The invention relates to a highly oriented polyolefin fiber containing polyolefin with an intrinsic viscosity of at least 5 dl/g, which fiber has a tensile strength of at least 26 cN/dtex and a modulus of tension of at least 700 cN/dtex, a process for the preparation thereof and the use in ropes or anti-ballistic shaped articles. The invention also relates to improved ropes and anti-ballistic shaped articles. The highly oriented polyolefin fiber according to the invention has improved properties in applications such as, in particular, anti-ballistic shaped articles since the fiber contains 0.05-5 wt. % of a solvent for the polyolefin (relative to the total fiber weight).

The invention relates to a highly oriented polyolefin fibre containing polyolefin with an intrinsic viscosity of at least 5 dl/g, which fibre has a tensile strength of at least 26 cN/dtex and a modulus of tension of at least 700 cN/dtex, a process for the preparation thereof and the use in ropes or anti-ballistic shaped articles. The invention also relates to improved ropes and anti-ballistic shaped articles.
The said highly-oriented polyolefin fibres are known from EP-A-0,205,960. The highly oriented polyolefin fibres described there have a very high tensile strength and modulus of tension and a low creep rate, making them particularly suitable for use in, inter alia, ropes and anti-ballistic shaped articles. The fibres are prepared by spinning a solution of a polyolefin into a gel fibre, extracting the solvent from the fibre, and drawing the extracted and dried fibre in one or more steps.
However, there is an ongoing need for further improvement of the quality of such fibres, or at least for optimization of the properties of the fibres to such an extent that the quality of the products, such as ropes and anti-ballistic shaped articles, made from these fibres can be improved. The aim of the invention therefore is to provide highly oriented polyolefin fibres with improved properties in said applications.
Surprisingly, this aim is achieved in that the fibre contains 0.05-5 wt. % of a solvent for the polyolefin (relative to the fibre""s total weight).
It has been found that the fibres according to the invention are eminently suitable for use in anti-ballistic shaped articles since shaped articles on the basis of these fibres have a high Specific Energy Absorption (SEA), which means that less fibre, and hence less weight, is needed to obtain the same level of protection. It has also been found that the fibres according to the invention are suitable for use in ropes, inter alia because their compactness is better without any loss in flexibility and because the strength of the ropes is enhanced.
The improved quality of the fibres is particularly surprising since up to now the presence of a significant amount of solvent in the fibre has been considered undesirable as this reduces the mechanical properties of the fibre, in particular because the fibre""s creep rate is higher and its strength and modulus are lower. It is also surprising that solvent-containing fibres have a higher anti-ballistic quality than xe2x80x9cdryxe2x80x9d fibres of comparable strength and modulus, for in itself the solvent cannot contribute to the level of protection, while it does increase the areal density.
Fibres that contain solvent are known in the state of the art. However, these fibres are not highly oriented and they are unsuitable for the desired applications as their mechanical properties are not good enough. Within the context of the present application, highly oriented is understood to mean that the fibre has a modulus of tension of at least 700 cN/dtex and a tensile strength of at least 26 cN/dtex (as determined according to the method specified below). The known solvent-containing fibres are intermediates in a process in which the fibre is prepared from a solution. The description makes it clear that the solvent is undesirable in the end product and therefore still needs to be removed. U.S. Pat. No. 5,213,745, for example, describes optimum extraction agents for the removal of mineral oil solvent from an undrawn gel fibre. This publication does not describe solvent-containing, highly oriented polyolefin fibres. EP-A-0,115,192 describes fibres having a high solvent content and a low tensile strength and modulus of tension. These fibres, too, are intermediates, and as such unsuitable for use in the said applications.
The tensile strength (or strength) and the modulus of tension (or modulus) are defined and are determined as specified in ASTM D885M, using a nominal gauge length of the fibre of 500 mm, a crosshead speed of 50%/min and Instron 2714 clamps. Before the measurement the fibre is twisted at 31 turns per meter. On the basis of the measured stress-strain curve the modulus is determined as the gradient between 0.3 and 1% strain. For calculation of the modulus and strength, the tensile forces measured are divided by the titer, as determined by weighing 10 meters of fibre. Creep is here and hereinafter understood to be the elongation as a percentage of the original length after 5 hours under a load of 8.11 gr/dtex at 50xc2x0 C. The elongation includes the elastic elongation.
A fibre is understood to be a continuous or semi-continuous object such as a monofilament, multifilament yarn, tapes or staple fibre yarn. In principle, the filaments may have any cross-sectional shape and thickness. Preferably, the filament titer is at most 5, more preferably at most 3 denier per filament. The advantage of such a low filament titer is that the fibre has better anti-ballistic properties.
Varying polyolefins can be used in the fibre according to the invention. Particularly suitable polyolefins are homo- and copolymers of polyethylene and polypropylene. In addition, the polyolefins used may contain small amounts of one or more other polymers, in particular other alkene-1-polymers. Good results are achieved if linear polyethylene (PE) is chosen as polyolefin. Linear polyethylene is here understood to be polyethylene with fewer than one side chain per 100 carbon atoms, and preferably fewer than one side chain per 300 carbon atoms, which may moreover contain up to 5 mol % of or more alkenes that can be copolymerized with it, such as propylene, butene, pentene, 4-methylpentene or octene. Besides the polyolefin and the solvent the fibre may contain small amounts of the additives that are customary for such fibres, such as anti-oxidants, spinfinish, thermal stabilizers, colourants, etc.
Preferably, the polyolefin fibre, in particular the polyethylene fibre, has an intrinsic viscosity (IV) of more than 5 dl/g. Because of their long molecule chains, polyolefin fibres with such an IV have very good mechanical properties, such as a high tensile strength, modulus, energy absorption at break. This is also the reason why even more preferably the polyolefin is a polyethylene with an IV of more than 10 dl/g. The IV is determined according to method PTC-179 (Hercules Inc. Rev. Apr. 29, 1982) at 135xc2x0 C. in decalin, the dissolution time being 16 hours, the anti-oxidant is DBPC, in an amount of 2 g/l solution, and the viscosity at different concentrations is extrapolated to zero concentration.
To ensure a good anti-ballistic effect, the tensile strength of the fibre is at least 26 cN/dtex and the modulus at least 700 cN/dtex. Preferably, the modulus is at least 880 cN/dtex, more preferably at least 1060 cN/dtex, and most preferably at least 1235 cN/dtex. The strength is preferably at least 31 cN/dtex, more preferably at least 33 cN/dtex, and most preferably at least 35 cN/dtex. Surprisingly, it has been found that at relatively low, but for the purpose of the invention effective, solvent concentrations, the creep of such a highly oriented fibre is only to a very low extent adversely affected by the solvent. Preferably, the fibre according to the invention has a tensile strength of at least 26 cN/dtex, a modulus of at least 700 cN/dtex, a solvent content of 0.05-2 wt. % and a creep of at most 20%, more preferably at most 15%, even more preferably at most 10% and most preferably at most 5%. Such a low creep is favourable in particular for use in ropes. When use is made of copolymer with more than 2 short side chains per 1000 carbon atoms, the creep can be reduced further. Preferably, the creep then is at most 10% and more preferably at most 5%.
Solvent is here and hereinafter understood to be a substance that is capable of dissolving the polyolefin in question. Suitable solvents for polyolefins are known to one skilled in the art. They can, for example, be chosen from the xe2x80x98Polymer Handbookxe2x80x99 by J. Brandrup and E. H. Immergut, third edition, chapter VII, pages 379-402. Preferably, use is made of a solvent with a chi-parameter for the polyolefin used, in particular polyethylene, of less than 0.5, more preferably less than 0.45, even more preferably less than 0.4, and most preferably less than 0.35. Chi-parameters of solvents are presented in Handbook of sol. parameters and other cohesion parameters, 2nd edition, published by Allan Barton, p. 386. This has the advantage that, at the same solvent content, the quality improvement can be greater, mutatis mutandis, that less solvent is needed to achieve the same improvement in anti-ballistic properties. Examples of suitable solvents for polyolefin, in particular for polyethylene, are, separately or in combination: decalin, tetralin, toluene, lower n-alkanes such as hexane, (para-)xylene, paraffin oil, squalane, mineral oil, paraffin wax, cyclooctane. For the reasons cited above, the solvent is most preferably paraffin oil or decalin.
Preferably, the solvent is a non-volatile solvent, such as paraffin oil. This has the advantage that the fibre has a better stability, which means that the properties of the fibre, and of the products based on it, do not deteriorate with time and that the useful service life is longer. Another advantage is that the fibre does not have such a bad smell and is not toxic or detrimental to health, which is relevant in particular in body protection applications. A non-volatile solvent is understood to be a solvent that virtually does not evaporate at a temperature below the melting temperature of the polyolefin. Preferably, these are solvents having a boiling temperature that is substantially, preferably 50 to 100xc2x0 C., higher than the fibre""s melting temperature.
The fibre according to the invention contains 0.05-5 wt. % of a solvent for polyolefin. Solvent contents below 0.05 wt. % have no or hardly any effect. Contents higher than 5 wt. % have the disadvantage that they no longer essentially contribute to the improvement in, or even impair, the anti-ballistic properties. The SEA increases with the solvent content up to a certain optimum solvent content, at which the contribution to the energy absorption no longer compensates for the increase in areal density and above which the SEA drops again. Although a higher than optimum solvent content in the shaped article ultimately obtained may be advantageous, since solvent is cheaper than fibres, the solvent content is preferably chosen with a view to obtaining the highest possible anti-ballistic quality. The optimum solvent content also depends on the fibre configuration, the quality of the solvent chosen, and the compression conditions. On the basis of the guidelines given here, one skilled in the art can determine the optimum amount for each process condition. For the above reasons, the solvent content in the fibre is preferably from 0.1 to 3 wt. %, more preferably 0.2-2 wt. %, even more preferably 0.2-1.2 wt. %, and most preferably 0.3-1.0 wt. %. Such low solvent contents are preferably used for good solvents, in particular solvents having a chi-parameter lower than 0-5, and for use in uni-directional composites. The solvent content of the fibres can be determined in a known way, for example directly by means of infrared techniques, C13 NMR, or indirectly by solvent removal, for example by extraction or head-space chromatography or combinations of said techniques.
The fibre according to the invention can be prepared by contacting a highly oriented xe2x80x9cdryxe2x80x9d polyolefin fibre with a solvent for the polyolefin, with the fibre taking up 0.05-5 wt. % of the solvent. The highly oriented xe2x80x9cdryxe2x80x9d polyolefin fibre may have been prepared in a known way from the polyolefin polymer, for example by gel spinning (Smith and Lemstra), by solid phase processing of virgin reactor powder (Chanzy and Smith), by extrusion from the melt (Ward) or by extrusion from powder recrystallized from solution (Kanamoto) with one or more drawing steps to increase the orientation.
Preferably, the fibre is prepared directly in a gel spinning process. The invention also relates to a process for the preparation of a highly oriented polyolefin fibre according to the invention comprising: forming a solution of a polyolefin in a solvent, forming a gel fibre by extruding this solution through one or more spinning apertures and subsequently cooling it to obtain a gel fibre, removing the solvent from the gel fibre and drawing the fibre in one or more steps. Such a process is known from EP-A-0,205,960. For the preparation of the fibre according to the invention this process is adapted in that not all of the solvent is removed from the gel fibre resulting, after one or more drawing steps, in the formation of a solvent containing precursor which is subsequently, at a temperature above the equilibrium melting temperature of the polyolefin, drawn to obtain the highly oriented polyolefin fibre containing 0.05 to 5 wt. % of solvent.
An advantage of the process according to the invention is that fewer steps are needed for the preparation of the fibre and that the fibre obtained by this process has better anti-ballistic properties than a fibre of comparable strength and modulus to which a similar amount of solvent has been added in another manner. A further advantage of the process according to the invention, for example compared with the processes described in EP-A-0,205,960, is that less fibre breakage occurs during drawing of the solvent-containing precursor fibre to a highly oriented fibre, at otherwise unchanged conditions. As a result, there are fewer production stops and a higher productivity can be achieved.
The precursor fibre may have been formed in a single step by simultaneous drawing and solvent removal or by separate solvent removal and drawing steps. The solvent content in the precursor fibre is chosen so that the end product, the highly oriented polyolefin fibre, contains the desired amount of solvent, between 0.05 and 5 wt. %, after drawing. It is possible that part of the solvent is removed during the last drawing step. Preferably, however, a non-volatile solvent is used, with the solvent content during drawing of the precursor fibre in the last drawing step being virtually constant. This has the advantage of better drawing process control, resulting in better drawability.
In one embodiment of the process the solvent in the highly oriented polyolefin fibre is the same as the solvent of the solution from which spinning takes place. The solvent content of the precursor fibre can be set by incomplete solvent removal, for example by shortening the evaporation or extraction time or by influencing the evaporation or extraction rate.
In a particularly preferred embodiment of the process according to the invention, the solvent substantially consists of a mixture of a first solvent (A) and a second solvent (B), with (A) being removed, and (B) remaining in the fibre.
The physico-chemical properties of these solvents (A) and (B) are so different that the solvent removal technique employed results in removal of (A) while solvent (B) substantially remains in the fibres. The advantage of this embodiment is that the amount of solvent (B) in the precursor fibre can be set directly and more accurately through the choice of the spinning solvent composition, without major changes in the other process parameters. In the light of the aim of the invention it is not necessary for the amount of (B) present in the solution during removal of (A) and/or drawing to remain completely in the fibre, but for process control purposes it is advantageous if the full amount of (B) remains in the fibre, at any rate during the removal of (A), so as to prevent contamination of the process. For this reason, (B) preferably almost entirely remains in the fibre also during drawing. There is no need for (A) to be fully removed, but for process control reasons (A) is preferably fully removed. Preferably, the content of (A) in the fibre is not higher than 0.5 wt. %, preferably lower than 0.3 wt. %, more preferably lower than 0.2 wt. %, and most preferably lower than 0.1 wt. %.
In an embodiment of the said process (B) has a higher boiling point than (A) and (A) is removed by evaporation at a temperature at which no or hardly any evaporation of (B) takes place. Preferably, the boiling temperature of (B) is chosen so that no or hardly any evaporation of (B) takes place at the drawing temperature, either. This has the advantage that drawing is better controlled since the fibre composition does not change during drawing and since the fibre is not cooled by withdrawal of the heat of solvent evaporation.
In the most preferred embodiment (B) is a non-volatile paraffin in the process and (A) a volatile solvent, preferably decalin. An added advantage of this embodiment over the embodiment mentioned earlier is that the solvent mixture is much less viscous than just paraffin as solvent, so that paraffin-containing fibres with low filament titers, in particular filament titers lower than 5 and preferably lower than 3, can more readily be prepared.
In another embodiment of the process (B) has a higher melting temperature than (A) and (A) is removed by extraction at a temperature at which no or hardly any extraction of (B) takes place. Preferably, (B) then is a paraffin wax and (A) paraffin oil.
The solvent-containing precursor fibre is drawn to a highly oriented polyolefin fibre at a temperature above approximately the equilibrium melting temperature of the polyolefin. The equilibrium melting temperature of the polyolefin is understood to be the peak temperature of the melting curve of the polyolefin powder, measured using a DSC at a heating-up rate of 10xc2x0 C. a minute. For polyethylene fibres this is preferably above about 140xc2x0 C. Obviously, the drawing temperature is not chosen so high that effective drawing can no longer take place. Most preferably, the drawing temperature is between 145 and 160xc2x0 C. and the solvent content of the precursor fibre during the last drawing step is everywhere between 0.05 and 5 wt. %. This has the advantage of a good productivity in combination with a very good strength and modulus.
The invention also relates to a highly oriented polyolefin fibre obtainable by the process described above. This fibre has better anti-ballistic properties than a fibre with otherwise comparable properties to which a similar amount of solvent has been added in a different way.
The invention also relates to the use of highly oriented polyolefin fibres according to the invention for the manufacture of ropes and to ropes containing highly oriented polyolefin fibres according to the invention. Compared with solvent-free fibres with comparable properties, the solvent-containing fibres can more easily be processed into ropes. The ropes are more compact, their feel is less woolly, and yet their flexibility is good. It has been found that the rope is also stronger.
The invention also relates to the use of the highly oriented fibres according to the invention as described above for the manufacture of anti-ballistic shaped articles. The advantage of the use of these fibres is in particular that the customary process for the preparation of these shaped articles can be used without essential modifications. Such processes are disclosed, for example, in WO97/00766 and WO95/00318. A major added advantage is that, for example in contrast with fibres or fibre layers that are wetted afterwards, the process equipment is not fouled with solvent.
The invention also relates to anti-ballistic shaped articles that contain highly oriented polyolefin fibres according to the invention. Compared with shaped articles on the basis of solvent-free fibres, these shaped articles have a higher anti-ballistic protection level at a comparable areal density. Preferably, the anti-ballistic shaped article according to the invention has a specific energy absorption (SEA) when hit by an AK47 MSC point of at least 115 J/kg/m2, preferably more than 120 J/kg/m2, even more preferably more than 135 J/kg/m2, and most preferably more than 145 J/kg/m2.
The invention will be elucidated on the basis of the following examples.
SK76 Dyneema yarn without paraffin was woven into a simple fabric with 8 yarns/cm in the warp and the weft. The areal density of the woven fabric was 318 gr/m2. Twenty layers of this fabric were compressed to form flat panels with 60 micron Stamylex (LLDPE) film between each layer. The pressure was 10 bar, the temperature was 125xc2x0 C. and the compression time was 20 min. After this compression time the panels were cooled while the pressure was maintained. The V50 was determined according to the Stanag 2920 standard test using 17 grain FSP. The V50 was 532 m/s, corresponding to an energy absorption (SEA) of 21.4 J/kg/m2.
The properties of the SK76 yarn employed are:
Strength: 36.0 cN/dtex
Modulus: 1180 cN/dtex
Creep: 4.1%

