A process reducing the levels of dimeric impurities in a statin to less than 0.08% by treatment of a statin containing more than 0.08% dimeric impurities with a mild base in a suitable solvent mixture.

The invention relates to a process of purifying Lovastatin or Simvastatin, which reduces the level of dimeric impurities in the resulting product.
Lovastatin and its analogs, e.g. simvastatin, are potent antihyper-cholesterolemic agents that function by limiting cholesterol biosynthesis. Lovastatin is one of the most important known cholesterol lowering agents. Lovastatin (CAS Registry No. 75330-75-5) is also known as mevinolin or monacolin K and is chemically known as: xcex2,xcex2-dihydroxy-7-[1,2,6,7,8,8a-hexahydro-2,6-dimethyl-8-(2-methyl-butyryloxy)-1-napthalen-1-yl]-heptanoic acid xcex2-lactone of the formula:
Lovastatin, is one member of a class of compounds, which are referred to generally as statins, are known to exist in open ring hydroxy acid and also in lactone form. The lactone form of Lovastatin is shown above.
Lovastatin and its analogs inhibit the enzyme 3-hydroxy-3-methyl-glutarylcoenzyme A reductase (xe2x80x9cHMG-CoA reductasexe2x80x9d). HMG-CoA reductase catalyzes the formation of mevalonic acid, an early intermediate of cholesterol biosynthesis. Lovastatin is specifically advantageous because, as a result of its application, biosynthetic intermediates that have a toxic steroid skeleton, formed at a later stage of biosynthesis fail to accumulate. Lovastatin also increases the number of LDL-receptors at the surface of the cell membrane, which remove the LDL cholesterol circulating in the blood, thereby inducing the lowering of blood plasma cholesterol level.
Lovastatin is routinely produced via fermentation. GB 2,046,737 discloses that Lovastatin can be produced by some strains belonging to the Monascus genus, e.g., by M. ruber 1005 cultivated between 7xc2x0 and 40xc2x0 C. As a culture medium, an aqueous solution of glucose, peptone, corn steep liquor and ammonium chloride was used. The fermentation was carried out for 10 days in aerobic conditions, and 87 mg Lovastatin was obtained from the filtrate of 5 liters of broth.
U.S. Pat. No. 4,294,926 discloses the biosynthesis of Lovastatin preferably by the application of microorganisms under the deposited numbers ATCC 20541 or 20542 belonging to the Aspergillus terreus species on a culture medium containing carbohydrates, e.g., glucose, fructose, maltose, as carbon source; nitrogen sources, e.g., yeast, hydrolyzed yeast, hydrolyzed casein, corn steep liquor, and mineral salts, e.g., calcium carbonate, magnesium sulfate, cobalt, iron, and manganese salts at a temperature of 20-37xc2x0 C. Similar procedures are described in U.S. Pat. Nos. 4,420,491; 4,342,767; 4,319,039 and 4,294,846 where the fermentations are carried out for 3-5 days on media containing 1-6% carbohydrates and 0.2-6% nitrogen sources.
German Patent No. 4,402,591 discloses biosynthesis of Lovastatin by microorganisms belonging to the Pleurotus genus, e.g., P. ostreatus, P. sapidus and P. saca, at 25-35xc2x0 C. during 7-14 days cultivation time on surface or submerged cultures.
Canadian Patent No. 2,129,416 discloses the preparation of Lovastatin with a microorganism belonging to the Coniothyrium genus, e.g., under the deposited number Coniothyrium fuckelii ATCC 74227 on a culture medium containing 3-15% glucose, 0.5-4% peptone, 0.5-5% amylase, 0.2-1% ammonium sulphate, 0.01-0.1% magnesium sulphate, 0.05-0.2% antifoaming agent, 0.2-1.5% L-isoleucine, 0.2-1.5% L-aspartic acid in the pH range of 5-6. According to the examples, the active ingredient concentration of the broth was within 19-430 mg/liter.
Hungarian Patent No. HU 208,997 discloses the application of the holotype strain Aspergillus obscurus numbered as MV-1, deposited under the number NCAIM(P)F 001189. The fermentation is preferably carried out on a medium containing yeast extract and/or peptone and/or casein as nitrogen source(s) and glucose and/or maltose or sucrose as carbon source(s). The activity of the broth at the end of the laboratory scale cultivation is between 400-850 mg/liter.
Simvastatin is a synthetic analog of Lovastatin, wherein the 8-acyl moiety is 2,2-dimethylbutyryl. Simvastatin is an even more potent HMG-CoA reductase inhibitor than Lovastatin. Simvastatin is chemically designated as 2,2-dimethylbutanoic acid (4R,6R)-6-[2[1S,2S, 6R,8S,8aR)-1,2,6,7,8,8a-hexahydro-2,6-dimethyl-1-[2-(tetrahydro-4-hydroxy-6-oxo-2H-pyran-2-yl)ethyl]-1-napthalenyl ester (CAS Registry No. 79902-63-9). The chemical structure of Simvastatin is:
Simvastatin is now commercially available as ZOCOR(copyright) in some markets. The preparation of Simvastatin was originally described in U.S. Pat. No. 4,444,784. The process involves deacylation of Lovastatin followed by a subsequent acylation with the 2,2-dimethylbutyryl moiety. Simvastatin has also been prepared by the alpha alkylation of the Lovastatin ester moiety as described in U.S. Pat. Nos. 4,582,915 and 4,820,850.
After the fermentation is complete, Lovastatin is present in the broth in both lactone and acid forms. The open hydroxy acid form of the statins is the biologically active form. However, the statins are generally administered to a patient in the lactone form, which is converted to its active metabolite, the hydroxy acid form, in the body. Thus, since only the lactone form is of commercial interest, the acid form is converted into the lactone form through a process called lactonization. The process of lactonization is an equilibrium reaction whereby the open dihydroxy acid form is converted into the closed lactone form. Because lactonization is an equilibrium process, to obtain a high yield of the lactone product, some means must be employed to shift the equilibrium to the lactone side of the equation. This equilibrium equation can be depicted as follows:
Lactonization is an intramolecular esterification. Intermolecular esterification, which leads to dimer formation and higher oligomeric species competes with lactonization:
Lactonization methods are known in the art and many such methods are discussed below. Following lactonization of Lovastatin or following synthesis of Simvastatin, the statins are isolated using crystallization techniques known in the art.
Processes known in the literature for the lactonization of the free, hydroxy acid or its salts are either carried out under high temperature conditions, i.e. refluxing with inert solvents, or catalyzed by strong acids when lactonization is effected at ambient temperature. The process disclosed in U.S. Pat. No. 4,820,850 involves heating the free acid or its salts, e.g. the ammonium salt, to reflux temperature (usually 100-110xc2x0 C.) in high boiling carbohydrate solvents such as toluene for 7-8 hours. The ambient acidity of the acid is believed to be responsible for the lactonization reaction at these high temperatures. In addition, water that is formed as a by-product of the reaction is continuously removed by azeotropic distillation, which forces the reaction to near completion (shifts the position of equilibrium to the lactone side). The process of lactonization under heat conditions of reflux temperatures is complicated by the formation of dimer impurities which lower the quality of the final lactone product. Once formed, the dimer impurity is difficult to remove and is often present at the levels between 0.4 to 0.08% in the product. To minimize dimerization, high dilutions are often used in the lactonization reaction at the cost of the efficiency of the reaction and process, which is disadvantageous on a commercial manufacturing scale.
