An imaging member comprising a polymer sheet, a primer layer contacting said polymer sheet, and an image receiving layer contacting said primer layer; wherein said primer layer comprises: a) polyethyleneimine; and b) latex; wherein the latex has a Tg lower than 25xc2x0 C. and c) hydrophilic colloid material.

The present invention relates imaging members having a polymer base, particularly a polyester base, and to a primer layer that improves adhesion of the imaging layer to the polymer base.
The use of polymeric bases in imaging members is well known. Typically, the base of the imaging member comprises a hydrophobic polymer, and the image receiving layer (also called the imaging layer) comprises hydrophilic colloids, such as gelatin.
Hydrophilic colloids such as gelatin have many unique and desirable properties that make them especially useful in the preparation of photographic materials. For example, gelatin has high swellability in aqueous media which allows rapid diffusion of compounds in and out of a gelatin-containing photographic layer during film processing. Gelatin is also an excellent dispersing medium for light-sensitive silver halide grains and aqueous gelatin solutions exhibit excellent coating properties and quickly undergo gelation when chilled; all of these properties are critical to the manufacture of photographic films. In the case of inkjet applications, the ability of gelatin containing layers to absorb water and water-based inks has promoted their use in inkjet image receiving media. In addition, crosslinked gelatin layers provide very good physical properties such as resistance to scratch, abrasion, ferrotyping, and blocking.
It is difficult to adhere photographic emulsions to oriented polyester supports, such as polyethylene terephthalate or polyethylene naphthalate. The primer layer must work both with unprocessed and processed film in the dry state, and must also adhere when the film is wet during the development process.
Several adhesion promoting xe2x80x9csubbingxe2x80x9d materials, such as poly(methyl acrylate-co-vinylidene chloride-co-itaconic acid) and poly(acrylonitrile-co-vinylidene chloride-co-acrylic acid) disclosed in U.S. Pat. Nos. 3,201,249 and 3,143,421, respectively, provide the required adhesion when applied before orientation but are not as effective when applied on oriented polyester support. The effectiveness of these adhesive materials may be enhanced by the use of swelling or attack agents such as resorcinol.
An alternative approach disclosed in U.S. Pat. No. 4,695,532 describes a discharged treated polyester film support having coated directly thereon a crosslinked layer of an aqueous vinyl acrylate copolymer and gelatin mixture. Although this system has good adhesion before processing, the adhesion performance is severely degraded by photographic developing solutions.
U.S. Pat. No. 5,298,192 discloses a subbing layer comprising a dye, a hydrophilic colloid, and a latex, but this layer needs to be applied to an already existing subbing layer coated on the support. Such a two-step coating process is costly and introduces more waste.
U.S. Pat. Nos. 4,695,532 and 4,689,359 describe a discharge treated polyester film support having coated directly thereon a subbing layer comprising a mixture of gelatin and an aqueous vinyl acrylate copolymer having a ratio of gelatin to polymer of between 5:95 to 40:60 and a dry coverage of between 0.11 and 0.55 g/m2. Although this subbing layer has good adhesion before processing, it has been found that adhesion after contact with photographic developing solutions is severely degraded.
U.S. Pat. No 5,639,589 describes a subbing composition comprising a mixture of gelatin and an aqueous vinyl acrylate copolymer described in U.S. Pat. Nos. 4,695,532 and 4,689,359 having a ratio of gelatin to polymer of between 55:45 to 97:3. This subbing layer performs well when poly(ethylene naphthalate) is glow discharge treated, but poor adhesion, especially when the film was in contact with wet processing solution, was found when it was applied to poly(ethylene terephthalate).
EP 0583787 A2 discloses the use of glow discharge treatment to enhance the adhesion of photographic elements. This treatment involves the use of high energy plasma under vacuum which requires specific equipment.
U.S. Pat. No. 5,378,592 discloses the use of a two-layer subbing layer (for photographic materials) wherein the first subbing layer is a layer of polyurethane latex cured with an epoxy compound or a dichloro-s-triazine derivative, and the second subbing layer is a hydrophilic colloid layer comprising gelatin.
U.S. Pat. No. 5,532,118 describes the use of a layer of a self-crosslinking polyurethane as an adhesion promoting material for polyester film support. U.S. Pat. No. 5,910,401 describes a similar use of a gelatin-grafted polyurethane for adhesion promotion.
Use of polyethyleneimine based primer layers on polypropylene substrates is known in the art. For example, U.S. Pat. No. 4,663,216 discloses a polyethyleneimine-primed synthetic paper substrate for allegedly improved ink absorption. U.S. Pat Nos. 5,248,364 and 5,510,180 disclose multi layer laminates containing a layer of a polypropylene material permanently bonded to a polyethyleneimine-primed substrate for packaging. U.S. Pat. No. 5,486,426 discloses use of a polyethyleneimine primer in a cold sealable polyolefin substrate. U.S. Pat. No. 5,776,604 discloses a lithographic printable polypropylene substrate, which is primed with polyethyleneimine. U.S. Pat. Nos. 5,827,615 and 6,013,353 disclose metallized multilayer polypropylene packaging films primed with polyethyleneimine. U.S. Pat. No. 6,232,056 discloses imaging elements with polyethyleneimine fuser layer for backside splice enhancement, particularly heat splicing in high speed photographic printers such Agfa MSP U.S. Ser. No. 10/044,874, filed Oct. 29, 1001now U.S. Pat. No. 6,514,660, describes the use of a mixture of gelatin and polyethyleneimine to form a primer for an image member, which can include photographic paper or films. For a discharge treated poly(ethyelene terephthalate) film, the primer comprising polyethyleneimine and gelatin provide pre-process dry adhesion and wet adhesion. However, the present invention, with its additional use of latex, provides superior post-process dry adhesion over the invention of U.S. Ser. No. 10/044,874, filed Oct. 29, 2001.
There is a critical need to develop imaging members, particularly those with highly hydrophobic supports such as oriented polyesters, with image receiving layers that exhibit good pre-process and post-process dry adhesion as well as good wet adhesion to said supports.
The present invention discloses a novel imaging member that exhibits superior adhesion between the imaging receiving layer and the polymer support.
The present invention discloses the use of a primer layer between the base and the image receiving layer of the element. The primer layer easily adheres to a hydrophobic polymeric sheet that constitutes the base for the imaging member.
The present invention makes it possible to superimpose an imaging layer on the primer layer, without any further surface treatment of the primer layer.
The present invention provides an imaging member comprising a polymer sheet, a primer layer contacting said polymer sheet, and an image receiving layer contacting said primer layer; wherein said primer layer comprises:
a) polyethyleneimine;
b) latex; wherein the latex has a Tg lower than 25 xc2x0 C. and
c) hydrophilic colloid material.
The present invention has numerous advantages. The invention discloses an imaging element that utilizes a novel primer to achieve excellent adhesion of the imaging layer to the polymer imaging support. The support may be a hydrophobic polymeric sheet with desirable mechanical and physical properties but which, by itself, has poor adhesion to the image receiving layer. The excellent adhesion characteristics of the novel primer composition can be realized in both dry and wet states.
The primer layer used in the instant invention comprises polyethyleneimine, a latex and hydrophilic colloid and it can be coated from an aqueous composition, which is environmentally more desirable than solvent based coating compositions.
The other advantage of the invention arises from the fact that the primer layer can be very thin, usually and preferably of sub-micron thickness, which does not necessitate massive drying capability at the support manufacturing site. The primer layer also adds very little to the overall weight and thickness of the imaging support, as compared to a co-extruded adhesion promoting layer. Eliminating a co-extruded layer also makes the manufacturing of the support simpler.
By utilizing primer layers of the invention to increase imaging layer adhesion to polymer layers, imaging layers can contain high levels of plasticizers to improve processing efficiency without the imaging layers separating from the base materials.
These and other advantages of the invention will be clear from the detailed description below.
The polyethyleneimine suitable for use in the primer layer of the invention can be a homopolymer or copolymer of ethyleneimine or mixtures thereof. Also suitable for the invention are polyvinylimines.
Although linear polymers represented by the chemical formula xe2x80x94[CH2CH2NH]xe2x80x94 may be used as the polyethyleneimine, materials having primary, secondary, and tertiary branches can also be used. Commercial polyethyleneimine can be a compound having branches of the ethyleneimine polymer. They are commercially prepared by acid-catalyzed ring opening of ethyleneimine, also known as aziridine. (The latter, ethyleneimine, is prepared through the sulfuric acid esterification of ethanolamine).
Polyethyleneimines can have an average molecular weight of about 100 to about 5,000,000 or even higher. Any polyethyleneimine is suitable for use in the present invention, however the preferred polyethyleneimines have a typical average molecular weight of up to about 3,000,000, preferably from about 200 to about 2,500,000, more preferably from about 300 to about 1,000,000. Polyethyleneimines that are water soluble or dispersible are most preferred.
Polyethyleneimines are commercially available from BASF Corporation under the trade name Lupasol(copyright) (also sold as Polymin(copyright)). These compounds can be prepared as a wide range of molecular weights and product activities. Examples of commercial PEI""s sold by BASF suitable for use in the present invention include, but are not limited to, Lupasol FG(copyright), Lupasol G-35(copyright)), Lupasol-P(copyright), Lupasol-PS(copyright), Lupasol-(Water-Free)(copyright) and the like.
Polyethyleneimines are also commercially available from Mica corporation as aqueous dispersions. One preferred product, suitable for application in the present invention is Mica A-131-X(copyright).
Polyethyleneimines can be protonated with acids to form a polyethyleneimine salt from the surrounding medium resulting in a product that is partially or fully ionized depending on pH. In general, polyethyleneimines can be purchased as their protonated or unprotonated form with and without water. Either form can be used in the present invention.