Process of making highly oriented polyolefin fiber


Systems and methods that may be used to determine the distance between an orbiting satellite and a ground station. A master clock divider circuit generates clock signals derived from a master clock. A transmit code generation circuit generates pseudo-random number codes and processes the pseudo-random number codes to produce a composite signal having positive and negative correlation peaks that is transmitted to the satellite as an analog signal. A digitizing circuit receives the analog signal transmitted from the satellite, and digitizes the analog signal. A frequency domain matched filter match filters the digitized analog signal to produce correlation peaks contained in the digitized analog signal. A central processing unit comprises a middle code software matched filter that generates an outer code bit, and computes the distance from the ground station to the satellite by calculating the difference between the time that the composite signal was received compared to the time that the composite signal was transmitted and dividing the difference value by the speed of light, and comprises an outer code software matched filter that produces a bit error rate signal indicative of the validity of the computed range value.

The present invention relates generally to satellites, and more particularly to systems and methods used to determine the distance between an orbiting satellite and a ground station.
The assignee of the present invention develops the system architecture of satellite ground stations. The assignee also designs and constructs electronic circuits that communicate with satellites found in these ground stations. An important task of a ground station is to maintain the orbit of satellites. A necessary parameter used to maintain a satellite""s orbit is its altitude. A satellite""s altitude is commonly derived from measuring the distance or range a satellite is from the ground station. It is often necessary to determine the distance a satellite is from a ground station. The assignee of the present invention has developed an improved method for use in determining satellite range from a ground station.
Heretofore, the assignee of the present invention has used a technique that employs a method that is slow, un-flexible, introduces spurious signals, and provides the user with no quality factor, i.e., a measure of the certainty of its range number. This method is slow because it employs a single correlator that shifts and dwells through entire code sequences. It is un-flexible because it uses only two fixed code lengths. Introduces spurious signals because the final code sequences are composed of a series of short code sequences. Finally, it provides a range value without an accurate assessment of how certain the range value is.
In both methods (new and the old), the distance (range) to the satellite from a ground station is determined as follows. The ranging equipment constructs a long binary PRN digital ranging code. An important property of this code is that it does not repeat in the time required for it to be sent and subsequently received. This PRN ranging code is then modulated by uplink telemetry system at the ground station onto a carrier which is then transmitted to the satellite. This signal is then echoed back (retransmitted) to the ground station by the satellite. The received ranging signal is then routed via a downlink telemetry system to a receiver portion of the ranging equipment. Because the ranging signal is corrupted by noise and distorted by Doppler, a correlation process is performed. The correlation process multiplies the received PRN ranging code with a clean delayed version of the transmitted PRN ranging code. When the value of the delay is correct a large output of the correlator is observed (a correlation peak). When the value of the delay is not correct, the correlator yields a small signal value, or no correlation peak. The correct delay is equal to the time of flight of the signal. The distance to the satellite can be calculated based on this delay.
While the basic method of sending and then correlating the returned signal is the same for the old and new methods, it is the construction of the transmitted code and how the received signal is processed that differentiates them. It would therefore be desirable, and it is an objective of the present invention to provide improved systems and methods that determine the distance between an orbiting satellite and a ground station.
To accomplish the above and other objectives, the present invention provides for systems and methods that may be used to determine the distance between an orbiting satellite and a ground station. The present invention accomplishes this by (1) using a final PRN ranging code sequence that is a composite of three long PRN codes; (2) Simultaneously correlating the inner and middle code sequences; (3) Correlating a subset of the outer code; and (4) Deriving a quality value of the range number based on a running bit error rate (BER) on the outer code.
The advantages of using three long PRN codes to construct the final ranging code are flexibility, reduced processing time, and a spurious free composite signal. Flexibility is achieved by custom tailoring the lengths of the inner, middle, and outer codes for the specific orbit and signal power requirements of the ground station and the satellite. By simultaneously correlating the inner and middle codes the speed of the ranging process is greatly enhanced. Correlating a subset of the outer code further reduces the acquisition time. A spurious free ranging signal is derived from the property that long PRN codes evenly spread their energy across the frequency spectral band. Thus when the ranging signal is combined with other telemetry signals it does not have spurious content that could cause interference. The bit sequence of the outer code is unique, any errors are easily monitored. A running bit error rate based on the number of errors found in the outer code is the basis for a measure of the confidence factor the ranging unit assigns to the range number.
An exemplary system comprises a custom circuit board (or card assembly) and a central processing unit (CPU). The custom circuit board includes seven main sub-circuits. These sub-circuits include a master clock divider circuit, a transmit code generation circuit, a time tag circuit, a digitizing circuit, a digital synthesizer circuit, a matched filter circuit, and a field programmable gate array (FPGA) integrated circuit.
The master clock divider circuit supplies the custom circuit board with all the necessary clocks at the correct frequency and phase. The function of the transmit code generator circuit is to construct a final PRN ranging code. The time tag circuit marks the arrival time of each complete inner code cycle.
The received signal is digitized by an Analog to Digital Converter (ADC). The received signal is a composite signal that contains the PRN ranging signal and telemetry signals that are corrupted by noise and contain a Doppler offset and/or shift. The digital synthesizer circuit is used to acquire the received signal ensuring the ADC yields coherent samples. A frequency domain matched filter processes the digitized analog signal to produce the inner code correlation peaks. The FPGA circuit is used to select the correct data from the matched filter and transmit it to the central processing unit.
The central processing unit comprises a middle code software matched filter that generates an outer code bit. The final location of the received code is known once seven bits of the outer code are processed. The central processing unit computes the distance from the ground station to the satellite by calculating the difference between the time that the composite signal was received compared to the time that the composite signal was transmitted and dividing the difference value by the speed of light. The central processing unit also tracks any errors found in the outer code and produces a bit error rate signal indicative of the validity of the computed range value.
An exemplary method for determining the distance between an orbiting satellite and a ground station comprises the following steps. Inner, middle and outer pseudo-random number codes are generated. The PRN ranging code is the composite of the inner, middle, and outer codes. The PRN ranging code is then transmitted from a ground station to a satellite whose range is to be determined. The analog signal is retransmitted from the satellite to the ground station.
The analog signal is digitized at the ground station. The digitized analog signal is match filtered to produce inner code correlation peaks. The middle matched filter then performs a correlation process on the output of the inner matched filter. The middle code correlation peaks are match filtered to determine a bit of the outer pseudo-random number code. A predetermined number of consecutive outer pseudo-random number code bits are match filtered to determine the position of the outer code in the composite code. The distance from the ground station to the satellite is determined by calculating the difference between the time that the code sequence was received compared to the time that the code sequence was transmitted.
The present invention provides for simultaneous correlation of the entire inner and outer code sequence. The present invention incorporates a matched filter early/late gate that acts as a digital phase detector. The present invention has a flexible range code to adapt to varying orbit distances, low signal to noise ratio environments, Doppler shifts, and changing Doppler shifts. The present invention also uses an applied bit error rate algorithm to give a confidence value to the range number (using the outer code).
The present invention has the ability to optimize performance of system by changing (inner, middle, outer) code(s) to adapt to all types of satellite orbits. The present invention has reduced acquisition time by using a matched filter fast Fourier transform (FT) correlator engine to simultaneously correlate the entire inner and middle code sequence verses the currently-used architecture discussed in the Background section. The output spectrum generated by the present invention minimize s interference with other signals due to the fact that ranging power is spread over the entire bandwidth of operation, similar in concept to CDMA (carrier detect multiple access).
BRIEF DESCRIPTION OF THE DRAWINGS
The various features and advantages of the present invention may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawing, wherein like reference numerals designate like structural elements, and in which:
FIG. 1 shows the operating environment of ranging systems and methods in accordance with the principles of the present invention;
FIG. 2 is a block diagram showing the architectural topology of exemplar y digital ranging equipment in accordance with the principles of the present invention that may be used to implement the present digital ranging systems and methods;
FIG. 3 is a block diagram showing the architectural topology of the inner code matched filter correlator engine shown in FIG. 2; and
FIG. 4 is a flow diagram showing an exemplary ranging method in accordance with the principles of the present invention.

Flexible digital ranging system and method


Some embodiments of the present invention provide a voltage-mode transmitter. The transmitter can include configuration circuitry, bias circuitry, and a set of driver slices. Each driver slice can include driver transistors which drive an output value. The outputs of each driver slice can be directly or capacitively coupled with the transmitter's outputs. Each driver slice can also include one or more impedance-matching transistors which are serially coupled to at least some of the driver transistors. The configuration circuitry can configure a subset of driver slices so that the down (or up) impedance of the transmitter is within a first tolerance of a desired impedance value. The bias circuitry can bias the one or more impedance-matching transistors in each driver slice in the subset of driver slices so that the up (or down) impedance is within a second tolerance of the down (or up) impedance.

1. Technical Field
This disclosure generally relates to communication circuitry.
More specifically, this disclosure relates to circuitry for matching the up and down impedances of a voltage-mode transmitter.
2. Related Art
Modern communication devices use voltage-mode transmitters partly because they use less power than their current-mode counterparts. Most high-speed communication standards impose stringent requirements on the characteristics of voltage-mode transmitters. Specifically, some standards require that a transmitter must not only output a differential voltage at a desired magnitude, but that the transmitter's output impedance must match the impedance of the signal traces of the channel on the circuit board in order to minimize reflections which can impair signal integrity.
A voltage-mode transmitter's output can be viewed as having two impedances: an up impedance looking up to the power supply voltage (e.g., VTT), and a down impedance looking down to ground. In addition to ensuring that the overall impedance of the transmitter matches a desired value (e.g., the impedance of the signal traces in the circuit board), the up and down impedances must also match each other. A mismatch between the up and down impedances of a transmitter can cause a mismatch in the rise and fall times of the differential voltage signal, and can cause excessive common mode noise. This, in turn, can degrade the transmitter's performance and can violate the specifications of the high-speed communication standard.
The relentless miniaturization of integrated circuits has increased the variability in the electrical characteristics of circuit elements. Moreover, the behavior of circuit elements changes with changing operating conditions. Hence, even if the transmitter's up and down impedances match at nominal operating conditions (e.g., at the nominal voltage and temperature), the impedances may not match once the operating conditions change.
Hence, what is needed are systems and techniques for ensuring that the overall impedance of a transistor matches a desired value, and that the up and down impedances of the transmitter match each other.

Circuitry for matching the up and down impedances of a voltage-mode transmitter


The present invention is related to a method for controlling a wind energy plant with plural control units, which perform control tasks in the wind energy plant, comprising the following steps:    a) one priority at a time is assigned to the control units, depending on the control tasks they must perform,    b) during the operation of the wind energy plant, the control units communicate continuously with each other and/or with a central communication unit,    c) in case that there is a failure of a first control unit of the wind energy plant, a second control unit of the wind energy plant takes over the control tasks of the defective control unit, wherein the second control unit is selected depending on the priority assigned thereto and has the same as or a lower priority than the defective control unit.

