A planographic printing plate manufacturing method is disclosed which comprises the step of developing a presensitized planographic printing plate with a developer with a pH of from 11.5 to less than 12.5 which does not substantially contain an organic solvent, wherein the presensitized planographic printing plate comprises a support having a roughened hydrophilic surface with a center line average surface roughness Ra of from 0.5 to 0.8 xcexcm, and provided thereon, a photopolymerizable light sensitive layer and an oxygen shielding layer in that order, the photopolymerizable light sensitive layer containing A) an addition polymerizable monomer having an ethylenic double bond, B) a photopolymerization initiator, C) a sensitizing dye, and D) a polymer binder, and the oxygen shielding layer containing E) polyvinyl alcohol and F) polyvinyl pyrrolidone.

The present invention relates to a method of preparing a planographic printing plate, the method comprising the step of developing a presensitized planographic printing plate comprising a photopolymerizable light sensitive layer with a liquid developer to form a negative image on the planographic printing plate.
It is generally known that a protective layer (oxygen shielding layer) is provided on a light sensitive layer of a photopolymerizable light sensitive material in order to prevent oxygen from inhibiting polymerization. As a method for providing the oxygen shielding layer, there is a method in which an aqueous solution of a water soluble polymer such as polyvinyl alcohol or polyvinyl pyrrolidone is coated on a light sensitive layer and dried to form a water soluble polymer layer. The water soluble polymer provides an excellent oxygen shielding ability, coatability and solubility to a developer used. However, a planographic printing plate, which is prepared by developing a presensitized planographic printing plate employing the water soluble polymer, has the problem that printing durability as well as ink receptivity are poor.
Use of a developer containing an organic solvent improves the ink receptivity, but results in a new problem such as malorder attributed to the organic solvent or deterioration of working environment.
An increase of pH of the developer makes it possible to eliminate the organic solvent from the developer without lowering developability or ink receptivity, but it has been found that the pH increase of the developer has an adverse effect on printing durability, when printing is carried out employing a specific ink, particularly soybean oil-based ink.
An object of the invention is to provide a method of developing a presensitized planographic printing plate with high sensitivity and high storage stability, employing a developer, which neither produces malodor nor lowers working environment, to obtain a planographic printing plate with high ink receptivity and high printing durability, wherein the presensitized planographic printing plate comprises a photopolymerizable light sensitive layer and provided thereon, an oxygen shielding layer containing polyvinyl alcohol and polyvinyl pyrrolidone which is firmly adhered to the light sensitive layer with good adhesion.
The above objects of the invention can be attained by the followings:
1. A method of manufacturing a planographic printing plate, the method comprising the step of developing a presensitized planographic printing plate with a developer with a pH of from 11.5 to less than 12.5, which does not substantially contain an organic solvent, wherein the presensitized planographic printing plate comprises a support having a roughened hydrophilic surface with a center line average surface roughness Ra of from 0.5 to 0.8 xcexcm, and provided thereon, a photopolymerizable light sensitive layer and an oxygen shielding layer in that order, the photopolymerizable light sensitive layer containing A) an addition polymerizable monomer having an ethylenic double bond, B) a photopolymerization initiator, C) a sensitizing dye, and D) a polymer binder, and the oxygen shielding layer containing E) polyvinyl alcohol and F) polyvinyl pyrrolidone.
2. the method of item 1, wherein the developer is a developer containing no organic solvent or a developer containing an organic solvent in an amount of not more than 2% by weight.
3. the method of item 1, wherein the presensitized planographic printing plate comprises a subbing layer containing a compound having a polyalkoxysilyl group between the support and the photopolymerizable light sensitive layer.
4. the method of item 3, wherein the compound having a polyalkoxysilyl group is a silane coupling agent having a (meth)acryloyl group.
5. the method of item 1, wherein the addition polymerizable monomer having an ethylenic double bond further has a phosphate bond in the molecule.
6. the method of item 1, wherein the photopolymerization initiator is a titanocene compound.
7. the method of item 1, wherein the sensitizing dye is a pyromethene dye.
8. the method of item 1, wherein the polymer binder is a reaction product of a vinyl copolymer having a carboxyl group in the molecule with a compound having a (meth)acryloyl group and an epoxy group in the molecule.
9. the method of item 1, wherein the polymer binder has an acid value of from 10 to 150.
10. the method of item 1, wherein the planographic printing plate is a printing plate used when printing is carried out employing soybean oil-based ink.
11. a method of manufacturing a planographic printing plate, the method comprising the step of developing a presensitized planographic printing plate with a developer with a pH of not less than 11.5 which does not substantially contain an organic solvent, wherein the presensitized planographic printing plate comprises a support having a roughened hydrophilic surface with a center line average surface roughness Ra of from 0.5 to 0.8 xcexcm, and provided thereon, a photopolymerizable light sensitive layer and an oxygen shielding layer in that order, the photopolymerizable light sensitive layer containing A) an addition polymerizable monomer having an ethylenic double bond, B) a photopolymerization initiator, C) a sensitizing dye, and D) a polymer binder, and the oxygen shielding layer containing E) polyvinyl alcohol and F) polyvinyl pyrrolidone.