U.S. Pat. No. 4,916,239 discloses lactonization at room temperature by treating the free ammonium salt of mevinic acid in a mixture of acetic acid and water, and in the presence of a strong acid catalyst. After the free hydroxy acid-lactone equilibrium is established (reaction has proceeded to 50% conversion), water is gradually added in an amount sufficient to effect crystallization of the lactone from the reaction medium. Removal of the lactone from solution favors lactone formation and thus drives the lactonization to completion. Since the lactone is continuously removed from solution, dimer formation is minimized. The disadvantages of this process stem from the inconvenience of using a strong acid catalyst in a large scale synthesis. The strong acid catalysts (e.g. formic, phosphoric, trifluoroacetic, sulphuric, hydrochloric, p-toluene, sulphonic, methanesulphonic acids) that are often used in quantities varying from 1.2 to 1.5 molar equivalents, can be difficult to handle and can pose environmentally unacceptable disposal problems, especially on an industrial scale. Furthermore, the excess acid catalyst that is used requires neutralization by adding a strong base before filtration of the product. Additionally, the lactonization reaction is only about 50% complete after the equilibrium is achieved. Any fast or premature addition of water can lead to serious crystallization and filtration problems. Additionally, reaction and subsequent work-up takes about 9-12 hours for completion, thereby decreasing the efficiency of the process.
U.S. Pat. No. 5,917,058 discloses a process of lactonization which avoids the use of strong corrosive acids and drastic heat conditions. The process involves treating the open hydroxy acid form of statins, preferably in their ammonium salt form, with acetic acid under inert anhydrous conditions at ambient or moderate temperatures. The acetic acid serves both as a solvent and as a catalyst. The lactonization proceeds without the addition of strong acid catalysts. The lactonized product is isolated after completion of reaction by the addition of an anti-solvent that has the ability to crystallize out the lactonized product. The anti-solvents disclosed are water, hexane, heptane, or cyclohexane. Since lactonization is an equilibrium reaction, the reaction by-productsxe2x80x94water and ammoniaxe2x80x94have to be removed to shift the equilibrium to the lactone side. The acetic acid used in the process consumes, in situ, the ammonia, resulting in the generation of ammonium acetate. The ammonium acetate, since it is hygroscopic in nature, absorbs the other by-productxe2x80x94water. This procedure is reported to yield 85-95% yield with 95-98% purity.
U.S. Pat. No. 5,939,564 also discloses a method of lactonization which avoids the use of strong corrosive acids. The open hydroxy acid in its salt form is heated in an organic solvent at a temperature ranging from ambient to the reflux temperature of the solvent under anhydrous conditions. This mixture is then treated with a mild catalyst at a temperatures ranging from about ambient temperature to about 50xc2x0 C. The mild catalysts are the salts of organic bases with inorganic or organic acids, such as pyridine hydrobromide, pyridine hydrocholoride, or pyridine p-toluene sulfonate. The lactonized product is then precipitated by the addition of water and finally the crystalline product is collected from the mixture. This method produces at the most, 98.7 % pure Lovastatin.
While the above methods of lactonization have decreased the environmental burden and lead to improved yields and purity, these methods still result in significant formation of dimers of Lovastatin. Additionally, during the synthesis of Simvastatin from Lovastatin, dimer impurities form during lactonization. Thus, there remains a need for a purification process that reduces the level of dimer impurity. The present invention addresses this need.
It has now been found that dimeric impurities may be removed from Lovastatin or Simvastatin by treatment with mild bases which selectively hydrolyze the dimers without concomitant ring opening of the lactone ring of Simvastatin or Lovastatin.
The preferred mild bases include aliphatic mono- or di- or triamines, aromatic amines, ammonium hydroxide, ammonia gas and an aqueous solution of the above agents.
Using the process of purification of the present invention, Lovastatin or Simvastatin containing less than about 0.08% dimeric impurities can be obtained. Thus, another aspect of the invention provides the compounds, Lovastatin and Simvastatin having less than about 0.08% dimeric impurities.
As discussed above, known processes of synthesizing Simvastatin or lactonization of Lovastatin, result in the formation of unwanted dimer impurities. The dimer impurities are hard to remove as they co-crystallize with the Lovastatin and Simvastatin. The present invention provides a process of purification of Lovastatin or Simvastatin, which reduces the level of these dimer impurities. The present invention provides a method of purifying Lovastatin or Simvastatin in substantially pure lactone forms. The process of the present invention produces Lovastatin or Simvastatin having less than about 0.08% dimeric impurities.
The process of the present invention utilizes a slightly alkaline condition in a solvent mixture containing Lovastatin or Simvastatin, to hydrolyze Lovastatin dimer or Simvastatin dimer and other ester-like impurities, without concomitantly opening up the lactone ring. A mild base agent of 0.4 molar equivalent or less is added to the solvent mixture to produce alkaline condition. The preferred mild base agents include aliphatic mono-, di- or triamines, aromatic amines, ammonium hydroxide, ammonia gas and aqueous solutions of the foregoing agents and mixtures thereof. The most preferred mild base agent is ammonium-hydroxide.
The lactone forms of simvastatin or lovastatin (the xe2x80x9cstatin lactonesxe2x80x9d) substantially differ in their solubility from the hydroxy acid forms and can be separated accordingly. Lovastatin dimer may be hydrolized to lovastatin hydroxy acid, anhydrolovastatin and lovastatin lactone. The observed ratio of anhydrolovastatin:lovastatin depends on the presence of water. The presence of water is limited because it helps the opening of the lactone form. The statin lactones recovered from the solvent mixture. The statin lactones may be recovered by crystallization from an appropriate solvent, using methods known in the art. Crystallization may be performed by cooling the solvent mixture used for hydrolyzing the lactone. Alternatively, the solvent mixture used for hydrolysis may be evaporated and the solid resuspended in a crystallizing solution. Preferred crystallization solvents include isobutyl acetate, ethanol, butylacetate, acetonitrile, mixtures of the afformentioned solvents, mixtures of ethanol-water and mixtures of methanol-water. A preferred solvent mixture is isobutyl acetate:ethanol at a ratio of about 3:1. For crystallization with ethanol and water, a preferred ratio is 0.8:1.1. For crystallization with methanol and water, a preferred ratio is 0.7:1.0. Preferably the crystallization is performed at a temperature of about xe2x88x9220xc2x0 C. to about +25xc2x0 C. More preferably the crystallization is performed at a temperature of about xe2x88x9215xc2x0 C. to about +15xc2x0 C., and most preferably at about xe2x88x9215xc2x0 C. to about +5xc2x0 C.
Another aspect of the present invention is directed to the solvent mixture used to purify the Lovastatin or Simvastatin. In one aspect of the invention, the solvent mixture comprises an alcohol ancl another solvent component or components. The alcohol in the solvent mixture can be any alkyl alcohol, aromatic alcohol, or a mixture of such alcohols. The preferred alcohols include, but are not limited to, methanol, ethanol, i-propanol, n-propanol, i-butanol, n-butanol, t-butanol or mixtures thereof. The most preferred alcohols are methanol and ethanol. A preferred solvent mixture of the present invention comprises an alcohol in an amount from 1-70 v/v %. More preferably the alcohol is present at 5-50 v/v% and most preferably the alcohol is present at 10-30 v/v %.
The other solvent component of the solvent mixture is believed to prevent the hydrolysis or lactone ring opening of Lovastatin and Simvastatin. Preferred solvent components, other than the alcohol of the solvent mixture, include alkane, alkyl-derivative solvents, and ester derivative solvents. Preferred solvents include dichloromethane, dichloroethane, chloroform, carbon tetrachloride, acetonitrile, petroleum ether, heptane, hexane, cyclohexane, acetone, and butyl-methyl keton, methyl acetate, ethyl acetate, propyl acetate, i-butyl acetate, n-butyl acetate, t-butyl acetate, methyl formate, ethyl formate, propyl formate and mixtures thereof. The most preferred solvents are alcohols, such as methanol and ethanol and acetates, such as i-butyl acetate and ethyl acetate.
Another advantage of the present invention is that the solvent mixture dissolves more Lovastatin and Simvastatin than pure solvents and can also be used in the crystallization. Thus, the present method results in increased yield of Lovastatin and Simvastatin in comparison to method previously known in the art.
The process of the present invention results in the production of Lovastatin and Simvastatin containing less than about 0.08% dimeric impurities. Thus, one aspect of the present invention is directed to the compounds of Lovastatin and Simvastatin having less than about 0.08% dimeric impurities.