The present invention is related to a method for controlling a wind energy plant with plural control units, which perform control tasks in the wind energy plant. For the operation of a wind energy plant, one central or plural decentral control units can be provided. For example, decentral control units can be provided for the pitch control of the blades, a main converter control, an azimuth angle control, a cooling system control, a lubrication control and so on. Optionally, a condition monitoring system (CMS) may also be provided, which has to detect a necessary maintenance operation in good time.
From DE 103 00 174 B3, the entire contents of which is incorporated herein by reference, a wind energy plant with plural components is known, which each one possess sensors and/or actuators and feature a control device. In this, the control devices are connected to a data network. Via this data network, the control devices can exchange signals with each other, concerning operating conditions of the respective controlled components, sensor values and/or control signals for other components. Thus, a central control is omitted in the known wind energy plant. Instead, the control takes place on the basis of the individual components. In this component based control of the wind energy plant, the communication between the components takes place independently from specific parameters. An advantage of this approach is that components of different manufacturers can be exchanged without great expense.
A problem arises when there is a failure of a control unit. In such a case, according to the circumstances, the control tasks to be performed by the control unit can no more be exerted. This may affect the operation of the wind energy plant.
Departing from the clarified state of the art, the present invention is therefore based on the objective to provide a method of the kind mentioned at the beginning, in which the availability of the wind energy plant and of its components is always at hand.

Method for controlling a wind energy plant


The composition contains carbamide peroxide (0.3-60%), xylitol (0.5-50%) potassic salt (0.001-10%) and fluorine salt (0.15-3%). There is also disclosed a gel which contains, in addition to the whitening composition, between 0.5 and 6% by weight of an appropriate gelifying agent. The gel is appropriate to the whitening of dental pieces through a treatment which comprises applying an efficient amount of said whitening gel onto the dental pieces to be whitened. The composition may also be presented in the form of a dental paste, mouth wash or elixir.