12. the method of item 11 above, wherein the pH of the developer is in the range of from 11.5 to less than 12.5.
13. the method of item 11 or 12 above, wherein a subbing layer containing a compound having a polyalkoxysilyl group is provided between the support and the photopolymerizable light sensitive layer.
14. the method of item 13 above, wherein the compound having a polyalkoxysilyl group is a silane coupling agent having a (meth)acryloyl group.
15. the method of any one of items 11 through 14 above, wherein the addition polymerizable monomer having an ethylenic double bond further has a phosphoric acid ester bond in the molecule.
16. the method of any one of items 11 through 15 above, wherein the photopolymerization initiator is a titanocene compound.
17. the method of any one of items 11 through 16 above, wherein the sensitizing dye is a pyrromethene dye.
18. the method of any one of items 11 through 17 above, wherein the polymer binder is a reaction product of a vinyl copolymer having a carboxyl group in the molecule with a compound having a (meth)acryloyl group and an epoxy group in the molecule.
It has been found that a planographic printing plate manufacturing method provides a planographic printing plate with high printing durability even when soybean oil-based ink is employed as a printing ink, the method comprising the step of developing a presensitized planographic printing plate with a developer with a pH of from 11.5 to less than 12.5 which does not substantially contain an organic compound, wherein the presensitized planographic printing plate comprises a support having a roughened surface with a center line average surface roughness Ra (according to JIS B 0601) of from 0.5 to 0.8 xcexcm, and provided thereon, a light sensitive layer and an oxygen shielding layer containing polyvinyl alcohol and polyvinyl pyrrolidone in that order. In the invention, the center line average surface roughness Ra is measured employing a method as described in JIS B 0601.
The invention will be detailed below.
 less than Support greater than
The presensitized planographic printing plate of the invention comprises a support having a hydrophilic surface, which is surface roughened to have a center line average surface roughness of from 0.5 to 0.8 xcexcm. As a support, a plate of aluminum, stainless steel, chromium, or nickel can be used. Among them, an aluminum plate is preferably used, which may be a pure aluminum plate or an aluminum alloy plate.
As the aluminum alloy, there can be used various ones including an alloy of aluminum and a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium or iron.
It is preferable that the support in the invention is subjected to degreasing treatment for removing rolling oil prior to surface roughening. The degreasing treatments include degreasing treatment employing solvents such as trichlene and thinner, and an emulsion degreasing treatment employing an emulsion such as kerosene or triethanol. It is also possible to use an aqueous alkali solution such as caustic soda for the degreasing treatment. When an aqueous alkali solution such as caustic soda is used for the degreasing treatment, it is possible to remove soils and oxidized films which can not be removed by the above-mentioned degreasing treatment alone. When an aqueous alkali solution such as caustic soda is used for the degreasing treatment, the resulting support is preferably subjected to desmut treatment in an aqueous solution of an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixture thereof, since smut is produced on the surface of the support.
The surface roughening methods include a mechanical surface roughening method and an electrolytic surface roughening method electrolytically etching the support surface. Though there is no restriction for the mechanical surface roughening method, a brushing roughening method and a honing roughening method are preferable.
After the support has been roughened mechanically, it is preferably dipped in an acid or an aqueous alkali solution in order to remove abrasives and aluminum dust, etc. which have been embedded in the surface of the support. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid and hydrochloric acid, and examples of the alkali include sodium hydroxide and potassium hydroxide. Among those mentioned above, an aqueous alkali solution of for example, sodium hydroxide is preferably used. The dissolution amount of aluminum in the support surface is preferably 0.5 to 5 g/m2. After the support has been dipped in the aqueous alkali solution, it is preferable for the support to be dipped in an acid such as phosphoric acid, nitric acid, sulfuric acid and chromic acid, or in a mixed acid thereof, for neutralization.
Though there is no restriction for the electrolytic surface roughening method, a method in which the support is electrolytically surface roughened in an acidic electrolytic solution. Though an acidic electrolytic solution generally used for the electrolytic surface roughening can be used, it is preferable to use an electrolytic solution of hydrochloric acid or that of nitric acid. The electrolytic surface roughening method disclosed in Japanese Patent Publication No. 48-28123, British Patent No. 896,563 and Japanese Patent O.P.I. Publication No. 53-67507 can be used. In the electrolytic surface roughening method, voltage applied is generally from 1 to 50 V, and preferably from 10 to 30 V. The current density used can be selected from the range from 10 to 200 A/dm2, and is preferably from 50 to 150 A/dm2. The quantity of electricity can be selected from the range of from 100 to 5000 C/dm2, and is preferably 100 to 2000 C/dm2. The temperature during the electrolytically surface roughening may be in the range of from 10 to 50xc2x0 C., and is preferably from 15 to 45xc2x0 C.
