention are aliphatic groups, preferably alkyl or alkylene groups, especially alkyl groups, which may be linear or branched. The total number of carbon atoms in the surfactants should be at least sufficient to impart the desired oil-solubility.
Phenols, for use in this invention, may be non-sulfurized or, preferably, sulfurized. Further, the term xe2x80x9cphenolxe2x80x9d as used herein includes phenols containing more than one hydroxyl group (for example, alkyl catechols) or fused aromatic rings (for example, alkyl naphthols) and phenols which have been modified by chemical reaction, for example, alkylene-bridged phenols and Mannich base-condensed phenols; and saligenin-type phenols (produced by the reaction of a phenol and an aldehyde under basic conditions).
Preferred phenols may be derived from the formula
where R represents a hydrocarbyl group and y represents 1 to 4. Where y is greater than 1, the hydrocarbyl groups may be the same or different.
The phenols are frequently used in sulfurized form. Sulfurized hydrocarbyl phenols may typically be represented by the formula:
where x is generally from 1 to 4. In some cases, more than two phenol molecules may be linked by Sx bridges.
In the above formulae, hydrocarbyl groups represented by R are advantageously alkyl groups, which advantageously contain 5 to 100, preferably 5 to 40, especially 9 to 12, carbon atoms, the average number of carbon atoms in all of the R groups being at least 9 in order to ensure adequate solubility in oil. Preferred alkyl groups are nonyl (tripropylene) groups.
In the following discussion, hydrocarbyl-substituted phenols will for convenience be referred to as alkyl phenols.
A sulfurizing agent for use in preparing a sulfurized phenol or phenate may be any compound or element which introduces xe2x80x94(S)xxe2x80x94 bridging groups between the alkyl phenol monomer groups, wherein x is generally from 1 to about 4. Thus, the reaction may be conducted with elemental sulfur or a halide thereof, for example, sulfur dichloride or, more preferably, sulfur monochloride. If elemental sulfur is used, the sulfurization reaction may be effected by heating the alkyl phenol compound at from 50 to 250, preferably at least 100xc2x0 C. The use of elemental sulfur will typically yield a mixture of bridging groups xe2x80x94(S)xxe2x80x94 as described above. If a sulfur halide is used, the sulfurization reaction may be effected by treating the alkyl phenol at from xe2x88x9210 to 120, preferably at least 60xc2x0 C. The reaction may be conducted in the presence of a suitable diluent. The diluent advantageously comprises a substantially inert organic diluent, for example mineral oil or an alkane. In any event, the reaction is conducted for a period of time sufficient to effect substantial reaction. It is generally preferred to employ from 0.1 to 5 moles of the alkyl phenol material per equivalent of sulphurizing agent.
Where elemental sulfur is used as the sulfurizing agent, it may be desirable to use a basic catalyst, for example, sodium hydroxide or an organic amine, preferably a heterocyclic amine (e.g., morpholine).
Details of sulfurization processes are well known to those skilled in the art.
Regardless of the manner in which they are prepared, sulfurized alkyl phenols useful in preparing overbased metal compounds generally comprise diluent and unreacted alkyl phenols and generally contain from 2 to 20, preferably 4 to 14, and most preferably 6 to 12, mass % sulfur based on the mass of the sulfurized alkyl phenol.
As indicated above, the term xe2x80x9cphenolxe2x80x9d as used herein includes phenols which have been modified by chemical reaction with, for example, an aldehyde, and Mannich base-condensed phenols.
Aldehydes with which phenols may be modified include, for example, formaldehyde, propionaldehyde and butyraldehyde. The preferred aldehyde is formaldehyde. Aldehyde-modified phenols suitable for use are described in, for example, U.S. Pat. No. 5,259,967.
Mannich base-condensed phenols are prepared by the reaction of a phenol, an aldehyde and an amine. Examples of suitable Mannich base-condensed phenols are described in GB-A-2 121 432.
