The present invention is directed to water-in-oil (W/O) emulsion compositions containing gellan gum which provide an enhanced rate of release of active ingredients for delivery to the skin or mucosa.

1. Field of the Invention
The present invention relates generally to topical water-in-oil (W/O) emulsion compositions containing gellan gum which provide an enhanced rate of release of active ingredients for delivery to the skin or mucosa.
2. Background
Topical formulations generally have to combine multiple, and sometimes competing, attributes, such as those relating to aesthetics, stability, delivery and compatibility. In regard to aesthetics, topical formulations are generally required to display appropriate tactile and visual properties when applied to the skin or mucosa, while often also maintaining functionality in regard to delivery of various active ingredients onto or into the skin or mucosa.
Emulsions are widely used as topical formulations for the delivery of active ingredients, including drug and cosmetic active ingredients, to the skin or mucosa. Emulsions are generally made by preparing separate hydrophobic and hydrophilic phases and mixing the two together, usually with one or more emulsifying agents (surfactants), which reduce the surface tension between the immiscible phases creating micelles, i.e., a surfactant effect, thereby making the dispersion physically stable. The two basic types of such dispersions usually comprise 1) an oil-in-water type emulsion (O/W), which is a dispersed hydrophobic phase in a continuous aqueous phase; and 2) a water-in-oil type emulsion (W/O), which is a dispersed aqueous phase in a continuous hydrophobic phase.
The rate of release of active ingredients from a composition onto the skin or mucosa can be an important aspect of treatment. An enhanced (increased) rate of release of active ingredients can give quick relief to conditions such as infections, pruritus (itching), or pain.

Water-in-oil emulsion compositions containing gellan gum for topical delivery of active ingredients to the skin or mucosa


A security system for electrical appliances and other items with electrical circuitry includes a signal source operating within a predetermined zone. A receiver within the appliance or other item receives the signal and activates a circuit thereby permitting operability of the appliance or other item when the signal is received. The appliance or other item is disabled upon removal from the zone.

This invention relates generally to a security system for the deterrence of theft of electrical appliances or other property with electrical circuitry and more particularly to a security system which deters by limiting the operability of electrical appliances or other items with electrical circuitry to the perimeters of a specified zone.
Various security systems exist within the prior art for the prevention of theft of property. One such system is disclosed in Bernhardt U.S. Pat. No. 4,559,529 in which radio signals are transmitted to protect monitored articles. An audible alarm is triggered if an improper code is received. Whalen, et al. U.S. Pat. No. 3,710,371 disclose a system which employs a mercury switch to energize an alarm, and the systems disclosed in Lent U.S. Pat. No. 4,284,983 and Matto, et al. U.S. Pat. No. 3,836,901 sound alarms if there is unauthorized disconnection of the monitored appliance and the appliance is moved from its original position. In addition, security systems disclosed in Manley, et al. U.S. Pat. No. 3,794,989 and Cline U.S. Pat. No. 3,484,775 trigger alarms when a monitored appliance is disconnected, and Boyd, et al. U.S. Pat. No. 4,573,042 and Antenore U.S. Pat. No. 4,136,338 disclose systems which sound alarms when physical parameters have been exceeded by a monitored appliance.
While the prior art provides various security systems for designated articles, there exists a need for a theft prevention system for electrical items with an effective deterrent alternative.

Security system for electrical appliances and other items with electrical circuitry


An image forming apparatus including: a conveyance mechanism conveying a first pattern formed by a first image forming unit among image forming units, a second pattern formed by a second image forming unit among the image forming units; a detection unit detecting the first pattern and the second pattern; and a control unit controlling, when a first condition is satisfied, a timing of conveying a recording sheet having the image formed by the first image forming unit is transferred based on a first time required after the formation of the first pattern and before detecting the first pattern, and controlling, when a second condition is satisfied, a timing of conveying the recording sheet having the image formed by the second image forming unit is transferred based on a second time required after the formation of the second pattern and before detecting the second pattern.

1. Field of the Invention
The present invention relates to an image forming apparatus and a conveyance control method.
2. Description of the Related Art
In an electrophotography image forming apparatus, an intermediate transfer belt to which an image formed by an image forming unit is transferred is expanded or contracted due to thermal expansion or contraction caused by the change in temperature.
In view of this, in order to form an image at an appropriate position on a recording sheet, it is necessary to perform image position correction for correcting the displacement in image transfer position or conveyance timing correction for correcting the paper conveyance timing in consideration of the expansion or contraction of the intermediate transfer belt.
In the technique disclosed in Japanese Patent Application Laid-open No. 2008-76534, based on the timing at which a first set of the displacement correction pattern is read, the timing of detecting second and subsequent sets of displacement correction patterns is decided. Therefore, even though the intermediate transfer belt is expanded or contracted, it is possible to perform the image position correction by certainly reading the displacement correction patterns of the second and subsequent sets.
Further, if a difference from a reference value of the time of detecting the displacement correction pattern is calculated and the conveyance timing correction is performed based on the calculated difference, the conveyance control of the recording sheet in consideration of the expansion and contraction of the intermediate transfer belt becomes possible.
In the conventional art as described above, the displacement correction pattern formed in color is used; however, from the viewpoint of the accuracy of the paper conveyance timing and the consumption of a developer, the conveyance timing correction using the displacement correction pattern formed in color may not be preferable.
The present invention has been made in view of the above circumstances, and an object is to provide an image forming apparatus and a conveyance control method, that can increase the accuracy of the conveyance control of the recording sheet while the extra consumption of a developer is reduced.

Image forming apparatus and conveyance control method


The invention hereby provides a novel flat knitting machine which is furnished with a pair of needle beds in the front and rear positions each having a plurality of knitting needles aligned in parallel in such a condition in which respective knitting needles face each other, where a loop expanding member is provided on a lateral surface of each knitting needle. When transferring a loop from a delivery-side knitting needle engaged with this loop to an opposite receiving-side knitting needle, the receiving-side knitting needle is carried forward before the loop engaged with the delivery-side knitting needle is expandably opened by the loop expanding member, and then, the receiving-side knitting needle receives the loop in order that the loop engaged with the delivery-side knitting needle can properly be transferred to the loop expanding member from a hook of the delivery-side knitting needle. Next, the loop expanding member expandably opens the loop engaged with the delivery-side knitting needle. Next, the hook at the tip end of the delivery-side knitting needle penetrates a clearance between the loop expanding member and a lateral surface of the delivery-side knitting needle to engage the expanded loop with the hook. When transferring loops, the apparatus securely guides stitch/loop to the delivery position without incurring load to the stitch while closing the hook of the delivery-side knitting needle or by way of retracting the delivery-side knitting needle on the way of closing the hook.

The present invention relates to a method of transferring loops using a flat knitting machine and to an apparatus for transferring the loops.
Normally, in order to expandably open a loop of a delivery-side knitting needle and to surely hook the loop with a hook of a receiving-side knitting needle, a loop expanding member is provided for any conventional knitting needle of a flat knitting machine incorporating a loop transfer function. The loop expanding member is attached to a lateral surface of the delivery-side knitting needle. The loop expanding member called "wing", enables a receiving-side knitting needle to penetrate into a clearance between a delivery-side knitting needle and said clearance (in transferring) in order that the loop of the delivery-side knitting needle can smoothly be transferred to the receiving-side knitting needle.
Generally, knitting needles provided for a flat knitting machine are classified into two kinds including the following: A "latch" needle having an end being swingably held by an aperture of a hook at the top end of each knitting needle. The aperture of this hook is opened and closed by means of a brush or knitting yarn that passes through the latch needle. The other one is called a "compound" needle whose aperture is opened and closed by means of a slider which is operated by a cam provided for a carriage unit.
While a carriage moves to the left in a flat knitting machine furnished with a number of latch needles, loci of the delivery-side knitting needles and receiving-side knitting needles in the course of transferring stitches from those knitting needles of the rear-side needle bed to those knitting needles of the front-side needle bed are typically illustrated in FIG. 1. On the other hand, FIG. 2 illustrates loci of the delivery-side knitting needles and the receiving-side knitting needles of a flat knitting machine furnished with compound needles.
Nevertheless, on the way of transferring stitches with a flat knitting machine furnished with latch needles, stitches held with those delivery-side knitting needles are apt to be slidably moved along the delivery-side knitting needles accompanying the forward movement of these knitting needles. In consequence, loops may not be properly guided to the predetermined delivery position of those delivery side knitting needles.
If loops were not properly guided, then loops cannot correctly be engaged with hooks of corresponding receiving-side knitting needles. If these loops were cleared from those delivery-side knitting needles, then all stitches will be constricted. To prevent this, those ascended delivery-side knitting needles are retracted in order to release tension between those knitting needles and stitches, and then, those delivery-side knitting needles are again set to the stitch delivery position before permitting those receiving-side knitting needles to move on themselves until reaching the loop receiving position so that loops can eventually be transferred to these receiving-side knitting needles.
In this case, those receiving-side and delivery-side knitting needles respectively start to intersect with each other at position X shown in FIG. 1. Therefore, the above cited conventional flat knitting machine needs to provide each delivery-side knitting needle with such a cam mount for releasing tension between the delivery-side knitting needle and stitch and another cam mount for again guiding those delivery-side knitting needles to the loop transferring position, thus requiring provision of a lock having an expanded width. In other words, the flat knitting machine needs to install a large-dimensional carriage.
Furthermore, since loops are forcibly lifted while knitting needles move forward, an unwanted load is applied to stitches to cause the knitting yarn to easily be cut off. In consequence, when composing a knit with those knitting yarns containing poor elasticity or by closely putting stitches together, independent of the forward and backward movements of knitting needles, any conventional flat knitting machine cannot securely prevent loops from being lifted forcibly.
The Japanese Patent Publication No. 1-37495 of 1989 proposes such a flat knitting machine furnished with compound needles. Nevertheless, as is clear from loci shown in FIG. 2, the installed lock is not provided with a pair of cam mounts essential for materializing those loci X1 and X2 shown in FIG. 1, which are necessary for the system to fully prevent loops from forcibly being lifted. In consequence, like the flat knitting machine furnished with latch needles cited above, loops engaged with those delivery-side knitting needles may also be lifted relative to the forward movement of the delivery-side knitting needles, thus preventing loops from properly being transferred to the receiving-side knitting needles.
Therefore, the invention has been achieved to fully solve those technical problems inherent in any of those conventional flat knitting machines. An object of the invention is to provide a novel method of and a novel apparatus for securely guiding stitches to the predetermined transferring position without incurring load to stitches on the way of a transfer operation. Characteristically, the novel method embodied by the invention enables anyone concerned to easily design and manufacture compact carriages.