Process for purifying lovastatin and simvastatin with reduced levels of dimeric impurities


A modular component shelter includes an adjacent side-by-side array of curved, interlocking, rigid panels. The panels curve upwardly and inwardly to a common vertex from a common base-level circumferential rim. The panels interlock between adjacent panels by means of raised interlocking ribs. The ribs extending in generally vertical planes along opposite side edges of each panel so as to form a first channel along a first side edge of each panel and second channel along an opposite second side edge of each panel. The first channel is shaped to snugly fit within the second channel along the length thereof. The first channel is releasably securable in the second channel.

This invention relates to the field of habitable shelters constructed from a plurality of light weight, insulated and rigid interlocking modular components. In particular, it relates to shelter components which are curved along the longitudinal axis to provide a substantially vertical wall portion and an upward and inwardly sloping roof portion which terminates at a common vertex. The components, or panels, by virtue of having an integrally formed channel adjacent each longitudinal edge may be efficiently interlocked and assembled in a side-by-side array to form a habitable shelter.
As a basis for satisfying the housing needs for the less fortunate in North America and in other countries, traditional residential construction based upon the current wood based methodology is impractical due to the cost of materials, the level of skill required of the labour force, and the length of time required to construct such residences. In addition such construction is impractical under many climate conditions.
Further, where the people in a locality have been deprived of their homes through the forces of a natural disaster or of political turmoil, or where exploration and development is undertaken in remote areas, shelters for use as dwellings, hospitals or storage areas are usually a priority.
When such shelters are required, the lack of available construction time, materials or expertise at the scene renders on site construction by traditional methods impracticable.
Presently, portable shelters which are available for transportation to such a site have several shortcomings such as their weight, their complex method of erection and assembly and that they generally provide only minimal protection from adverse temperatures, heavy rains or strong gusts of wind.
In the prior art within this field, the applicant is aware of U.S. Pat. No. 5,513,471 and Canadian Patent No. 2,103,103 which are corresponding patents issued to the same inventor and describe a contiguous wall panel section which is formed in three planar portions; namely a vertical lower portion, a relatively gently inwardly sloping intermediate portion and a more aggressive inwardly sloping upper portion. The wall panels are formed with parallel longitudinal sides, each of which has an integrally formed rib or channel and into which the channel of the corresponding side rib of successive wall panels are nested and secured.
Corner panels are formed in the same way as the wall panels except that the vertical lower portion is curved in a horizontal plane. Two corner panels are utilized at a comer. The longitudinal sides of the lower section are parallel, while the outer sides of the intermediate and the upper section sections of adjacent comer panels converge toward the top of the panel to match adjacent side wall panels. Separate panels provide a roof enclosure.
The applicant is also aware of U.S. Pat. No. 4,068,421, in which is revealed an integrally formed, smoothly curved wall panel which is formed as a hemi-spheroidal section. The longitudinal edges of each panel has a channel which can be interfitted with the channel on adjacent panels which are then bolted together. Intermediate or wall panels having parallel longitudinal sides can be used to enlarge the structure to a generally ellipsoidal shape. Separate upper panels provide a roof enclosure.
It is the object of the present invention to provide a habitable shelter constructed from separate interlocking components or panels. The panels can be fabricated from a rigid, light weight material such as Fiberglas or the like material, suitably treated to resist degradation when exposed to ultra violet radiation, and embody both end wall and side wall panels. The end wall panels are spherical triangular segments having an exterior horizontal arc equal to 45 degrees. Side wall panels, having generally parallel longitudinal edges, may also be provided which can be utilized to lengthen and widen the shelter. The panels may typically contain thermal insulation and selective panels may be provided with integral windows and entry doors.
Thus the present invention provides a sturdy weather proof shelter suitable for habitation which is assembled from pre-made modular components. The components take the form of wall panels which are curved inwardly and upwardly from a common base-level rim to a common vertex. The vertex is generally enclosed by a roof cap which provides a weatherproof cover. Each panel can be securely interlocked to the adjacent panel by means of raised channels which extend along the length of the panel in generally vertical planes adjacent and parallel to the longitudinal side edges of the panel.
A first channel is formed adjacent a first longitudinal side edge of the panel and a second channel is formed adjacent a second longitudinal side edge of the panel. First channels of each panel are formed so as to snugly fit within the second channels formed adjacent the second longitudinal side edge of panels when positioned in a side-by-side array. The channels are secured in an interlocked relationship by means of releasable fasteners such as bolts or the like.
Lateral displacement of the side-by-side array of panels is further inhibited by the formation of a first channel step formed along a first side of the first channel and a first channel lip formed on a second side of the first channel. The first channel lip protrudes laterally outwardly from the first channel. A corresponding second channel lip protrudes laterally outwardly from the first side of the second channel, and a raised auxiliary rib is formed parallel to and spaced from the opposite second edge of the second channel.
During assembly of these shelter components, the first longitudinal side edge of a panel is placed over a second side edge of an adjacent panel in the side-by-side array so that the second channel is securely nested within the overlying first channel. Such positioning ensures that the second channel lip, adjacent the second channel, is placed in engagement beneath the first channel step, adjacent the first channel, and the first channel lip is snugly fitted between the second channel and the raised auxiliary rib. Releasable fasteners such as bolts can then be placed through aligned holes in the ribs.
In summary, the modular component shelter of the present invention includes an adjacent side-by-side array of curved, interlocking, rigid panels. The panels curve upwardly and inwardly to a common vertex from a common base-level circumferential rim. The panels interlock between adjacent panels by means of raised interlocking ribs. The ribs extend in generally vertical planes along opposite side edges of each panel so as to form a first channel along a first side edge of each panel and second channel along an opposite second side edge of each panel. The first channel is shaped to snugly fit within the second channel along the length of the channels. The first channel is releasably securable in the second channel by means of releasable fasteners such as bolts.
In the modular shelter of the present invention the panels include at least one curved array of end panels, the array of end panels in adjacent side-by-side array forming a rounded first end cap of the shelter. The end cap is formed as a generally spherical triangle. The modular shelter further includes a second end cap, identical to the first end cap, the first and second end caps in opposed facing relation.
For a smaller modular shelter the first and second end caps are mounted to each other. For a larger modular shelter intermediate panels are mounted in parallel array in the adjacent side-by-side array between the first and second end caps so as to form an elongate shelter.
In the modular shelter of the present invention the first channel further includes a step formed along a first edge of the first channel and a first channel lip formed along, so as to protrude outwardly of, an opposite second edge of the first channel. The second channel further includes a second channel lip formed along, so as to protrude outwardly of, a first edge of the second channel. A raised auxiliary rib is parallel to and spaced from an opposite second edge of the second channel. When the second channel of one of the panels is interlocked within the first channel of an adjacent panel in the adjacent side-by-side array, by snug fitment of the first channel over the second channel, the second channel lip mates snugly under the step and the first channel lip fits snugly between the second edge of the second channel and the auxiliary rib. A roof cap may be mounted over the common vertex. One of the intermediate panels may have a door portal formed therein.


Provided are method of producing a shaped fluoropolymer articles. The methods include subjecting a composition comprising a fluoropolymer to additive processing in an additive processing device. Also provided are articles obtained with the methods and 3D-printable compositions.

Fluoropolymers are widely used as raw materials for their chemical inertness, in particular for articles requiring low friction properties and/or inertness to chemical reactivity, heat, or both.
Fluoropolymers are typically classified into thermoplastics and elastomers (sometimes also referred to as fluororubbers).
Fluorothermoplastics can be processed by conventional melt shaping methods, such as injection molding and extrusion. Fluorothermoplastics typically are copolymers of tetrafluoroethylene (TFE) with one or more other perfluorinated, partially fluorinated or non-fluorinated comonomers. Copolymers of TFE and perfluorinated alkyl or allyl ethers are known in the art as PFA's (perfluorinated alkoxy polymers). Copolymers of TFE and hexafluoropropylene (HFP) with or without other perfluorinated comonomers are known in the art as FEP's (floor mated ethylene propylene). Copolymers of TFE, HFP and vinylidenefluoride (VDF) are known in the art as THV. Other types of melt-processable fluoropolymers are based on vinylidenefluoride homo- or copolymers, known in the art as PVDF. Copolymers of TFE and ethylene are known as ETFE.