In general, the phenols may include substituents other than those mentioned above provided that such substituents do not detract significantly from the surfactant properties of the phenols. Examples of such substituents are methoxy groups and halogen atoms.
Salicylic acids used in accordance with the invention may be non-sulfurized or sulfurized, and may be chemically modified and/or contain additional substituents, for example, as discussed above for phenols. Processes similar to those described above may also be used for sulfurizing a hydrocarbyl-substituted salicylic acid, and are well known to those skilled in the art. Salicylic acids are typically prepared by the carboxylation, by the Kolbe-Schmitt process, of phenoxides, and in that case, will generally be obtained (normally in a diluent) in admixture with uncarboxylated phenol.
Preferred substituents in oil-soluble salicylic acids from which overbased detergents in accordance with the invention may be derived are the substituents represented by R in the above discussion of phenols. In alkyl-substituted salicylic acids, the alkyl groups advantageously contain 5 to 100, preferably 9 to 30, especially 14 to 20, carbon atoms.
Sulfonic acids used in accordance with the invention are typically obtained by sulfonation of hydrocarbyl-substituted, especially alkyl-substituted, aromatic hydrocarbons, for example, those obtained from the fractionation of petroleum by distillation and/or extraction, or by the alkylation of aromatic hydrocarbons. Examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, biphenyl or their halogen derivatives, for example, chlorobenzene, chlorotoluene or chloronaphthalene. Alkylation of aromatic hydrocarbons may be carried out in the presence of a catalyst with alkylating agents having from 3 to more than 100 carbon atoms, such as, for example, haloparaffins, olefins that may be obtained by dehydrogenation of paraffins, and polyolefins, for example, polymers of ethylene, propylene, and/or butene. The alkylaryl sulphonic acids usually contain from 7 to 100 or more carbon atoms. They preferably contain from 16 to 80, or 12 to 40, carbon atoms per alkyl-substituted aromatic moiety, depending on the source from which they are obtained.
When neutralizing these alkylaryl sulfonic acids to provide sulfonates, hydrocarbon solvents and/or diluent oils may also be included in the reaction mixture, as well as promoters and viscosity control agents.
Another type of sulfonic acid which may be used in accordance with the invention comprises alkyl phenol sulfonic acids. Such sulfonic acids can be sulfurized. Whether sulfurized or non-sulfurized these sulfonic acids are believed to have surfactant properties comparable to those of sulfonic acids, rather than surfactant properties comparable to those of phenols.
Sulfonic acids suitable for use in accordance with the invention also include alkyl sulfonic acids, such as alkenyl sulfonic acids. In such compounds the alkyl group suitably contains 9 to 100, advantageously 12 to 80, especially 16 to 60, carbon atoms.
Carboxylic acids which may be used in accordance with the invention include mono-and dicarboxylic acids. Preferred monocarboxylic acids are those containing 1 to 30, especially 8 to 24, carbon atoms. (Where this specification indicates the number of carbon atoms in a carboxylic acid, the carbon atom(s) in the carboxylic group(s) is/are included in that number.) Examples of monocarboxylic acids are iso-octanoic acid, stearic acid, oleic acid, palmitic acid and behenic acid. Iso-octanoic acid may, if desired, be used in the form of the mixture of C8 acid isomers sold by Exxon Chemicals under the trade name xe2x80x9cCekanoicxe2x80x9d. Other suitable acids are those with tertiary substitution at the xcex1-carbon atom and dicarboxylic acids with more than 2 carbon atoms separating the carboxylic groups. Further, dicarboxylic acids with more than 35, for example, 36 to 100, carbon atoms are also suitable. Unsaturated carboxylic acids can be sulphurized. Although salicylic acids contain a carboxylic group, for the purposes of the present invention they are considered to be a separate group of surfactants, and are not considered to be carboxylic acid surfactants. (Nor, although they contain a hydroxyl group, are they considered to be phenol surfactants.)