It should be noted that linear polyethyleneimines as well as mixtures of linear and branched polyethyleneimines are useful in the compositions of the present invention. Methods for preparing linear polyethyleneimines as well as branched polyethyleneimines are more fully described in Advances in Polymer Science, Vol. 102, pp. 171-188, 1992 (references 6-31) which are incorporated in their entirety herein by reference.
A hydrophilic colloid material for the purpose of this invention can include any water-soluble polymer. A particularly suitable hydrophilic colloid material for application in the primer of the invention is gelatin. Gelatin is well known in the imaging industry, particularly photographic industry. Any of the known types of gelatin, used in imaging elements can be used, as per the invention. These include, for example, alkali-treated gelatin (cattle bone or hide gelatin), acid-treated gelatin (pigskin or bone gelatin), modified gelatins such as those disclosed in U.S. Pat. No. 6,077,655 and references cited therein, gelatin derivatives such as partially phthalated gelatin, acetylated gelatin, and the like, preferably deionized gelatins as well as gelatin grafted onto vinyl polymers, such as those disclosed in U.S. Pat. Nos. 4,855,219; 5,248,558; 5,330,885; 5,952,164; and references therein.
Other hydrophilic colloids that can be utilized in the present invention, either alone or in combination with gelatin include dextran, gum arabic, zein, casein, pectin, collagen derivatives, collodion, agar-agar, arrowroot, albumin, and the like. Still other useful hydrophilic colloids are water-soluble polyvinyl compounds such as polyvinyl alcohol, polyacrylamides, polymethacrylamide, poly(N,N-dimethacrylamide), poly(N-isopropylacrylamide), poly(vinylpyrrolidone), poly(vinyl acetate), and the like. Other water soluble polymers suitable for the invention can comprise polyalkylene oxides such as polyethylene oxide, poly 6, (2-ethyloxazolines), polystyrene sulfonate, polysaccharides, or cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, and the like.
Most preferred hydrophilic colloids for the primer of the invention include gelatin and poly vinyl alcohol.
The latex polymers of this invention may be prepared by emulsion polymerization, or solution polymerization followed by dispersion of the polymer in water by addition of the organic solution to water containing a surfactant. Polymers prepared by either method, as described in standard textbooks known to those skilled in the art, can be utilized in the primer of the invention.
In latex polymerization the selected monomers are colloidally emulsified in an aqueous medium that usually contains a cationic, nonionic, or zwitterionic surfactant and a polymerization catalyst such as 2,2xe2x80x2-azobis(2-amidinopropane)hydrochloride. The resulting colloidal emulsion is then subjected to conditions conducive to polymerization of the monomeric constituents to produce an aqueous colloidal dispersion commonly called a latex.
Solution polymerization generally involves dissolving the selected monomers in an organic solvent containing a polymerization initiator such as 4,4xe2x80x2-azobis(4-cyanovaleric acid), 2,2xe2x80x2-azobis(2-methylpropionitrile) and 2,2xe2x80x2-azobis(2-amidinopropane)hydrochloride. The solution is maintained under a nitrogen atmosphere and heated at about 60xc2x0 C. The resulting polymer is then dispersed in water at about 1-5 percent solids. The polymer is then purified by diafiltration.
Useful starting monomers having a primary amine addition salt component include 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl) methacrylamide hydrochloride, and p-aminostyrene hydrochloride. Addition salts of other acids can also be used, e.g., hydrobromic, phosphoric, sulfuric, and benzoic acids.
Useful hydrophilic nonionic vinyl monomers include 1-vinylimidazole, 2-methyl-l-vinylimidazole, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide and 2-acetoxyethyl methacrylate.
Useful hydrophobic monomers include vinylidene chloride copolymers, water-soluble polyesters and polyacrylates such as butadiene, butyl acrylate, N-butyl methacrylate, ethyl methacrylate, styrene, and the like. The weight ratio of polyethyleneimine, latex and hydrophilic colloid in the primer layer of the invention can vary according to need. The polyethyleneimine in the primer composition can be from 0.1% to 98%, based on the dry weight of the primer layer; the latex in the primer composition can be from 0.1% to 98%; and hydrophilic colloid in the primer composition can be from 0.1% to 98%, based on the dry weight of the primer layer. It is preferred that polyethyleneimine varies from 1% to 90%, and more preferably from 1% to 25%, based on the dry weight of the primer layer. It is preferred that the latex varies from 1% to 90%, and more preferably from 1% to 25%, based on the dry weight of the primer layer. It is preferred that the hydrophilic colloid is from 1% to 98%, and more preferably from 50% to 98%, based on the dry weight of the primer layer. The dry coverage of the primer layer can vary according to need from 0.1 mg/m2 to 50 g/m2. However, it is preferred to be between 1 mg/m2 and 10 g/m2, and more preferably between 1 mg/m2 and 5 g/m2.
The primer layer of the invention can be formed by any method known in the art. Particularly preferred methods include coating from a suitable coating composition by any well known coating method such as air knife coating, gravure coating, hopper coating, roller coating, spray coating, and the like. The coating composition can be based on water or organic solvent(s) or a mixture of water and organic solvent(s). Alternatively, the primer layer can be formed by thermal processing such as extrusion and co-extrusion with and without stretching, blow molding, injection molding, lamination, etc.
The surface on which the primer layer is formed can be activated for improved adhesion by any of the treatments known in the art, such as acid etching, flame treatment, corona discharge treatment, glow discharge treatment, ultraviolet radiation treatment, ozone treatment, electron beam treatment, etc, or can be coated with any other suitable primer layer. However, corona discharge treatment and flame treatment are the preferred means for surface activation.
In addition to the polyethyleneimine, the latex and hydrophilic colloid, the primer layer of the invention may comprise any other material known in the art. These materials include surfactants, defoamers or coating aids, charge control agents, thickeners or viscosity modifiers, coalescing aids, crosslinking agents or hardeners, soluble and/or solid particle dyes, antifoggants, fillers, matte beads, inorganic or polymeric particles, antistatic or electrically conductive agents, other adhesion promoting agents, bite solvents or chemical etchants, lubricants, plasticizers, antioxidants, voiding agents, colorants or tints, roughening agents, and other addenda that are well-known in the art.
In a preferred embodiment, the primer layer can comprise electrically conductive agents to function as an antistatic layer, and control static charging during manufacturing, finishing and end use of the imaging element. Thus, in this embodiment, the layer of the invention can fulfill the dual purpose of adhesion promotion as well as static control. In this embodiment, any of the electrically conductive agents known in the art for antistatic application can be effectively incorporated in the primer layer of the present invention. These electrically conductive agents can comprise an ionic conductor or an electronic conductor or both.
In ionic conductors, charge is transferred by the bulk diffusion of charged species through an electrolyte. Here the resistivity of the antistatic layer is dependent on temperature and humidity. Antistatic materials containing simple inorganic salts, alkali metal salts of surfactants, ionic conductive polymers, polymeric electrolytes containing alkali metal salts, and colloidal metal oxide sols (stabilized by metal salts), natural or synthetic clays and other siliceous materials, described previously in patent literature, fall in this category and can be incorporated in the present invention. Of particular preference for application in the present invention are those ionic conductors, which are disclosed in U.S. Pat. Nos. 6,077,656; 6,120,979; and references therein.
The conductivity of antistatic layers employing an electronic conductor depends on electronic mobility rather than ionic mobility and is independent of humidity. Antistatic layers containing electronic conductors such as conjugated conducting polymers, conducting carbon particles, crystalline semiconductor particles, amorphous semiconductive fibrils, and continuous semiconducting thin films can be used more effectively than ionic conductors to dissipate static charge since their electrical conductivity is independent of relative humidity and only slightly influenced by ambient temperature. All of these aforementioned electronic conductors can be incorporated in the present invention. Of the various types of electronic conductors, electrically conducting metal-containing particles, such as semiconducting metal oxides, and electronically conductive polymers, such as, substituted or unsubstituted polythiophenes, substituted or unsubstituted polypyrroles, and substituted or unsubstituted polyanilines are particularly effective for the present invention.
Electronically conductive particles which may be used in the present invention include, e.g., conductive crystalline inorganic oxides, conductive metal antimonates, and conductive inorganic non-oxides. Crystalline inorganic oxides may be chosen from zinc oxide, titania, tin oxide, alumina, indium oxide, silica, magnesia, barium oxide, molybdenum oxide, tungsten oxide, and vanadium oxide or composite oxides thereof, as described in, e.g., U.S. Pat. Nos. 4,394,441; 4,416,963; 4,571,361; 4,999,276 and 5,122,445. The conductive crystalline inorganic oxides may contain a xe2x80x9cdopantxe2x80x9d in the range from 0.01 to 30 mole percent, preferred dopants being aluminum or indium for zinc oxide; niobium or tantalum for titania; and antimony, niobium or halogens for tin oxide. Alternatively, the conductivity can be enhanced by formation of oxygen defects by methods well known in the art. The use of antimony-doped tin oxide at an antimony doping level of at least 8 atom percent and having an X-ray crystallite size less than 100 xc3x85 and an average equivalent spherical diameter less than 15 nm but no less than the X-ray crystallite size as taught in U.S. Pat. No. 5,484,694 is specifically contemplated. Particularly useful electronically conductive particles which may be used in the conductive primer layer include acicular doped metal oxides, acicular metal oxide particles, acicular metal oxides containing oxygen deficiencies, acicular doped tin oxide particles, acicular antimony-doped tin oxide particles, acicular niobium-doped titanium dioxide particles, acicular metal nitrides, acicular metal carbides, acicular metal silicides, acicular metal borides, acicular tin-doped indium sesquioxide and the like.