When the support is electrolytically surface roughened by using an electrolytic solution of nitric acid, voltage applied is generally from 1 to 50 V, and preferably from 5 to 30 V. The current density used can be selected from the range from 10 to 200 A/dm2, and is preferably from 20 to 150 A/dm2. The quantity of electricity can be selected from the range of from 100 to 5000 C/dm2, and is preferably 100 to 2000 C/dm2. The temperature during the electrolytically surface roughening may be in the range of from 10 to 50xc2x0 C., and is preferably from 15 to 45xc2x0 C. The nitric acid concentration in the electrolytic solution is preferably from 0.1% by weight to 5% by weight. It is possible to optionally add, to the electrolytic solution, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid or oxalic acid.
When the support is electrolytically surface roughened by using an electrolytic solution of hydrochloric acid, voltage applied is generally from 1 to 50 V, and preferably from 2 to 30 V. The current density used can be selected from the range from 10 to 200 A/dm2, and is preferably from 50 to 150 A/dm2. The quantity of electricity can be selected from the range of from 10 to 5000 C/dm2, and is preferably 100 to 2000 C/dm2. The temperature during the electrolytically surface roughening may be in the range of from 10 to 50xc2x0 C., and is preferably from 15 to 45xc2x0 C. The hydrochloric acid concentration in the electrolytic solution is preferably from 0.1% by weight to 5% by weight. It is possible to optionally add, to the electrolytic solution, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid or oxalic acid.
After the support has been electrolytically surface roughened, it is preferably dipped in an acid or an aqueous alkali solution in order to remove aluminum dust, etc. produced in the surface of the support. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid and hydrochloric acid, and examples of the alkali include sodium hydroxide and potassium hydroxide. Among those mentioned above, the aqueous alkali solution is preferably used. The dissolution amount of aluminum in the support surface is preferably 0.5 to 5 g/m2. After the support has been dipped in the aqueous alkali solution, it is preferable for the support to be dipped in an acid such as phosphoric acid, nitric acid, sulfuric acid and chromic acid, or in a mixed acid thereof, for neutralization.
The mechanical surface roughening and electrolytic surface roughening may be carried out singly, and the mechanical surface roughening followed by the electrolytic surface roughening may be carried out.
After the surface roughening, anodizing treatment may be carried out. There is no restriction in particular for the method of anodizing treatment used in the invention, and known methods can be used. The anodizing treatment forms an anodization film on the surface of the support. For the anodizing treatment there is preferably used a method of applying a current density of from 1 to 10 A/dm2 to an aqueous solution containing sulfuric acid and/or phosphoric acid in a concentration of from 10 to 50%, as an electrolytic solution. However, it is also possible to use a method of applying a high current density to sulfuric acid as described in U.S. Pat. No. 1,412,768, a method to electrolytically etching the support in phosphoric acid as described in U.S. Pat. No. 3,511,661, or a method of employing a solution containing two or more kinds of chromic acid, oxalic acid, malonic acid, etc. The coated amount of the formed anodization film is suitably 1 to 50 mg/dm2, and preferably 10 to 40 mg/dm2. The coated amount of the formed anodization film can be obtained from the weight difference between the aluminum plates before and after dissolution of the anodization film. The anodization film of the aluminum plate is dissolved employing for example, an aqueous phosphoric acid chromic acid solution which is prepared by dissolving 35 ml of 85% by weight phosphoric acid and 20 g of chromium (IV) oxide in 1 liter of water.
The support which has been subjected to anodizing treatment is optionally subjected to sealing treatment. For the sealing treatment, it is possible to use known methods using hot water, boiling water, steam, a sodium silicate solution, an aqueous dicromate solution, a nitrite solution and an ammonium acetate solution.
After the above treatment, the support is suitably undercoated with a water soluble resin such as polyvinyl phosphonic acid, a polymer or copolymer having a sulfonic acid in the side chain, or polyacrylic acid; a water soluble metal salt such as zinc borate; a yellow dye, an amine salt; and so on. The sol-gel treatment support, which has a functional group capable of causing addition reaction by radicals as a covalent bond, is suitably used.
In the invention, an aluminum plate, which has been subjected to surface roughening, subjected to anodizing treatment, subjected to sealing treatment, and then subjected to undercoating treatment, is especially preferred.
 less than Subbing Layer greater than
In the presensitized planographic printing plate of the invention, a subbing layer is preferably provided on a support in order to improve adhesion between the support and the photopolymerizable light sensitive layer. A compound used in the subbing layer is preferably a compound having a polyalkoxy silyl group. The compound having a polyalkoxy silyl group is preferably a silane coupling agent having a (meth)acryloyl group. Examples thereof include xcex3-methacryloxypropyltrimethoxysilane.
 less than Photopolymerizable Light Sensitive Layer greater than
The support in the invention is prepared employing the method as described above to have a roughened hydrophilic surface with a center line average surface roughness Ra of from 0.5 to 0.8 xcexcm. A photopolymerizable light sensitive layer is provided on the resulting support, which contains A) an addition polymerizable ethylenic double bond-containing monomer, B) a photopolymerization initiator, C) a sensitizing dye, and D) a polymer binder.