Examples of other surfactants which may be used in accordance with the invention include the following compounds, and derivatives thereof: naphthenic acids, especially naphthenic acids containing one or more alkyl groups, dialkylphosphonic acids, dialkylthiophosphonic acids, and dialkyldithiophosphoric acids, high molecular weight (preferably ethoxylated) alcohols, dithiocarbamic acids, thiophosphines, and dispersants. Surfactants of these types are well known to those skilled in the art. Surfactants of the hydrocarbyl-substituted carboxylalkylene-linked phenol type, or dihydrocarbyl esters of alkylene dicarboxylic acids, the alkylene group being substituted with a hydroxy group and an additional carboxylic acid group, or alkylene-linked polyaromatic molecules, the aromatic moieties whereof comprise at least one hydrocarbyl-substituted phenol and at least one carboxy phenol, may also be suitable for use in the present invention; such surfactants are described in EP-A-708 171.
Further examples of detergents useful in the present invention are optionally sulfurized alkaline earth metal hydrocarbyl phenates that have been modified by carboxylic acids such as stearic acid, for examples as described in EP-A-271 262 (LZ-Adibis); and phenolates as described in EP-A-750 659 (Chevron).
Also suitable for use in the present invention are overbased metal compounds, preferably overbased calcium detergents, that contain at least two surfactant groups, such as phenol, sulfonic acid, carboxylic acid, salicylic acid and naphthenic acid, that may be obtained by manufacture of a hybrid material in which two or more different surfactant groups are incorporated during the overbasing process.
Examples of hybrid materials are an overbased calcium salt of surfactants phenol and sulfonic acid; an overbased calcium salt of surfactants phenol and carboxylic acid; an overbased calcium salt of surfactants phenol, sulfonic acid and salicylic acid; and an overbased calcium salt of surfactants phenol and salicylic acid.
By an xe2x80x9coverbased calcium salt of surfactantsxe2x80x9d is meant an overbased detergent in which the metal cations of the oil-insoluble metal salt are essentially calcium cations. Small amounts of other cations may be present in the oil-insoluble metal salt, but typically at least 80, more typically at least 90, for example at least 95, mole %, of the cations in the oil-insoluble metal salt, are calcium ions. Cations other than calcium may be derived, for example, from the use in the manufacture of the overbased detergent of a surfactant salt in which the cation is a metal other than calcium. Preferably, the metal salt of the surfactant is also calcium.
Preferably, the TBN of the overbased calcium detergent is at least 330, such as at least 350, more preferably at least 400, most preferably in the range of from 400 to 600, such as up to 500.
In the instance where at least two overbased metal compounds are present, any suitable proportions by mass may be used, preferably the mass to mass proportion of any one overbased metal compound to any other metal overbased compound is in the range of from 5:95 to 95:5; such as from 90:10 to 10:90; more preferably from 20:80 to 80:20; especially from 70:30 to 30:70; advantageously from 60:40 to 40:60.
Particular examples of hybrid materials include, for example, those described in WO-A-97/46643; WO-A-97/46644; WO-A-97/46645; WO-A-97/46646; and WO-A-97/46647.
Typically, the amount of overbased metal compound in the lubricant is at least 0.5, particularly in the range of from 0.5 to 20, such as from 3 to 12 or 2 to 7, mass % based on active ingredient per mass of lubricant.
The overbased metal compounds of the present invention may be borated, and typically the boron contributing compound, e.g the metal borate, is considered to form part of the overbasing. In the instance where a borated overbased metal compound is used in the present invention, the use of a borated dispersant and/or an oil-soluble or oil-dispersible boron compound may, or may not, be necessary provided the lubricant composition comprising the borated overbased metal compound has a viscosity index and TBN as defined herein. For the purpose of avoidance of doubt, non-borated dispersants are not excluded in the present invention in combination with a borated overbased metal compound.