The invention is also applicable where the conductive agent comprises a conductive xe2x80x9camorphousxe2x80x9d gel such as vanadium oxide gel comprised of vanadium oxide ribbons or fibers. Such vanadium oxide gels may be prepared by any variety of methods, including but not specifically limited to melt quenching as described in U.S. Pat. No. 4,203,769, ion exchange as described in DE 4,125,758, or hydrolysis of a vanadium oxoalkoxide as claimed in WO 93/24584. The vanadium oxide gel is preferably doped with silver to enhance conductivity. Other methods of preparing vanadium oxide gels which are well known in the literature include reaction of vanadium or vanadium pentoxide with hydrogen peroxide and hydrolysis of VO2OAc or vanadium oxychloride.
Conductive metal antimonates suitable for use in accordance with the invention include those as disclosed in, e.g., U.S. Pat. Nos. 5,368,995 and 5,457,013. Preferred conductive metal antimonates have a rutile or rutile-related crystallographic structures and may be represented as M+2Sb+52O6(where M+2=Zn+2, Ni+2, Mg+2,Fe+2, Cu+2, Mn+2, Co+2) or M+3Sb+5O4(where M+3=In+3, Al+3, Sc+3, Cr+3, Fe+3). Several colloidal conductive metal antimonate dispersions are commercially available from Nissan Chemical Company in the form of aqueous or organic dispersions. Alternatively, U.S. Pat. Nos. 4,169,104 and 4,110,247 teach a method for preparing M+2Sb+52O6 by treating an aqueous solution of potassium antimonate with an aqueous solution of an appropriate metal salt (e.g., chloride, nitrate, sulfate, etc.) to form a gelatinous precipitate of the corresponding insoluble hydrate which may be converted to a conductive metal antimonate by suitable treatment.
Conductive inorganic non-oxides suitable for use as conductive particles in the present invention include: titanium nitride, titanium boride, titanium carbide, niobium boride, tungsten carbide, lanthanum boride, zirconium boride, molybdenum boride, and the like, as described, e.g., in Japanese Kokai No. 4/55492, published Feb. 24, 1992. Conductive carbon particles, including carbon black and carbon fibrils or nanotubes with single walled or multiwalled morphology can also be used in this invention. Example of such suitable conductive carbon particles can be found in U.S. Pat. No. 5,576,162 and references therein.
Suitable electrically conductive polymers that are preferred for incorporation in the primer layer of the invention are specifically electronically conducting polymers, such as those illustrated in U.S. Pat. Nos. 6,025,119; 6,060,229; 6,077,655; 6,096,491; 6,162,596; 6,187,522; and 6,190,846. These electrically conductive polymers include substituted or unsubstituted aniline-containing polymers (as disclosed in U.S. Pat. Nos. 5,716,550; 5,093,439 and 4,070,189), substituted or unsubstituted thiophene-containing polymers (as disclosed in U.S. Pat. Nos. 5,300,575; 5,354,613; 5,370,981; 5,443,944; and 4,731,408), substituted or unsubstituted pyrrole-containing polymers (as disclosed in U.S. Pat. Nos. 5,665,498 and 5,674,654), and poly(isothianaphthene) or derivatives thereof. These electrically conducting polymer may be soluble or dispersible in organic solvents or water or mixtures thereof. Preferred electrically conducting polymers for the present invention include polypyrrole styrene sulfonate (referred to as polypyrrole/poly (styrene sulfonic acid) in U.S. Pat. No. 5,674,654); 3,4-dialkoxy substituted polypyrrole styrene sulfonate, and 3,4 dialkoxy substituted polythiophene styrene sulfonate. The most preferred substituted electrically conductive polymers include poly(3,4-ethylene dioxypyrrole styrene sulfonate) and poly(3,4-ethylene dioxythiophene styrene sulfonate).
The conductive particles that can be incorporated in the primer layer are not specifically limited in particle size or shape. The particle shape may range from roughly spherical or equiaxed particles to high aspect ratio particles such as fibers, whiskers or ribbons. Additionally, the conductive materials described above may be coated on a variety of other particles, also not particularly limited in shape or composition. For example the conductive inorganic material may be coated on non-conductive silica, alumina, titania and mica particles, whiskers or fibers.
In another preferred embodiment of the invention, the primer layer of the invention comprises pigments such as colorants or tints, typically used in imaging elements. In display type imaging members, such as photographic paper, the resin layer coated or laminated on the paper base (primarily for waterproofing), also serves as a carrier layer for titanium dioxide and other whitening materials as well as tinting materials. By experience, it has been shown that a bluish tint is necessary as the background for images on paper type bases to obtain a favorable response from customers of these products. It would be desirable if the colorant materials rather than being dispersed throughout the polyethylene layer could be included in a layer of the photographic materials that is not subjected to the rigors of high temperature extrusion, which is the most common way of manufacturing the melt extruded resin layer. In this embodiment of the invention, the tinting materials can be easily incorporated in the coatable form of the primer layer of the invention.
The preferred color of the pigment or pigment combinations used in the invention is blue so that it offsets the native yellowness of the gelatin, yielding a neutral background for the image layers. Suitable pigments used in this invention can be any inorganic or organic, colored materials such as those disclosed in U.S. Pat. No. 6,180,330. The preferred pigments are organic, and are those described in Industrial Organic Pigments: Production, Properties, Applications by W. Herbst and K. Hunger, 1993, Wiley Publishers. These include: Azo Pigments such as monoazo yellow and orange, disazo, naphthol, naphthol reds, azo lakes, benzimidazolone, disazo condensation, metal complex, isoindolinone and isoindoline, Polycyclic Pigments such as phthalocyanine, quinacridone, perylene, perinone, diketopyrrolo pyrrole and thioindigo, and Anthrquinone Pigments such as anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone, dioxazine, triarylcarbodium and quinophthalone. The most preferred pigments are the anthraquinones such as Pigment Blue 60, phthalocyanines such as Pigment Blue 15, 15:1, 15:3, 15:4 and 15:6, and quinacridones such as Pigment Red 122, as listed in NPIRI Raw Materials Data Handbook, Vol. 4, Pigments, 1983, National Printing Research Institute. These pigments have a dye hue sufficient to overcome the native yellowness of the gelatin imaging layer and are easily dispersed in a aqueous solution.
The primer layer of the invention can comprise any number of hardeners or crosslinking agents in any amount known in the art for use in imaging elements. Preferred hardeners include 1,2-bis(vinylsulfonylacetamido)ethane (BVSAE), bis(vinylsulfonyl)methane (BVSM), bis(vinylsulfonylmethyl)ether (BVS ME) and bis(vinylsulfonylethyl)ether (BSEE), 1,3-bis(vinylsulfonylpropane (BVSP), 1,3-bis(vinylsulfonyl)-2-hydroxypropane (BVSHP), 1,1,-bis(vinylsulfonyl)ethylbenzenesulfonate sodium salt, 1,1,1-tris(vinylsulfonyl)ethane (TVSE), tetrakis(vinylsulfonyl)methane, tris(acrylamido)hexahydro-s-triazine, copoly(acrolein-methacrylic acid), glycidyl ethers, acrylamides, dialdehydes, blocked dialdehydes, alpha-diketones, active esters, sulfonate esters, active halogen compounds, s-triazines, diazines, epoxides, formaldehydes, formaldehyde condensation products anhydrides, aziridines, active olefins, blocked active olefins, mixed function hardeners such as halogen-substituted aldehyde acids, vinyl sulfones containing other hardening functional groups, 2,3-dihydroxy-1,4-dioxane (DHD), potassium chrome alum, polymeric hardeners such as polymeric aldehydes, polymeric vinylsulfones, polymeric blocked vinyl sulfones and polymeric active halogens. The hardener can be incorporated in any amount to provide cross-linking not only to the primer layer of the invention but also to any other layer(s) of the imaging element, especially those in contact with the primer layer, for any advantageous effect. For example, BVSM can be added to the primer layer to harden the primer layer as well as the bottom layer of a color negative working silver halide emulsion.
The primer layer of the invention can comprise any number of bite solvents. Bite solvents are typically solvents used for etching or plasticizing the polymer sheet upon which the primer layer is formed. These bite solvents can include any of the volatile aromatic compounds disclosed in U.S. Pat. No. 5,709,984, as xe2x80x9cconductivity-increasingxe2x80x9d aromatic compounds, comprising an aromatic ring substituted with at least one hydroxy group or a hydroxy substituted substituents group. These compounds include phenol, 4-chloro-3-methyl phenol, 4-chlorophenol, 2-cyanophenol, 2,6-dichlorophenol, 2-ethylphenol, resorcinol, benzyl alcohol, 3-phenyl-1-propanol, 4-methoxyphenol, 1,2-catechol, 2,4 dihydroxytohene, 4-chloro-2-methyl phenol, 2,4-dinitrophenol, 4-chlororesominol, 1-naphthol, 1,3-naphthalenediol and the like. These bite solvents are particularly suitable for polyester based polymer sheets of the invention. Of this group, the most preferred compounds are resorcinol and 4-chloro-3-methyl phenol.
The primer layer of the invention can be formed on any polymer sheet, with particular preference for those, which are known for their application as supports in imaging members. The polymer sheet can comprise homopolymer(s), copolymer(s) and/or mixtures thereof Typical imaging supports comprise cellulose nitrate, cellulose acetate, poly(vinyl acetate), polystyrene, polyolefins including polyolefin ionomers, polyesters including polyester ionomers, polycarbonate, polyamide, polyimide, glass, natural and synthetic paper, resin-coated or laminated paper, voided polymers including polymeric foam, microvoided polymers and microporous materials, or fabric, or any combinations thereof. Preferred polymers are polyesters, polyolefins and polystyrenes, mainly chosen for their desirable physical properties and cost.