Certain types of thermoplastics, have a very high melt viscosity (low melt flow index (MFI) and are termed in the art as "non-melt processable". Non-melt processable fluoropolymers include homopolymers of TFE or copolymers of TFE with other copolymerizable perfluorinated monomers, wherein the amount of comonomers is limited to less than 1% wt. Such TFE homo- and copolymers are referred to in the art as PTFE. PTFE has such a high melt viscosity that it cannot be processed by conventional melt processing techniques such as extrusion, injection molding or blow molding. Instead PTFE articles typically are produced by paste extrusion, or by sintering to produce blocks or billets which are then shaped into articles. For example by skiving, turning, machining (i.e., substractive methods where material is removed to shape articles).
In WO2007/133912 A2 an additive manufacturing process for special thermoplastic fluoropolymers (PVDF and PCTF) are described but examples are not provided. In CN103709737 A and CN 105711104 A methods for 3D printing are described where the use of PTFE is mentioned. The materials are processed by irradiating a polymer powder with infrared or lasers and melting the powder in selected areas exposed to the IR- or laser irradiation. These methods are known in art of 3D-printing as laser melting or laser sintering. In U.S. Pat. No. 7,569,273 B2 a different method is described that is reported to be suitable for PVDF. Examples are also not provided. The method described in U.S. Pat. No. 7,569,273 B2 involves adding a fluid through a nozzle to a solid composition comprising the polymer and an adhesive particulate material. The articulate material becomes adhesive upon contact with the fluid and thus is reported to crease an article by distributing the fluid on selected areas.
There is a need for providing alternative methods of processing fluoropolymers by additive processing and in particular there is a need for processing fluoropolymers of the non-melt processable type.


A device for determining the location or the position of an object moving along a known course includes equipment associated with the object. The equipment includes at least one central computer, at least one receiver/decoder of signals originating from one or more satellites, a radio interface and a database having a mapping of the course of the object. The device includes further central equipment including a central computer, one or more radio interfaces, a bus system, a database including the mapping of the course, an application for managing modifications of the mapping and at least one console, and moving-object/central-equipment and man/moving-object interface elements.

The present invention relates to a method for securely determining the location and/or the positioning of an object moving along a course which is known by the location device.
The term xe2x80x9ccoursexe2x80x9d is intended to mean a subset of the space delimited by a tubular surface of arbitrary and variable cross section, in which the vehicle is strictly constrained to move. In the event that the cross section of this tube can be neglected, this gives two equations linking longitude, latitude and altitude of the moving object.
The present invention relates more precisely to a method for determining the location of a train moving on a railway track whose exact path is known.
The same principle can be applied to the case in which a single equation is known (movement of the moving object on a known surface).
The present invention relates to a method for determining the location and/or the positioning of a vehicle, this securely in terms of railway transport, that is to say it involves being able to determine the location, or more precisely the zones of non-presence of said vehicle on a section, this quasi-instantaneously, for a vehicle moving on a known course, and doing so with a given probability.
This location is based on the use of navigation satellites or equivalent terrestrial navigation beacons, generically referred to below as xe2x80x9csatellitesxe2x80x9d.
In railway signaling, a train is not permitted to enter a specific section of track until it is certain that the train in front has departed therefrom, that is to say that the track section in question is free. To that end, it is necessary to ascertain with a margin of error which is predetermined, and of course extremely small, and to do so securely in terms of railway transport; for example with a maximum error level of the order of 10xe2x88x929 and preferably of the order of 10xe2x88x9212, the zones in which non-presence of a train can be relied upon, and to do so at each iteration of the calculation.
It is known to determine the precise location of an object, and a fortiori of a train, with the aid of calculation of the position with respect to three satellites, the receivers that can receive the information from said satellites being capable of calculating the coordinates of said moving object with a relatively high precision.
However, it is necessary to add a precise measurement of the universal time, which may prove to be complex and sometimes costly to implement at the level of a receiver, for example one arranged in the train. Furthermore, it should be noted that it is necessary for the various satellites to belong to the same constellation and for them to use the same reference time.
For this reason, a fourth satellite is generally used, which permits precise location of the object in question by solving a system of four equations with four unknowns, so as to obtain the three coordinates of the point in question and the value of the time.
In reality, on the basis of knowledge of the coordinates of these satellites, an estimate is made by calculating the distance separating said satellites from the receiver object whose location is intended to be estimated.
Numerous strategies for increasing the quality and/or the quantity of information being used, in both the civilian and military fields, have made it possible to improve the precision of these measurements.
To that end, the following may be mentioned, inter alia:
increase of the number of satellites involved in the measurement (including on the ground),
correlation between successive measurements in order to reduce the weight of certain causes of errors,
radio broadcasting (via satellite or otherwise) of local correction information (DGPS, WAAS, for example),
increase of the precision of the timing measurement by synchronisation with the carriers of the satellites,
use of maintenance and control information broadcast by the ground monitoring network or networks of the constellations of satellites.
These various items of information are compiled in order to refine as much as possible the most probable value of the position of the object of interest and to increase its precision.
Furthermore, coding and autocorrelation techniques have also been suggested in order to assure protection against electromagnetic interference or malicious acts liable to occur when measurements are being taken.
Lastly, for certain applications, the satellite location system may be supplemented with complementary sensors, which can further improve the quantity or the quality of the available information, for example atmospheric pressure sensors in aeronautics, train-axle rotation sensors coupled with a Doppler radar, partial or complete inertial stations, etc.
It is therefore an aim of the present invention to describe a method and a device which permit secure location and/or positioning of an object, and thus a fortiori of a vehicle such as a train, moving on a known course.
The term secure location is intended to mean the location, or more exactly the non-presence of a train outside a zone which is redefined at each calculation, with a error level of less than 10xe2x88x929 and preferably capable of reaching 10xe2x88x9212.
The present invention relates to a method for determining the location and/or the positioning of an object, in particular a vehicle such as a train, moving along a known course, and this securely in terms of railway transport, characterised in that said location and/or said positioning of said object is determined by a valid calculation at a given time based on the one hand, on an elementary measurement involving at least one satellite and, on the other hand, on a secure mapping of said known course.
Preferably, said secure mapping makes it possible to obtain two relationships with three unknowns representing the coordinates of said object whose location and/or positioning is intended to be ascertained, while at least one other relationship between the same three unknowns is obtained with the aid of the information transmitted by at least one satellite whose position is known.
More precisely, the present invention relates to a method in which each elementary measurement consists in determining an individual domain along said course between two mileage points, said domain depending on the standard deviation of the timing measurement errors of said elementary measurement, the speed of light, a coefficient linked with the coordinates of said satellite in question and the course of the track, and a weighting factor defining the geometry of the error distribution for any measurement recording, so that the probability of non-presence of the train in said individual domain is predefined.
Advantageously, each measurement recording is redundant, which makes it possible to determine a plurality of individual domains by a plurality of elementary measurement recordings carried out simultaneously at the same given time, which are based on different satellites or on pairs of satellites.
According to a first embodiment, an elementary measurement will be carried out with the aid of a pair of satellites using the same reference time. Preferably, the pair of satellites will belong to the same constellation.
According to another preferred embodiment, an elementary measurement will be carried out with the aid of at least one satellite belonging to a constellation and a receiver linked with the object moving along the known course, said receiver having a clock synchronised with the reference time of said constellation to which the satellite belongs.
This means that it is sufficient to increase the number of satellites in order to take a plurality of elementary measurements simultaneously.
Preferably, the existence of a common domain is determined, which is defined as the intersection of the, and preferably of all the, various individual domains. Particularly advantageously, the individual domains which have no point in common with the common domain are rejected.
Hence, if there is a non-null common domain, the domain of possible presence of the moving object is determined as the union of the non-rejected individual domains.
It is deduced from this that the probability of non-presence outside the union domain is defined as the product of the probabilities of non-presence in the known individual domains.