Method of transferring loops integrated with a flat knitting machine


This disclosure relates to a multi-piece shield comprising a fence, a lid, and an insert. The lid attaches to the fence, which is attached to the circuit board. The lid is a relatively thick, flexible material for supporting the insert. The lid has a recess so that the insert can be recessed into the lid to position the insert closer to the circuit for enhanced heat absorption. The insert is made of a thicker heat absorbing material than the lid, again to facilitate heat absorption. The insert can be press-fit into the recess of the lid. The lid can have a dovetail configuration to retain the insert in the lid.

Field of the Disclosure
The disclosure relates generally to shielding elements, and more particularly to a multi-piece shield for circuitry on a circuit board.
Related Art
Shielding elements are used in electrical circuits to protect specific components of the circuit from electromagnetic radiation (e.g., spurious emission or irradiation). In particular, screening or shielding elements are used to comply with EMC (electromagnetic compatibility) standards.
One piece shields are typically used for thin devices where replaceable lids are not practical due to height restrictions and/or to minimize costs (e.g., compared to two piece shields). Two piece shields are generally more popular for circuit reworkability and testing, but are typically higher cost.


A directional lighting fixture can receive an elongated lamp. The fixture has a spaced pair of connective devices each having a barrel with an electrical contact adapted to connect to opposite ends of the lamp. A tubular lamp cover has a light transmissive section and a light reflective section. Each section is contiguous to the other and trough-shaped. The lamp cover is rotatably mounted around the barrels of the connective devices.

1. Field of the Invention
The present invention relates to directional lighting fixtures and in particular, to fixtures having rotatable reflective devices.
2. Description of Related Art
Lamp fixtures ought to be convenient and adaptable to various situations. For elongated lamps such as fluorescent lamps, a fixture may be designed as a single assembly with connectors that connect to the opposite ends of the fluorescent lamp. Such lamp fixtures are designed to be attached to ceilings, walls or other surfaces such as the underside of cabinets over a work surface.
Lamp fixtures often include a lamp cover that may have a diffuser to soften the light and avoid shadows with sharp edges. Such covers can also prevent dust collection inside the lamp fixture and also prevent individuals from touching the lamp or its electrical connectors. Because lamp life is limited, lamp fixtures should also be designed to facilitate lamp replacement. Therefore, lamp covers should be easily removed and reinstalled for the purpose of replacing lamps.
Such lamp fixtures may be manufactured as a single unit with an integral power switch and with connectors for bringing power to the fixture either through a power cord or other adapters. Also, power connectors can be designed to connect a number of lamp fixtures in series, daisy-chain style.
It is often desirable to direct light output to a desired location. For example, one may wish to balance the lighting in a room or workspace by adjusting the direction of the light from individual fixtures. In some cases the fixture may provide accent lighting or be designed to illuminate an area of interest such as a painting. Also, a lighting fixture may be mounted under a cabinet over a work surface but offcenter. In that case one may wish to redirect the light from the fixture to the center of the work surface. Moreover, one may wish to periodically readjust the direction of the lighting depending on what portion of the work surface requires the most lighting.

Directional adjustable swivel lighting-fixture


An implementation-quality synthesis process begins with a logical design of an integrated circuit and, through a series of steps, generates a fully synthesized physical design of the integrated circuit. One of the steps is clock synthesis, which generates the clock network for the integrated circuit. In certain embodiments, a method includes the following steps. A reduced clock synthesis process is applied, rather than the implementation-quality clock synthesis process. This generates a clock network for the logical design, which will be referred to as a proxy clock network because it is used as a proxy to estimate power consumption of the fully synthesized clock network. Because the reduced clock synthesis process runs much faster than the implementation-quality clock synthesis process, the front end designer may use these power estimates in the front end design process, including to explore different design variations in the logical design.

Designing a very large scale integrated (VLSI) circuit is a complex process. At a high level the design process is divided into two parts: the front end or logical design and the back end or physical design. These two parts are typically performed by different people. The front end designer develops the logical design using a hardware description language (HDL) description of the design. The front end designer uses the HDL to develop a register transfer level (RTL) description for the design. The RTL is synthesized into a gate level netlist.
The back end designer takes the gate level netlist and works on the physical aspects of the design implementation, including floorplanning, placement, and routing. A floorplanned design includes a core boundary, input/output pads, placement of cells and global routing result. The fully implemented physical design includes optimization of the physical design and high quality placement of cells and detailed routing.

Clock network power estimation for logical designs


A multi-primary color display device is capable of handling an increased number of primary colors for color image display with a reduced number of external parts, with reduced increase in the amount of drive circuit and reduced increase in operating speed. An active matrix liquid crystal panel includes a display section constituted by pixel formation portions, each made of four sub pixel-formation portions which handle four primary colors. These four sub pixel-formation portions are arranged in a 2×2 matrix pattern. With such a pixel configuration, a source driver drives as many as M source lines, which is two times the number M of pixels arranged in a horizontal direction. A gate driver is formed on the liquid crystal panel integrally with pixel circuit in the display section, and drives as many as N gate lines, which is two times the number N of the pixels arranged in a vertical direction.

Color image display in a display device is implemented generally by additive color mixing of three primary colors consisting of red (R), green (G) and blue (B). Specifically, in color image display, each pixel is constituted by an R subpixel, a G subpixel and a B subpixel, which handle red, green and blue respectively. Therefore, in a liquid crystal color-display panel for example, each pixel formation portion for forming a pixel is constituted by an R sub pixel-formation portion, a G sub pixel-formation portion and a B sub pixel-formation portion for controlling the amount of light transmission in red, green and blue respectively. In this case, the three sub pixel-formation portions (R sub pixel-formation portion, G sub pixel-formation portion and B sub pixel-formation portion) which handle the three primary colors of RGB are typically all vertically long rectangular, and are positioned side by side in the direction in which the gate lines extend, forming a pixel formation portion.
Meanwhile, in recent years, liquid crystal display devices in television receivers, for example, begin to use multi-primary color technology for improved display performance, in which traditional three primary colors of RGB for the color image display are replaced by four or more primary colors.
For example, in a four primary color liquid crystal display device in which color image display is based on four primary colors, it is a common practice to use a configuration as shown in FIG. 18, where four sub pixel-formation portions Ps(i, j) which handle the four primary colors are formed side by side in the direction in which the gate lines Lg extend (hereinafter, this direction will also be referred to as "horizontal direction" regardless of the actual direction since this direction is generally the horizontal direction in actual applications) (also, the above-described configuration will be called "vertically long subpixel configuration" hereinafter).
On the other hand, there is also proposed a configuration as shown in FIG. 19, where four sub pixel-formation portions Ps(i, j) which handle the four primary colors are formed side by side in the direction in which the source lines Ls extend (hereinafter, this direction will also be referred to as "vertical direction" regardless of the actual direction since this direction is generally the vertical direction in actual applications) (also, the above-described configuration will be called "horizontally long subpixel configuration" hereinafter).
The following Patent Literatures 1 and 2 disclose techniques relevant to the present invention. Specifically, Patent Literature 1 discloses a matrix display device including a display section formed by: a plurality of scanning lines and a plurality of data lines disposed in a matrix pattern; unit pixels which have a predetermined color order in the vertical direction of the display screen and are arranged in a matrix pattern; and constituent elements R, G and B which handles the colors in the pixel and are disposed at one of the intersections made by the scanning lines and the data lines. This matrix display device is classified as a horizontally long subpixel configuration category described above. In this matrix display device, data signal supply to the data lines is performed a plurality of times (three times according to an embodiment) for the respective colors during the period of 1H, and selection pulse supply to the scanning lines is performed a plurality of times (three times according to the embodiment) for the respective colors during the period of 1H. Patent Literature 2 discloses a liquid-crystal color display device in which each pixel is constituted by four kinds of color filter elements each corresponding to a pixel electrode, and these four kinds of color filters which constitute one pixel are disposed at up and down, left and right positions (i.e., disposed in a matrix of 2×2).


The present invention relates to a method of analysing cardiac data relating to a patient, comprising: providing cardiac data relating to the patient—optionally by using a means for providing physiological data (20); determining one or more properties of the data, wherein the or each property is determined over a particular context length, the context length being selected based on the or each property—optionally using an analysis module (24); comparing the or each property against a respective predetermined threshold value, thereby to indicate a probability of the patient experiencing a cardiac event—optionally using a means for providing an output (26); and providing an output based on the comparison. A system and apparatus corresponding to this method is also disclosed.