Preferably, additives a) and b) are discrete molecules, but additives a) and b) may, if required, be consolidated into a single molecule, for example a borated overbased metal detergent.
(C) Auxiliary Additive Component
As stated, such components are preferably xe2x80x9cashlessxe2x80x9d by which is meant that it is a non-metallic organic material that forms substantially no ash on combustion, in contrast to metal-containing and hence, ash forming compounds.
As examples of such compounds, there may be mentioned oil-soluble sulfurized organic compounds such as sulfurized alkylphenols, phosphorosulfurized or sulfurized hydrocarbons, and sulfides of oils, fats of polyolefins, in which a sulfur group having two or more sulfur atoms is adjoined and bounded together in a molecular structure. Examples include sulfurized sperm oil, sulfurized pinene oil, sulfurized soybean oil, sulfurized polyolefin, sulfurized esters, dialkyl disulfide, dialkyl polysulfide, dibenzyl disulfide, ditertiary butyl disulfide, polyolefin polysulfide, and thiadiazole type compounds such as bis-alkyl polysulfide thiadiazole. Such compounds fall within the components (C1) according to the present invention.
Falling within the components (C2) according to the present invention are amine phosphates which include the neutralisation or partial neutralisation products of acidic phosphorus-containing intermediates and amines. The acidic intermediates are preferably formed from a hydroxy-substituted triester of a phosphorothioic acid with an inorganic phosphorus reagent selected from the group consisting of phosphorus acids, phosphorus oxides, and phosphorus halides. Thus, the amine phosphates may fall within the components (C2) according to the present invention such as in the form of amine dithiophosphates.
The hydroxy-substituted triesters of phosphorothioic acids include principally those having the structural formula
wherein R is selected from the class consisting of substantially hydrocarbon radicals and hydroxy-substituted substantially hydrocarbon radicals, at least one of the R radicals being a hydroxy-substituted substantially hydrocarbon radical, and X is selected from the class consisting of sulphur and oxygen, at least one of the X radicals being sulphur. The substantially hydrocarbon radicals include aromatic, aliphatic, and cycloaliphatic radicals such as aryl, alkyl, aralkyl, alkaryl, and cycloalkyl radicals. Such radicals may contain a polar substituent such as chloro, bromo, iodo, alkoxy, aryloxy, nitro, keto, or aldehydo group. In most instances there should be no more than one such polar group in a radical.
Specific examples of the substantially hydrocarbon radical are methyl, ethyl, isopropyl, secondary-butyl, isobutyl, n-pentyl, dodecyl, polyisobutene radical (molecular weight of 1500), cyclohexyl, cyclopentyl, 2-heptyl-cyclohexyl, phenyl, naphthyl, xenyl, p-heptylphenyl, 2,6-di-tertiary-butylphenyl, benzyl, phenylethyl, 3,5-dodecylphenyl, chlorophenyl, alpha-methoxy-beta-naphthyl, p-nitrophenyl, p-phenoxyphenyl, 2-bromomethyl, 3-chlorocyclohexyl, and polypropylene (molecular weight of 300)-substituted phenyl radical.
The hydroxy-substituted substantially hydrocarbon radicals include principally the above-illustrated substantially hydrocarbon radicals containing a hydroxy group. Those having less than 8 carbon atoms are preferred because of the convenience in preparing such hydroxy-substituted triesters. Examples of such radicals are hydroxymethyl, hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxycyclohexyl, 2-hydroxycyclopentyl, 2-hydroxy-1-octyl, 1-hydroxy-3-octyl, 1-hydroxy-2-octyl, 2-hydroxy-3-phenyl-cyclohexyl, 1-hydroxy-2-phenylethyl, 2-hydroxy-1-phenylethyl, 2-hydroxy-1-p-tolylethyl, and 2-hydroxy-3-butyl radicals. Other hydroxy-substituted substantially hydrocarbon radicals are exemplified by 2,5-dihydroxyphenyl, alpha-hydroxy-beta-naphthyl, 3-hydroxy-4-dodecyl, 3-hydroxy-6-octadecyl, and p-(p-hydroxyphenyl)-phenyl radicals.