A) Addition Polymerizable Ethylenic Double Bond-containing Monomer
As the addition polymerizable ethylenic double bond-containing monomer in the invention, known monomers can be used. Examples thereof include a monofunctional acrylate such as 2-ethylhexyl acrylate, 2-hydroxypropyl acrylate, glycerol acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate, tetrahydrofurfuryloxyhexanorideacrylate, an ester of 1,3-dioxane-xcex5-caprolactone adduct with acrylic acid or 1,3-dioxolane acrylate; a methacrylate, itaconate, crotonate or maleate alternative of the above acrylate; a bifunctional acrylate such as ethyleneglycol diacrylate, triethyleneglycol diacrylate, pentaerythritol diacrylate, hydroquinone diacrylate, resorcin diacrylate, hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, hydroxypivalic acid neopentyl glycol diacrylate, neopentyl glycol adipate diacrylate, diacrylate of hydroxypivalic acid neopentyl glycol-xcex5-caprolactone adduct, 2-(2-hydroxy-1,1-dimethylethyl)-5-hydroxymethyl-5-ethyl-1,3-dioxane diacrylate, tricyclodecanedimethylol acrylate, tricyclodecanedimethylol acrylate-xcex5-caprolactone adduct or 1,6-hexanediol diglycidylether diacrylate; a dimethacrylate, diitaconate, dicrotonate or dimaleate alternative of the above diacrylate; a polyfunctional acrylate such as trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, trimethylolethane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexacrylate, dipentaerythritol hexacrylate-xcex5-caprolactone adduct, pyrrogallol triacrylate, propionic acid dipentaerythritol triacrylate, propionic acid dipentaerythritol tetraacrylate or hydroxypivalylaldehyde modified dimethylolpropane triacrylate; a polymethacrylate, polyitaconate, polycrotonate or polymaleate alternative of the above polyacrylate; and an oligomer of these esters.
A prepolymer can be used, and examples of the prepolymer include compounds as described later. The prepolymer with a photopolymerizable property, which is obtained by incorporating acrylic acid or methacrylic in an oligomer with an appropriate molecular weight, can be suitably employed. This prepolymer can be used singly, as an admixture of the above described monomers and/or oligomers.
Examples of the prepolymer include polyester (meth)acrylate obtained by incorporating (meth)acrylic acid in a polyester of a polybasic acid such as adipic acid, trimellitic acid, maleic acid, phthalic acid, terephthalic acid, hymic acid, malonic acid, succinic acid, glutaric acid, itaconic acid, pyromellitic acid, fumalic acid, pimelic acid, sebatic acid, dodecanic acid or tetrahydrophthalic acid with polyol such as ethylene glycol, ethylene glycol, diethylene glycol, propylene oxide, 1,4-butane diol, triethylene glycol, tetraethylene glycol, polyethylene glycol, grycerin, trimethylol propane, pentaerythritol, sorbitol, 1,6-hexanediol or 1,2,6-hexanetriol, an epoxyacrylate such as bisphenol Axc2x7epichlorhydrinxc2x7(meth)acrylic acid or phenol novolakxc2x7epichlorhydrinxc2x7(meth)acrylic acid obtained by incorporating (meth)acrylic acid in an epoxy resin, an urethaneacrylate such as ethylene glycolxc2x7adipic acidxc2x7tolylenediisocyanatexc2x72-hydroxyethylacrylate, polyethylene glycolxc2x7tolylenediisocyanatexc2x72-hydroxyethylacrylate, hydroxyethylphthalylmethacrylatexc2x7xylenediisocyanate, 1,2-polybutadieneglycolxc2x7tolylenediisocyanatexc2x72-hydroxyethylacrylate or trimethylolpropanexc2x7propylene glycolxc2x7tolylenediisocyanatexc2x72-hydroxyethylacrylate, obtained by incorporating (meth)acrylic acid in an urethane resin, a silicone acrylate such as polysiloxane acrylate, polysiloxanexc2x7diisocyanatexc2x72-hydroxyethylacrylate, and an alkyd modified acrylate obtained by incorporating a methacroyl group in an oil modified alkyd resin and a spiran resin acrylate.
The light sensitive layer in the invention may contain a monomer such as a phosphazene monomer, triethylene glycol, an EO modified isocyanuric acid diacrylate, an EO modified isocyanuric acid triacrylate, dimethyloltricyclodecane diacrylate, trimethylolpropane acrylate benzoate, an alkylene glycol acrylate, or a urethane modified acrylate, or an addition polymerizable oligomer or prepolymer having a structural unit derived from the above monomer.
The monomer used in the invention is preferably a phosphate compound having at least one ethylenic double bond. The phosphate compound is a compound with an ethylenic double bond in which at least one hydroxyl group of phosphoric acid is esterified, and is preferably a compound having a (meth)acryloyl group. Examples of the phosphate compound include Light Ester P-1M, Light Ester P-2M, Light Ester HOP-PM, Light Acrylate-P-1A and Light Acrylate-P-2A each produced by Kyoeisha Kagaku Co., Ltd.