The present invention relates to the analysis of cardiac data, in particular, the invention relates to a system and method of determining the probability of a cardiac event occurring. This may enable timely preventative action to be taken, or may enable the determination of periods where increased monitoring of a person may be beneficial.
There are numerous conditions which may result in the deterioration of a patient's health; accurate prediction of these conditions would, usefully, enable preventative action to be taken. One such condition is sudden cardiac death (SCD), which is death caused by a loss of heart function; this is expressed by sudden loss of consciousness, occurring within 1 hour after the primary onset of the acute symptoms. Despite the harm caused by SCD, there remains difficulty in determining, with a sufficient prediction time, the likelihood of SCD occurring.
Current prediction methods use echocardiography and magnet resonance tomography; whilst these methods can be used to predict long-term risk of cardiac events (over a timescale of months to years), they are, problematically, not currently useable to determine short to medium term risk (minutes to hours/days). It is often not possible, or economical, to monitor a high-risk patient constantly for years, therefore there is needed a method that can indicate the risk of a cardiac event over these shorter timescales.
At present, many patients are continuously monitored in hospital wards and other settings, where measurements of the electrical activity of the heart, such as electrocardiograms, are taken on a regular basis, sometimes continuously. These measurements enable characteristics of cardiac activity to be extracted. However, only minimal processing is applied to the data, resulting in healthcare providers being confronted with large amounts of noisy raw data. While current technology allows for algorithmic analysis and description of the patient's cardiac activity at the time of analysis (and, as aforementioned, potentially allows for determination of a long-term risk), it does not provide predictive analysis of short to medium term potential future    cardiac activity. The present invention aims to make the measured data more useful and actionable through sophisticated data analysis and the use of artificial intelligence, so that cardiac events (and more generally periods of increased risk, where additional attention should be given to a patient) may be predicted.


A system for advertising on a Peer-to-Peer network detects a search request of a node in a Peer-to-Peer network. After detecting a search request, the system prepares an unsolicited response (e.g., advertisement) to the search request of the node. Once the unsolicited response is prepared, the system sends the unsolicited response to the node. For example, a Peer-to-Peer network node issues a search request and a system prepares an advertisement (e.g., an unsolicited response). After preparing the advertisement, the system sends the advertisement to the Peer-to-Peer network node that issued the search request. The process of sending advertisements can be made to each node issuing a search request without discrimination. In one example, the system detects a search request of a node in a Peer-to-Peer network; prepares an advertisement in response to the search request of the node based on a predetermined search criteria; and sends the advertisement to the node for advertising on the Peer-to-Peer network.

Peer-to-Peer network users issue over 800 million searches a day compared to the 250 million searches a day users issue on the World Wide Web. A Peer-to-Peer network relies primarily on the computing power and bandwidth of participants in a network and are generally used for connecting nodes via connections. One use for such a network is sharing content files. Content files may contain audio, video, data, or other digital formats. The content is typically accessed in real-time data using Peer-to-Peer technology. To access a Peer-to-Peer network for sharing, a user utilizes a Peer-to-Peer network software application that is capable of connecting to the Peer-to-Peer network.
An example Peer-to-Peer network includes multiple nodes, where each node has a file server and a client capable of sending and receiving data, such as a "communication message" between nodes. A node is typically connected to other nodes in a network. In some Peer-to-Peer networks, a node connects to other nodes over a communications path, such as the Internet or proxy. For example, FIG. 1 shows a Peer-to-Peer network connection capable of searching for shared files. To search on a Peer-to-Peer network, a process issues a search request and an originating node sends the search request to receiving nodes (e.g., each node that the originating nodes is connected). Each receiving node searches for a match and responds to the requesting node with location information for each match. Another variation of a Peer-to-Peer network is shown in FIG. 3. In particular, FIG. 3 shows a non-proxy loop network wherein each node is directly connected to another.
In other Peer-to-Peer proxy networks, there may be multiple nodes as illustrated in FIG. 2. FIG. 2 shows node A connected to node B and, in turn, node B is connected to node C. In this example, node A is not directly connected to node C. In use, node A issues a search request to node B and node B searches shared files for a match. If a match is found, node B sends a response back to node A including a location for the shared file. After responding to node A, node B forwards node A's request to node C. In response, node C searches the shared files for a match and responds to node B with a location of each shared file. Node B then forwards a response back to node A.
Peer-to-Peer networks may also use a leaf node/main node proxy topology as illustrated in FIG. 4. In this network variation, one or more nodes are classified as main nodes and the other nodes are classified as leaf nodes. A leaf node may only connect to main nodes and main nodes can connect to other main nodes. Thus, if a leaf node issues a search request, the leaf node sends the search request to a main node connects to the leaf node. Upon receiving the search request, the main node forwards the request to each leaf node and main nodes connected to the requesting main node. The receiving main node forwards each search request to each of the leaf nodes that they are in connection with.
In some cases, Peer-to-Peer networks can include millions of nodes that use a large amount of bandwidth. To reduce the bandwidth used in operating such networks, many Peer-to-Peer networks restrict the "distance" of messages traveling the network (e.g., limit hops or Time to Live (TTL)). For example, a Peer-to-Peer network may be limited to performing only five hops as shown in FIG. 5. For example, Node A may issue a search request to Node B. In turn, Node B passes the search request to Node C, and so forth until reaching Node F. Since, the Peer-to-Peer network is limited to five hops, the search requests end at Node F and do not pass to any additional nodes. It is useful to note that other mechanisms are also employed in networks for limiting the search capabilities of users.
FIG. 6 shows network nodes communicating over a transmission distance of three nodes. In particular, node A 605 communicates with each node within the A circle 610. Similarly, node B 615 communicates with each node within the B circle 620. Likewise, node C 625 communicates with each node within the C circle 630 and with each node within the B circle 620 that is overlapping the C circle 630. However, no node can communicate with a non-overlapping area or within a corresponding circle. Thus, there is a need to access nodes without regard to location while using unlimited search requests in a manner positive to business development.

System and method for advertising on a peer-to-peer network


An eco-friendly (meth)acrylic flame retardant copolymer includes a phosphorous-based acrylic monomer to provide a high index of refraction and excellent flame retardancy.

Recently, there has been an increasing demand for exterior materials for electric and electronic products or automobiles having high functionality and high performance. In particular, there is increasing demand for exterior materials that ensure flame retardancy together with good scratch resistance and pleasant tactile texture.
As commercially available resins capable of exhibiting scratch resistance, acrylic resins, specifically polymethyl methacrylate (PMMA) resins, have excellent transparency, weather resistance, mechanical strength, surface gloss, adhesion, and the like. However, acrylic resins have drawbacks in that impact resistance and flame retardancy are very poor.
In order to achieve both scratch resistance and flame retardancy, it is proposed to add a flame retardant to impose flame retardancy in preparation of polymethyl methacrylate (PMMA) resins having good scratch resistance of a pencil hardness level of 3H to 4H. In this case, however, it is necessary to add a large amount of flame retardant. As a result, the flame retardant monomer can escape from the resins, which can cause environmental problems and deterioration in mechanical properties of the resin.
In addition, the acrylic resin, specifically a polymethyl methacrylate (PMMA) resin, can be mixed with a polycarbonate resin exhibiting good mechanical strength and flame retardancy to provide good scratch resistance and flame retardancy. However, due to high index of refraction of the polycarbonate resin, the polymethyl methacrylate resin can suffer from deterioration in transparency and colorability when mixed with the polycarbonate resin. Moreover, in order to have good compatibility with the polycarbonate resin, the acrylic resin is required to have a high index of refraction.

(Meth)acrylic-based flame retardant copolymer and method for manufacturing the same


Techniques for performing lead functionality tests, e.g., lead impedance tests, for implantable electrical leads are described. In some of the described embodiments, an implantable medical device determines whether a patient is in a target activity state, e.g., an activity state in which lead impedance testing will be unobtrusive, such as when a patient is asleep, or capture information of particular interest, such as when the patient is active, in a particular posture, or changing postures. The implantable medical device performs the lead functionality test based on this determination. Additionally, in some embodiments, the implantable medical device may group a plurality of measurements for a single lead functionality test into a plurality of sessions, and perform the measurement sessions interleaved with delivery of therapeutic stimulation.