Suitable polyolefins include polyethylene, polypropylene, polymethylpentene, polystyrene, polybutylene and mixtures thereof. Polyolefin copolymers, including copolymers of propylene and ethylene such as hexene, butene and octene and mixtures thereof are also useful.
Suitable polyesters include those, which are derived from the condensation of aromatic, cycloaliphatic, and aliphatic diols with aliphatic, aromatic and cycloaliphatic dicarboxylic acids and may be cycloaliphatic, aliphatic or aromatic polyesters. Exemplary of useful cycloaliphatic, aliphatic and aromatic polyesters which can be utilized in the practice of their invention are poly(ethylene terephthalate), poly(cyclohexlenedimethylene), terephthalate) poly(ethylene dodecate), poly(butylene terephthalate), poly(ethylene naphthalate), poly(ethylene(2,7-naphthalate)), poly(methaphenylene isophthalate), poly(glycolic acid), poly(ethylene succinate), poly(ethylene adipate), poly(ethylene sebacate), poly(decamethylene azelate), poly(ethylene sebacate), poly(decamethylene adipate), poly(decamethylene sebacate), poly(dimethylpropiolactone), poly(para-hydroxybenzoate), poly(ethylene oxybenzoate), poly(ethylene isophthalate), poly(tetramethylene terephthalate, poly(hexamethylene terephthalate), poly(decamethylene terephthalate), poly(1,4-cyclohexane dimethylene terephthalate) (trans), poly(ethylene 1,5-naphthalate), poly(ethylene 2,6-naphthalate), poly(1,4-cyclohexylene dimethylene terephthalate) (cis), and poly(1,4-cyclohexylene dimethylene terephthalate (trans) and copolymers and/or mixtures thereof.
Polyester compounds prepared from the condensation of a diol and an aromatic dicarboxylic acid are preferred for use in this invention. Illustrative of such useful aromatic carboxylic acids are terephthalic acid, isophthalic acid and a o-phthalic acid, 1,3-napthalenedicarboxylic acid, 1,4 napthalenedicarboxylic acid, 2,6-napthalenedicarboxylic acid, 2,7-napthalenedicarboxylic acid, 4,4xe2x80x2-diphenyldicarboxylic acid, 4,4xe2x80x2-diphenysulfphone-dicarboxylic acid, 1,1,3-trimethyl-5-carboxy-3-(p-carboxyphenyl)-idane, diphenyl ether 4,4xe2x80x2-dicarboxylic acid, bis-p(carboxy-phenyl) methane and the like. Of the aforementioned aromatic dicarboxylic acids, those based on a benzene ring (such as terephthalic acid, isophthalic acid, orthophthalic acid) are preferred for use in the practice of this invention. Amongst these preferred acid precursors, terephthalic acid is particularly preferred acid precursor.
Preferred polyesters for use in the practice of this invention include poly(ethylene terephthalate), poly(butylene terephthalate), poly(1,4-cyclohexylene dimethylene terephthalate), poly(ethylene isophthalate), and poly(ethylene naphthalate) and copolymers and/or mixtures thereof. Among these polyesters of choice, poly(ethylene terephthalate) and poly(ethylene naphthalate) which may be modified by small amounts of other monomers, are most preferred.
The polymer sheet can comprise a single layer or multiple layers according to need. The multiplicity of layers may include any number of auxiliary layers such as antistatic layers, backmark retention layers, tie layers or adhesion promoting layers, abrasion resistant layers, curl control layers, cuttable layers, conveyance layers, barrier layers, splice providing layers, UV absorption layers, antihalation layers, optical effect providing layers, waterproofing layers, flavor retaining layers, fragrance providing layers, adhesive layers, imaging layers and the like.
The polymer sheet can be formed by any method known in the art such as those involving extrusion, coextrusion, quenching, orientation, heat setting, lamination, coating and solvent casting. It is preferred that the polymer sheet is an oriented sheet formed by any suitable method known in the art, such as by a flat sheet process or a bubble or tubular process. The flat sheet process involves extruding or coextruding the materials of the sheet through a slit die and rapidly quenching the extruded or coextruded web upon a chilled casting drum so that the polymeric component(s) of the sheet are quenched below their solidification temperature. The quenched sheet is then biaxially oriented by stretching in mutually perpendicular directions at a temperature above the glass transition temperature of the polymer(s). The sheet may be stretched in one direction and then in a second direction or may be simultaneously stretched in both directions. The preferred stretch ratio in any direction is at least 3:1. After the sheet has been stretched, it is heat set by heating to a temperature sufficient to crystallize the polymers while restraining to some degree the sheet against retraction in both directions of stretching.
The polymer sheet may be subjected to any number of coatings and treatments, after extrusion, coextrusion, orientation, etc. or between casting and full orientation, to improve its properties, such as printability, barrier properties, heat-sealability, spliceability, adhesion to other supports and/or imaging layers. Examples of such coatings can be acrylic coatings for printability, polyvinylidene halide for heat seal properties, etc. Examples of such treatments can be flame, plasma and corona discharge treatment, ultraviolet radiation treatment, ozone treatment and electron beam treatment to improve printability and adhesion. Further examples of treatments can be calendaring, embossing and patterning to obtain specific effects on the surface of the web. The polymer sheet can be further incorporated in any other suitable support by lamination, adhesion, cold or heat sealing, extrusion coating, or any other method known in the art.
The polymer sheets most preferred for application in the present invention are the polymeric supports disclosed in U.S. Pat. Nos. 4,042,398; 4,699,874; 5,326,624; 5,466,519; 5,866,282; 5,888,683; 6,020,116; 6,030,759; 6,045,965; 6,071,654; 6,074,788; 6,153,367; and 6,197,486; These supports can comprise natural or synthetic paper, coated or laminated resin layers, voided polymers, specifically microvoided polymers, non-voided polymers, woven polymer fibers, cloth, and various combinations thereof, in mainly image display applications. Other most preferred polymeric supports include those disclosed in U.S. Pat. Nos. 5,138,024; 5,288,601; 5,334,494; 5,360,708; 5,372,925; 5,387,501; 5,556,739; 5,580,709; 6,207,361 in mainly image capture applications.
The primer layer of the invention can be placed on any side of the polymer sheet of the imaging member, e.g., on the top side, or the bottom side, or both sides. However, it is preferred to be placed on the top side of the polymer sheet. The aforementioned top side refers to the image receiving side whereas the bottom side refers to the opposite side of the polymer sheet.
A preferred application of the invention is in imaging members, including those utilizing photographic, electrophotographic, electrostatographic, photothermographic, migration, electrothermographic, dielectric recording, thermal dye transfer, inkjet and other types of imaging. A more preferred application of the invention is in photographic imaging elements, including photographic papers and films. Most preferred application of the invention is in photographic image capture products.
The preferred photographic element is a material that utilizes photosensitive silver halide in the formation of images. In the case of thermal dye transfer or ink jet, the image layer that is coated on the imaging element may be any material that is known in the art such as such as gelatin, pigtnented latex, polyvinyl alcohol, polycarbonate, polyvinyl pyrrolidone, polyalkylene oxide, starch, andmethacrylate. The photographic elements can be single color elements or multicolor elements. Multicolor elements contain image dye-forming units sensitive to each of the three primary regions of the spectrum. Each unit can comprise a single coupler and emulsion layer or multiple coupler and emulsion layers each sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. In an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer.
The photographic emulsions useful for this invention are generally prepared by precipitating silver halide crystals in a colloidal matrix by methods conventional in the art. The colloid is typically a hydrophilic film forming agent such as gelatin, alginic acid, or derivatives thereof.
The crystals formed in the precipitation step are washed and then chemically and spectrally sensitized by adding spectral sensitizing dyes and chemical sensitizers, and by providing a heating step during which the emulsion temperature is raised, typically from 40.degree. C. to 70.degree. C., and maintained for a period of time. The precipitation and spectral and chemical sensitization methods utilized in preparing the emulsions employed in the invention can be those methods known in the art.
Chemical sensitization of the emulsion typically employs sensitizers such as: sulfur-containing compounds, e.g., allyl isothiocyanate, sodium thiosulfate and allyl thiourea; reducing agents, e.g., polyamines and stannous salts; noble metal compounds, e.g., gold, platinum; and polymeric agents, e.g., polyalkylene oxides. As described, heat treatment is employed to complete chemical sensitization. Spectral sensitization is effected with a combination of dyes, which are designed for the wavelength range of interest within the visible or infrared spectrum. It is known to add such dyes both before and after heat treatment.
After spectral sensitization, the emulsion is coated on a support. Various coating techniques include dip coating, air knife coating, curtain coating and extrusion coating.
The silver halide emulsions utilized in this invention may be comprised of any halide distribution. Thus, they may be comprised of silver chloride, silver chloroiodide, silver bromide, silver bromochloride, silver chlorobromide, silver iodochloride, silver iodobromide, silver bromoiodochloride, silver chloroiodobromide, silver iodobromochloride, and silver iodochlorobromide emulsions. It is preferred, however, that the emulsions be predominantly silver chloride emulsions. By predominantly silver chloride, it is meant that the grains of the emulsion are greater than about 50 mole percent silver chloride. Preferably, they are greater than about 90 mole percent silver chloride; and optimally greater than about 95 mole percent silver chloride.
The silver halide emulsions can contain grains of any size and morphology. Thus, the grains may take the form of cubes, octahedrons, cubo-octahedrons, or any of the other naturally occurring morphologies of cubic lattice type silver halide grains. Further, the grains may be irregular such as spherical grains or tabular grains. Grains having a tabular or cubic morphology are preferred.