According to a preferred embodiment, the individual domains defining the union domain depend on a parameter defining the geometry of the error distribution which is greater than or equal to the parameter selected for determining the individual domains defining the common domain.
The invention also relates to a device for determining the location and/or the positioning of an object, preferably a vehicle such as a train, moving along a known course, and this securely in terms of railway transport, comprising at least:
equipment associated with said object, said equipment comprising at least one central computer, at least one receiver/decoder of signals coming from one or more satellites, a radio interface and a database comprising the mapping of the course executed by said object,
central equipment comprising a central computer, one or more radio interfaces, a bus system, a database comprising the mapping of the course, an application for managing the modifications of said mapping and at least one console, as well as moving-object/central-equipment and man/moving-object interface elements.
Advantageously, the receiver/decoder comprises a clock synchronised with the reference time of the constellation of satellites.
Preferably, the device of the invention furthermore comprises a plurality of complementary sensors.
Preferably, the central equipment is optionally portable.
The method for determining the location and/or the positioning of an object, and more particularly of a train, moving along a known course, can in fact be interpreted according to two different modes of operation:
the linear mode, when the train is travelling along a track with no branching in the vicinity of its position, and
the topological mode, when the train is going to enter a switching-points zone or when it is not yet possible to be sure that it has departed therefrom.
The present invention relates more precisely to the location of a train moving in linear mode.
In the event of movement in topological mode, that is to say in a switching-points zone, for example, examples of implementation are described below which make it possible to revert rapidly from the topological mode to the linear mode, and therefore to apply the method according to the present invention
Of course, any generalisation to a vehicle moving along a known course may be made, for example to a boat moving on a canal network, a car moving on a motorway whose exact course is known, etc.
It should be noted that, in the field of railway signaling, the course of the object, and more precisely of the train, is known with precision and securely. It is therefore simply expedient to check that a train is not approaching a dangerous point (specific section of track) and to signal its presence to the train following it, until the latter can enter without any risk of colliding with it.
The refresh time in a railway system should be at most from one to a few seconds.
The Linear Mode
In this mode, the train is localised in terms of a domain defined by two mileage points, that is to say as a confidence interval defined by two curvilinear coordinates in which, for an identified track whose exact path is known (or at the very least if not the exact path, the probable path in the securely sense of the term), it is possible to define the non-presence of a train with an error level which is as small as necessary.
The mapping of the track gives two securely known equations between three coordinates (altitude, latitude and longitude). The mapping is stored in a secure database and is loaded on board the train at the start of service, while guaranteeing the integrity of the contents by the conventional railway transport secure means: coding, redundancy. Its updating, when appropriate, is preferably managed by a suitable protocol.
The third equation will be given by an elementary measurement involving at least one satellite, and preferably a pair of satellites. It is:
either a measurement of the transmission time between a satellite and the receiver arranged on the moving object (the train), which defines the distance between said satellite and the receiver, this being done in the event that said receiver has a clock synchronised with the reference time of the constellation to which the satellite belongs,
or a measurement of the difference between the transmission times of each of the satellites of a pair of satellites and their receiver arranged in the moving object (the train), in the event that said receiver is not provided with a clock synchronised with the reference time of the constellation to which the satellites belong.
It should be noted that, in the case of recording an elementary measurement with the aid of two satellites, belonging preferably to the same constellation, or at the very least to constellations using the same reference time, it will not be necessary for the receiver arranged in the train to have a clock synchronised with this reference time.
Conversely, in the case in which an elementary measurement is carried out with a single satellite, it is essential for the receiver arranged in the train to be provided with a clock synchronised with the reference time of the constellation to which this satellite belongs.
This increases the implementation cost of the method according to the present invention, but will reduce the number of satellites needed for each elementary measurement.
During an elementary measurement (i=1), an attempt will therefore be made to determine, using a system of equations (three or four) with a plurality of unknowns (three or four), the positioning of said moving vehicle, or more precisely the domain Di defined on the course by the two mileage points Mimin and Mimax, which are counted from a reference that is arbitrary but unique for each line, and which are separated by a distance
2 xcex7a c "sgr"i xcex1i, where
xcex7 is a dimensionless coefficient defining the geometry of the error distribution,
c is the speed of light,
"sgr"i is the known standard deviation of the timing measurement errors, and
xcex1i is a dimensionless coefficient linked with the coordinates of the satellites and with the course of the track.
If "sgr"1 denotes the known standard deviation of the timing measurement errors during this first elementary measurement, performed for example with the aid of a first pair of satellites, then xc2x1xcex7a "sgr"1 may be regarded as being the limit of the measurement error with a probability Pa (10xe2x88x922 to 10xe2x88x924, for example), which defines xcex7a as a dimensionless coefficient that allows the assumption to be made that the distribution is Gaussian when an elementary measurement is taken. Usually, xcex7a is between 1 and 4, and preferably between 2 and 3. Specifically, if xcex7a is too great, this decreases the stringency criteria on the measurements, that is to say it increases the error level probability. Conversely, if xcex7a is too small, the risk of the measurements not converging, and therefore of rejecting said elementary measurement, is increased.
xcex7a and the number of elementary measurements (and therefore the number of satellites being used) need to be selected in order to achieve the predefined probability conditions.
It should be noted that "sgr"1 includes the random distribution errors linked, for example:
with the propagation speed of the wave in the ionosphere and the troposphere,
with the relative calibration errors of the internal clocks of the satellites,
with the errors between their actual position and their transmitted position,
with the errors of synchronisation with the received messages,
etc.
The elementary measurement is repeated k times (with k satellites or k different pairs of satellites). The k elementary measurements may be carried out by using different constellations. This determines domains D2a . . . Dka of the same kind as D1a.
If all these domains Dia contain a subset of mileage points which is common to them, the common domain D0a is defined as the intersection of the domains Dia. In this case, the parameters of the subsystem of satellites which are used are in their normal mode of operation, at least for the measurement required at this moment. This may be imposed as a necessary condition in the calculation algorithm.
Furthermore, if the D0a existence condition is satisfied, the probability of having an unknown anomaly in the subset of satellites which is being used may be neglected; such an anomaly would lead to a measurement being void, or to underestimation of the error probability in the calculated domain. In the converse case, complementary measurements may be employed by using one or two additional satellites.
It should be noted that the reasoning adopted above is carried out on the basis of pairs of satellites. The same reasoning could of course be carried out with the aid of individual satellites acting interactively with the receiver, so long as the receiver itself has a clock synchronised with the reference time of the constellation to which the satellite or satellites belong(s). Nevertheless, the provision of a clock synchronised with the reference time of the constellation, such as a caesium clock, is still relatively expensive and it is very probable that this solution will not be directly contemplated.
If, lastly, the satellite pairs which are used belong to different constellations, or if suitable monitoring makes it possible to ensure that there is no common-mode error within a given constellation, then the probability that the actual location is outside a union domain: Dub (defined as the union of the individual domains Dib: 2 xcex7b c "sgr"1 xcex11) will be at most equal to (Pb)k, which gives access to the error probabilities ranging from 10xe2x88x929 to 10xe2x88x9212 that are necessary.
The coefficient xcex7b is defined with xcex7b xcex7a, such that the probability Pb of having a location outside the domain 2 xcex7b c "sgr"i xcex1i can be selected to be as small as possible (10xe2x88x923 to 10xe2x88x926, for example).
Within a given constellation, the non-presence of common-mode error may be determined, for example, by looking for the position of known fixed stations on the basis of the same pairs of satellites. An anomaly may be communicated to the trains either via the command post or via a local radio link. The time needed for this operation must then be added to the calculation time per se.
The Topological Mode
As already described above, the movement of a train in a topological mode should be reverted as quickly as possible to a movement in a linear mode, so that the method according to the present invention can be implemented.
By way of example, if one train is following another train and the track between the two does not contain any switching points, the positioning of the train behind is carried out exclusively in linear mode; its allowed limit of movement will be calculated on the basis of possible knowledge of the rear of the train in front of it, which may involve direct or indirect dialogue with this train.