Implantable medical devices may be used to deliver therapeutic electrical stimulation to patients to treat a variety of symptoms or conditions, such as chronic pain, tremor, Parkinson's disease, epilepsy, incontinence, or gastroparesis. To treat such symptoms or conditions, an implantable medical device may deliver stimulation via electrical leads that include electrodes located proximate to the spinal cord, pelvic nerves, or stomach, or within the brain of a patient. In general, implantable medical devices deliver stimulation in the form of electrical pulses. Implantable medical devices coupled to electrode-carrying leads may additionally or alternatively be used to sense electrical activity within a patient.
An electrical lead may carry multiple electrodes, and each electrode may be coupled to a respective insulated conductor within the lead. An electrode, associated conductor, and tissue proximate to the electrode may form an "electrical path." The impedance of the various electrical paths provided by a lead may vary over the life of an implantable medical device due to, for example, material degradation or tissue growth proximate to the electrode. Further, a lead may develop a short between two or more conductors when insulation fails, or a conductor may fracture due to bending or other stresses placed on the lead by patient movement or manipulation.
Changes in lead impedance impair the ability of an implantable medical device to effectively sense electrical activity and/or deliver stimulation. Consequently, it may be desired to identify such changes in order to take corrective action, such as implantation of a new lead, or selection of different electrodes for sensing or delivery of stimulation. Traditionally, clinicians have used a programming device during an office visit to manually direct an implantable medical device to perform a lead integrity or functionality test. Manual lead functionality testing may include manually defining a plurality electrode combinations and, for each combination, directing the implantable medical device to measure the impedance presented by electrical paths the combination, or another electrical parameter for the combination, such as the current flowing through the electrical paths. The impedances, currents, or other electrical parameters of the various combinations may allow the clinician to identify changes in impedance or failures of the electrical path associated with a particular electrode.
Manual testing may be desired to confirm and maintain device efficacy, but is also very tedious. Because of the large number of possible electrode combinations that may be available on the one or more leads coupled to an implantable medical device, testing can take several minutes. During this time, therapeutic stimulation is generally not available, which can result in discomfort for or danger to the patient because symptoms are not suppressed.
Furthermore, significant changes in impedance, or other lead functionality issues, may occur between clinic visits, and may occur gradually over time. In some cases, such as where an implantable medical device is used for sensing, or to deliver deep brain stimulation, which are generally not perceivable by the patient, the patient may not detect a degradation of lead functionality. In such cases, the sensing or therapy may be inadequate for a significant period of time, e.g., until the next regularly-scheduled clinic visit, which may pose risks for the patient.
Also, a conductor short or fracture may be intermittent, and more likely to manifest during periods when the patient is changing posture, within a particular posture, or otherwise active. In such cases, a clinician may not be able to detect a conductor problem with a manual lead functionality test performed during an office visit. The existence of undiscovered conductor problems may limit the effectiveness of therapy and sensing, as discussed above.

This patent is subject to a terminal disclaimer.


A structure includes a semiconductor substrate including a first semiconductor region and a second semiconductor region, a first transistor in the first semiconductor region, and a second transistor in the second semiconductor region. The first transistor includes a first gate dielectric over the first semiconductor region, a first work function layer over and contacting the first gate dielectric, and a first conductive region over the first work function layer. The second transistor includes a second gate dielectric over the second semiconductor region, a second work function layer over and contacting the second gate dielectric, wherein the first work function layer and the second work function layer have different work functions, and a second conductive region over the second work function layer.

Transistors are basic building elements in integrated circuits. The formation of the transistors may include forming replacement gates, which include high-k gate dielectrics and metal gate electrodes over the high-k gate dielectrics. The formation of a replacement gate typically involves depositing a high-k gate dielectric and metal layers over the high-k gate dielectric, and then performing Chemical Mechanical Polish (CMP) to remove excess portions of the high-k gate dielectric and the metal layers. The remaining portions of the metal layers form the metal gates.
In conventional formation methods of the MOS devices, the threshold voltages of the transistors may be adjusted by stacking a plurality of work function layers. For example, for p-type transistors, a plurality of titanium nitride layers may be stacked to reduce the threshold voltages of the p-type transistors and to generate multiple threshold levels.

Method of tuning threshold voltages of transistors

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.


A generally loose-fitting tubular sheath article, such as a condom, which has a closed distal end and an open proximal end which is bounded by a knitted material that bears compressively on the sheathed member to provide retention. The knitted material may be in the form of a band which is affixed to the sheath by everting a portion of the sheath material at the proximal end over the knitted material and attaching the sheath material to itself, thereby creating a toroidal enclosure in which the knitted material is disposed. Constriction of the sheathed member is minimized by the knitted material which provides a large surface area for retentive contact.

1. Field of the Invention
This invention relates to a generally tubular sheathing article, e.g., a condom or prophylactic article, comprising a knitted retention structure for compressively retaining the sheathing article on the member or element being sheathed, as well as to a method of making such sheathing articles.
2. Description of the Related Art
In the field of prophylactic or condom articles, much effort has been directed in recent years to improving the structure and rate of fabrication of such articles, under the impetus of significant increases in the incidence and spread of sexually transmitted diseases, as a result of the evolution of increasingly antibiotic-resistant strains of disease-causing organisms, e.g., those responsible for diseases such as gonorrhea and syphilis, and the absence of any effective cure for acquired immunodeficiency syndrome (AIDS).
The aforementioned disease factors have also created an increased consumer demand for condoms, in view of their benefits as a safe, low cost, and generally reliable means for reducing the risk of infection and transmission of sexually transmitted diseases, as well as their traditional function as a barrier-type contraceptive means.
Against this background, design and manufacturing efforts have been focused on the develop of condoms characterized by increased ease of application to the penis of the wearer, and comfort in use, to thereby enhance the appeal of using condoms in coital activity.
Currently, most condoms are produced from a latex resin via a dipping process in which a cylindrical and rounded-end mold is dipped into a resin bath, so that the mold is coated with a thin layer of the latex material. The thickness of the latex coating on the mold is dependent on the viscosity of the latex, and the speed of extracting the mold from the latex bath. Similar latex dipping processes have been employed with suitably shaped molds to form tight-fitting gloves such as surgical gloves, as well as other sheathing articles.
Structurally, the conventional latex condom comprises a tubular main sheath with a closed distal end and an open proximal end. The open proximal end may be circumscribingly bounded by a filament of elastic material, to aid in retaining the condom on the penis of the wearer, to demarcate the proximal opening for use of the condom, and to prevent tearing of or damage to the tubular main sheath of the condom during its application and use.
In addition, the circumscribing filament serves as a "rolling core" onto which the main sheath portion of the condom may be rolled along its length in conventional fashion to produce a toroidal roll surrounding a distal end portion of the sheath when the condom is in a fully rolled conformation; subsequently, the condom is simply reverse-rolled onto the penis of the wearer, from the glans to the base of the penis.
To the extent that the elastic filament bears compressively against the circumference of the base of the penis, a further enhanced protection is provided against leakage of seminal fluid and sperm from the condom, and against entry of vaginal exudates or other coital secretions from the recipient coital partner, into the interior volume of the condom containing the penis, during sexual activity.
In order to accommodate the sealing and retention function of the elastic filament at the proximal opening of the condom, the elastic filament must be significantly stretched in application of the condom to the wearer's penis. As a result, the condom is often difficult to don, due to the small size of the condom's proximal opening, and the resistance to stretching of the proximal opening and the bounding filament which is intended to provide a tight fit once the condom is installed on the penis of the wearer.
During their commercial production, condoms made of latex rubber typically are rolled, as hereinabove discussed, to render them easier to package, store, and apply, relative to unrolled condoms. Although rolling gives the condom a more compact structure, thereby facilitating ease of packaging and storage, the donning of rolled condoms frequently is difficult since the user must stretch the roll apart in the donning operation. Generally, the "spreadability" of the rolled condom is made difficult by its tightly compacted character, and the required positioning of the rolled condom on the invariably asymmetric glans of the penis to initiate unrolling.
Further, the roll portion of the condom initially must be grasped with the fingers for application to the glans and unrolling onto the penis. The size of the condom roll is typically sufficiently small, e.g., generally being less than about 3/16 inch in roll diameter, so that it is difficult to grasp the roll with the fingertips and to install the condom on the penis of the wearer. This is particularly true in the case of very thin or form-fitting condoms which are characterized by a very tiny roll.
As a result of the small size (diameter) of the roll, the need to utilize the fingers in installation of the condom, and the absence of good grippability, the fingertips are often tightly pinched onto the roll to gain purchase thereon. This in turn raises the risk of shredding or puncturing of the condom material by the fingernails or otherwise breaking the condom as a result of such pinching or grasping, so that the condom, when subsequently unrolled, has breaks or discontinuities therein which render the condom deficient or even useless for its intended function.
The foregoing problems attendant to the use of conventional rolled condoms with elastic filament retaining rings has stimulated the development of alternative condom designs, wherein the retention structure is of a different type than elastic filaments. This effort has been made in the context of an evolution of condom technology to embrace the use of materials of construction other than latex rubber for the condom sheath.
Wheeler U.S. Pat. No. 4,964,416 discloses condoms formed of thermoplastic elastic materials such as thermoplastic elastomers, e.g., polyurethanes, polyesters, polyethers, multi-block copolymers, olefinic homopolymers and copolymers, etc. This patent discloses the use of an annular sealing element at the proximal end portion of the condom which features a circumscribed opening bounded by the annular body of the sealing element. The sealing element is formed of a thin film material, so that when the condom is donned, the inner edge surface of the annular element opening bears compressively on the external surface of the base of the penis, to provide enhanced sealing thereagainst.
Although the Wheeler patented condom provides an effective seal against the exterior surface of the penis, and the interior opening of the annular sealing element permits ready passage of the penis therethrough when the condom is installed on the penis, after installation the compressive retention force is applied to the surface of the penis only over the inner circumferential surface of the thin film annular sealing element. As a result the compressive pressure of the annular sealing element on the penis is substantial, and although the thin film annular element is radially and circumferentially yielding in character, the constrictive force exerted by the sealing element may exceed the limit of comfort, particularly when the penis being sheathed is significantly larger in circumference than the inner opening of the annular sealing element.
Considering as illustrative examples the above-discussed elastic filament retention structures of conventional latex condoms, and the annular sealing element of the Wheeler patent, it is appreciated that the compressive retention structure of a condom must satisfy several competing criteria:
(1) the retention structure must provide adequate compressive force on the penis for effective sealing of the sheath of the condom against leakage into or out of the condom sheath interior volume containing the penis, such as may compromise the contraceptive and/or prophylactic efficacy of the condom; PA1 (2) the retention structure must allow ready ingress of the penis into the sheath of the condom, which means that the retention structure must be expandable from its initial compressive or gathered state to permit the condom to be easily rolled or pulled onto the penis for installation thereon; PA1 (3) the retention structure must provide a constrictive action which however does not produce discomfort or otherwise interfere with coital pleasure and satisfaction; and PA1 (4) the retention structure must be readily securable to or formable with the sheath structure of the condom, so that the condom can be easily, quickly, and economically produced in mass production quantities--it is to be recognized that the compressive retention structure is desirably structurally consolidated with the sheath of the condom, as a unitary product article, during the condom manufacturing process, and this typically involves expansion of the retention structure prior to and/or during its being joined with the sheath, followed by relaxation of the stretched retention structure. PA1 (i) a generally tubular sheath member having a closed first end and an open second end defining an enclosed interior volume within the sheath member accessible by the open second end, for introduction of the sheathable part into the interior volume through the open second end; and PA1 (ii) a knitted retention structure associated with the sheath member at a proximal portion of the sheath member in the vicinity of its open second end, for exerting a compressive retaining action on the sheathable part at the proximal portion of the sheath member. PA1 (a) providing a generally tubular sheath member having a closed first end and an open second end; PA1 (b) disposing a circumferentially extending knitted retention band about an exterior surface second end portion of the sheath member, in spaced relation to the open second end thereof, to thereby define a proximal segment of the sheath member between the knitted retention band and the open second end; PA1 (c) everting the proximal segment of the sheath member between the knitted retention band and the open second end so that the everted proximal segment enclosingly overlies the knitted retention band; and PA1 (d) securing the everted proximal segment of the sheath member to an overlaid exterior surface region of the sheath member to form an enclosure volume containing the knitted retention band.
Considering the manufacturability factors identified in (4) above, it is apparent that the stretching of a small diameter elastic filament or 0-ring for connection to the sheath presents significant processing problems. In conventional latex condom manufacture, the retention ring is stretched over the mandrel bearing the latex sheath member (formed by drying of the latex solution applied to the mandrel during dipping thereof, as previously described hereinabove), and is positioned at a proximal part of the sheath. The condom then is rolled on the mandrel, about the elastic filament as a rolling core. In the rolling operation, a portion of the ring or resultingly formed roll may, during the rolling operation, preferentially grip or gain purchase on, the film, so that uneven tension is imposed on the sheath, which may cause it to subsequently tear or split in use. Further, the generally circular cross-section of the elastic filament and its typically very small diameter make it very difficult to gain purchase on and to position or translate with high accuracy (these are the manufacturing analogs of the purchase/manipulability use problems discussed earlier hereinabove), and these factors again may lead to the aforementioned uneven rolling problems.
The above-described Wheeler patented condom avoids the aforementioned problems incident to the use of the elastic filament as a compressive retention structure, but presents its own difficulties in the handling and processing of the thin film annular sealing element, which must of course be leak-tightly secured to the inner surface of the condom sheath to achieve its intended purpose. The thickness of the annuiar thin film sealing element may for example be commensurate with the thickness of the sheath itself, and leak-tight sealing of such low thickness films requires very accurate sealing techniques, such as heat sealing or ultrasonic bonding at low dimensional tolerances, which avoid the rupture or piercing of the films during their bonding to one another.
U.S. Pat. No. 4,855,169 issued Aug. 8, 1989 to M. W. McGlothlin et al., describes a prophylactic device including a sheath of elastomeric sheet material with a 100% tensile modulus of at least about 200 psi and a thickness of less than about 0.0014 inch. The sheath has an open end and a border containing a resilient material of reduced 100% tensile modulus, relative to the elastic sheet material. In this device, the ratio of the thickness of the border to the thickness of the sheath is from about 10 to about 300. The materials disclosed in the patent for the sheath include polyurethane and various other thermoplastic elastomeric materials. The patent discloses that the border may be constituted by a ring which is either bonded or unbonded to the sheath, or, alternatively, the border may be constituted by a flat band encircling the proximal open end of the sheath of either bonded or unbonded type.
The McGlothlin et al. patent discloses that the augmented border which is provided as the retention structure of the described prophylactic article may be formed of low modulus materials such as polyurethanes, plasticized polyurethanes, latex rubbers, silicone elastomers, ethylene/propylene thermoplastic elastomers, styrene block copolymer thermoplastic elastomers, olefinic thermoplastic elastomers, polyether block amide thermoplastic elastomers, polyvinylchlorides, acrylic-based thermoplastic elastomers, hot-melt or pressure adhesive materials, and foam polymers.
An improvement on the condom of the McGlothlin patent is disclosed in prior copending patent application Ser. No. 07/693,550 filed Apr. 30, 1991 in the name of John T. Leffler. This application discloses a condom comprising an elongate sheath having an open proximal end and a closed distal end, which is rolled or rollable on a roll ring having an axial thickness dimension and a transverse (width) dimension each of which is at least 0.125 inch, wherein the thickness of the sheath is from about 0.0004 inch to about 0.003 inch, and the ratio of the transverse width of the roll ring to the thickness of the sheath is in the range of from about 350 to about 5,000. The roll ring in such condom structure may be of a low durometer material such as a highly plasticized or solvent-swollen polymer having a gelatinous consistency rendering the sheath easily rollable thereon.
While the thrust of the teachings of the aforementioned McGlothlin et al. patent and Leffler patent application are in favor of relatively large roll rings or band structures as rolling cores, having a number of intrinsic advantages as described in these references, there is a continuing need in the art for compressive retention structures of improved type, which afford the various advantages taught to be characteristic of the McGlothlin et al. and Leffler ring and band retention structures, but which are more compact in size, and which fully meet the criteria (1)-(4) referred to and discussed hereinabove.
Accordingly, it is an object of the present invention to provide a sheath article having a compressive retention structure of improved type, affording such aforementioned advantages.
It is another object of the invention to provide a sheath article of such type, which is easily, simply, and economically manufacturable in character.
It is a still further object of the present invention to provide a method of making an improved sheath article of such type.
Other objects and advantages of the present invention will be more fully apparent from the ensuing disclosure and appended claims.