The composition comprises carbamide peroxide (0.3-60%), xylitol (0.5-50%), a potassium salt (0.001-10%) and a fluorine salt (0.15-3%). A gel is disclosed that contains, as well as the bleaching composition, between 0.5 and 6% by weight of an appropriate gelling agent. The gel is suitable for bleaching dental pieces by means of a treatment that comprises applying an effective quantity of said bleaching gel to the dental pieces to be bleached. The composition can also be presented in the form of a toothpaste, colutory or elixir.
1. Field of the Invention
This invention relates to a composition suitable for bleaching the teeth, based on carbamide peroxide as well as presentation formulations thereof
2. Background of the Invention
Dental discoloration, or loss of whiteness of dental pieces with subsequent appearance of stains thereon, is a complex process in which numerous and different causes may be implicated. Types of dental discoloration can be classified in accordance with the localisation and aetiology of the stains. Recent studies propose the classification of dental stains (extrinsic and intrinsic) according to the chemistry of the dental discoloration [Nathoo, S. A., xe2x80x9cThe chemistry and mechanism of extrinsic and intrinsic discolorationxe2x80x9d, JADA, 1997, 128:65-95]. According to this work, extrinsic dental stains, that is to say, those that are found on the surface of the dental pieces, are classified into the following groups:
(a) direct dental stains, that may be: (i) of N1 type, when the chromogen which binds to the dental surface to provoke the discoloration has a colour similar to that of the dental stain and may be due to the formation of a film of saliva that leads to fixing of components from the saliva by the dental enamel, to the ingestion of certain drinks and foods such as tea, coffee and wine, to bacterial adhesion and to the presence of metals in the oral cavity, or (ii) of type N2, when the chromogen changes colour after binding to the dental piece, due, for example, to the accumulation or chemical modification of proteins present in the film of saliva by means, for example, of denaturing with acids or detergents or else due to darkening, with the passage of time, of the dental stains of type N1 caused by drinks and foods; and
(b) indirect dental stains, in which a transparent material (or pre-chromogen material) binds to the dental piece and undergoes chemical reaction that produces the stain Among the products that provoke this type of stain there can be found, for example, food products rich in carbohydrates and sugars as well as certain therapeutic agents, for example, tin fluoride.
The intrinsic discoloration of the dental pieces is due to the presence of chromogenic material within the enamel or dentin. This type of discoloration can be due, among other things, to a fluorosis provoked by an excessive ingestion of fluorine during dental development, to the administration of tetracycline during the years of tooth formation, to a congenital malformation of the dental tissue, to certain hematologic disorders (erythroblastosis fetalis, thalassemia), to cracks and breaks in the dental pieces, to haemorrhages in the dental pulp, and to the normal ageing process.
Different methods and systems are known for eliminating dental discoloration and for provoking the bleaching of the dental pieces that comprise the use either of abrasives, such as prophylactic pastes, or a combination of abrasives and surfactants, for example, whitening toothpastes. ES-B-2079325 discloses a bleaching toothpaste containing an abrasive system (silica) and a detergent (sodium laurylsarcosinate). The use of abrasives for whitening dental pieces is not recommendable as it may lead to the elimination of part of the dental enamel along with the stains themselves which would facilitate the appearance of tooth decay and erosions due too the elimination of the natural defensive structure of the enamel with the subsequent dental hyperesthesia.
A tooth whitening composition in the form of a gel is provided by U.S. Pat. No. 5,718,886, wherein it is disclosed a stabilized anhydrous tooth whitening gel composition comprising carbamide peroxide dispersed in an anhydrous gelatinous carrier, said carrier comprising a polyol, a thickener, and xanthan gum in order to stabilize the gel composition against viscosity degradation during oral use.
In general, said whitening methods avoid the accumulation, and, to a certain extent, eliminate extrinsic dental stains although total and satisfactory elimination of the dental stains depends on the type of discoloration. In general, the extrinsic stains of type N1 can be avoided or eliminated by means of good oral hygiene, while the extrinsic stains of type N2, which are more difficult to eliminate, require the skill of a professional for dental bleaching. This is also true for stains of type N3. On the other hand, the elimination of intrinsic dental stains requires the use of products that penetrate the enamel and dentin with the aim of discolouring and dissolving the chromogens responsible for these stains.
Dental discoloration occurs widely in society (it is estimated that two out of every three adults suffers from some type of dental discoloration). It produces a certain anti-aesthetic effect that can even inhibit the smile of people suffering from discoloration. The occurrence can become particularly important in certain situations and professions where showing clean and white teeth is essential.
There exists, therefore, the need to have a new medium suitable for eliminating dental stains and bleaching the dental pieces that overcomes the drawbacks mentioned hereinabove. This objective may be attained by means of the use of a bleaching composition provided by this invention whose use leads to a clearing up of the dental enamel, which thus starts to a acquire a whiter and more brilliant appearance.
The invention provides a dental bleaching composition, hereinafter, composition of the invention, that comprises:
The carbamide peroxide is a mixture of hydrogen peroxide and carbamide whose amino groups neutralise the acidity of the hydrogen peroxide. This compound acts as an oxidative bleaching agent that liberates oxygen. It is able to oxidatively degrade numerous organic colouring agents present both in food products and in pharmaceutical products that produce dental colourings. In general, the organic colouring agents owe their dyeing capacity to the present of chromophor groups, that is to say, chemical groups rich in electrons, generally conjugated double bonds. Illustrative examples of organic colorants are, erythrosine, used as a developer for bacterial plaque, tartracine, used as a food additive, indigotine, used in the formulation of some drugs, and tetracycline, an antibiotic that produces dental colourings that range from yellow to brown. It is believed that oxidative degradation (oxidative bleaching) of this type of colorant occurs via a mechanism that implicates the decomposition of hydrogen peroxide and the formation of free radicals (HOxe2x80x94) that attack the double bonds present in the molecules of said colorants and, subsequently, produce the breakage of the double bonds and the oxidation of the carbons implicated to corresponding carbonyl groups. The carbonyl groups formed, although they also possess xcfx80 (Pi) electrons as in the Cxe2x95x90C double bonds, absorb in the ultraviolet zone of the spectrum and so do not contribute to discoloration. Numerous studies show that the bleaching activity of the carbamide peroxide (see for example, Van B. Haywood, xe2x80x9cHistory, safety and effectiveness of current bleaching techniques and applications of the nightguard vital bleaching techniquexe2x80x9d, Quintessence Int. 23: 471-488 (1992); Howard E. Strassaler et al., xe2x80x9cCarbamide Peroxide At-Home Bleaching Agentsxe2x80x9d, The New York State Dental Journal, April 1992, 30-34; Van. B. Haywood, xe2x80x9cNight Guard vital bleaching: Effects of various solutions on enamel surface texture and colourxe2x80x9d, Quintessence Int. 22: 775-782 (1991); and Van B. Haywood, xe2x80x9cSituacixc3x3n actual del blanquemiento dental mediante cubetasxe2x80x9d, Journal of Aesthetic Dentistry, Ed. Espaxc3x1ola, 2: 10-15 (1992)].
Xylitol (1,2,3,4,5-pentapentol) is a natural sweetener that reduces the dental plaque and has activity as an inhibitor of tooth decay. This polyalcohol, due to its molecular size, helps to complex the formulation and, furthermore, contributes to making the solution more alkaline and so it would not be absolutely necessary to incorporate other alkalinising agents.
As a potassium salt, any salt may be used that releases potassium ions in a suitable quantity. The potassium acts as a desensitiser in cases of dental hypersensitivity. Illustrative examples, not limiting, of potassium salts that may be used in the composition of the invention include potassium citrate (including tripotassium citrate), potassium fluoride, potassium benzoate, potassium bicarbonate, potassium carbonate, potassium chloride, potassium lactate, potassium pyrophosphate, potassium phosphate, and mixtures thereof, preferably potassium citrate.
The fluorine salt is a salt able to release fluoride ions in a suitable quantity. By way of example for illustrative purposes, and not limiting, said fluorine salt may be a fluoride of a alkaline metal, for example, sodium fluoride, potassium fluoride, sodium monofluorophosphate, di-potassium hexafluorosilicate, and mixtures thereof, preferably, potassium fluoride. The fluoride acts as a re-mineralising agent of the enamel. The inclusion of fluoride in the composition of the invention reduces the losses of said ion that are produced during the bleaching actions.
The composition of the invention may be prepared by mixing and homogenising the different components in suitable quantities.
The composition of the invention may be present in different presentation formulations, including formulations of solid or semi-solid administration, for example, toothpastes, liquids, for example, colutories or elixirs; or gels; for which the additives are incorporated, suitable vehicles and excipients for processing thereof in the desired presentation formulation. These presentation formulations of the composition of the invention can be easily prepared by means of the use of conventional techniques [Tratado de Farmacia Galxc3xa9nica, C. Fualxc3xad I Trillo, Luzxc3xa1n 5 S. A. de Ediciones, 1st Edition, (1993), especially chapters 35, 47 and 59; Cosmetologxc3xada Texc3xa9rico-Prxc3xa1ctica, published by the Consejo General de Colegios Oficiales de Farmacxc3xa9uticos, 3rd Edition (1985), Chapter 7].