A preferred class of the hydroxy-substituted triesters comprises those having the structural formula
where Rxe2x80x3 is a substantially hydrocarbon radical illustrated above and Rxe2x80x2 is a bivalent substantially hydrocarbon radical such as alkylene or arylene radicals derived from the previously illustrated substantially hydrocarbon radicals. A convenient method for preparing such esters involves the reaction of a phosphorodithioic acid with an epoxide or a glycol. Such reaction is known in the art. The following equations are illustrative of the reaction.
where
is an epoxide and HOxe2x80x94Rxe2x80x2xe2x80x94OH is a glycol.
For reasons of economy, aliphatic epoxides having less than about 8 carbon atoms and styrene oxides are preferred for use in the above process. Especially useful epoxides are exemplified by ethylene oxide, propylene oxide, styrene oxide, alpha-methylstyrene oxide, p-methylstyrene oxide, cyclohexene oxide, cyclopentene oxide, dodecene oxide, octadecene oxide, 2,3-butene oxide, 1,2-butene oxide, 1,2-octene oxide, 3,4-pentene oxide, and 4-phenyl-1,2-cyclohexene oxide. Glycols include both aliphatic and aromatic di-hydroxy compounds. The latter are exemplified by hydroquinone, catechol, resorcinol, and 1,2-dihydroxynaphthalene. Aliphatic glycols are especially useful such as ethylene glycol, trimethylene glycol, tetramethylene glycol, decamethylene glycol, di-ethylene glycol, triethylene glycol, and pentaethylene glycol.
Another convenient method for preparing the hydroxy-substituted triesters comprises the addition of a phosphorodithioic acid to an unsaturated alcohol such as allyl alcohol, cinnamyl alcohol, or oleyl alcohol such as is described in U.S. Pat. No. 2,528,723. Still another method involves the reaction of a metal phosphorothiate with a halogen-substituted alcohol described in U.S. RE. Pat. No. 20,411.
The phosphorodithioic acids from which the hydroxy-substituted triesters can be derived are likewise well-known. They are prepared by the reaction of phosphorus pentasulfide with an alcohol or a phenol. The reaction involves 4 moles of the alcohol or phenol per mole of phosphorus pentasulfide and may be carried out within the temperature range from about 50xc2x0 C. to 200xc2x0 C. Thus, the preparation of O,Oxe2x80x2-di-n-hexylphosphorodithioic acid involves the reaction of phosphorus pentasulfide with 4 moles of n-hexyl alcohol at 100xc2x0 C. for 2 hours. Hydrogen sulfide is liberated and the residue is the defined acid. The preparation of the phosphoromonothioic acid may be effected by treatment of corresponding phosphorodithioic acid with steam. Phosphorotrithioic acids and phosphorotetrathioic acids can be obtained by the reaction of phosphorus pentasulfide with mercaptans or mixtures of mercaptans and alcohols.
The reaction of phosphorus pentasulfide with a mixture of phenols or alcohols (e.g., isobutanol and n-hexanol in 2:1 weight ratio) results in phosphorodithioic acids in which the two organic radicals are different. Such acids likewise are useful herein.
The inorganic phosphorus reagent useful in the reaction with the hydroxy-substituted triesters of phosphorothioic acids is preferably phosphorus pentoxide. Other phosphorus oxides such as phosphorus trioxide and phosphorus tetroxide likewise are useful. Also useful are phosphorus acids, and phosphorus halides. They are exemplified by phosphoric acid, pyrophosphoric acid, metaphosphoric acid, hypophosphoric acid, phosphorous acid, pyrophosphorous acid, metaphosphorous acid, hypophosphorous acid, phosphorous trichloride, phosphorus tribromide, phosphorous pentachloride, monobromophosphorus tetrachloride, phosphorus oxychloride, and phosphorus triiodide.