Tubular sheathing article comprising knitted retention structure, and method of making the same


The invention relates to a center break switch having a contact system for electrical current conduction and bus transfer switching. The contact system includes two moving contacts. One of the two moving contacts includes a finger contact and the other moving contact includes a first contact. Each moving contact includes a contact for bus transfer switching, wherein one of the two contacts includes a spherical contacting element, and the other contact includes a rectangular contacting element. The spherical contacting element and the rectangular contacting element engage during switching for the bus transfer, and stay in contact when the finger contact is engaged with the first contact for electrical current conduction.

Switchgear (e.g. disconnector) may be used for load transfer between buses (bus transfer). In such applications, the switchgear has the making/breaking capability, to handle the electrical/mechanical stresses involved in the bus transfer. Usually the switchgear contacts (fixed/moving) are designed to handle the electrical/mechanical stresses in the bus transfer. These contacts are typically the contact pins and/or the contact plate/fingers, either of which may be provided as a fixed or movable contact.
With increase in demand, high voltage switchgear (e.g. around 100 kV or above) for higher current ratings (e.g. around 2000 A, or more) are desired. It is required to support bus transfer switching at such ratings. Also, depending on the type, different making/breaking capabilities are required. As the rating increases, the switchgear contacts are exposed to higher wear and tear as a result of increase in the electrical/mechanical stresses.
Consider a center break switch with two moving contacts. One moving contact may have contact fingers, and the other contact may have complimentary first contact. The contact fingers and first contact are not suitable to handle the electrical/mechanical stresses for such high ratings.
In view of the above, there is a need for switchgear with improved contact systems for such higher ratings.

Spring loaded auxiliary contact system for bus transfer switching in a center break switch


A straddle-riding vehicle includes a vehicle body frame including an engine supporting portion that supports an engine and a front wheel supporting portion arranged in front of the engine supporting portion, wherein a wheel supporting arm that supports the front wheel and a suspension arm that supports the wheel supporting arm are mounted to the front wheel supporting portion. At least a portion of a secondary air introduction unit that introduces secondary air into an exhaust passage of the engine is positioned directly behind the front wheel supporting portion.

1. Field of the Invention
The present invention relates to a straddle-riding type vehicle, and more particularly, to an arrangement of a secondary air introduction unit.
2. Description of the Related Art
A straddle-riding type vehicle may include a secondary air introduction unit that introduces secondary air into an exhaust passage of an engine.
In a straddle-riding type vehicle, in particular, an ATV (All Terrain Vehicle), which is used on an uneven ground, dirt and sand may be thrown up by the front wheels from the forward direction. Such dirt and sand may hit the secondary air introduction unit.


A compression part of a rotary compressor includes an intermediate partition plate that is arranged between an upper cylinder and a lower cylinder, an upper vane that sections an upper cylinder chamber formed within the upper cylinder into an upper suction chamber and an upper compression chamber, and a lower vane that sections a lower cylinder chamber formed within the lower cylinder into a lower suction chamber and a lower compression chamber. The intermediate partition plate is formed with an injection hole that injects a liquid refrigerant into the upper compression chamber and the lower compression chamber and an injection passage that supplies the liquid refrigerant to the injection hole. The injection passage is formed along a straight line that does not cross a rotary shaft insertion hole into which a rotary shaft is inserted.