Besides the above compounds, compounds disclosed in Japanese Patent O.P.I. Publication Nos. 58-212994, 61-6649, 62-46688, 62-48589, 62-173295, 62-187092, 63-67189, and 1-244891, compounds described on pages 286 to 294 of xe2x80x9c11290 Chemical Compoundsxe2x80x9d edited by Kagakukogyo Nipposha, and compounds described on pages 11 to 65 of xe2x80x9cUVxc2x7EB Koka Handbook (Materials)xe2x80x9d edited by Kobunshi Kankokai can be suitably used. Of these compounds, compounds having two or more acryl or methacryl groups in the molecule are preferable, and those having a molecular weight of not more than 10,000, and preferably not more than 5,000 are more preferable.
The light sensitive layer in the invention contains the monomer described above in an amount of preferably 1.0 to 80.0% by weight, and more preferably 3.0 to 70.0% by weight.
B) Photopolymerization Initiator
The light sensitive layer of the presensitized planographic printing plate of the invention contains a polymerization initiator.
The photopolymerization initiators include carbonyl compounds, organic sulfur compounds, peroxides, redox compounds, azo or diazo compounds, halides and photo-reducing dyes disclosed in J. Kosar, xe2x80x9cLight Sensitive Systemsxe2x80x9d, Paragraph 5. The examples thereof are disclosed in British Patent No. 1,459,563.
Examples of the photopolymerization initiator will be shown below.
A benzoin derivative such as benzoin methyl ether, benzoin i-propyl ether, or xcex1,xcex1-dimethoxy-xcex1-phenylacetophenone; a benzophenone derivative such as benzophenone, 2,4-dichlorobenzophenone, o-benzoyl methyl benzoate, or 4,4xe2x80x2-bis(dimethylamino)benzophenone; a thioxanthone derivative such as 2-chlorothioxanthone, 2-i-propylthioxanthone; an anthraquinone derivative such as 2-chloroanthraquinone or 2-methylanthraquinone; an acridone derivative such as N-methylacridone or N-butylacridone; xcex1,xcex1-diethoxyacetophenone; benzil; fluorenone; xanthone; an uranyl compound; a triazine derivative disclosed in Japanese Patent Publication Nos. 59-1281 and 61-9621 and Japanese Patent O.P.I. Publication No. 60-60104; an organic peroxide compound disclosed in Japanese Patent O.P.I. Publication Nos. 59-1504 and 61-243807; a diazonium compound in Japanese Patent Publication Nos. 43-23684, 44-6413, 47-1604 and U.S. Pat. No. 3,567,453; an organic azide compound disclosed in U.S. Pat. Nos. 2,848,328, 2,852,379 and 2,940,853; orthoquinondiazide compounds disclosed in Japanese Patent Publication Nos. 36-22062b, 37-13109, 38-18015 and 45-9610; various onium compounds disclosed in Japanese Patent Publication No. 55-39162, Japanese Patent O.P.I. Publication No. 59-14023 and xe2x80x9cMacromoleculesxe2x80x9d, Volume 10, p. 1307 (1977); azo compounds disclosed in Japanese Patent Publication No. 59-142205; metal arene complexes disclosed in Japanese Patent O.P.I. Publication No. 1-54440, European Patent Nos. 109,851 and 126,712, and xe2x80x9cJournal of Imaging Sciencexe2x80x9d, Volume 30, p. 174 (1986); (oxo) sulfonium organoboron complexes disclosed in Japanese Patent O.P.I. Publication Nos. 5-213861 and 5-255347; titanocenes disclosed in Japanese Patent O.P.I. Publication Nos. 59-152396 and 61-151197; transition metal complexes containing a transition metal such as ruthenium disclosed in xe2x80x9cCoordination Chemistry Reviewxe2x80x9d, Volume 84, p. 85-277 (1988) and Japanese Patent O.P.I. Publication No. 2-182701; 2,4,5-triarylimidazol dimmer disclosed in Japanese Patent O.P.I. Publication No. 3-209477; carbon tetrabromide; and organic halide compounds disclosed in Japanese Patent O.P.I. Publication No. 59-107344.
Among these compounds, titanocenes are preferred. Examples of the titanocenes include di-cyclopentadienyl-Ti-dichloride, dicyclopentadienyl-Ti-bisphenyl, dicyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophenyl, dicyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophenyl, dicyclopentadienyl-Ti-bis-2,4,6-trifluorophenyl, dicyclopentadienyl-Ti-bis-2,6-difluorophenyl, dicyclopentadienyl-Ti-bis-2,4-difluorophenyl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-pentafluorophenyl, di-methylcyclopentadienyl-Ti-bis-2,3,5,6-tetrafluorophenyl, di-methylcyclopentadienyl-Ti-bis-2,4-difluorophenyl, and bis (cyclopentadienyl)-bis(2,6-difluoro-3-(pyriyl)phenyl)titanium (IRUGACURE 784, produced by Ciba Specialty Co., Ltd.), but are not limited thereto.
C) Sensitizing Dye
The light sensitive layer of the presensitized planographic printing plate of the invention contains a sensitizing dye.