Similarly, when a train is travelling towards a switching point, the system gives it the certainty that there is no other object between this switching point and itself, allowing it for example to take possession of a (single-line) token associated with the switching points.
When it is in possession of this token, it can change the switching point according to the route assigned to this train by the control centre. Having confirmation that the switching point is locked in the required position, the topology of the track for this train in the vicinity of the switching point is known: the situation has therefore reverted to the previous case and the location can again operate in linear mode, apart from the fact that it may be necessary to change the reference mileage point after having crossed the switching point in order to fix it in the new track being taken.
The token is given back to the switching point when the fact that the end of the train has departed from it has been registered; it is then available for the train following it.
Giving back the token will often entail a change of mapping (new known course).
In conclusion, the situation in this exemplary case has reverted to a linear movement mode.

Method for secure determination of an object location, preferably a vehicle moving along a known course


A photoreactive composition containing an effective amount of a polymer which includes as a recurring structure: ##STR1## wherein Ar is a bivalent aromatic radical, and M is selected from the class consisting of hydrogen, alkali metal, ammonium, and substituted ammonium. These compositions are useful in a wide variety of photochemical and photomechanical processes and are particularly suited for use as photopolymers, photoinitiators and photosensitizers in light sensitive coatings of presensitized lithographic plates.

This invention generally relates to novel photosensitive compositions which are useful in a wide variety of photochemical processes such as, for example, planographic, letterpress, gravure and silk screen printing processes as well as photomechanical processes such as, for example, the production of printed circuits, chemical milling and chemical etching. An important aspect of the present invention is directed to novel photoreactive compositions which are especially suitable for use as photopolymers, photoinitiators and photosensitizers in light sensitive coatings used in lithographic plates.
In commercial lithography, a light sensitive coating on a backing member is generally subjected to a controlled light exposure and thereafter developed to provide an image area which is insoluble in a particular solvent and a non-image area which is soluble in that solvent. Typically, the image area is grease-receptive and water repellent, while the non-image area is water-receptive and grease-repellent. Oil-based inks therefore adhere only to the image area, from which they can be transferred to a surface in a suitable printing operation such as, for example, by offset printing.
Early lithographic plates typically had light sensitive surface coatings which generally contained bichromated colloids such as bichromated albumin that underwent a sol-gel transformation upon being subjected to light. Since these bichromated colloids are sensitive to moisture, they deteriorate rapidly on being subjected to atmospheric conditions and their use has been generally limited to so-called wipe-on plates, that is, systems wherein the light sensitive bichromated coating is applied to the plate or backing member immediately prior to its being exposed to light.
Subsequently, light sensitive diazo compounds have been used as the light sensitive coating in presensitized lithographic plates, namely, plates which have the light sensitized diazo coating applied thereto prior to actual use. While diazo-sensitized plates are extensively commercially used at this time, they are characterized by certain disadvantages which include, for example, limited shelf life, and the need for a barrier coating between the diazo coating and the backing member. In addition, the diazo coatings present handling problems by reason of their sensitivity to heat, moisture and tungsten light.
More recently, the efforts to overcome the disadvantages of the above mentioned prior art compositions have involved the use of photopolymer coatings which can be applied to a suitable backing member long prior to actual use and which, upon being subjected to light, become insolubilized by polymerization or crosslinking. These photopolymer coatings have been composed of various materials, for example, the cinnamate ester resins of polyvinyl alcohol and cellulose as well as those based on epoxy resins. Similarly, acrylic coatings and polyamide coatings are other types of photopolymerizable coatings which have been discussed in the prior art. These known photopolymer coatings, however, often require the addition of photosensitizers and photoinitiators. Also, when used in lithographic plates, these known photopolymer coatings have presented relatively difficult manufacturing problems and have required development procedures which are more complex than desired.
It is, therefore, an important object of the present invention to provide a new class of photosensitive compositions characterized by improved photoreactive properties enabling them to be used in a wide variety of photochemical and photomechanical processes.
Another object of the present invention is to provide a new and useful class of photoreactive compositions which are useful in virtually all printing processes including planographic, relief, gravure and silk screen printing processes.
Another object of the present invention is to provide a new and useful class of photoreactive compositions which can be used alone, or if desired, in conjunction with a wide variety of resins, both saturated and unsaturated, to provide improved photoreactive coatings.
Another object of the present invention is to provide a class of novel photoreactive compositions which include an effective amount of multi-functional glyoxylated substituents.
Another object of the present invention is to provide a class of photoreactive polymeric compositions advantageously suitable for use as photoinitiators, photosensitizers or photopolymers, which compositions include, as a repeated structure, a plurality of glyoxylated groups, present either wholly or partially as pendant groups from the polymeric chain which exhibit advantageous oxygen insensitivity.
Another object of the present invention is to provide a class of photoreactive compositions suitable for use as photoinitiators, photosensitizers, and photopolymers characterized by long shelf life, enabling them to be particularly suitable for use in presensitized lithographic plates.
Another object of the present invention is to provide a class of photoreactive compositions which can be used alone or in conjunction with a wide variety of resins, to provide photoreactive coatings which are developable with water or alcohol-based solvents or desensitizers.
Another object of the present invention is to provide a class of improved photoreactive compositions which, upon controlled exposure to actinic light, are capable of forming insoluble image areas that exhibit long running characteristics on backing members in lithographic plates.
Another object of the present invention is to provide a class of improved photoreactive compositions which can be used in ink and coating formulations to make such ink and coating formulations photocurable.
These and other objects of the present invention will be apparent to those skilled in the art from reading the following more detailed description.
In accordance with an important aspect of the present invention, novel polymers are provided which are soluble in a suitable solvent, typically an aqueous solvent or an organic solvent such as acetone or methylethyl ketone.
These novel polymers, upon exposure to actinic light, photoreact and become insoluble. As such, the polymers of this invention are particularly suitable for use in photoreactive processes including photochemical as well as photomechanical processes and find advantageous use either alone, or in conjunction with other materials, in photoreactive coatings used on lithographic plates.
The novel compositions of this invention generally comprise polymers which include as a recurring structure: ##STR2## wherein Ar is a bivalent aromatic radical and M is selected from the class consisting of hydrogen, alkali metal, ammonium and substituted ammonium.
In the above formula, the preferred alkali metals in the M group are sodium, potassium and lithium. Correspondingly, the substituted ammonium substituents encompassed by the definition of the M group are those which provide a compound which is water soluble and include, for example, triethylamine, ethylamine, aniline, substituted aniline (e.g. chloroaniline, cyanoaniline and methyoxyaniline), pyridine, substituted pyridine (e.g. picoline and 2,6-lutidine), the alkanolamines such as, for example, mono, di and tri-alkanolamines wherein the alkanol group is ethanol or isopropanol, the alkylamines such as, for example, the mono, di and tri-alkylamines wherein the alkyl group is ethyl or propyl, morpholine and the cycloaliphatic amines such as, for example, cyclohexylamine.
As used herein, the "Ar" group is intended to include all bivalent structures exhibiting aromaticity, including: carbon ring structures such as, for example, phenylene, diphenylene and the like; fused ring structures such as, for example, bivalent derivatives of pyridine, furan, thiophene, pyrrole, quinoline, indole, and the like. In the preferred embodiments of this invention, however, the "Ar" groups are phenylene and naphthalene.