A rotary compressor is known that injects a liquid refrigerant into a cylinder chamber in which a refrigerant is compressed to increase the compression efficiency of the refrigerant (refer to Patent Literature 1). A compression part of a two-cylinder rotary compressor includes an upper end plate blocking the upper side of an upper cylinder chamber, a lower end plate blocking the lower side of a lower cylinder chamber, and an intermediate partition plate separating the upper cylinder chamber and the lower cylinder chamber. The upper end plate is provided with an upper discharge hole causing an upper compression chamber of the upper cylinder chamber to communicate with an upper end plate cover chamber and is provided with a lead valve type upper discharge valve opening and closing the upper discharge hole. The lower end plate is provided with a lower discharge hole causing a lower compression chamber of the lower cylinder chamber to communicate with a lower end plate cover chamber and is provided with a lead valve type lower discharge valve opening and closing the lower discharge hole. The intermediate partition plate is provided with an injection hole and an injection passage supplying a liquid refrigerant to the injection hole. The rotary compressor injects the liquid refrigerant into the upper compression chamber and the lower compression chamber via the injection hole at a certain timing and can thereby improve efficiency.


A cooling water flow control device of a cooling system for a vehicle can shorten a warm-up time of a cooling water being supplied to an exhaust gas recirculation (EGR) cooler. The cooling water flow control device includes: the EGR cooler that cools an exhaust gas supplied to an intake system of an engine using cooling water and includes an EGR cooler outlet through which the cooling water is discharged; a water pump to circulate the cooling water to the EGR cooler and the engine at an engine startup; and a direct flow path connected to a vent hole formed in the engine to guide the cooling water from the vent hole to a downstream side of an EGR cooler outlet.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In general, an exhaust gas recirculation (EGR) cooler serves to lower the temperature of an engine exhaust gas in the process of recirculating the exhaust gas to an intake system. The exhaust gas that is supplied to the engine through the EGR cooler is re-burnt, and thus nitrogen oxide included in the exhaust gas is burnt to be able to reduce toxic substances of the exhaust gas being discharged out of the vehicle.
Such an EGR cooler cools the exhaust gas using cooling water that is used for engine cooling. For this, the EGR cooler is configured so that heat can be exchanged between the cooling water being supplied through a water pump and the exhaust gas being supplied from an exhaust system.
According to the EGR cooler in the related art, in order to secure durability for the high-temperature exhaust gas, the cooling water may circulate before the cooling water circulates in the engine at the engine startup, and in this case, the cooling water circulating in the EGR cooler has a temperature that is lower than the temperature of the cooling water being stored in a water jacket provided inside the engine.
According to the EGR cooler as described above, the cooling water having the temperature that is lower than the temperature of the cooling water inside the engine constantly circulates from the initial engine startup, and this may cause a warm-up time of the cooling water on the EGR cooler to be lengthened.
Meanwhile, if the temperature of the cooling water circulating in the EGR cooler is equal to or lower than a predetermined cold temperature, condensate water is created in the EGR cooler, and in severe cases, a large amount of condensate water is created and gathered in the EGR cooler.
The condensate water being created in the EGR cooler is high-density acidic condensate water, and thus it causes corrosion to occur on the inside of the EGR cooler. If the inside of the EGR cooler is corroded, the cooling water is mixed with the recirculating exhaust gas being supplied to the engine, and thus engine failure may occur to cause very dangerous situations.
According to the EGR system in the related art, if the temperature of the cooling water in the EGR cooler is equal to or lower than the predetermined temperature, the EGR cooler does not operate, and if the EGR cooler is unable to be used as described above, it is not possible to improve the vehicle fuel economy through the operation of the EGR cooler.
The above information disclosed in this background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

Cooling water flow control device of cooling system for vehicle


Segmented polyurethane/ureas useful in the production of spandex are produced by chain extending an isocyanate-terminated prepolymer with a diamine chain extender that includes: (1) from about 7 to 25 equivalent percent of an asymmetric aliphatic and/or cycloaliphatic diamine and (2) a linear diamine such as ethylene diamine in the presence of a solvent. The isocyanate-terminated prepolymer is produced by reacting a stoichiometric excess of an isocyanate with an isocyanate-reactive component that includes: (1) from about 10 to about 70 equivalent percent of a polyoxypropylene diol having a molecular weight in excess of 1500 Da and an average unsaturation level no greater than about 0.03 meq/g and (2) from about 30 to about 90 equivalent percent of a polytetramethylene ether glycol having a molecular weight of at least 600 Da.