Sensitizing dyes, which can induce sensitivity to the wavelengths of the visible and near infrared regions, include cyanines, phthalocyanines, merocyanines, porphyrins, spiro compounds, ferrocenes, fluorenes, fulgides, imidazoles, perylenes, phenazines, phenothiazines, polyenes, azo compounds, diphenylmethanes, triphenylmethanes, polymethine acridines, cumarines, ketocumarines, quinacridones, indigos, styryl dyes, pyrylium dyes, pyrromethene dyes, pyrazolotriazole compounds, benzothiazole compounds, barbituric acid derivatives, thiobarbituric acid derivatives, and compounds disclosed in European Patent No. 568,993, U.S. Pat. Nos. 4,508,811 and 5,227,227, and Japanese Patent O.P.I. Publication Nos. 2001-125255 and 11-271969.
Of these sensitizing dyes, pyrromethene dyes are preferred, and examples thereof include those disclosed in Japanese Patent O.P.I. Publication No. 11-271969. Examples of the pyrromethene dyes also include the compounds represented by the following formulae:
The addition amount of the photopolymerization initiator is not specifically limited, but is preferably 0.1 to 20 parts by weight based on 100 parts by weight of the addition polymerizable compound. The content ratio by mole of the photopolymerization initiator to the sensitizing dye in the light sensitive layer is 1:100 to 100:1.
D) Polymer Binder
The presensitized planographic printing plate of the invention comprises a polymer binder in the photopolymerizable light sensitive layer.
As the polymer binder can be used a polyacrylate resin, a polyvinylbutyral resin, a polyurethane resin, a polyamide resin, a polyester resin, an epoxy resin, a phenol resin, a polycarbonate resin, a polyvinyl butyral resin, a polyvinyl formal resin, a shellac resin, or another natural resin. These resins can be used as an admixture of two or more thereof.
As the polymer binder, a vinyl copolymer obtained by copolymerization of an acryl monomer is preferred. The copolymer is preferably a copolymer of (a) a carboxyl group-containing monomer, or (b) alkyl methacrylate or alkyl acrylate with another monomer.
Examples of the carboxyl group-containing monomer include an xcex1,xcex2-unsaturated carboxylic acid, for example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride or a carboxylic acid such as a half ester of phthalic acid with 2-hydroxymethacrylic acid.
Examples of the alkyl methacrylate or alkyl acrylate include an unsubstituted alkyl ester such as methylmethacrylate, ethylmethacrylate, propylmethacrylate, butylmethacrylate, amylmethacrylate, hexylmethacrylate, heptylmethacrylate, octylmethacrylate, nonylmethacrylate, decylmethacrylate, undecylmethacrylate, dodecylmethacrylate, methylacrylate, ethylacrylate, propylacrylate, butylacrylate, amylacrylate, hexylacrylate, heptylacrylate, octylacrylate, nonylacrylate, decylacrylate, undecylacrylate, or dodecylacrylate; a cyclic alkyl ester such as cyclohexyl methacrylate or cyclohexyl acrylate; and a substituted alkyl ester such as benzyl methacrylate, 2-chloroethyl methacrylate, N,N-dimethylaminoethyl methacrylate, glycidyl methacrylate, benzyl acrylate, 2-chloroethyl acrylate, N,N-dimethylaminoethyl acrylate or glycidyl acrylate.
The polymer binder in the invention can further contain, as another monomer unit, a monomer unit derived from the monomer described in the following items (1) through (14).
(1) A monomer having an aromatic hydroxy group, for example, o-, (p- or m-)hydroxystyrene, or o-, (p- or m-)hydroxyphenylacrylate.
(2) A monomer having an aliphatic hydroxy group, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, N-methylolacrylamide, N-methylolmethacrylamide, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 5-hydroxypentyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, N-(2-hydroxyethyl)acrylamide, N-(2-hydroxyethyl)methacrylamide, hydroxyethylvinyl ether,
(3) A monomer having an aminosulfonyl group, for example, m- or p-aminosulfonylphenyl methacrylate, m- or p-aminosulfonylphenyl acrylate, N-(p-aminosulfonylphenyl)methacrylamide, N-(p-aminosulfonylphenyl)acrylamide,
(4) A monomer having a sulfonamido group, for example, N-(p-toluenesulfonyl)acrylamide, N-(p-toluenesulfonyl)methacrylamide,
(5) An acrylamide or methacrylamide, for example, acrylamide, methacrylamide, N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl-N-phenylacrylamide, N-4-hydroxyphenylacrylamide, N-4-hydroxyphenylmethacrylamide,
(6) A monomer having a fluorinated alkyl group, for example, trifluoromethyl acrylate, trifluoromethyl methacrylate, tetrafluoropropyl methacrylate, hexafluoropropyl methacrylate, octafluoropentyl acrylate, octafluoropentyl methacrylate, heptadecafluorodecyl methacrylate, heptadecafluorodecyl methacrylate, N-butyl-N-(2-acryloxyethyl)heptadecafluorooctylsulfonamide,
(7) A vinyl ether, for example, ethyl vinyl ether, 2-chloroethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether,
(8) A vinyl ester, for example, vinyl acetate, vinyl chroloacetate, vinyl butyrate, vinyl benzoate,
(9) A styrene, for example, styrene, methylstyrene, chloromethystyrene,
(10) A vinyl ketone, for example, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone,
(11) An olefin, for example, ethylene, propylene, isobutylene, butadiene, isoprene, 0086]
(12) N-vinylpyrrolidone, N-vinylcarbazole, N-vinylpyridine,
(13) A monomer having a cyano group, for example, acrylonitrile, methacrylonitrile, 2-pentenenitrile, 2-methyl-3-butene nitrile, 2-cyanoethyl acrylate, o-, m- or p-cyanostyrene,
(14) A monomer having an amino group, for example, N,N-diethylaminoethyl methacrylate, N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, polybutadiene urethane acrylate, N,N-dimethylaminopropyl acrylamide, N,N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N,N-diethylacrylamide,
Further another monomer may be copolymerized with the above monomer. As the polymer binder is also preferred an unsaturated bond-containing copolymer which is obtained by reacting a carboxyl group contained in the above vinyl copolymer molecule with for example, a compound having a (meth)acryloyl group and an epoxy group.