In a particular and preferred embodiment of this invention the formulation of presentation of the composition of the invention is a gel. In this case, in the composition of the invention a suitable gelling agent is introduced, such as a natural or synthetic polymer, in an appropriate amount to form a tri-dimensional matrix in the solution or suspension to be gelled. The gelling agent is selected from a group formed by a carboxyvinyllic polymer, a co-polymer of polyoxyethylene and polypropylene, and mixtures thereof In a particular embodiment, the gelling agent is a synthetic polymer that gives rise to a gel depending on the pH of the medium, such as a carboxyvinyllic polymer or a vinyl polymer that contains active carboxyl groups [The Merck Index, 11th Edition, 1989, Merck and Co., Inc., Rahway, N.J., United States, page 278, Monograph no. 1836] that produces the gelling of solutions and suspensions by neutralisation with a base. Examples of carboxyvinyllic polymers are those conmmercialised with the tradename Carbopol(copyright) (The B.F. Goodrich), that produce gels of varying viscosity depending, among other things, on the type of Carbopol(copyright) used (Carbopol(copyright) 940, Carbopol(copyright) 934) and the pH of the medium. Other gelling agents that can also be used are polyvinylpyrrolidone (polymer of N-vinylpyrrolidone), the polymers of polycarboxylates, for example, those conmmercialised with the denomination Gantrez ACV-4006, and the co-polymers of polyoxyethylene and polyoxypropylene such as those known as poloxamers or Pluronics (Pluronic F127, F108 and F98). The gelling agent can be present in the gel composition in an amount lying between 0.5 and 6% by weight with respect to the total of the composition.
The incorporation of the gelling agent also allows slow release of the carbamide peroxide present in the composition of the invention thus taking fuller advantage of its bleaching effect.
The gel provided by this invention, hereinafter the bleaching gel of the invention, has a pH approximately neutral and can have a carbamide peroxide content lying between 0.3 and 60% by weight with respect to the total, preferably, between 3 and 50% by weight with respect to the total. The gels that contain between 3 and 6% by weight of carbamide peroxide are particularly suitable for use in the daily brushing of teeth in combination with a whitening toothpaste that contains, advantageously, the composition of the invention, while the gels that contain between 10 and 15% by weight of carbamide peroxide are suitable for use in daily brushing of teeth and for topical application to the dental pieces. Finally, gels that contain between 20 and 50% by weight of carbamide peroxide are suitable for topical application to dental pieces. Topical application of the gets provided by this invention may be effected with the help of a suitable instrument, such as a brush or a dental spatula.
The bleaching gel of the invention may also contain other appropriate additives such as alkalinising agents, aromatising agents, sweeteners, thickeners and moisteners that assist in adjusting the pH, improve the organoleptic characteristics and/or conditions of elaboration. They may be those typically used in the sector of the art Such additives can be conventional additives regularly used in this sector of the art. By way of example, alkalinising agents can be mentioned such as sodium hydroxide or triethanolamine, although the alkalinising power of the latter of these may by substituted modifying the amount of potassium salt present in the composition or even by the alkalinising power of xylitol; sweeteners such as saccharine or derivatives of cyclamic acid; thickeners such as triethanolamine, derivatives of starch, xanthane gum, colloidal silicas and similar substances; and moisteners, such as glycerine. Each one of the alkalinising additives, aromatising agents, sweeteners and thickeners can be present in the composition of gel in an amount lying between 0 and 6% by weight with respect to the total of the composition, while the moistener may be present in an amount lying between 40 and 80% by weight with respect to the total of the composition.
In a specific preferred embodiment of the invention, there is provided a bleaching gel that has the following composition:
(1) Preferably, the gelling agent is a carboxyvinyllic polymer that contains active carboxyl groups of the type of those commercialised with the tradename Carbopol(copyright).
The bleaching gel of the invention can be used to bleach dental pieces. Therefore, the invention also provides a method for bleaching dental pieces that comprises the use of the bleaching gel of the invention.
In a particular embodiment of the invention, the bleaching method of the dental pieces provided by this invention can by carried out using a bleaching gel of the invention that contains between 10 and 15% by weight, preferably, 12% by weight, of carbamide peroxide. Said method comprises preparing a splint that may be placed over the dental pieces to be bleached, applying the bleaching gel to the inside of the splint and placing the splint with the bleaching gel over the dental pieces to be bleached.
The preparation of the splint may be carried out by any conventional method, for example, taking an impression in alginate of the teeth or dental pieces to be bleached, preparing a model in plaster and constructing the splint from a tablet of flexible resin. The bleaching gel of the invention is applied to the inside of the splint, either by means of some drops, or forming a line, and then, the splint loaded with bleaching gel is placed over the teeth or dental pieces to be bleached and is worn for the time the specialist considers opportune, normally between 3 and 4 weeks. This splint, loaded with bleaching gel, can be worn for during the day, during the night, in the user""s own home, or both day and night.
In an alternative embodiment, the invention provides a method for bleaching dental pieces using a bleaching gel of the invention that contains between 20 and 50% by weight, preferably, 30% by weight, of carbamide peroxide. This method is effected in the practice or dental clinic and comprises (a) applying the bleaching gel to the external face of the teeth or dental pieces to be bleached with the aid of a suitable instrument, such as a brush or a dental spatula, keeping the lips apart using a soft-tissue extractor or with rolls of cotton, and (b) allowing the gel to act for a suitable period of time, lying between 15 and 30 minutes, normally 20 minutes. By means of carrying out this alternative it is possible to possible to bleach to a middle tone or several teeth between 15 and 30 minutes. This method can be carried out as the start of treatment with a splint or to accelerate this process, with application is sessions of 15 to 30 minutes once a week.
The tests carried out have shown that:
application of the bleaching gel of the invention does not require the use of gum protectors or lip protectors
the results depend on the duration of the treatment and on the number of hours that the gel is used daily,
it can be applied nocturnally and/or during the day according to the requirements of each person,
it supplies the inner tooth with oxygen,
it improves the gingival health
the novel supply of fluorine makes the appearance of post-bleaching sensitivity almost non-existent and, therefore, it is more agreeable to the user;
The novel inclusion of xylitol means that the duration of the bleaching process also provides an anti-tooth decay effect
the release of potassium, both by the potassium fluoride and by the potassium citrate, means that in the case of very sensitive teeth the duration of the bleaching process also provides a blockade of the sensitivity thanks to the potassium; and
it is especially indicated in the bleaching of teeth yellowed or stained by tetracyclines (moderate stains), tobacco, ageing and fluorosis.
Different tests have also demonstrated that the time necessary for dental bleaching using the gel provided by this invention, depends, among other things, on the initial discoloration and on the carbamide peroxide concentration present in the bleaching gel, reducing the time needed for dental bleaching.
In another particular embodiment of this invention, the presentation formulation of the composition of the invention is a toothpaste, for which, the conventional appropriate additives and excipients are introduced into the composition of the invention to improve its properties and characteristics and for facilitating its processing, such as abrasives, binding agents, aromatising agents, colorants, preservatives, sweeteners, thickeners, moisteners, lubricating agents, clouding agents, re-mineralisers, flavourings, buffers (pH regulators), surfactants and vitamins, regularly used in this sector of the art for the formulation of toothpastes The toothpaste, if so desired, may also incorporate up to 0.5% by weight of a gelling agent of the type described previously in relation to the bleaching gel of the invention.
The abrasive may a system based on silica that comprises a mixture of viscosing silica and abrasive silica. The binding agent may be, for example, tragacanth gum. As an aromatising agent, colorant and flavouring any of those regularly used in the formulation of toothpastes may be used, for example, mint aroma and Brilliant blue FCF, CI.42090 (KIRSCH PHARMA). The preservative may be a benzoic acid derivative, for example, methyl p-hydroxy-benzoate. As a sweetener substances that may be used include, for example, sodium saccharine or cyclamic acid and derivatives thereof, for example sodium cyclamate. The thickener may be, for example, derivatives of starch, xanthane gum, or colloidal silicas. As a moistener glycerine may be used for example, although xylitol also may act as a moistener. The lubricant may be, for example, dimethicone (polymer of dimethylpolysiloxane), which is a surfactant that contributes to conferring good Theological properties on the toothpaste provided by this invention. The clouding agent may be, for example, titanium dioxide. As a re-mineralising agent a source of fluoride may be used. As a buffer any of those regularly used may be employed that gives the desired pH. The vitamins that, optionally, may be present in the toothpaste provided by this invention are selected from the group formed by vitamin A, vitamin B5, vitamin C, vitamin E and mixtures thereof.
In another particular embodiment of this invention, the formulation of presentation of the composition of the invention is an elixir or a colutory, preferably lacking alcohol, that contains the additives, suitable vehicles and excipients for the elaboration of said formulations of presentation. In a particular embodiment the colutory may be prepared extemporaneously maintaining the carbamide peroxide in solid form and adding water to the mixture in the quantity necessary when it is to be used.