The present invention relates to segmented polyurethane/ureas having excellent elasticity, mechanical and thermal properties, to fibers made with such polyurethane/ureas and to processes for the production of such polyurethane/ureas and fibers. More particularly, the present invention pertains to polyurethane/ureas and spandex fibers made from isocyanate-terminated prepolymers derived from a mixture of a polytetramethylene ether glycol (PTMEG) and a low unsaturation, high molecular weight polyoxyalkylene diol by chain extending the prepolymer with a linear diamine and at least one asymmetric aliphatic and/or cycloaliphatic diamine.
Polyurethane/ureas having elastomeric characteristics in the forms of fibers and films have found wide acceptance in the textile industry. The term xe2x80x9cspandexxe2x80x9d, often used to describe these elastomeric polyurethane/ureas, refers to long chain synthetic polymers made up of at least 85% by weight of segmented polyurethane. The term xe2x80x9celastanexe2x80x9d is also used (e.g., in Europe) to describe these polymers. Spandex is used for many different purposes in the textile industry, especially in underwear, form-persuasive garments, bathing wear, and elastic garments or stockings. The elastomeric fibers may be supplied as core spun elastomer yarns spun round with filaments or staple fiber yarns or as a staple fiber in admixture with non-elastic fibers for the purpose of improving the wearing qualities of fabrics which are not in themselves highly elastic.
In the past, thread made of natural rubber was the only material available to provide elasticity to fabrics. Spandex, originally developed in the 1950s, has numerous advantages over such rubber filaments. The most important of these is its higher modulus. Typically, for a given denier, spandex has at least twice the recovery, or retractive power, of rubber. This enables stretch garments to be manufactured with less elastic fiber and thus be lighter in weight. Additional advantages over natural rubber include the ability to obtain spandex in much finer deniers, higher tensile strength and abrasion resistance, and in many cases, higher resilience. Additionally, spandex exhibits improved resistance to many cosmetic oils, to solvents (for example, those used in dry cleaning), and a high resistance to oxidation and ozone as well. Furthermore, in contrast to rubber filaments, spandex fibers can be dyed relatively easily with certain classes of dyestuffs.
Preparation of polyurethane elastomers by the polyaddition process from high molecular weight, substantially linear polyhydroxyl compounds, polyisocyanates and chain lengthening agents which have reactive hydrogen atoms by reaction in a highly polar organic solvent is known. The formation of fibers, filaments, threads, and films from these solvent-borne polyurethane elastomers and by reactive spinning is also known. See, e.g., U.S. Pat. Nos. 3,483,167 and 3,384,623 which disclose preparation of spandex fibers from isocyanate-terminated prepolymers prepared with polymeric diols.
Spandex made with PTMEG-derived prepolymers and polymers does not have the elongation or the low hysteresis of natural rubber but it is characterized by improved retractive power, higher tensile strength and the ability to better withstand oxidative aging. These improved features have made PTMEG-derived spandex the industry standard, despite the difficulties associated with PTMEG-derived prepolymers and polymers, and the relatively high cost of PTMEG itself.
For the reasons discussed above, the commercially preferred polymeric diol is polytetramethylene ether glycol (PTMEG). PTMEG is a solid at room temperature and produces prepolymers, particularly, diphenylmethane diisocyanate (xe2x80x9cMDIxe2x80x9d) prepolymers having extremely high viscosities.
However, despite the inherent difficulties of handling PTMEG, its high cost and the unsatisfactory hysteresis of fibers made with PTMEG, PTMEG continues to be the mainstay of spandex production because, to date, no satisfactory substitute has been found.
One potential substitute for PTMEG which has been evaluated is polyoxypropylene glycol (xe2x80x9cPPGxe2x80x9d) which, in principle, could be used to prepare spandex fibers. Preparation of spandex fibers from a prepolymer made with a polyol component composed primarily of PPG is attractive from an economic point of view because the cost of PPG is significantly lower than that of PTMEG. In addition, fiber prepared from prepolymers made with PPGs exhibit excellent elongation and retractive or holding power. PPGs are inherently easier to handle than PTMEG because they are non-crystallizable, relatively low viscosity liquids with low pour points. By contrast, PTMEGs are typically solids at 20 to 40xc2x0 C. depending on the grade.
U.S. Pat. No. 3,180,854, for example, discloses a polyurethane/urea fiber based on a prepolymer made with a 2000 Da molecular weight polyoxypropylene glycol. However, the properties of polyoxypropylene-derived spandex fibers are generally inferior to those of fibers based on PTMEG. Consequently, polyoxypropylene glycols have not been utilized commercially in spandex production. See, e.g., the POLYURETHANE HANDBOOK (Gunther Oertel, Ed., Carl Hanser Verlag Pub., Munich 1985, p. 578) which states: xe2x80x9cPolypropylene glycols have so far been used as soft segments only in experimental products since they produce inferior elastanesxe2x80x9d. (at page 578)
High molecular weight polyoxypropylene glycols made by conventional processes contain high percentages of terminal unsaturation or monofunctional hydroxyl-containing species (xe2x80x9cmonolxe2x80x9d). The monol is believed by many to act as a chain terminator, limiting the formation of the required high molecular weight polymer during chain extension and yielding products which are generally inferior in comparison to PTMEG-derived elastomers.
The majority of polyoxyalkylene polyether polyols are polymerized in the presence of a pH-basic catalyst. For example, polyoxypropylene diols are prepared by the base catalyzed oxypropylation of a difunctional initiator such as propylene glycol. During base catalyzed oxypropylation, a competing rearrangement of propylene oxide to allyl alcohol continually introduces an unsaturated, monofunctional, oxyalkylatable species into the reactor. The oxyalkylation of this monofunctional species yields allyl-terminated polyoxypropylene monols. The rearrangement is discussed in BLOCK AND GRAFT POLYMERIZATION, Vol. 2, Ceresa, Ed., John Wiley and Sons, pp. 17-21.
Unsaturation is measured in accordance with ASTM D-2849-69 xe2x80x9cTesting Urethane Foam Polyol Raw Materials,xe2x80x9d and expressed as milliequivalents of unsaturation per gram of polyol (meq/g).
Due to the continual formation of allyl alcohol and its subsequent oxypropylation, the average functionality of the polyol mixture decreases and the molecular weight distribution broadens. Base-catalyzed polyoxyalkylene polyols contain considerable quantities of lower molecular weight, monofunctional species. In polyoxypropylene diols of 4000 Da molecular weight, the content of monofunctional species may lie between 30 and 40 mol percent. In such cases, the average functionality is lowered to approximately 1.6 to 1.7 from the nominal, or theoretical functionality of 2.0. In addition, the polyols have a high polydispersity, Mw/Mn due to the presence of a substantial amount of low molecular weight fractions.
Lowering unsaturation and the attendant large monol fraction in polyoxypropylene polyols has been touted as a means for production of polyurethane elastomers having improved properties. For example, use of polyols having a low content of monofunctional species has been suggested as a method for increasing polymer molecular weight; and increased polymer molecular weight has, in turn, been cited as desirable in producing higher performance polymers.
Reducing unsaturation in polyoxyalkylene polyols by lowering catalyst concentration and decreasing the reaction temperature is not feasible because even though low unsaturation polyols may be prepared, the reaction rate is so slow that oxypropylation takes days or even weeks. Thus, efforts have been made to discover catalysts capable of producing polyoxypropylated products in a reasonable amount of time without introducing monofunctionality due to allylic species.
In the early 1960""s, double metal cyanide catalysts such as zinc hexacyano-cobaltate complexes were developed to accomplish this objective. Such complexes are disclosed in U.S. Pat. Nos. 3,427,256; 3,427,334; 3,427,335; 3,829,505; and 3,941,849. Although the unsaturation level is lowered to approximately 0.018 meq/g, the cost of these catalysts coupled with the need for lengthy and expensive catalyst removal steps prevented commercialization of processes for the production of polyoxyalkylene polyols using these catalysts.
Other alternatives to basic catalysts such as cesium hydroxide and rubidium hydroxide are disclosed in U.S. Pat. No. 3,393,243. Barium and strontium oxide and hydroxide catalysts (disclosed in U.S. Pat. Nos. 5,010,187 and 5,114,619) enabled modest improvements with respect to unsaturation levels. However, catalyst expense, and in some cases, toxicity, and the modest level of improvement attributable to these catalysts, mitigated against their commercialization. Catalysts such as calcium naphthenate and combinations of calcium naphthenate with tertiary amines have proven to be useful in preparing polyols with unsaturation levels as low as 0.016 meq/g, and more generally in the range of from 0.02 to 0.04 meq/g. (See, e.g., U.S. Pat. Nos. 4,282,387; 4,687,851; and 5,010,117.)
In the 1980""s, use of double metal cyanide complex (DMC) catalysts was revisited. Improvements in catalytic activity and catalyst removal methods encouraged commercial use of DMC catalyzed polyols having low unsaturation levels (in the range of from 0.015 to 0.018 meq/g) commercially for a brief time. However, base catalysis continued to be the primary method used to produce polyoxypropylene polyols. pH-basic catalysts continue to be the catalysts which are primarily used in commercial polyoxyalkylene polyol production processes.
Major advances in DMC catalysts and polyoxyalkylation processes have enabled preparation of ultra-low unsaturation polyoxypropylene polyols on a commercial scale. High molecular weight polyols (molecular weight in the 4000 Da to 8000 Da range) typically exhibit unsaturation levels in the range of from 0.004 to 0.007 meq/g when catalyzed by these improved DMC catalysts. At these levels of unsaturation, only 2 mol percent or less of monofunctional species is present. GPC analysis of these polyols shows them to be virtually monodisperse, often exhibiting polydispersities of less than 1.10. Several such polyols have recently been commercialized as ACCLAIM(trademark) polyols.
U.S. Pat. No. 5,340,902 discloses that unsaturation levels of less than 0.03 milliequivalents/g are beneficial in the production of spandex fibers but does not provide any examples which illustrate use of polyols having unsaturation levels of less than 0.03 meq/g in the production of spandex fibers. U.S. Pat. No. 5,691,441 discloses that blends of low monol polyols with unsaturation levels of less than 0.010 meq/g are needed to achieve the benefits of the disclosed invention.
U.S. Pat. No. 5,691,441 teaches that xe2x80x9cThe ultra-low unsaturation polyols have been found to be quantitatively different than both conventional polyols and low unsaturation polyolsxe2x80x9d. In view of this teaching, it would be expected that the properties of spandex made with blends of PTMEG and polyoxypropylene diols having relatively high levels of unsaturation (greater than 0.010 meq/g) would have properties which are markedly inferior to those of fibers based on blends of PTMEG and polyoxypropylene diols containing ultra-low levels of unsaturation (i.e., less than 0.010 meq/g). U.S. Pat. No. 5,691,441 also teaches that xe2x80x9cethylene diamine as the sole chain extender is particularly preferredxe2x80x9d.
It is an object of the present invention to provide polyurethane/ureas useful for the production of spandex fibers which are made from a significant amount of PPG and have physical properties comparable to those of spandex fibers made with 100% PTMEG.
It is another object of the present invention to provide a process for the production of polyurethane/ureas and spandex fibers made from such polyurethane/ureas in which the advantageous physical properties of fiber made with PTMEG are achieved and the prepolymer viscosity and fiber hysteresis are reduced.
It is a further object of the present invention to provide polyurethane/ureas and spandex fibers made from such polyurethane/ureas which are based in part on less expensive and easier to handle polyoxypropylene glycols and which exhibit improved properties as compared to spandex fibers made solely with PTMEG.
It is also an object of the present invention to provide spandex fibers and a process for making spandex fibers characterized by excellent tenacity, elongation, retractive power, and set.
These and other objects which will be apparent to those skilled in the art are achieved by chain extending an isocyanate-terminated prepolymer which has been produced from an isocyanate-reactive component satisfying specified criteria with a chain extender component that includes: (1) from about 7 to 25 equivalent percent of an asymmetric aliphatic and/or cycloaliphatic diamine and (2) a linear diamine such as ethylene diamine. The isocyanate-reactive component includes: (1) at least one PTMEG and (2) at least one polyoxypropylene glycol having a molecular weight greater than about 1500 Da and an unsaturation level less than or equal to 0.03 meq/g. The elastomer thus obtained is then spun into fiber.