The reaction of the hydroxy-substituted triesters of phosphorothioic acids with the inorganic phosphorus reagent results in an acidic product. The chemical constitution of the acidic product depends to a large measure on the nature of the inorganic phosphorus reagent used. In most instances the product is a complex mixture the precise composition of which is not known. It is known, however, that the reaction involves the hydroxy radical of the triester with the inorganic phosphorus reagent. In this respect the reaction may be likened to that of an alcohol or a phenol with the inorganic phosphorus reagent. Thus, the reaction of the hydroxy-substituted triester with phosphorus pentoxide is believed to result principally in acidic phosphates, i.e., mono- or di-esters of phosphoric acid in which the ester radical is the residue obtained by the removal of the hydroxy radical of the phosphorothioic triester reactant. The product may also contain phosphonic acids and phosphinic acids in which one or two direct carbon-to-phosphorus linkages are present.
The acidic product of the reaction between the hydroxy-substituted triester with phosphorus oxyhalide or phosphoric acid is believed to result in similar mixtures of acidic phosphates, phosphonic acids, and/or phosphinic acids. On the other hand, the reaction of the hydroxy-substituted triester with phosphorus trichloride or phosphorus acid is believed to result principally in acidic organic phosphites. Still other products may be obtained from the use of other inorganic phosphorus reagents illustrated previously. In any event, the product is acidic and as such is useful as the intermediate for the preparation of the neutralized products useful in invention.
Usually, from 2 moles to 5 moles of the triester is used for each mole of the inorganic phosphorus reagent. The preferred proportion of the triester is about 3-4 moles for each mole of the phosphorus reagent. The use of amounts of either reactant outside the limits indicated here results in excessive unused amounts of the reactant and is ordinarily not preferred.
The reaction of the hydroxy-substituted triester with the inorganic phosphorus reagent to produce the acidic intermediate can be effected simply by mixing the two reactant at a temperature above about room temperature, preferably above 50xc2x0 C. A higher temperature such as 100xc2x0 C. or 150xc2x0 C. may be used but ordinarily is unnecessary.
The amines useful for neutralizing the acidic intermediate may be aliphatic amines, aromatic amines, cycloaliphatic amines, heterocyclic amines, or carbocyclic amines. Amines having from 4 to 30 aliphatic carbon atoms are preferred and aliphatic primary amines containing at least 8 carbon atoms and having the formula, Rxe2x80x3xe2x80x94NH2, where Rxe2x80x3 is, for example, an aliphatic radical such as tert-octyl, tert-dodecyl, tert-tetradecyl, tert-octadecyl, cetyl, behenyl, stearyl, eicosyl, docosyl, tetracosyl, hexatriacontanyl, and pentahexacontanyl, are especially useful. Examples of other aliphatic amines include cyclohexyl amine, n-hexylamine, dodecylamine, di-dodecylamine, tridodecylamine, N-methyl-octylamine, butylamine, behenylamine, stearyl amine, oleyl amine, myristyl amine, and N-dodecyl trimethylene diamine, aniline, o-toluidine, benzidine, phenylene diamine, N,Nxe2x80x2-di-sec-butylphenylene diamine, beta-naphthylamine, alpha-naphthylamine, morpholine, piperazine, menthane diamine, cyclopentyl amine, ethylene diamine, hexamethylene tetramine, octamethylene diamine, and N,Nxe2x80x2-dibutyl-phenylene diamine. Also useful are hydroxy-substituted amines such as ethanolamine, diethanolamine, triethanolamine, isopropanolamine, para-aminophenol, 4-amino-naphthol-1,8-amino-naphthol-1, beta-aminoalizarin, 2-amino-2-ethyl-1,3-propandiol, 4-amino-4xe2x80x2-hydroxy-diphenyl ether, 2-amino-resorcinol, etc.