The photographic elements of the invention may utilize emulsions as described in The Theory of the Photographic Process, Fourth Edition, T. H. James, Macmillan Publishing Company, Inc., 1977, pages 151-152. Reduction sensitization has been known to improve the photographic sensitivity of silver halide emulsions. While reduction sensitized silver halide emulsions generally exhibit good photographic speed, they often suffer from undesirable fog and poor storage stability.
Reduction sensitization can be performed intentionally by adding reduction sensitizers, chemicals which reduce silver ions to form metallic silver atoms, or by providing a reducing environment such as high pH (excess hydroxide ion) and/or low pAg (excess silver ion). During precipitation of a silver halide emulsion, unintentional reduction sensitization can occur when, for example, silver nitrate or alkali solutions are added rapidly or with poor mixing to form emulsion grains. Also, precipitation of silver halide emulsions in the presence of ripeners (grain growth modifiers) such as thioethers, selenoethers, thioureas, orammonia tends to facilitate reduction sensitization.
Examples of reduction sensitizers and environments which may be used during precipitation or spectral/chemical sensitization to reduction sensitize an emulsion include ascorbic acid derivatives; tin compounds; polyamine compounds; and thiourea dioxide-based compounds described in U.S. Pat. Nos. 2,487,850; 2,512,925; and British Patent 789,823. Specific examples of reduction sensitizers or conditions, such as dimethylamineborane, stannous chloride, hydrazine, high pH (pH 8-11) and low pAg (pAg 1-7) ripening are discussed by S. Collier in Photographic Science and Engineering, 23,113 (1979). Examples of processes for preparing intentionally reduction sensitized silver halide emulsions are described in EP 0 348934 A1 (Yamashita), EP 0 369491 (Yamashita), EP 0 371388 (Ohashi), EP 0 396424 A1 (Takada), EP 0 404142 A1 (Yamada), and EP 0 435355 A1 (Makino).
The photographic elements of this invention may use emulsions doped with Group VIII metals such as iridium, rhodium, osmium, and iron as described in Research Disclosure, September 1996, Item 38957, Section I, published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND. Additionally, a general summary of the use of iridium in the sensitization of silver halide emulsions is contained in Carroll, xe2x80x9cIridium Sensitization: A Literature Review,xe2x80x9d Photographic Science and Engineering, Vol. 24, No. 6, 1980. A method of manufacturing a silver halide emulsion by chemically sensitizing the emulsion in the presence of an iridium salt and a photographic spectral sensitizing dye is described in U.S. Pat. No. 4,693,965. In some cases, when such dopants are incorporated, emulsions show an increased fresh fog and a lower contrast sensitometric curve when processed in the color reversal E-6 process as described in The British Journal of Photography Annual, 1982, pages 201-203.
A typical multicolor photographic element of the invention comprises the invention laminated support bearing a cyan dye image-forming unit comprising at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a magenta image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler; and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler. The element may contain additional layers, such as filter layers, interlayers, overcoat layers, subbing layers, and the like. The support of the invention may also be utilized for black and white photographic print elements.
The photographic elements may also contain a transparent magnetic recording layer such as a layer containing magnetic particles on the underside of a transparent support, as in U.S. Pat. Nos. 4,279,945 and 4,302,523. Typically, the element will have a total thickness (excluding the support) of from about 5 to about 30 xcexcm.
In the following Table 1, reference will be made to (1) Research Disclosure, December 1978, Item 17643, (2) Research Disclosure, December 1989, Item 308119, and (3) Research Disclosure, September 1996, Item 38957, all published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire PO10 7DQ, ENGLAND. The table and the references cited in the table are to be read as describing particular components suitable for use in the elements of the invention. The table and its cited references also describe suitable ways of preparing, exposing, processing and manipulating the elements, and the images contained therein.
The photographic elements can be exposed with various forms of energy which encompass the ultraviolet, visible, and infrared regions of the electromagnetic spectrum as well as with electron beam, beta radiation, gamma radiation, x-ray, alpha particle, neutron radiation, and other forms of corpuscular and wave-like radiant energy in either noncoherent (random phase) forms or coherent (in phase) forms, as produced by lasers. When the photographic elements are intended to be exposed by x-rays, they can include features found in conventional radiographic elements.
The photographic elements are preferably exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image, and then processed to form a visible image, preferably by other than heat treatment. Processing is preferably carried out in the known RA-4(copyright) (Eastman Kodak Company) Process or other processing systems suitable for developing high chloride emulsions.
The following examples illustrate the practice of this invention. They are not intended to be exhaustive of all possible variations of the invention. Parts and percentages are by weight unless otherwise indicated.


A rotor disk is inspected using an inspection apparatus including an inspection fixture which has a base, and at least one guide extending from the base. Each guide is slidably engagable to one of the rotor slots of the rotor disk and has a guide side shaped to slidably conform to the rotor slot side, and a guide bottom having a guide bottom surface which, in combination with a slot bottom surface, defines an elongated inspection cavity extending parallel to the axis of revolution of the rotor disk. The inspection fixture is mated to the rotor disk such that each guide slides into one of the rotor slots. A sensor apparatus includes a sensor, such as an eddy current sensor, sized to slide into the inspection cavity with a close facing relation thereto, and a sensor drive that moves the sensor parallel to a direction of elongation of the inspection cavity. Inspection is performed by inserting the sensor into the inspection cavity, and sensing the rotor slot bottom using the sensor.

This invention relates to the inspection of rotor slot bottoms of rotor disks and, more particularly, to a fixture that aids in performing the inspections.
In an aircraft gas turbine (jet) engine, air is drawn into the front of the engine, compressed by a shaft-mounted compressor, and mixed with fuel. The mixture is combusted, and the resulting hot combustion gases are passed through a turbine mounted on the same shaft. The flow of gas turns the turbine by contacting an airfoil portion of the turbine blade, which turns the shaft and provides power to the compressor. The hot exhaust gases flow from the back of the engine, driving it and the aircraft forward. There may additionally be a turbofan that drives a bypass flow of air rearwardly to improve the thrust of the engine.
The compressor, the turbine, and the turbofan have a similar construction, in that they each include a rotor disk and a set of removable blades extending radially outwardly from the rotor disk. The rotor disk has a series of rotor slots extending parallel to the axis of revolution of the rotor disk, and the roots of the blades are slidably engaged into the slots. The slots and the roots of the blades are conformably shaped to hold the blades in the rotor disk when the rotor disk rotates about its axis of rotation. In current practice, the rotor slots and the roots of the blades have a conformable dovetail shape. While the compressor, the turbine, and the turbofan share this basic configuration, the materials of construction of the rotor disks and the blades, as well as the shapes and sizes of the rotor disks and the blades, vary in these different sections of the gas turbine engine.
One of the failure modes of the rotor disk is the formation of cracks in the bottoms of the rotor slots. These cracks typically initiate due to a combination of creep and fatigue. One of the cracks eventually may enlarge sufficiently that it propagates and leads to a catastrophic failure of the rotor disk.
To avoid such a failure, the slot bottoms are periodically inspected using visual or fluorescent penetrant inspection (FPI) techniques. These techniques identify cracks at the bottoms of the slots when they are small and before they can grow to a size that they propagate, so that the cracks may be repaired. These techniques, while operable, are subjective in that they depend upon the skill, judgment, and state of mind of the person performing the inspection. They are only semiquantitative in nature, in that the number, length, and type of cracks are subjectively judged. Visual and FPI approaches are also not always reproducible and do not lend themselves to automation of the inspection.
There is accordingly a need for an approach which improves upon the existing inspection techniques. The present invention fulfills this need, and further provides related advantages.
The present invention provides an inspection apparatus and method for inspecting the slot bottoms of rotor slots. The present approach provides for objective analysis of the state of the slot bottoms. It does not depend upon the state of mind of the person performing the test, yields quantitative results, provides for extensive automation of the inspection procedure, and has excellent reproducibility of the inspection.
An inspection apparatus is used in relation to a rotor disk having a plurality of circumferentially adjacent rotor slots therein extending parallel to an axis of revolution of the rotor disk. Each rotor slot has a rotor slot side and a rotor slot bottom with a slot bottom surface. The inspection apparatus comprises an inspection fixture including a base, and at least one guide extending from the base. Each guide is slidably engagable to one of the rotor slots and has a guide side shaped to slidably conform to the rotor slot side. Each guide further has a guide bottom with a guide bottom surface which, in combination with the slot bottom surface, defines an elongated inspection cavity, which is preferably substantially cylindrical with its cylindrical axis extending parallel to the axis of revolution of the rotor disk. Preferably, the inspection fixture comprises more than one guide, each guide as set forth above. The guides are spaced apart and angled so as to slidably engage the respective rotor slots of the rotor disk.
The inspection apparatus may further include a sensor apparatus comprising a sensor sized to slide into the inspection cavity. The sensor is preferably an eddy current sensor. The sensor apparatus typically also includes a sensor drive that moves the sensor parallel to a direction of elongation of the inspection cavity. In the case of the eddy current sensor, the sensor drive rotates the sensor about its sensor axis while in the inspection cavity. Eddy current inspection of the slot bottoms is an important advance over visual and FPI techniques. It may be automated and is not dependent upon operator skill. It produces quantitative results that are reproducible. In the preliminary development by the inventors leading to the present invention, the advantages of eddy current inspection were recognized but could not be achieved because the sensor could not be positioned sufficiently accurately relative to the slot bottoms. The inspection fixture solves this problem, allowing the eddy current sensor to be precisely and reproducibly positioned relative to the slot bottoms during the inspection procedure, so that its full advantages may be achieved.