Examples of the compound having a (meth)acryloyl group and an epoxy group in the molecule include glycidyl acrylate, glycidyl methacrylate and an epoxy group-containing unsaturated compound disclosed in Japanese Patent O.P.I. Publication Nos. 11-27196.
The weight average molecular weight of the above copolymer is preferably 10,000 to 200,000 measured by gel permeation chromatography (GPC), but is not limited thereto.
The content of the polymer binder in the light sensitive layer is preferably from 10 to 90% by weight, more preferably from 15 to 70% by weight, and still preferably from 20 to 50% by weight in view of sensitivity.
The acid value of the polymer binder is preferably from 10 to 150, more preferably from 30 to 120, and still preferably from 50 to 90, in view of balance of polarity of the light sensitive layer, which can prevent coagulation of pigment used in the light sensitive layer coating liquid.
The thickness of the light sensitive layer is preferably 0.5 to 4 g/m2, and more preferably 1 to 3 g/m2.
 less than Oxygen Shielding Layer greater than
The presensitized planographic printing plate of the invention comprises a photopolymerizable light sensitive layer and an oxygen shielding layer containing polyvinyl alcohol and polyvinyl pyrrolidone provided on the photopolymerizable light sensitive layer. Polyvinyl alcohol has the effect of preventing oxygen from transmitting and polyvinyl pyrrolidone has the effect of increasing adhesion between the oxygen shielding layer and the light sensitive layer adjacent thereto.
Besides the above two polymers, the oxygen shielding layer may contain a water soluble polymer such as polysaccharide, polyethylene glycol, gelatin, glue, casein, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, hydroxyethyl starch, gum arabic, sucrose octacetate, ammonium alginate, sodium alginate, polyvinyl amine, polyethylene oxide, polystyrene sulfonic acid, polyacrylic acid, or a water soluble polyamide.
In the presensitized planographic printing plate of the invention, adhesive strength between the oxygen shielding layer and the light sensitive layer is preferably not less than 35 g/10 mm, more preferably not less than 50 g/10 mm, and still preferably not less than 75 g/10 mm.
The adhesive strength in the invention can be measured according to the following procedure.
When an adhesive tape with sufficient adhesive strength having a predetermined width is adhered onto the oxygen shielding layer, and then peeled at an angle of 90xc2x0 to the plane of the presensitized planographic printing plate, strength necessary to peel the oxygen shielding layer from the light sensitive layer is measured as the adhesive strength.
The oxygen shielding layer may further contains a surfactant or a matting agent. The oxygen shielding layer is formed by coating on the light sensitive layer a coating liquid in which the above oxygen shielding layer composition is dissolved in an appropriate coating solvent, and drying. The main solvent of the coating solvent is preferably water or an alcohol solvent such as methanol, ethanol, or isopropanol.
The thickness of the oxygen shielding layer is preferably 0.1 to 5.0 xcexcm, and more preferably 0.5 to 3.0 xcexcm.
The coating liquid for the photopolymerizable light sensitive layer in the invention preferably contains a polymerization inhibitor in addition to the compounds described above, in order to prevent undesired polymerization of the ethylenically unsaturated monomer during the manufacture or after storage of the presensitized planographic printing plate. Examples of the polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrrogallol, t-butylcatechol, benzoquinone, 4,4xe2x80x2-thiobis(3-methyl-6-t-butylphenol), 2,2xe2x80x2-methylenebis(4-methyl-6-t-butylphenol), N-nitrosophenylhydroxylamine cerous salt, and 2-t-butyl-6-(3-t-butyl-6-hydroxy-5-mrthylbenzyl)-4-methylphenyl acrylate.
The polymerization inhibitor content is preferably 0.01 to 5% by weight based on the total solid content of the photopolymerizable light sensitive layer composition. Further, in order to prevent polymerization induced by oxygen, a higher fatty acid such as behenic acid or a higher fatty acid derivative such as behenic amide may be added to the layer, or may be localized on the surface of the layer in the drying step after coating. The higher fatty acid or higher fatty acid derivative content is preferably 0.5 to 10% by weight based on the total solid content of the photopolymerizable light sensitive layer composition.