Of the various available hydroxy-substituted amines which can be employed, a preference is expressed for hydroxy-substituted aliphatic amines, particularly those which conform for the most part to the formula
wherein Rxe2x80x3 is as previously defined; A is a lower alkylene radical such as methylene, ethylene, propylene-1,2, tri-methylene, butylene-1,2, tetramethylene, amylene-1,3, pentamethylene, etc.; x is 1-10, inclusive; and Q is hydrogen, (AO)xH, or Rxe2x80x3. The use of such hydroxy-substituted aliphatic amines in many instances imparts improved rust-inhibiting characteristics. Examples of such preferred hydroxy-substituted aliphatic amines include N-4-hydroxybutyl-dodecyl amine, N-2-hydroxyethyl-n-octylamine, N-2-hydroxypropyl dinonylamine, N,N-di-(3-hydroxypropyl)-tert-dodecyl amine, N-hydroxytrieth-oxyethyl-tert-tetradecyl amine, N-2-hydroxyethyl-tert-dodecyl amine, N-hydroxyhexa-propoxypropyl-tert-octadecyl amine, N-5-hydroxypentyl di-n-decyl amine, etc. A convenient and economical method for the preparation of such hydroxy-substituted aliphatic amines involves the known reaction of an aliphatic primary or secondary amine with at least about an equimolecular amount of an epoxide, preferably in the presence of a suitable catalyst such as sodium methoxide, sodamide, sodium metal, etc.
In the above formulae, Rxe2x80x3, x and A are as previously defined. A particular preference is expressed for N-monohydroxyalkyl substituted mono-tertiary-alkyl amines of the formula tert-Rxe2x80x94NHAOH, wherein tert-R is a tertiary-alkyl radical containing from 11 to 24 carbon atoms. In lieu of a single compound of the formula tert-Rxe2x80x94NHAOH, it is often convenient and desirable to use a mixture of such compounds prepared, for example, by the reaction of an epoxide such as ethylene oxide, propylene oxide, or butylene oxide with a commercial mixture of tertiary-alkyl primary amines such as C11-C14 tertiary-alkyl primary amines, C13-C22 tertiary-alkyl primary amines, etc.
The neutralization of the acidic intermediate with the amine is in most instances exothermic and can be carried out simply by mixing the reactants at ordinary temperatures, preferably from 0xc2x0 C. to 200xc2x0 C. The chemical constitution of the neutralized product of the reaction depends to a large extent upon the temperature.
Thus, at a relatively low temperature, such as less than 80xc2x0 C., the product comprises predominantly a salt of the amine with the acid. At a temperature above 100xc2x0 C., the product may contain amides, amidines, or mixtures thereof. However, the reaction of the acidic intermediate with a tertiary amine results only in a salt.
The relative proportions of the acidic intermediate and the amines used in the reaction are preferably such that a substantial portion of the acidic intermediate is neutralized. The lower limit as to the amount of amine used in the reaction is based primarily upon a considerable of the utility of the product formed. In most instances, enough amine should be used as to neutralize at least 50% of the acidity of the intermediate. For use as additives in hydrocarbon oils, substantially neutral products such as are obtained by neutralization of at least 90% of the acidity of the intermediate are desirable. Thus the amount of the amine used may vary within wide ranges depending upon the acidity desired in the product and also upon the acidity of the intermediate as determined by, for example, ASTM procedure designation D-664 or D-974.
A particularly preferred amine phosphate is when the acidic intermediate is derived from the reaction of P2O5 with hydroxypropyl O,O-di(4-methyl-2-pentyl) phosphorodithioate. This acidic intermediate may then be neutralised or partially neutralised with a C12 to C14 tertiary aliphatic primary amine. An example of such an amine may be commercially purchased under the trade name of Primene 81R.
Preferred are sulfurized alkylphenols such as those described above in connection with the preparation of overbased metal detergents for example present in the lubricant is an amount of at least 0.5, such as at least 1.5 or 2, for example up to 8, 10, 15 or 20 mass %, and amine dithiophosphates, for example present in the lubricant in an amount of at least 0.1, for example up to 10, such as in the range of 0.4 to 5, or 0.6 to 2, mass %.