The inspection apparatus is used to inspect a rotor disk as described above. The method includes providing an inspection apparatus comprising the inspection fixture as described above, and assembling the inspection fixture to the rotor disk such that each guide slides into one of the rotor slots. The sensor apparatus as described above is provided, and the sensor is inserted into the inspection cavity. The rotor slot bottom is sensed using the sensor. Preferably, the sensor drive rotates the eddy current sensor about its sensor axis and also permits moving the eddy current sensor parallel to the direction of elongation of the inspection cavity during the sensing operation.
The inspection fixture precisely positions the sensor of the sensor apparatus. The sensor must be tightly constrained to a close facing contact to the slot bottom surface during the inspection process. If the sensor were allowed to separate from the surface of the slot bottom by even 0.001 inch, the inspection sensitivity would be reduced and defects might be undetected. The inspection fixture, sensor drive, and split-sensor structure cooperate to ensure that the sensor remains in intimate contact with the slot bottom. In the preferred case where the sensor is an eddy current sensor, the intimate contact is maintained as the sensor is rotated about its sensor axis and moved parallel to the sensor axis.
Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Rotor slot bottom inspection apparatus and method


Lights, in particular for motor vehicles, comprising at least one light source and a cover that is arranged in front of the light source in the direction of radiation, wherein the cover includes an electric diffuser which may change the optical properties thereof to generate multi-functionality.

The invention relates to a light, in particular for motor vehicles, comprising at least one light source and a cover. The cover is arranged in front of the light source in the direction of radiation.
Lights for motor vehicles comprise one or more light sources, in which generally optical means for generating a certain light distribution are assigned. The light sources are usually arranged in a light housing, which is covered with a panel. The panel can be an optic device, for example a lens or a diffusing screen. Due to design specifications and for other design reasons also non-optic clear panels are used increasingly as the cover. All optically active elements such as lamps, reflectors and other light-guiding devices are arranged on the inside of the light. This has the advantage that the generally required adjustment possibilities, for example a height adjustment of a radiating light cone, can be implemented more easily. Clear cover panels are desirable in particular for headlights, but also increasingly for rear lights and interior lighting.
On the other hand, the above-described diverse light distribution that modern vehicle lights must provide leads to a variety of different luminous components, such as reflectors or light sources having different sizes and different colors and additional caps and diffusing elements in the light housings. In order to achieve the desired light distribution, often non-symmetrical shapes, coatings or screens are required. This, however, especially in the case of combination lights such as headlight combinations where several lighting elements are accommodated in one housing, can also lead to the fact that the unobstructed view into the inside of the light is found to be unpleasant for the overall optical impression of the light. Moreover the increasing number of functions, for example an additional day-time driving light adjustment, which is required of modern vehicle lights, leads to ever more complicated and costly designs with an increasing number of luminous components. Since in modern combination lights usually limited space is available and the exterior housing shape is basically specified by design parameters, the accommodation of additional components is problematic, additionally also leading to increased weight.
For the targeted switching and distribution of optical light beams, so-called electrical diffusers are known from the electro-technology field. These are components in which a liquid crystal layer is arranged between two transparent electrodes. By applying electric potential, the randomly distributed liquid crystals can be aligned. While the random liquid crystal layer scatters an incident optical beam diffusely, the radiation can pass unimpaired when the liquid crystals are aligned appropriately. In this way the diffuser becomes transparent for the radiation. This effect is utilized in many ways in optical elements, such as LCD displays.
Comparable optical elements are also already employed in vehicular technology, for example, in a display unit for the targeted illumination of specifiable areas of a dial face (DE 195 40 813 C1) or in a device for use as an area light and as transparent glazing (DE 198 52 593 A1).
In the display unit known from DE 195 40 813 C1, a light valve, the transparency of which is variable, is arranged between the dial face and a light source. In a preferred embodiment, the light valve is designed as a liquid crystal film, containing symbols and numbers by transparent electrodes that are applied on either side. The electrode pairs can be supplied with electric potential independently from each other. By applying electric potential to the individual electrode pairs, the film becomes transparent in the corresponding areas so that in those areas transillumination occurs in the direction of the observer on the side facing the dial face. In the remaining areas, the light of the light source is scattered. An additional dark transparent covering pane moreover absorbs the diffused light so that the numbers become visible only in the areas in which the liquid crystal film is subject to electric potential. The objective is to create a display unit in which the symbols and numbers can be varied in a simple fashion between a normal display and a visually differing type of display.
The disadvantage is that the light valve switches only individual numbers of the film or of the dial face into transparent mode via the individual electrode pairs. Such a light valve is not suitable for vehicular lights. The expert only receives the information that a light valve should be used in connection with a display unit.
In the device known from DE 198 52 593 A1 for use as an area light and as transparent glazing, a panel is arranged on the side of a pane that faces away from the direction of light beam. On the end face of the pane a light source is arranged, which, via a pane edge, can be coupled into the pane. The pane comprises scattering points, in which the coupled light is scattered to all sides. The panel can be switched into transparent or specular reflecting mode. In the reflecting state, the light that is scattered from the pane in the direction of the panel is reflected from the surface of the panel in a desired direction, and in a preferred embodiment into the inside of a vehicle. The panel then serves as the area light when actively connected with the pane and the light source. When the light source is switched off, the panel is switched in the transparent mode and then serves as overhead glazing in the roof of the vehicle.
The disadvantage of this known device is that the permanent cattering points in the pane limit transparency, thus preventing complete transparency. Since the pane is arranged first in the direction of the light beam, while the panel is arranged on the other side of the pane, the arrangement of the pane impairs the view through the panel. The degree of scattering cannot be varied on the pane. This limits the adjustment possibilities of the light. The pane represents an additional costly component. Moreover, it leads to increased energy consumption since the panel is switched in the transparent mode when the light is turned off by the permanent supply of electric potential.
It is therefore one of many objects of the present invention to create a vehicle light, using as few luminous components as is possible, that has a high functional diversity, can be used in a flexible fashion and makes a high-quality optical impression.
This object is achieved according to the invention by providing a light especially for motor vehicles, including at least one light source and a cover that is arranged in front of the light source in the direction of radiation, wherein the cover has an electrical diffuser that can change its optical properties to generate multi-functionality.
Due to the fact that the cover comprises an electrical diffuser, the light distribution level of radiation passing through the cover can be influenced. This offers the opportunity of generating different light distribution levels that are adapted to the application by means of the cover. The number of luminous components can be reduced, which has a cost-saving effect. The decrease in the number of components also leads to weight savings. Moreover, a more compact construction is possible by saving space.
It is possible to use commercially available diffuser models or models that were produced specifically based on the known design. In principle, a liquid crystal layer is arranged between two transparent area layers, which can be subjected to electric potential and are designed as an electrode pair. By applying electric potential, the light transmission level can be influenced specifically by the diffuser. The diffuser can be connected to the cover and form a single component with it. It is, however, also templated that the diffuser represents a separate component, which is assigned to the cover.
Pursuant to a preferred embodiment of the invention, the diffuser assumes a first functional state, in which it is switched into an opaque, view protection mode, which prevents viewing in the direction of the light source.
In the first functional state, the diffuser forms a view protection by remaining without electric potential and acting as a diffusing screen. Scattering of the light prevents a view into the inside of the light. The luminous components are hence not visible, particularly when the light source is switched off. In this way, the inside of the light, i.e. the luminous components, can be designed without consideration of its appearance to the observer, resulting in a design advantage.
Pursuant to another preferred embodiment of the invention, the diffuser is designed in a second functional state, in which it can be varied between randomly translucent and transparent when the light source is switched on, as a device for generating application-specific light distribution.
By applying electric potential on the electrode layers, the diffuser can be switched into transparent mode. By controlling the electric potential appropriately, the level of alignment of the liquid crystals in the diffuser can be adjusted. Here, also, intermediate steps between an opaque diffuse cover and a completely transparent cover are possible. In this way, the light distribution can be adapted to the respective application of a light, and the light hence has very flexible uses.
Through the function of the cover with the diffuser as an optical element that can be varied between a protected view and an application-adapted light distribution level the multi-functionality feature is achieved.
Pursuant to another preferred embodiment of the invention, a light housing that is covered by a cover comprising the diffuser forms a headlight together with at least one luminous component that is arranged in the light housing.
In the case of headlights, the diffuser can be employed particularly beneficially since here, frequently, clear cover panels are used. By switching the diffuser to "opaque", the technical details of the headlight are not visible when the light is switched off. The possibility of radiating light at the "transparent" setting when the light is switched on and radiating only scattered light at the "diffuse" setting results in a savings potential in terms of luminous components since no separate luminous components are required for the focused radiation and the scattered radiation.
Pursuant to another preferred embodiment of the invention, the radiation of the headlight can be switched between a daytime driving light, in the case of a diffuser that is switched to randomly translucent, and high beam, in the case of a diffuser that is switched to transparent, when the light is turned on, and the diffuser assumes its first functional state when the light is turned off.
The use of the diffuser for switching between high beam (focused radiation to illuminate the road) and a daytime driving light (scattered radiation for better visibility of the vehicle) is especially inexpensive and weight-saving since additional components for the daytime driving light can be foregone. In the switched-off state, the view protection feature is beneficially activated.
Pursuant to a further preferred embodiment of the invention, the light housing that is covered with the cover comprising the diffuser forms an indicator lamp together with the at least one luminous component that is arranged in the light housing.
Indicator lamps are implemented increasingly with uncolored and at least partially clear cover panels and colored bulbs or otherwise colored light sources. Here, the diffuser can serve especially beneficially as a view protection since a colored bulb is considered rather optically disadvantageous. Due to the cover panel, the optical properties of which can be varied, the indicator lamp can be designed especially cost-effective comprising few components.