The compositions of the present invention are polymeric in form and include polymers wherein the abovedefined recurring structure is present as a part of the polymeric backbone as well as polymers wherein the recurring structure is present as pendant groups from a backbone structure, the chemical nature of which is not critical except in its ability to partically incorporate and/or bondably connect with aromaticglyoxy groups generally in accordance with the aforementioned structure. As such, these polymeric backbone structures can be organic, organometallic or inorganic and be in oligomeric or polymeric form. In this regard, it should be noted that the term polymeric is used to include homopolymers and copolymers which are characterized by two or more dissimilar monomeric units and are produced by polymerization, condensation or addition. These copolymers can be in graft, random or alternating form. Examples of suitable backbones include: the aliphatics such as methylene, ethylene and propylene; the aromatics such as phenylene, biphenylene, naphthalene and anthracene; the substituted aromatics such as tolylene, ethylphenylene, aminophenylene, alkoxyphenylenes (e.g. methoxyphenylene), cyanophenylene, hydroxyphenylene, the halophenylenes (e.g. chlorophenylene), ethylnaphthalene, carboxyphenylene, difunctional drivatives of the phthalates and substituted phthalates such as the hydroxy alkylphthalate compounds (e.g. hydroxyethylphthalate) and acyloxyphenylenes (e.g. acetoxyphenylene); cyclic hydrocarbons such as difunctional derivatives of cyclopentane and cyclohexane; heterocyclics such as difunctional derivatives of thiophene and pyrrole; the organometallics such as difunctional derivatives of the metallocenes such as ferrocene and cuprocene; polymeric materials such as the polyalkylenes (e.g. polyethylene, polypropylene and polybutylene); polyesters such as polyethyleneterephthalate and polyethyleneadipate; polyurethanes such as the toluene diisocyanate polyol urethanes; polyamides such as polyhexamethyleneadipamide; copolymers such as vinylidene chloride/vinyl chloride copolymers; the polysiloxanes; the polyalkyleneoxides (e.g. polyethylene oxide, polypropylene oxide, polybutylene oxide, polytetramethylene ether and polyepichlorohydrin); the polyalkylene imines such as polyethylenimine and polypropylenimine; substituted polyalkylenes such as polyvinylpyrrolidone; and phenolic derivatives such as novolac, resole and polyphenylene oxide.
As previously noted, photoreactive compositions of the present invention can be used alone or in conjunction with other materials to provide photoreactive compositions suitable in a wide variety of photomechanical and photochemical processes. For example, these novel compositions exhibit advantageous utility as photoinitiators with both saturated and unsaturated resins including resins which are not photosensitive in themselves. In particular, durable insoluble photoreaction products have been formed through the conjoint use of the photoreactive compositions of the present invention as photosensitizers with a wide variety of resins, including: the acrylic polymers and acrylic ester resins such as polymethylmethacrylate, polyethylmethacrylate, and copolymers of methyl and butyl methacrylate (e.g. "Elvacite"); polyurethane resins such as those formed by reacting diisocyanates such as, for example, toluene diisocyanate with low molecular weight polyesters or low molecular weight polyethylene glycols (e.g. "Estane" polyurethane resins); blocked urethane resins such as, for example, phenol blocked polyurethane resins (e.g. "Tranco 3A" blocked urethane resins); alkyl celluloses such as ethyl cellulose (e.g. "Hercules K-type" ethyl cellulose); epoxy resins (e.g. "Epon 1004" which is the condensation product formed from bisphenol A and epichlorohydrin); phenoxy resins (e.g. "Bake-lite PKHH" phenoxy resin); vinyl acetate/vinyl chloride copolymers (e.g. "Bakelite VYHH" an 86% vinyl chloride, 14% vinyl acetate copolymer medium molecular weight resin); vinyl modified polyethylene such as ethylene/vinyl acetate copolymer containing 2 to 50% vinyl acetate ("Ultrathene" ethylene/vinyl acetate copolymer); partially (5 to 80%) hydrolyzed vinyl acetate resin (e.g. "Bakelite" MA 28-18 18% hydrolyzed vinyl acetate); phenolic resins (e.g. "Plenco 1000" novolac resin); acrylamide and modified acrylamide polymers such as diacetone acrylamide homopolymer, N-methylol acrylamide, N-alkoxymethyl acrylamide and partially hydrolyzed acrylamide; water-soluble cellulose derivatives such as the hydroxyethylated celluloses and hydroxypropyl cellose (e.g. "Klucel" hydroxypropyl cellulose); and water-soluble polyether resins such as the polyalkylene oxides (e.g. "Polyox WSRN-80" polyethylene oxide).
The amount of the aromaticglyoxy substituted polymers of the present invention which will be used in a given photoreactive composition will vary over a broad range depending upon the intended function of the compound in the composition. For this reason, the concentration of these constituents in a given photoreactive composition is best described as an "effective amount" and ranges from 0.01% to 100% based on the total weight of reactive material in the composition. For example, when these aromaticglyoxy substituted polymers are used as photoinitiators in a particular coating composition which includes polymerizable monomers (for example, acrylic or vinyl monomers), the amounts of these compounds will generally range from approximately 0.01% to 10% by weight, based on the total weight of reactive material in the composition. When used as a photopolymer with other resins, whether saturated or unsaturated, however, the amounts of the aromaticglyoxy substituted polymers of the present invention can be as low as 5 weight percent and still provide a satisfactory photoreactive coating which, upon being subjected to actinic radiation forms an insoluble species. However, amounts of aromaticglyoxy substituted polymers of the present invention of at least 50 weight percent are preferred for photoreactive coatings suitable for most end uses. Correspondingly, the novel polymers of the present invention can be used alone, that is, without any other thermoplastic resin, to provide a photoreactive coating composition which can be advantageously employed in virtually all photochemical and photomechanical processes including, in particular, the manufacture of presensitized lithographic plates.
In those embodiments of the present invention wherein the aromaticglyoxy groups are wholly or partially present as pendant groups from the polymeric chain, the degree of substitution of these glyoxy substituents can best be described as an amount sufficient to provide the polymer with the ability to form an insoluble species upon being subjected to light. Since the acid form of these compounds is preferred in applications wherein these compounds are applied as a solution to a backing or support member, the minimum degree of substitution which is preferred with such embodiments is that amount which will provide an overall composition soluble in the solvent used in such solution. In this regard, the preferred minimum degree of substitution of the acid form of the aromaticglyoxy groups on a polymeric backbone is that amount which provides an overall compound which is soluble in an aqueous alkaline solution.
If desired, known photoactive compounds may be used in photoreactive compositions which include the aromaticglyoxy substituted polymers of the present invention to impart improved photoeffectiveness thereto or for imparting other desired film characteristics thereto. Illustrative examples of such photoactive compounds include the various ketones, guinones, aldehydes, aromatic compounds, conjugated aromatics and olefins, aromatic nitrogen compounds, peroxides and peroxide compounds, and the miscellaneous photoactive compounds specified in U.S. Pat. No. 4,046,577 at column 5, line 50, through column 9, line 42, the disclosure of which is incorporated herein by reference.
These compounds, oligomers and polymers may enhance the performance of the base aromaticglyoxy polymers of the present invention by changes in spectral response. They or counterparts thereof which exhibit similar properties and characteristics may be used with the polymers of the present invention or with such polymers and an unsaturated species. Correspondingly, if desired, combination of two or more of these sensitizers may be advantageously employed. For example, benzoin and Michlers ketone, benzophenone and thio-Michlers ketone, benzophenone and triethanolamine, etc. Any single species or combination may be used as long as the storage stability, due to premature decomposition, is not affected. Certain of these compounds and even solvents are believed to have ordering as well as plasticizing effects which are beneficial. By plasticizing, functional group or segment mobility is increased. Ordering results in more efficient photolysis. The aromatic ketones and diazo compounds as well as oligomers and polymers are particularly useful. Peroxides are similarly effective. The solubilization and cosolubilization of the aromaticglyoxy polymer with the sensitizers for purpose of film casting can be established by solubility parameter matching. Often dispersions, colloidal dispersions or emulsion are sufficient for film formation.
The unsaturated materials which advantageously can be combined with the aromaticglyoxy polymers of this invention may be defined as any monomer, oligomer or polymer having a single or multiple carbon to carbon unsaturation which is capable of contributing to the formation of an insoluble film when present with these aromaticglyoxy polymers. As such, these unsaturated materials may be generally represented by the following structural formula: ##STR3## wherein X, Y, R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be hydrogen, alkyl, aryl, halo, acetyl, carbonyl, carboxy, carboxy ester, amide, sulfonyl, sulfonyl ester or amide, sulfonic, phosphonyl, phosphoryl and the esters and amides thereof. X, Y, R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be the same or different. X and Y additionally may be polymeric or they may be sites from which an unsaturated structure is pendant. Preferably, the species are liquids or solids. Normally gaseous species are acceptable only if they can be complexed to prevent losses in the cast films.