The invention concerns a method for producing a paper web. According to the method a stock is produced from the fibrous raw material and the stock is formed to a web which is dried on a paper machine. According to the invention the stock is formed from a mechanical pulp prepared from wood material of the Populus family and from bleached chemical spruce pulp, whereby the amount of the mechanical pulp is 20 to 70 weight-% and the amount of the bleached chemical softwood pulp is 80 to 30 weight-% of the dry matter of the stock. It is preferred to use an aspen pulp, over 70% of the fiber fractions of which comprise fiber fractions +100, +200 and xe2x88x92200, and the proportion of the xe2x88x92200 fraction is 45% or less. A coated fine paper can be produced from the paper web whose properties are better than those of a traditional fine paper having the corresponding bulk and grammage, on the same capacity level the paper produced by the invention will give a yield gain of up to more than 20%.

The present invention relates papermaking. In particular the invention concerns a method for producing a paper web. According to a method of this kind, a fibrous raw material is slushed to form a stock, a web is formed from the stock and the web is dried.
With the aid of the present invention it is possible to produce a base paper which is particularly well suited to the manufacture of fine paper. The surface weight of a base paper of this kind is generally 20 to 200 g/m2.
High-quality printing matters, such as brochures, advertising materials and catalogues, are made from fine papers which have good opacity, an even surface structure and high brightness.
Traditionally, fine papers have been manufactured from cellulosic hardwood or softwood pulps or mixtures thereof. The problem associated with the known art is that it is not possible at low grammage to reach sufficiently high opacity for the pulp or the paper manufactured therefrom. The formation of the chemical pulp and the paper made from it remains rather poor when high opacity is aimed at.
Light, coated paper qualities containing mechanical pulp are also known in the art. These are manufacture from a mechanical pulp made from spruce and they usually contain about ⅓ to xc2xc softwood pulp which reinforces the pulp and improves the strength properties of the paper.
The particular advantages of mechanical pulps in comparison to chemical pulps are their lower production costs and greater yield. The coarse, stiff fibers of the pulp lead, however, to fiber coarsing, which shows in offset printing Further, the disadvantages of groundwood of spruce include its poor dewatering at low drainability and the large energy consumption of the whole pulping process. A problem of known papers based on groundwood is also their low brightness and poor brightness stability. They are not either shelf stable if spruce GW has been used.
Paper qualities containing mechanical pulps and combinations of mechanical pulps and chemical pulps, respectively, have not been used for fine papers. Instead, said types of papers (e.g. LWC) are primarily used as magazine papers.
It is an object of the present invention to eliminate the problems of the prior art and provide a solution for producing a base paper suitable for the manufacture of fine papers. It is also an object of the present invention to provide a fine paper of a novel kind, having the high brightness and good smoothness of traditional fine papers and which further exhibits the good opacity and excellent printability due to the good formation characteristic for mechanical printing papers.
The present invention is based on the concept of combining groundwood of hardwood and chemical pulp of softwood and of producing a base paper from a mixture of the mechanical and the chemical pulp. In connection with the present invention it has been found that a mechanical pulp (in particular Pressure Ground Wood, PGW) manufactured from aspen and other wood species of the Populus family contain a great amount of short fibers which improve the traditionally insufficient bulk and light scattering of fine paper. Although the strength properties of aspen GW, as regards, for example ScottBond strength, are not entirely sufficient, by combining aspen GW with a chemical pulp produced from softwood, it becomes possible to produce a basepaper which exhibits excellent opacity at high brightness and an even surface and good strength. Due to the good bonding strength of softwood, aspen GW can be used in an amount of up to 30 to 70% of the dry weight of the pulp.
More specifically, the solution according to the present invention is mainly characterized in that the stock is formed from a mechanical pulp of a wood raw material of the Populus family and a bleached chemical softwood pulp, the amount of mechanical pulp being 20 to 70wt-% and the amount of bleached softwood pulp being 80 to 30 weight-% of the dry matter of the stock.
Considerable advantages are obtained by means of the invention Thus, using the base paper according to the invention it is possible to obtain better opacity on the same level of brightness as that exhibited for traditional fine papers. The paper contains more fines and its bulk and opacity are greater, which gives it good printing properties, Surprisingly, we have found that by means of the present invention it has become possible at lower grammage to produce a fine paper having an extremely high brightness. When the fine papers produced from the present base paper are compared with traditional fine papers, thanks to the low grammage, a yield gain of up to about 20% can be obtained; on the same opacity level the present paper will give more printing surface per weight unit than traditional fine papers.
The short-fibered aspen gives the paper good light scattering properties.
According to the invention it is therefore possible to provide a paper which fulfills all the quality requirements of coated fine papers consisting solely of chemical pulp but which, at the same time, provides high opacity and bulk and excellent printability properties.
In the following, the invention, its features and benefits will be examined in greater detail with reference to a detailed description and a number of working examples.
The fiber structure of aspen and wood species belonging to the same family differ from the fiber structures of the hardwood species most frequently used for pulp making, such as birch. The dimensions of the aspen fiber, the fiber length and width are smaller than for spruce and birch The tracheids of aspen are smaller (length 0.9 mm) than the tracheids of birch (1.0-1.1 mm). In both, the proportion of vasculum cells is about 25%. Traditionally, the tubular cells contained in aspen have been considered to cause runability problems on the paper machine and they have not been believed to provide for bonding. As a result of the short fibers and the poor bonding of the vasculum cells, dusting of the paper can occur on the paper machine and during posttreatment.
According to the present invention it has now surprisingly been found that by using a combination of mechanical pulp produced from aspen and chemical softwood pulp, the runability problems caused by the tubular cells can be avoided and a pulp can be produced which has impeccable strength properties. Since the aspen pulp has shorter fibers than the birch pulp and even much shorter than spruce, at a given grammage there are more aspen fibers than birch or spruce fibers. This leads to a greater light scattering coefficient and bulk in the present invention. Further, the advantageous fiber length distribution gives the paper an excellent formation i.e. variation of the grammage of paper on a small scale, typically  less than 3 g/m2. The smoothness of the paper is also good.
Due to all these factors, it is now possible to achieve a base paper which can be coated for production of high-quality line papers, which have excellent printability properties
The advantages of the special aspen pulp in comparison to spruce groundwood comprise high brightness and brightness stability. The stability of the brightness is in particular due to the low lignin-content of aspen groundwood or corresponding mechanical pulp and to the low concentration of carbonyl groups compared to spruce groundwood. Further, it should be pointed out that a paper web produced from aspen has clearly better dewatering properties than a web produced from spruce. The shorter dewatering time and the higher dry matter content together give a sheet with more porosity.
The greatest advantage of the fiber distribution of aspen is obtained when the pulp has been beaten to the drainability of fine papers. It should be mentioned that spruce has to be refined to a higher degree of beating because of the stiff fibers contained therein. The long and stiff fibers of mechanical pulps produced from spruce cause a coarsing of the paper surface fibers during coating and, in particular, during printing. The phenomenon is rather typical for mechanical printing papers and it substantially deteriorates the quality of the printing surface. The requirements for the printing surface of fine papers are very strict and no coarsing of the paper surface is acceptable. With the particular aspen pulp according to the present invention, not fiber coarsing problems occur, which relates to the fact that practically all long and stiff fibers of the +14 and +28 fractions have been eliminated.
As an example of the fiber length distribution of aspen, the following table can be presented which indicates the fiber fractions retained by various sieves (mesh). The determination have been made from dosing pulps and the table compares aspen fibers to birch and spruce fibers, respectively:
The average fiber length of aspen of PGW is smaller than of spruce (FS is typically about 0.54xc2x10.01).
Preferably the mechanical aspen pulp contains about 10 to 20% of +20 . . . +48 mesh fibers, which confer mechanical strength to the pulp. In order to maximize light scattering, the portion of +100, +200 and xe2x88x92200 fractions should be as large as possible. Preferably they stand for distinctly more than 50% of the whole pulp. In particular their proportion of the whole pulp is over 70%, preferably over 80%. On the other hand, the amount of the smallest fraction, i.e. the 200 mesh, should not be too large, because then dewatering on the paper machine would become more difficult. Preferably the proportion of this fraction is smaller than 50%, in particular 45% or less.
The proportion of +14 and +28 mesh fiber fractions are below 10%, preferably below 5%, and in particular below 3%. The amounts of Pulmac shives at 0.8 mm/mg/g are below 1, in particular below 0.5.
In addition to the aspen mentioned above, pulp produced from any mechanical pulp made of a tree of the Populus family can be used for the base paper. Suitable species are, for example, P. tremula, P tremuloides, P balsanea, P. balsamifera, P. trichocarpa and P. heterophylla. A preferred embodiment comprises using aspen (trembling aspen, P. tremuta; Canadian aspen, P. tremuloides), or aspen varieties known as hybride aspens produced from different base aspens by hybridizing as well as other species produced by recombinant technology, or poplar. The raw material is processed to groundwood (GW) or pressure groundwood (PGW) or it is disintegrated to chips and the chips are used for producing thermomechanical pulp (TMP) of chemimecbanical pulp (CTMP) in a manner known per se.
The mechanical pulp is bleached after grinding or refining, respectively. Preferably the pulp is peroxide bleached at alkaline conditions. According to a preferred embodiment the pulp is bleached with a one, two or multistage bleaching sequence, the pulp being acidified between the bleaching stages and the peroxide residue being reduced. Generally the peroxide dosage is about 2 to 3.5 weight-% of the dry matter of the pulp, for aspen pulp 0.5 to 1.5%, in particular 0.7 to 1.2%. A dithionite bleaching step comprising the treatment of the pulp with Na2S2O4 can be incorporated into the peroxide bleaching sequence.
The mechanical pulp is washed before bleaching and after the bleaching with a mixture of water from the pulping section and a clarified recirculation water of the paper machine in a washing press (fabric press) by using typically about 0.1 to 10 m3 water per ton of pulp. By using the washing press water is removed from the pulp in order to increase the dry matter content of the pulp to about 20 to 30%. The waters from the dewatering are recycled to the production of the mechanical pulp. By the washing press it is possible to prevent impurities from being transferred to the paper machine.
The bleached pulp is then refined to the desired degree of beating, which is, e.g. 30 to 100 CSF, preferably about 40 to 80 CSF.
A stock is formed from the mechanical pulp together with a chemical pulp. The stock can contain other fiber materials and additives, such as fillers. Calcium carbonate is an example of a filler. The dry matter content of the stock is about 0.1 to 5% Clarified filtrate of a circulating water of the paper machine is used as the aqueous phase of the stock The chemical pulp used comprises in particular a fully bleached chemical softwood pulp, whereby a paper web suitable as a base paper of fine papers is obtained. Said web has high bulk, high brightness and high opacity and good formation. The amount of the mechanical pulp is then for example 20 to 70 weight-%, preferably 30 to 60 weight-%, and the amount of the bleached softwood pulp is for example 80 to 30 weight-%, preferably 70 to 40 weight-% of the dry matter of the stock.
Preferably the chemical pulp used for the preparation of the base paper is produced by method known as a modified batch-type cooking (Superbatch Cook). This cook is discribed in literature [cf., for example, Malinen, R. Paperi ja Puu (Paper and Timber), 75 (1993) 14-18]. The cook in question is a modified cooking method which utilizes an alkaline cooking liquor just as the sulphate cook, but wherein delignification has been enhanced so that the kappa number of the chemical pulp is lowered without a significant reduction of viscosity. Typically with a Superbatch process, pulp is cooked to a kappa number of 20 or less.
A paper web is formed from the stock of aspen pulp and chemical pulp on a paper machine. Preferably a gap former is used for web forming. In said technique the web is dried between two webs, water being removed in both directions. Thus, as regards printability, an advantageous distribution of the fines is obtained in the direction of the Z axis; the fines are gathered on both surfaces of the base paper web. A xe2x80x9csmilingxe2x80x9d distribution is formed in transversal direction when the fines accompany the leaving water. A paper according to the invention contains substantially much more fibes than for example a traditional spruce groundwood-based LWC. The fines of the aspen and the fillers added to the stock are accumulated on the surfaces of the paper. Because aspen has a rather good brightness and a good brightness stability, it is possible to get abundant amounts of aspen fibers on the surface of the paper. The coating is also accumulated on the surface of such a paper and, thus, a good coverage can be obtained. Therefore, by combining the use of a gap former with the present fiber mixture it is possible to provide a base paper which has rather advantageous printing properties after coating.
As regards the runability of the above-described fiber mixture it is particularly advantageous to set the dosing pH of the stock at 6.8 to 7.2 and the pH of the machine pulp at 7.1 to 7.5, preferably at about 7.1 to 7.3.If necessary a suitable base or acid is used for setting the pH and for adjusting the pH during paper making. The bases used comprise in particular alkali metal bicarbonates or carbonates and alkali metal hydroxides. The acids used include mineral acids and acid salts. The preferred acids are sulphuric acid and its acid salts such as alum, and the preferred base is sodium bicarbonate. The consistency of the headbox is adjusted to 0.6 to 0.8.
By using the invention, the following properties can be obtained for the base paper:
From a base paper of this kind a high-quality fine paper can be produced by coating it twice with a suitable coating colour containing pigments. The coating colour can be applied on the material web in a manner known per se. The method according to the invention for coating paper and/or paperboard can be carried out on-line or off-line by using a conventional coater, i.e. a doctor blade coater, or by film press coating or by surface spraying
According to a particularly preferred embodiment, the paper web is double-coated, whereby the first coating is for example carried out by the film press method, and the second coating is performed by doctor blade coating. The precoating is preferably performed by film press coating e.g. at high speed (at least 1450 m/s, preferably even 1600 m/min or more). Generally, the amount of coating colour applied to the web by the film press method is typically about 5 to 50 g coating colour/m2, whereas the corresponding amount for doctor blade coating is 10 to 60 g coating colour/m2. The coating weights have been calculated from the dry matter of the coating colour.
The solution according to the invention is particularly well suited to coating by using in the coating colour a pigment with a steep distribution whereby the pigment will provide good coverage and the paper will have good opacity. By steep pigment size distribution is meant a distribution in which a maximum of 35% of the particles are smaller than 0.5 xcexcm and preferably a maximum of 15% are smaller Man 0.2 xcexcm.
After coating and supercalendering the fine paper obtained typically has the following properties:

Paper web and a method for the production thereof


A side rail assembly for a vehicle having a chassis beam and a protective beam that are secured together by interlocking elements. The protective beam is preferably formed of a softer material than the chassis beam. The protective beam has an outboard wall that is spaced from an inboard wall and s-shaped wall sections interconnecting the outboard wall and inboard wall. The cell walls and an upper portion of the upper wall are preferably curved to facilitate preferential deformation in the event of an impact.

The present invention relates to a rocker panel side impact beam for a vehicle.
Vehicle frames normally include side rails in the vicinity of the vehicle rocker panel. The side rails of the vehicle are generally covered by body panels and trim. In the event of an impact to the side of a vehicle passenger compartment, forces are generally absorbed by body panels, such as the door or rocker panel. To repair a vehicle after a side collision, it may be necessary to repair or replace a substantial number of body panels and straighten the vehicle frame. The prior art has largely ignored the issue of limiting damage to a vehicle in the event of a side impact.
Conventional vehicle frames include steel frame rails, uni-body construction or, more recently, aluminum space frames. Generally, these types of structures have uniform strength and deformation properties and do not include specially designed impact absorption mechanisms. They also do not include structure defining crush zones that may be easily replaced while minimizing transmission of impact forces to the vehicle frame.
Beams have been developed that are incorporated in the doors of vehicles for improved side impact protection, for example, U.S. Pat. No. 5,573,297 discloses a side impact beam that is contained between the inner and outer door panels and is a relatively complex product that does not protect the vehicle frame. This patent also fails to disclose structure that limits damage by the use of impact absorbing crush zones.
In U.S. Pat. No. 5,954,390, a side impact system is disclosed wherein a cross-car beam extends laterally between the B-pillars of a vehicle and is also used to provide support for front seat assemblies. This patent also fails to disclose the use of impact absorbing crush zones.
These and other problems and disadvantages associated with prior art side impact beams and side impact systems are addressed by Applicant""s invention as described below.
According to the present invention, a side impact beam assembly is provided for a vehicle. The side impact beam assembly includes a first beam of a chassis of the vehicle that is formed of a first material and extends along the side of the vehicle. A second beam is attached to the first beam and is formed of a second material that may be less rigid than the first material. The second beam has an outer portion that is spaced from the first beam and intermediate structure that is deformable with the outer portion toward the first beam upon impact.
The invention may also be characterized as an impact-absorbing beam assembly for a vehicle that comprises a chassis beam formed of an extruded metal having a predetermined degree of crushed strength. The assembly also includes a protective beam formed of an extruded metal having a predetermined degree of crush strength that is less than the crush strength of the chassis beam to which the protective beam is secured.
The present invention may also be characterized as a side impact beam assembly for a vehicle comprising a rocker beam having an exterior wall and an interior wall that are connected on their upper ends by a top wall and on their lower ends by a bottom wall. A side impact beam is secured to the rocker beam and has an outboard wall spaced from the exterior wall of the rocker beam and an inboard wall that is connected to the exterior wall of the rocker beam. At least one cell wall interconnects the outboard wall and the inboard wall forming closed cells between the inboard and outboard walls of the side impact beam.
The side impact beam assembly may also include a cell wall that is curved to provide limited reinforcement of the outboard wall against compression toward the inboard wall upon impact. The side impact beam assembly may include one cell wall or two or more cell walls, if desired.
The upper portion of the side impact beam may include a concave curved portion and two S-curved cell walls that facilitate compression of the cells as the outboard wall is impacted. The curved portion of the upper portion of the side impact beam and the S-curved cell walls may be bent to an increased extent of curvature instead of being compressed, thereby providing limited crush resistance.
According to another aspect of the present invention, the side impact beam assembly may include a first set of interlocking elements that are provided on the rocker beam and a second set of interlocking elements that are provided on the side impact beam. The interlocking elements on the side impact beam are adapted to engage the first set of interlocking elements on the rocker beam to secure the side impact beam to the rocker beam. The interlocking element provided on the rocker beam may include an upper rib formed on the top wall and a lower rib formed on the bottom wall of the rocker beam. First and second hook ribs may be formed on the upper end of the side impact beam and on the lower end of the side impact beam. The first and second hook ribs are adapted to engage the upper and lower ribs on the rocker beam to secure the side impact beam to the rocker beam.
Attachment of the side impact beam to the rocker beam may also be assured by providing a bonding agent in a recess formed between the two beams.
The rocker beam may include attachment flanges for securing the rocker panel to the compartment panel of the vehicle. The rocker beam may also include a double wall portion that defines a pocket extending lengthwise along the rocker beam. The pocket formed by the double wall of the rocker beam may be used as a conduit for wiring or tubing, if desired.
The rocker beam is preferably formed of a extruded aluminum and the side impact beam is preferably formed of a extruded aluminum compound that is less rigid than the extruded aluminum compound used to form the rocker beam. Alternatively, the side impact beam may be formed of an extruded polymeric material that would deform preferentially to the extruded aluminum used to form the rocker beam.
These and other advantages and objects of the present invention will be better understood upon review of the attached drawings in light of the following detailed description.