Pursuant to another preferred embodiment of the invention, the indicator lamp is designed as a rear light, in which the diffuser is switched to the randomly translucent mode when the taillight is turned on, and in which the diffuser assumes its first functional state when the taillight is turned off, and in which the diffuser is switched to be transparent when the brakes are actuated, wherein a brake light is radiated.
The multi-functionality of the cover is especially important in rear light combinations since, here, the taillight and brake light can be implemented with a view protection in a particularly compact and cost-effective manner. Moreover, the diffuse radiation generates a particularly homogeneous taillight and the preferably completely transparent cover generates a focused, bundled and hence especially conspicuous brake signal when the brake is actuated.
Pursuant to another preferred embodiment of the invention, the indicator lamp is designed as a flashing light, in which the diffuser is switched to the transparent mode when the flashing signal is turned on, and in which the diffuser assumes its first functional state when the flashing signal is turned off.
The generally yellow bulbs used in flashing lights with clear cover panels are covered by the diffuser without allowing a view inside when the flashing signal is not turned on. Especially in light combinations, in which the flashing lights are frequently included as an integral component, the view protection function improves the optical appearance of the light for the observer. When the flashing signal is turned on, the cover can be completely transparent in order to radiate an especially clear flashing signal. This radiation is considered optically more beneficial as compared with radiation that is generated with conventional covers having a scattering effect.
In principle, individual cover parts can also contain separate diffusers in light combinations in order to switch the various desired optical effects of the individual luminous components that are assigned to a cover section separately in the light combination.
Pursuant to another preferred embodiment of the invention, the light housing that is covered by a cover including the diffuser forms an interior light, together with the at least one luminous component that is arranged in the light housing. The radiation of the interior light can be varied between an area interior light when the diffuser is switched to the randomly translucent mode and a focused reading light when the diffuser is switched to the transparent mode.
The diffuser/cover allows an inexpensive interior light to be implemented, which can be used optionally to illuminate the area, preferably on the inside of a vehicle, or as a reading light by radiating a focused light cone. In the switched-off state the diffuser serves as a view protection feature. In this way, the interior light has a flat construction and adapts harmonically to an adjoining inside molding of the vehicle.
Pursuant to a further preferred embodiment of the invention, the light source is designed as a bulb or as a gas discharge lamp or as an LED, and the luminous component is designed as the at least one light source or as an application-specific combination of the at least one light source with the at least one reflector.
The luminous components of the light can be designed appropriately for the respective application. Various combinations of light source and reflectors, as well as of additional elements with optical effects, are possible. Light emitting diodes, abbreviated as LEDs, are suited for interior, signal and rear lights due to their low space requirements and their low heat dissipation especially for the combination with a diffuser.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

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Compostions of GLA and/or other EFAs with TA or related compounds, and their use in therapy or nutrition or in preparation of composition for therapy or nutrition, especially to improve cell membrane EFA concentration and/or (particularly in diabetic complications) impaired nerve function and blood flow.

The invention relates to therapeutic and dietary compositions.
Gamma-linolenic acid (GLA), its immediate metabolite dihomogamma-linolenic acid, (DGLA) and, in certain circumstances, the DGLA metabolite arachidonic acid (AA), have wide ranges of desirable biological effects as essential nutrients and as nutrients or therapeutic agents specific preventative or therapeutic effects in various diseases including those of the skin (such as eczema and psoriasis), those of metabolism (in particular diabetes and its complications such as retinopathy, neuropathy, nephropathy and cardiovascular problems), those of inflammation and autoimmunity (such as rheumatoid arthritis, osieoarthritis, Sjogren""s syndrome, systemic lupus, Crohn""s disease, ulcerative colitis), those of the respiratory system (including asthma, pulmonary hypertension and pulmonary fibroses), those of the psyche and central nervous system (such as schizophrenia, dementia of Alzheimer and vascular or other types, depression and multiple sclerosis), those of the cardiovascular system (such as hypertension and coronary and peripheral arterial disease), those of the kidney (such as glomerulonephritis and other inflammatory and autiommuune conditions), those of the gastrointestinal system (such as oesophagitis, gastritis, peptic ulcer, Crohn""s disease and ulcerative colitis) and those of the endocrine system and its target organs (such as benign breast disease and benign prostatic disease). Cancer and pre-cancerous conditions may also respond to treatment with GLA and DGLA. GLA and DGLA have also been found to be beneficial in animal diseases and also in the care of diseased and of normal skin where they improve skin blood flow and skin smoothness.
Other essential fatty acids, of the n-3 series, notably stearidonic acid (SA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) also have many desirable nutritional and therapeutic effects, and many of the prior patents filed by the present applicants, relate to use of either or both series of essential fatty acids in various condition EPA 0 218 460, concerning the complications of diabetes being one example.
Both series of essential fatty acids are well known in themselves and their terminology and relations are set out below
The acids, which in nature are of the allxe2x80x94cis configuration, arc systematically named as derivatives of the corresponding octadecanoic, cicosanoic or docosanoic acids, e.g. z,z-octadeca-9,12 -dienoic acid or z,z,z,z,z,z-docosa-4,7,10,13,16,19-hexaenoic acid, but numerical designations based on the number of carbon atoms, the number of centres of unsaturation and the number of carbon atoms from the end of the chain to where the unsaturation begins, such as, correspondingly, 18:2 n-6 or 22.6 n-3, are convenient. Initials, e.g. EPA, and shortened forms of the name e.g. eicosapentaenoic acid, are used as trivial names in some instances. Further the acids beyond the 6desaturation step are informally known as the xe2x80x9c6-desaturatedxe2x80x9d acids.
Quite different types of chemical entity are xcex1-lipoic acid, also known as thioctic acid (TA), and related compounds. In the body TA is converted to dihydrolipoic acid (DHL) during the formation of acetyl-CoA from pyruvic acid or the formation of succinyl-CoA from xcex1-oxoglutaric acid, and during other oxido-reduction reactions. DHL can be converted back to TA by lipoic acid dehydrogenase, which requires the co-factor AND. TA and DHL have been seen as equivalent since they are rapidly interconverted in the body. The structures are:
with R, S and racemic forms and
also with R, S and racemic forms. In the context of this application thioctic acid means isomerically pure D- or S- alpha-lipoic acid, racemic alpha-lipoic acid or any mixture of the R- and S- isomers, and correspondingly for compounds related to thioctic acid including the reduced forms.
TA and the related free disulphide compounds, which are strongly lipophilic, are antioxidant agents capable of forming a redox couple in the body and they have for example been found to be of therapeutic value in the management of complications of diabetes, especially diabetic neuropathy Such complications are believed to be associated with excessive rates of oxidation of lipids and proteins and the TA/DHL redox couple has been seen as significant in neutralising many species of free radicals. Furthermore it can xe2x80x9crecyclexe2x80x9d other important antioxidants such as xcex1-tocopherol and ascorbate and bring about an increase of intracellular glutathione. In addition to diabetic complications, there is evidence that TA can enhance sensitivity to insulins so being of value in the pre-diabetic syndrome X and in obesity.
Metabolites of TA with similar function to TA are tetranorlipoic acid (TALA), bisnorlipoic acid (BALA) and 8-hydroxy-bisnorlipoic acid (8BALA) with R and S isomers as a with lipoic acid.
The antioxidant properties and consequent previously proposed clinical applications of xcex1-lipoic acid and its reduced form in diabetes and other conditions are discussed in the Handbook of Antioxidants (eds. E Cadanas and L Packer, Marcel Dekkar, New York 1996) see Chapter 18 pages 545-591, by Packer Witt and Tritschler Further, the applicants"" prior patent application PCT GB 96/01053 (WO 96/34846) discloses fatty acid/antioxidant derivatives of 1,3-propane diol and their use in conditions which antioxidants are beneficial including cardiovascular diseases, cancer and inflammatory disorders. Particular diesters disclosed are of GLA or DHA and lipoic acid. Related compounds, formally derivatives of dihydroxy methane, are disclosed in the applicants"" further specification PCT GB 96/01052 (WO 96/34855). In those applications it is however emphasised that compounds containing moieties of the fatty acid and lipoic acid are used: there is no reference to the co-administration of fatty acids and lipoic acid as separate molecules nor for particular purposes. In Hoechst U.S. Pat. No. 5,043,328 lipoic acid is mentioned as an antioxidant though in a prostaglandin-metabolism context, on gastro-intestinal problems and skin and subdermal tissue malfunctions.
Available therapies in treatment and prevention of most of the conditions mentioned so far, including diabetes, insulin resistance, syndrome X, and diabetic complications such as neuropathy and retinopathy, are far from satisfactory It seemed to us that the use of the above two different approaches simultaneously might be worth testing in relation to diabetic complications. GLA is believed to work mainly on the micro-circulation whereas TA/DHL is believed to work mainly on oxidation mechanisms, but it seemed reasonable to see whether the co-application of these agents might have at least additive effects.
In fact in measurements of nerve conduction velocity and nerve blood flow a dramatic and unexpected synergism was observed, with the effect of the two agents applied together being far greater than the sum of the effects of the two agents when applied alone. The results are shown in FIGS. 1 and 2. In diabetic animals both nerve conduction and nerve blood is flow are considerably affected. Both can be completely normalised by the co-administration of amounts of GLA and TA that have little effect alone.
The results with EFA""s and their synergistic effects with TA were completely unexpected and we decided to investigate them further. Vitamin E, like TA, is a lipophilic antioxidant and is one which is generally regarded as being physiologically more important than TA. However, when vitamin E was administered together with GLA in animals with diabetes there was no enhancement at all of the effect of GLA. Equally, in several clinical studies we have shown that the effects of GLA in conditions like atopic eczema, breast pain, rheumatoid arthritis and cardiovascular disease are not enhanced by the co-administration of vitamin E. There was therefore no reason at all to suspect the dramatic potentiation we have observed, which we do not think can be explained by the antioxidant effect.