The preferred unsaturated materials which can be combined in photoreactive compositions with the aromaticglyoxy polymers of this invention are the polyfunctional, low molecular weight, acrylates and methacrylates, illustrative examples of which as well as other suitable unsaturated materials are set forth at column 10, line 28, through column 16, line 61, of the aforementioned U.S. Pat. No. 4,046,577.
These unsaturated materials may be used with the aromaticglyoxy substituted polymer or with both the aromaticglyoxy substituted polymer and the photosensitizers. Further, a mixture of two or more of these unsaturated materials may be advantageously employed with the aromaticglyoxy polymers of the present invention or with such aromaticglyoxy polymers and a mixture of two or more sensitizers. Oligomeric acrylics are preferred unsaturated materials for use in the compositions of the present invention.
Additives such as, for example, pigments, dyes, solvents, plasticizers, antihalation agents, adhesives, extenders, fillers, flow control agents, inhibitors, antioxidants, and other polymers may be used in the compositions of the present invention provided that they not adversely affect the compositions. Solvents used therein may be water based, organic or a mixture of both. Likewise, conventionally known plasticizers may be employed in these compositions such as phthalate esters, adipates, phosphates, and the like.
As previously indicated, the novel polymers of the present invention can also function as sensitizers, that is, they exhibit a property of absorbing light and transferring energy to the photosensitive material associated therewith to provide increased photosensitivity in a given photosensitive or photoreactive composition. As such, these photosensitizers can be used alone or in conjunction with other known sensitizers. Examples of additional sensitizing agents which can be used in conjunction with the compositions of this invention include Michler's ketone, picric acid, 2,4,6-trinitrobenzoic acid, 1,2-benzanthraquinone, 2,5-diphenyl-p-quinone, 4,4'-tetraethyl diamino diphenyl ketone, 4,4'-tetraethyl diaminodiphenyl carbinol, 4,4'-tetramethyl diamino benzophenone imide, 1-methy-2-benzoylmethylene-beta-naphthothiazoline, 4,4'-diazodistilbene-2,2'-disulfonic acid, and auramine base. Other sensitizers exhibiting similar properties and characteristics which may be used in conjunction with the photosensitizers of the present invention will be apparent to those skilled in this art. In this regard, it should be noted that the photoreactive coating compositions of the present invention do not require the addition of other sensitizers such as those identified above in order to exhibit satisfactory sensitivity.
In general, it has been found that when the photoreactive materials of the present invention are used in photosensitive coatings which include a monomer such as a vinyl or acrylic monomer that an antioxidant such as, for example, 2,6-di-tert-butyl-p-cresol or p,p'-biphenol also can be advantageously employed therewith.
It has been found that the composition of the present invention is also quite stable if stored away from light, however, in certain instances it may be desirable to include a small quantity of a polymerization inhibitor, such as, for example, hydroquinone, which is sufficient to maintain the stability of the composition but insufficient to prevent, or materially affect, polymerization when the composition is later exposed to actinic light.
In preparing products made with the polymers of the present invention, such as, for example, lithographic plates, a solution of these novel aromaticglyoxy substituted polymers alone, or in conjunction with other thermoplastic resins, photoinitiators, photosensitizers, and other optional constituents, is applied to a support for backing member in any manner such as spraying, whirler coating, and the like after which the solvent is evaporated either by air drying or heating to produce a thin film on the support member. Typically, the support member may comprise any rigid substrate and will be characterized by a surface which is hydrophilic and to which the film or coating of the photoreactive composition will adhere. Glass, paper, resin impregnated or reinforced paper, solid resinous sheets, or metal plates, such as aluminum, zinc, magnesium or copper having a coating providing the desired properties and characteristics may be used as the material of construction in the support member. In addition, the support member may be in plate, sheet or foil form and may be smooth or grained. For example, in the case of an aluminum plate backing member, the surface thereof may be anodized and treated with an aqueous alkali metal silicate, silicic acid or equivalent which provides the metal with a hydrophilic surface. Likewise, if desired, the base plate or backing member may be provided with a resinous coating which is adapted to receive the light sensitive coating material. Exemplary of resinous coatings of this type are those fully described in U.S. Pat. Nos. 3,073,723, 3,161,517 and 3,232,738.
It will be appreciated that the precise composition of the photosensitive coating solution will be variable to a considerable extent, with the usual requirement being that there be a sufficient amount of photoreactive materials in the solution to deposit a resultant coating on a backing member which will be able to provide an image area which possesses the desired coating thickness and toughness. In general, solvent solutions containing approximately 1/2% by weight to 10% by weight of the active photoreactive constituents have been found to be suitable for most purposes, including the production of presensitized lithographic plates. Preferably, the concentration of the aromaticglyoxy substituted polymer of the present invention and other thermoplastic resins which may be included therewith will be approximately 2% by weight based on the total weight of the solution. If additional photoinitiators or photosensitizers are used, the concentration thereof will usually range from about 0.1% to 20% by weight based on the weight of the other photoreactive constituents.
After the backing or support member has been coated with a film which includes the photoreactive materials of the present invention, it is dried and can be stored for extended periods of time until ready for use. If desired, heat may be used to insure that the residual solvent is driven off for the purpose of facilitating photoinsolubilization when the lithographic plate is exposed to a controlled actinic light source.
In use, the photosensitive coating is exposed to a controlled actinic light source, preferably a mercury lamp with a strong light output of between 250 and 500 nm. It will be appreciated, however, that a wide range of different light sources may be used, depending upon the particular structure of the photoreactive composition and whether or not additional sensitizers and/or initiators are used in conjunction therewith. The exposure to light is done through a stencil, negative, template or pattern to produce a desired light exposure or image area on the surface of the photoreactive coating. This exposure results in a photoinsolubilization within the coating at those locations which receive the light. The duration of exposure is, of course, widely variable depending upon the intensity and type of the light source, the precise composition of the coating, the thickness of the film, and the like. The unexposed areas remain soluble, thereby enabling the image to be solvent developable. In instances wherein water soluble photoreactive compositions are employed, the non-exposed areas can be washed away with a suitable water or alcohol based solution. The plate can then be desensitized in accordance with known techniques.
The exposed lithographic plate, if desired, may be developed through the use of any emulsion developer of the type well known in the art which causes the exposed surface underlying the light exposed photoreactive coating areas to be hydrophilic and the light exposed photoinsolubilized areas to become oleophilic in a single operation. Such developers eliminate the necessity of subsequently desensitizing the plate after development.
While not necessary, if desired, the coated plate may then be subjected to baking to increase further the strength of the insoluble polymeric image area. For example, the coating composition and support member may be oven baked at a temperature below the softening temperature of the support member, for example, below about 150.degree. C. when an aluminum plate is used as the backing member. Also, a UV "bump" postexposure may be used.
It should be noted that while the foregoing description of a specific application of the materials of the present invention has been directed to the manufacture of lithographic plates, these novel compositions may be likewise advantageously used in other photochemical and photomechanical processes such as, for example, other printing processes, the preparation of etched electrical circuits, chemical milling and the like as well as in the preparation of photocurable inks and coatings which, for example, can be of a decorative or protective nature.
A preferred method for preparing the photoreactive composition of the present invention involves the glyoxylation of recurring aromatic groups in polymers such as, for example, polystyrene and vinyl naphthalene polymers. Preferably this glyoxylation involves Friedel-Crafts glyoxylation by reacting ethyloxalyl chloride in the presence of an anhydrous aluminum trichloride catalyst with a polymeric backbone structure which typically includes from 5 to 10,000 repeating monomeric units. The degree of glyoxylation, however, need not be complete. For example, glyoxylation of from 20 to 80 percent of the aromatic groups present in the backbone structure provides compositions which are eminently satisfactory.

Device for use in photochemical and photomechanical processes