The present invention is directed to polyurethane/ureas suitable for use in the production of spandex fibers, to spandex fibers produced from these polyurethane/ureas and to processes for the production of such polyurethane/ureas and spandex fibers.
The polyurethane/ureas of the present invention are prepared from isocyanate-terminated prepolymers. Suitable prepolymers are produced by reacting an isocyanate-reactive component which is generally composed of diols with an excess of a diisocyanate. The isocyanate-terminated prepolymers typically used to produce this type of elastomer have a relatively low isocyanate content. Isocyanate contents of from about 1 to about 3.75 are preferred. Particularly preferred prepolymers have isocyanate contents of from 2-3.5%. The prepolymer is then chain extended in solution.
It has surprisingly been found that spandex systems based on an isocyanate-reactive component which is a blend of PPG and PTMEG produce fibers with acceptable mechanical properties even if the PPG component has an unsaturation level as high as 0.030 meq/g if the chain extender component of the present invention is used. Contrary to what is taught in the prior art, spandex fibers with excellent mechanical properties are obtained even with a PPG component having unsaturation levels greater than 0.010 meq/g if a chain extender component which includes from about 7 to about 25 equivalent percent of an asymmetric aliphatic and/or cycloaliphatic diamine and a linear diamine (e.g., ethylene diamine) is used.
A key feature of the present invention is the use of a chain extender component which includes at least one asymmetric aliphatic and/or cycloaliphatic diamine and at least one linear diamine to chain extend the isocyanate-terminated prepolymer. The asymmetric aliphatic and/or cycloaliphatic diamine should be present in an amount of from about 7 to about 25 equivalent percent, based on total equivalents of chain extender component, preferably from about 7 to about 20 equivalent percent, most preferably, from about 10 to about 15 equivalent percent. The remainder of the chain extender component is linear diamine.
Examples of suitable asymmetric aliphatic and/or cycloaliphatic chain extenders include: 1,2 diaminopropane; isophorone diamine; methyl-1,3-diaminocyclo-hexane; 1,3-diaminocyclohexane; 2-methyl-pentamethylenediamine (commercially available from DuPont under the name Dytek A); 1,4-diamino-2-methylpiperazine; 1,4-diamino-2,5-di-methylpiperazine; and methyl bis-propylamine.
Examples of suitable linear amine chain extenders include: ethylene diamine; hydrazine; 1,3-propylene diamine; and tetramethylene diamine. Ethylene diamine is most preferred.
Any of the known aliphatic and/or aromatic diisocyanates may be used to produce the isocyanate-terminated prepolymers employed in the present invention. Preferred isocyanates include: linear aliphatic isocyanates such as 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butylene diisocyanate, 1,6-hexylene diisocyanate, 1,8-octylene diisocyanate, 1,5-diisocyanato-2,2,4-trimethylpentane, 3-oxo-1,5-pentane diisocyanate, and the like; cycloaliphatic diisocyanates such as isophorone diisocyanate, the cyclohexane diisocyanates, preferably 1,4-cyclohexane diisocyanate, fully hydrogenated aromatic diisocyanates such as hydrogenated tetramethylxylylene, diisocyanate, hydrogenated toluene diisocyanates, and hydrogenated methylene diphenylene diisocyanates; and aromatic diisocyanates such as the toluene diisocyanates, particularly the 2,4-isomer, the methylene diphenylene diisocyanates, particularly 4,4xe2x80x2-methylene diphenylene diisocyanate (4,4xe2x80x2-MDI), tetramethylxylylene diisocyanate, and the like. 4,4xe2x80x2-MDI is particularly preferred.
The isocyanate-reactive component used to prepare the isocyanate-terminated prepolymers includes: (1) at least one high molecular weight, low unsaturation polyoxypropylene polyol and (2) at least one PTMEG.
The unsaturation level of the high molecular weight polyoxy-propylene polyol component employed in the present invention must be less than or equal to 0.03 meq/g. Most preferably, the entire amount of high molecular weight polyoxyalkylene polyol present in the polyol component has an unsaturation level of less than 0.03 meq/g, more preferably less than 0.02 meq/g, and most preferably less than 0.015 meq/g. However, it is within the scope of the present invention to include a minor portion of high molecular weight polyoxypropylene polyol which has a somewhat higher unsaturation level.
As used herein, the term xe2x80x9clow unsaturation polyoxypropylene polyol (or glycol),xe2x80x9d means a polymer glycol prepared by oxypropylating a dihydric initiator with propylene oxide in the presence of a catalyst in a manner such that the total unsaturation of the polyol product is less than or equal to 0.03 meq/g.
The polyoxypropylene glycol may contain oxyethylene moieties distributed randomly or in block fashion. If the oxyethylene moieties are contained in a block, the block is preferably a terminal block. However, randomly distributed oxyethylene moieties are preferred when such moieties are present. In general, the polyoxypropylene glycol should contain no more than about 30 weight percent of oxyethylene moieties, preferably no more than 20 percent, and more preferably no more than about 10 percent. The polyoxypropylene glycol may also contain higher alkylene oxide moieties such as those derived from 1,2- and 2,3-butylene oxide and other higher alkylene oxides, or oxetane. The amount of such higher alkylene oxides may be as much as 10-30% by weight of the polyoxypropylene polyol. However, preferably, the polyoxypropylene polyol is substantially derived from propylene oxide or propylene oxide in admixture with minor amounts of ethylene oxide. All such glycols containing a major portion of oxypropylene moieties are considered polyoxypropylene glycols as that term is used herein.
The high molecular weight, low unsaturation polyoxypropylene glycols useful in the practice of the present invention will generally have a molecular weight of at least about 1500 Da, preferably at least about 2000 Da, and may range up to 20,000 Da or higher. It is particularly preferred that the molecular weight be in the range of from about 3000 Da to about 8,000 Da, and most preferably be in the range of from about 4000 Da to about 8000 Da.
xe2x80x9cMolecular weight(s)xe2x80x9d and xe2x80x9cequivalent weight(s)xe2x80x9d as used herein are expressed in Da (Daltons) and are the number average molecular weight(s) and number average equivalent weight(s), respectively, unless specified otherwise.
The number average molecular weight for each polyether glycol is determined from the hydroxyl number of the polyether glycol as measured by the imidazole-pyridine catalyst method described by S. L. Wellon et al., xe2x80x9cDetermination of Hydroxyl Content of Polyurethane Polyols and Other Alcoholsxe2x80x9d, ANALYTICAL CHEMISTRY, Vol. 52, NO. 8, pp. 1374-1376 (July 1980).
It is, of course, possible to use a blend of more than one high molecular weight polyoxypropylene polyol, or to add low molecular weight diols in a minor i.e., up to 10% by weight quantity. However, when such blends are used, the average molecular weight of the blend of high molecular weight components should be at least 1500 Da.
Preferably, the prepolymers are prepared from substantially all difunctional polyols, particularly those which are polyoxypropylene glycol-derived. The term xe2x80x9cpolyoxypropylene glycolxe2x80x9d as used herein includes a minor amount, i.e., up to about 5 weight percent or more of a triol.
The polytetramethylene ether glycol (PTMEG) used to make the polyurethane/urea elastomers of the present invention has a molecular weight greater than 600 Da, preferably from about 600 to about 6,000 Da, most preferably from about 600 to about 3,000 Da.
The PTMEG may be prepared by any of the known methods. One suitable method is the polymerization of tetrahydrofuran in the presence of a Lewis acid catalyst. Suitable polymerization catalysts include anhydrous aluminum chloride and boron trifluoride etherate. Such catalysts are well known and are the subject of numerous patents and publications. PTMEG polyols are commercially available in a variety of molecular weights from numerous sources. For example, DuPont sells PTMEG polyols under the trademark Terathane(copyright). BASF Corporation sells PTMEG polyols under the designation PolyTHF. Penn Specialty Chemicals, Inc. sells such polyols under the trademark POLYMEG(copyright).
The isocyanate-reactive component, preferably, a polyol component used to produce the prepolymer from which the spandex fibers of the present invention are produced is predominantly a diol component, i.e., the diol component is preferably from about 30 equivalent percent to about 90 equivalent percent PTMEG, and more preferably from about 50 equivalent percent to about 90 equivalent percent PTMEG, the remainder of the diol component preferably being a polyoxypropylene diol component having an average unsaturation no greater than about 0.03 meq/g, preferably less than about 0.02 meq/g, and most preferably less than about 0.015 meq/g.
However, it should be noted that polyoxypropylene diols having unsaturation levels greater than 0.03 meq/g may be included in the polyol component used to produce the prepolymers of the present invention provided that the overall average unsaturation level of the total polyoxyalkylene portion of the polyol component is about 0.03 meq/g or lower.
The diol component used in the practice of the present invention includes: (1) one or more PTMEG diols, and (2) one or more polyoxy-alkylene diols having an average unsaturation level in the polyoxyalkylene diol portion of the diol component of no more than about 0.03 meq/g. The polyol component used to make prepolymers suitable for use in the practice of the present invention includes this diol component and may also include minor amounts of any other hydroxyl or other reactive species which, together with the diol component, will form an isocyanate-terminated prepolymer when reacted with the isocyanate component.
The isocyanate-reactive component is reacted with an excess of the desired diisocyanate, preferably under an inert atmosphere or under vacuum at slightly elevated temperature, i.e., between 50xc2x0 C. and 100xc2x0 C., more preferably between 60xc2x0 C. and 90xc2x0 C. In the embodiment of the invention in which the prepolymer is formed in the presence of at least 10% dimethylacetamide, lower temperatures (i.e., temperatures in the range of from about 50 to about 60xc2x0 C.) may be used to obtain a prepolymer having a desirable viscosity. The amount of excess isocyanate is selected so as to provide a % NCO group content in the prepolymer of between about 1.0 weight percent and 3.75 weight percent, preferably between about 2 and 3.5 weight percent.
The reaction of the isocyanate with the polyol and any other isocyanate-reactive materials may be catalyzed with any of the catalysts known to promote the reaction of isocyanate and hydroxyl amine groups, but the reaction may also take place without the use of a catalyst. In a preferred embodiment of the invention, a catalyst which promotes linear polymerization but does not degrade the polymer such as a metal salt of a C6-C20 monocarboxylic acid or naphthenic acid is included in the prepolymer-forming mixture. Zinc octoate and calcium octoate are particularly preferred catalysts.
In general, the reaction of the polyol and isocyanate components proceeds until the point at which the isocyanate content becomes constant.
The isocyanate-terminated prepolymer is then dissolved in a solvent, generally, a polar aprotic solvent such as dimethyl acetamide, dimethyl formamide, dimethyl sulfoxide, N-methylpyrrolidone, or the like, and then chain-extended with the chain extender component of the present invention.
The term xe2x80x9cpolar aprotic solventxe2x80x9d as used herein means a solvent having the capability to dissolve the chain extended polyurethane at the desired concentration while being essentially non-reactive to isocyanate groups.
The polyurethane/urea thus obtained has both hard and soft segments. The terms xe2x80x9csoft segmentxe2x80x9d and xe2x80x9chard segmentxe2x80x9d refer to specific portions of the polymer chains. The soft segments are the polyether-based portions of the segmented polyurethane/urea polymer, derived from the PTMEG and the polyoxypropylene glycol. The hard segments are those portions of the polymer chains that are derived from the diisocyanate and chain extender. The term xe2x80x9cNCO contentxe2x80x9d refers to the isocyanate group content of the prepolymer, before chain extension.
A chain terminator is generally included in the reaction mixture to adjust the final molecular weight, and thus the intrinsic viscosity, of the polyurethane/urea polymer to the desired value. Usually, the chain terminator is a monofunctional compound such as a secondary amine (e.g., diethylamine or dibutylamine).
Any of the processes for producing spandex polymers known to those skilled in the art may be used to produce the polyurethane/urea elastomers and spandex fibers of the present invention. Such processes are disclosed, for example, in U.S. Pat. Nos. 3,384,623; 3,483,167; and 5,340,902, which are herein incorporated by reference.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only and are not intended to be limiting unless otherwise specified.

Polyurethane/ureas useful for the production of spandex and a process for their production