In an effort to explore the effect further, we have performed preliminary experiments on rats on the effects of the administration of either GLA, EPA or DHA with or without the so anti-oxidants vitamin E, vitamin C or TA. Each fatty acid was added to the food at 0.1% by weight for a period of two weeks. The diet also contained either no other added material (control) or 0.1% by weight of vitamin E, vitamin C or TA. After two weeks the animals were killed and the levels of the fatty acids or their immediate metabolites determined in plasma phospholipids and in red cell membrane phospholipids. Neither vitamin E nor vitamin C had any effects on the levels of the fatty acids in either plasma or red cells. We can therefore conclude that there is no effect of anti-oxidants per se on the metabolism of the GLA, EPA or DHA in this situation. Equally, there were no effects of TA on the plasma phospholipid fatty acid composition. In contrast, in each of the groups the concentrations of the relevant fatty acids in red cell phospholipids were increased by 10-20%. This demonstrates that TA has a thitherto unknown and unsuspected effect on the incorporation of EFAs into cell membranes. This effect does not appear to be related to antioxidant activity.
What we are showing is that TA can enhance the incorporation of EFAs into cell membrane phospholipids. This will have effects on membrane structure and on the availability of the EFAs for cell signalling systems and is likely to account for the synergistic effects we have observed on nerve function and nerve blood flow in the diabetic animals. The effect is a general one which is applicable to all EFAs and not just to GLA.
The invention broadly concerns compositions of GLA and/or other EFAs, with the TA or related compounds, and their use in therapy or nutrition or in preparation of compositions to for therapy or nutrition. The conditions concerned are set out herein but especially the invention is concerned to improve cell membrane EFA concentration and/or, particularly in diabetic complications specifically, impaired nerve function (for example motor nerve conduction velocity) and blood flow Impaired blood flow may also be important it other illnesses, especially disorders of the heart and peripheral circulation. Impaired EPA incorporation into membranes may be an important problem, in most of the conditions listed.
In particular the invention provides:
1. Use in the manufacture of a medicament for treatment to improve or maintain cell membrane EFA concentration in health or any of the conditions set out herein, or use in such treatment itself, of an essential fatty acid, particularly one beyond the 6desaturation step in the n-6 and n-3 metabolic pathways, and a bioactive disulphide, particularly TA or a related compound, including the use of one active where for co-administration with the other and each active being present as such or as a derivative releasing the active in the body.
2. Use in the manufacture of a medicamnent for therapy (including prophylaxis of impaired nerve function for example motor-nerve conduction velocity) or blood flow in any of the conditions set out herein but particularly in diabetic neuropathy, retinopathy, nephorpathy or other complications of diabetes, or use in such therapy itself, of an essential fatty acid, particularly one beyond the 6desaturation step in the n-6 and n-3 metabolic pathways, and a biocompatible disulphide, particularly TA or a related compound, including the use of one active where for co-administration with the other and each active being present as such or as a derivative releasing the active in the body.
3. Use as above, the actives comprising at least one of GLA, DGLA and AA, and/or SA EPA, DPA and DHA.
4. Use as above, the actives comprising one or more of TA, TALA, BALA or 8-BALA as such or in respective reduced form.
5. Use as above the actives further comprising one or more other essential nutrients particularly vitamins A, D and E; B group vitamins such as riboflavin pyridozine niacin or niacinamide; folic acid, vitamin C; or assimilable zinc chromium magnesium or selenium.
6. Use as above the fatty acid and the disulphide being presented for administration of 1 mg to 100 g/day of each preferably 10 mg to 10 g/day very preferably 50 mg to 5 g/day and in a weight ratio of 1:20 to 20:1 more preferably 1:5 to 5:1 very preferably 1:3 to 3:1.
7. Use as above, in the context of the treatment management or prevention of any of the conditions referred to herein and in particular but without restriction in:
a) diabetes and its complications particularly diabetic retinopathy, all forms of insulin resistance and syndrome X, related conditions such as obesity, diabetic neuropathy, diabetic retinopathy, diabetic nephropathy, diabetic macrovascular coronary and peripheral arterial disease, diabetic leg ulcers and diabetic impotence.
b) disorders in which reduced blood flow to any tissue is important, particularly insulin resistance, type II diabetes, and coronary peripheral or cerebral vascular disease of any actiology.
c) any inflammatory disorder particularly rheumatoid arthritis, osteoarthritis and asthma.
d) any psychiatric or central nervous system disorder particularly schizophrenia, depression, ischameic dementas, Alzheimer""s disease, other dementias, multiple sclerosis, and attention deficit hyperactivity disorder
e) eczema and psoriasis.
f) any respiratory disorder particularly asthma, pulmonary hypertension and pulmonary fibrosis.
g) any cardiovascular disorder particularly hypertension, coronary or peripheral arterial disease or thrombotic disorder.
h) Crohn""s disease or ulcerative colitis
i) any endocrine disorder, particularly benign breast and prostaic diseases.
j) any form of cancer or pre-cancerous condition, including cachexia associated with cancer.
k) improvement of athletic performance, for example, by increasing muscle blood flow and the utilisation of energy in humans or in animals.
As noted above the most effective EFAs are the 6desaturated EFAs particularly GLA, AA, DGLA, SA, EPA, DPA or DHA suitably in a dose range of 1 mg to 100 g, preferably 10 mg to 10 g and very preferably 50 mg to 5 g per day. The disulphides, such as TA, BALA, TAL and 8BALA or their reduced forms may be used in similar dose ranges. The weight ratio of the EFA to disulphide may for example be from 1:20 to 20:1 but is preferably from 1:5 to 5:1, more preferably from 1:3 to 3:1. The EFAs and the disulphide may, further, each be used in any appropriate combined chemical form that is pharmacologically acceptable and capable of raising the concentration of the EFA or the disulphide related compound in blood or other bodily tissues. Such prongs may include triglycerides, phospholipids, other glycerides, propane diol derivatives, germinal diols and others known to those skilled in the art. The EFA and the disulphide may even be combined in the same molecule, whose function is then to act as a pro-drug for both the EFA and the disulphide. Examples are 1,3-propane diol derivatives made as disclosed in our PCT application GB 96/01053 (WO 20 96/34836) and germinal diol derivatives made as disclosed in our PCT application GB 96/01052 (WO 96/34855).
The actives may be presented together or separately with instructions stating how they are to be administered. When presented in separate dosage forms the two may be provided together in packs. They may be presented for example by oral, eternal, parenteral, topical, rectal, or vaginal routes using formulations known to those experienced in the arm
The actives may also be provided in nutritional supplements, medical foods, functional foods, nutraceuticals or ordinary foods together with other essential nutrients including minerals and vitamins such as vitamins A, D and E; B group vitamins such as riboflavin, pyridoxine, niacin or nicotinamide; folic acid; vitamin C; or assimilable zinc, chromium, magnesium or selenium. Such nutrients may be provided in any appropriate bioassimilable chemical form.
Initial experimental evidence was obtained by studying rats made diabetic by the administration of streptozotocin. In such animal, complications resembling human complications of diabetes develop, and are characterised by reduction in conduction velocity to of impulses along the sciatic nerve and reduction in blood flow to the sciatic nerve. The reduction in blood flow is particularly important and is likely to be relevant to many complications of diabetes including retinopathy, nephropathy macrovascular arterial disease of the heart and peripheral arteries, impotence and leg ulceration. It may also be relevant to many of the other conditions in which essential fatty acids are useful treatments, including the inflammatory disorders.
Five groups of animals given streptozotocin (STZ) were tested. They were accepted into the study only if they developed unequivocal elevation of blood glucose after the STZ. Ten animals acted as normal controls.
Ten animals were diabetic but untreated. Eight animals were treated with TA alone. 11 with GLA alone and 11 with combined TA and GLA. The GLA was added to the food to give an approximate dose of 20 mg/kg/daily and TA was given by daily intraperitoneal injection at a dose of 20 mg/kg/day. Because fats are metabolised in relation to the surface area, and because the surface area/volume ratio is much higher in a small animal than in a large one, these doses are very approximately equivalent to a dose of around 2-3 mg/kg/daily in an adult human.
The animals were made diabetic by injection of 45 mg kg STZ intraperitoneally. Rats were males of the Sprague Dawley strain and were 19 weeks old at the time of STZ injection. The animals were left for 6 weeks after the STZ to allow the nerve damage to develop and were then given treatment with nothing or with GLA or TA or both together for 2 weeks At the end of the two weeks, the animals were anaesthetised and the motor nerve conduction velocity measured in the perineal branch of the sciatic nerve. Sciatic nerve blood flow was also measured by microelectrode polarography hydrogen clearance
Figures for the motor nerve conduction velocity and the total nerve blood flow were plotted. The TA alone and the GLA alone both produced small improvements in nerve conduction velocity and in nerve blood flow but the improvements at these doses were far from restoration of normality. Estimated additive effects of the two compounds added to together were also far from restorative of normality. However, and in contrast to an expected additive effect, the two compounds together effectively normalised both nerve conduction velocity and nerve blood flow. Based on previous dose/response studies of GLA alone or ALA alone, the presence of GLA or of TA appeared to amplify the effect of the other compound around ten-fold. It contrasts with an absence of effect on nerve conduction with TA alone referred to in Packer et al (loc. cit., pages 570-572).

Therapeutic and dietary compositions containing essential fatty acids and bioactive disulphides