Co-Additives
The lubricants may include an antiwear agent as a co-additive and may also contain other co-additives, for example, antioxidants, antifoaming agents and/or rust inhibitors. Further details of particular co-additives are as follows.
Oxidation inhibitors, or antioxidants, reduce the tendency of mineral oils to deteriorate in service, evidence of such deterioration being, for example, the production of varnish-like deposits on metal surfaces and of sludge, and viscosity increase. Suitable oxidation inhibitors include sulphurized alkyl phenols and alkali or alkaline earth metal salts thereof; diphenylamines; phenyl-naphthylamines; and phosphosulphurized or sulphurized hydrocarbons.
Other oxidation inhibitors or antioxidants which may be used in the lubricant comprise oil-soluble copper compounds. The copper may be blended therein as any suitable oil-soluble copper compound. By oil-soluble is meant that the compound is oil-soluble under normal blending conditions in the base stock or an additive package. The copper may, for example, be in the form of a copper dihydrocarbyl thio- or dithio-phosphate. Alternatively, the copper may be added as the copper salt of a synthetic or natural carboxylic acid, for example, a C8 to C18 fatty acid, an unsaturated acid, or a branched carboxylic acid. Also useful are oil-soluble copper dithiocarbamates, sulphonates, phenates, and acetylacetonates. Examples of particularly useful copper compounds are basic, neutral or acidic copper Cu I and/or Cu II salts derived from alkenyl succinic acids or anhydrides.
Additional detergents and metal rust inhibitors include the metal salts, which may be overbased and have a TBN less than 300, of sulphonic acids, alkyl phenols, sulphurized alkyl phenols, alkyl salicylic acids, thiophosphonic acids, naphthenic acids, and other oil-soluble mono- and dicarboxylic acids. Representative examples of detergents/rust inhibitors, and their methods of preparation, are given in EP-A-208 560. In the case of metal salts of salicylic acids, the TBN of the metal salts may be less than 200.
Antiwear agents, as their name implies, reduce wear of metal parts. Zinc dihydrocarbyl dithiophosphates (ZDDPs) are very widely used as antiwear agents. Especially preferred ZDDPs are those of the formula Zn[SP(S)(OR1)(OR2)]2 wherein R1 and R2 represent hydrocarbyl groups such as alkyl groups that contain from 1 to 18, preferably 2 to 12, carbon atoms.
Pour point depressants otherwise known as lube oil flow improvers, lower the minimum temperature at which the fluid will flow or can be poured. Such additives are well known. Foam control may be provided by an antifoamant of the polysiloxane type, for example, silicone oil or polydimethyl siloxane.
Proportions
Typical proportions for additives for an MDCL (a marine diesel cylinder lubricant), additional to additives (C) of this invention, are as follows:
When a plurality of additives is employed it may be desirable, although not essential, to prepare one or more additive packages or concentrates comprising the additives, whereby several additives can be added simultaneously to the base stock to form the lubricant. Dissolution of the additive package(s) into the base stock may be facilitated by solvents and by mixing accompanied with mild heating, but this is not essential. The additive package(s) will typically be formulated to contain the additive(s) in proper amounts to provide the desired concentration, and/or to carry out the intended function, in the final lubricant when the additive package(s) is/are combined with a predetermined amount of base stock. Thus, components (B) and (C) in accordance with the present invention may be admixed with small amounts of base stock or other compatible solvents together with other desirable additives to form additive packages containing active ingredients in an amount, based on the additive package, of, for example, from 2.5 to 90 and preferably from 5 to 75 and most preferably from 8 to 60, mass %, the remainder being base stock.
The final lubricant may typically contain about 5 to 40 mass % of the additive package(s), including diluent, the remainder being base stock.