An interchangeable lens which is mountable to a camera body and operates according to a command from the camera body includes a diaphragm operable to regulate an amount of light from a subject by changing an aperture, a drive unit operable to change the aperture of the diaphragm, and a lens controller operable to control the drive unit to change the aperture of the diaphragm according to an instruction received from the camera body. When the lens controller receives a new instruction from the camera body while changing the aperture of the diaphragm, the lens controller controls the drive unit to change the aperture of the diaphragm based on the new instruction without waiting for completion of the change of the aperture according to a previous instruction.

1. Technical Field
The technical field relates to an interchangeable lens mountable to a camera body, and a camera body to which an interchangeable lens is mountable.
2. Related Art
Some electronic still cameras have a function of being able to display a moving image of a subject captured by an imaging device on a liquid crystal display (see, for example, JP11-112865A). In such an electronic still camera, when such a function is turned on, a moving image of a subject is displayed on a liquid crystal display.
In addition, in the electronic still camera, when a release button is not operated, exposure control is performed by controlling only an electronic shutter with a diaphragm means being fixed to a preset aperture value. On the other hand, when the release button is operated, exposure control is performed by controlling the diaphragm means to an appropriate aperture value and controlling the electronic shutter. By such control, in the electronic still camera, when a moving image of a subject is displayed, an unnatural brightness change due to the switching of the diaphragm is prevented and power consumption is reduced to a minimum, and upon recording a still image, an excellent image with no smear or the like can be recorded.
However, the electronic still camera disclosed in JP11-112865A is premised on the recording of still images and is not premised on the recording of moving images. That is, in the electronic still camera disclosed in JP11-112865A, exposure regulation is performed only by changing the shutter speed. Thus, when the brightness of the surroundings gets brighter than a predetermined level upon recording a moving image, the shutter speed is increased. Hence, in the electronic still camera disclosed in JP11-112865A, it is difficult to record a smooth moving image. In addition, conventionally, none of such interchangeable lens type cameras that drive a diaphragm of an interchangeable lens in response to a command from a camera body performs recording of a moving image.


Inhalatory pharmaceutical compositions containing Formoterol as active ingredient, comprising:

The present invention relates to pharmaceutical compositions for the administration to the lungs of Formoterol in aqueous solution.
The inhalation therapy in the field of respiratory tract diseases includes different methods for the administration of the drug to the lungs. The aerosol can be obtained by nebulization of the product from a pressurized metered dose inhaler, by dispersion of a dry powder with suitable devices and by mechanical or ultrasound atomization of aqueous solutions or suspensions.
The currently used formulations contain excipients physiologically compatible with the bronchial epithelium, usually consisting of co-solvents, preservatives, chelating agents, pH regulators and surfactants.
In the case of solution products, the respirable fraction is determined by the atomization efficiency and by the size of the aerosol particles produced by the nebulizing equipment. In the case of suspensions, the respirable fraction is determined also by the particle size of the used micronized active ingredient.
A characteristic of some active ingredients is the poor chemical (degradation) or physical (crystal morphological changes) stability in solution or suspension. As a consequence, the shelf life of the finished product upon storage in normal ambient condition, and sometime even in refrigerator, is insufficient.
Formoterol is a drug belonging to the class of beta2-agonists, characterized by rapid onset of broncho-dilating action which lasts for many hours. For the treatment of asthma, Formoterol is usually administered through the inhalatory route by means of the so called dry powder inhalers (DPI), storable under normal ambient conditions, or in form of suspensions or solutions by means of pressurized metered dose inhalers, which should be stored in refrigerator, in view of the above discussed poor stability of the active ingredients in aqueous medium.
The stability problem of active ingredients in solutions may also be solved by a conventional technology adopted in the pharmaceutical and para-pharmaceutical fields, based on reservoir container systems designed for the reconstitution of solution immediately before use, wherein a liquid component (solvent) and a solid component (soluble material) are placed in separate compartments.
Two basic problems are met if this technology is considered for Formoterol formulations for the inhalatory use. The first is the possibility to dose the quantity of active ingredient with sufficient precision. The standard dose of Formoterol is within the range of some tens of micrograms, usually about 12 micrograms: with the current technology it is quite impossible to dose such quantities with sufficient precision in industrial processes. This problem can be by-passed by the method disclosed in WO 99/17754, consisting in the dissolution of the active ingredient and solid excipients in wter, filling of solution in a reservoir container and followed by freeze drying in order to obtain a solid state open matriz network. The other problem is that the excipients have to be chosen only among those approved for the respiratory use, with demonstrated tolerability on the respiratory tract.
The present invention solves the problems concerning active ingredient stability, dosage uniformity and tolerability of the formulation to the lungs, by applying the technology of capsule production to the container system for the extemporaneous reconstitution of a solution immediately before use.
The invention provides pharmaceutical compositions for the inhalatory use comprising Formoterol in dry powder form.
The compositions of the invention comprise:
a vial containing a sterile liquid vehicle suitable for inhalation;
a reservoir chamber cap containing a powder mixture consisting of Formoterol or a related salt in micronized form and one or more excipients, soluble in the vehicle and suitable for respiratory use. A barrier of suitable material that has the function to maintain the solid component separated from the liquid component delimits this chamber caps. The caps also have a mechanism in order to easily remove or break this separation.
Immediately before the use, the patient breaks the barrier and shakes the container so as to contact the two components (liquid and solid).
The excipients of the solid component dissolve in the liquid and Formoterol is dissolved or suspended in the liquid, depending on the composition of the liquid component. After this step, the vial can be opened and the mixture is transferred into the nebulizer equipment, for inhalation according to the instructions of each device, which may be air-driven or ultrasound-driven.
This container system is suitable for delivering both single dose and multidose. In this case the container must be closed again after delivery of the first dose and stored in refrigerator for subsequent use.
The system of the invention is also useful for combinations of Formoterol with other active ingredients, such as Budesonide, Fluticasone, Mometasone, Flunisolide, Ipratropium bromide and others that can be in solution in the liquid component or in the solid component mixed with the others solid excipients.
The extemporaneously prepared product showed very good stability for the period of administration that, normally, last no longer than 15 minutes.
In case of product in suspension, the preferred size of the active ingredient crystals is that normally used for respiratory powders, namely less than 10 microns, preferably 1 to 5 microns, that is the range usually required for respiratory products.
In case of product for dissolution in the liquid component, tests were performed with both micronized crystalline active ingredient and active ingredient premixed with the other excipients (for instance lactose) and dissolved in a suitable solvent. After that, a powder easily soluble in the liquid component was obtained by means of spray dry technology.
In both cases the xe2x80x9cin vitroxe2x80x9d respirable fraction values obtained were similar to those of other products marketed in the form of inhalatory solution or suspension (15-25%).
The liquid vehicle contained in the vial is preferably sterile water, which may be added with co-solvents and other excipients, for example preservative and surfactants, such as cetostearyl alcohol, polysorbate 80, sorbitan trioleate and cetyl pyridinium chloride. Examples of co-solvents are ethanol and propylene glycol.
Preferred surfactants are cetostearyl alcohol and polysorbate 80, in quantity from 0.01 to 0.5% w/w.
A preferred co-solvent is propylene glycol in amounts from 10 to 50%, preferably from 20 to 40%.
The isotonicity of the solution may be adjusted by addition of a suitable quantity of sodium chloride to the liquid component, to improve physiological tolerance.
Formoterol is used in the formulations of the invention preferably as fumarate, in a dose range from 5 to 25 micrograms.
The solid excipients mixed with Formoterol include saccharides, amino acids and other components suitable for respiratory use. Preferred excipients are lactose, mannitol, glucose and isoleucine in quantity from 5 to 200 mg per dose.
Therefore, the invention solves the problem of product instability, since the active ingredient remains in solution or suspension for the time of administration only.
Another aspect of the invention is related to the application of capsules filling technology currently used for the production of respiratory powder in capsules. The homogeneous mix of solid excipient and active ingredient may be dosed in the reservoir in a precise quantity, e.g. from 5 to 200 mg, preferably 24 mg. This technology solves the problem of dosage uniformity.
The problem of components compatibility is solved by suitably selecting excipients of current use in respiratory products. In particular, lactose monohydrate is widely used in dry powder inhalatory formulations.
The present invention also relates to a method for the preparation of the formulation according to the previous claims, wherein micronized Formoterol is homogeneously mixed with the powder excipients, the resulting mix is filled in the reservoir caps and the reservoir caps are placed on the vials previously filled with the liquid component.
The following examples illustrate the invention in greater detail.