A colorant can be also used. As the colorant can be used known materials including commercially available materials. Examples of the colorant include those described in revised edition xe2x80x9cGanryo Binranxe2x80x9d, edited by Nippon Ganryo Gijutu Kyoukai (publishe by Seibunndou Sinkosha), or xe2x80x9cColor Index Binranxe2x80x9d.
Kinds of the pigment include black pigment, yellow pigment, red pigment, brown pigment, violet pigment, blue pigment, green pigment, fluorescent pigment, and metal powder pigment. Examples of the pigment include inorganic pigment (such as titanium dioxide, carbon black, graphite, zinc oxide, Prussian blue, cadmium sulfide, iron oxide, or chromate of lead, zinc, barium or calcium); and organic pigment (such as azo pigment, thioindigo pigment, anthraquinone pigment, anthanthrone pigment, triphenedioxazine pigment, vat dye pigment, phthalocyanine pigment or its derivative, or quinacridone pigment).
Among these pigment, pigment is preferably used which does not substantially have absorption in the absorption wavelength regions of a spectral sensitizing dye used according to a laser for exposure. The absorption of the pigment used is not more than 0.05, obtained from the reflection spectrum of the pigment measured employing an integrating sphere and employing light with the wavelength of the laser used. The pigment content is preferably 0.1 to 10% by weight, and more preferably 0.2 to 5% by weight, based on the total solid content of the photopolymerizable light sensitive layer composition.
When an argon laser (488 nm) or an SHG-YAG laser (532 nm) is used as a light source for exposure, violet pigment or blue pigment is preferably used in view of the above absorption wavelength relationship or image visibility after the exposure. Such pigment examples include Cobalt Blue, cerulean blue, alkali blue lake, Victria Blue lake, metal free phthalocyanine, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue, indigo, dioxane violet, isoviolanthrone violet, Indanthrone Blue, and Indanthrene BC. Among these, Phthalocyanine Blue and dioxane violet are preferred.
The above composition can contain a surfactant as a coatability improving agent, as long as performance of the invention is not jeopardized. The surfactant is preferably a fluorine-contained surfactant.
Further, in order to improve the light sensitive layer, the layer can contain an inorganic filler or a plasticizer such as dioctyl phthalate, dimethyl phthalate or tricresyl phosphate. The content of such a material is preferably not more than 10% by weight, based on the total solid content of the light sensitive layer composition.
(Coating)
The solvents used in the preparation of a coating liquid for the photopolymerizable light sensitive layer in the invention include an alcohol such as sec-butanol, isobutanol, n-hexanol, or benzyl alcohol; a polyhydric alcohol such as diethylene glycol, triethylene glycol, tetraethylene glycol, or 1,5-pentanediol; an ether such as propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, or tripropylene glycol monomethyl ether; a ketone or aldehyde such as diacetone alcohol, cyclohexanone, or methyl cyclohexanone; and an ester such as ethyl lactate, butyl lactate, diethyl oxalate, or methyl benzoate.
The prepared coating liquid for the photopolymerizable light sensitive layer is coated on a support according to a conventional method, and dried to obtain a presensitized planographic printing plate. Examples of the coating method include an air doctor coating method, a blade coating method, a wire bar coating method, a knife coating method, a dip coating method, a reverse roll coating method, a gravure coating method, a cast coating method, a curtain coating method, and an extrusion coating method.
A low drying temperature of the coated light sensitive layer cannot provide sufficient printing durability, while too a high drying temperature of the coated light sensitive layer results in marangoni and produces fog at non-image portions. The drying temperature is preferably from 60 to 160xc2x0 C., more preferably from 80 to 140xc2x0 C., and still more preferably from 90 to 120xc2x0 C.
(Manufacturing Method of Planographic Printing Plate)
The manufacturing method of the planographic printing plate of the invention comprises imagewise exposing the presensitized planographic printing plate described above, and developing the exposed plate with a developer described later.
The light sources for the imagewise exposure of the presensitized planographic printing plate in the invention include, for example, a laser, an emission diode, a xenon flush lamp, a halogen lamp, a carbon arc light, a metal halide lamp, a tungsten lamp, a high pressure mercury lamp, and a non-electrode light source.
When the presensitized planographic printing plate is imagewise exposed, a mask material having a negative image pattern made of a light shielding material is put on the plate to be in close contact with the plate, and exposure is carried out through the mask.
When an array light such as an emission diode array is used or exposure using a halogen lamp, a metal halide lamp or a tungsten lamp is controlled using an optical shutter material such as liquid crystal or PLZT, a digital exposure according to an image signal is possible and preferable. In this case, direct writing is possible without using any mask material.
When a laser is used for exposure, which can be condensed in the beam form, scanning exposure according to an image can be carried out, and direct writing is possible without using any mask material. When the laser is employed for imagewise exposure, a highly dissolved image can be obtained, since it is easy to condense its exposure spot in minute size.
As the laser, argon laser, He-Ne gas laser, YAG laser or semi-conductor laser is preferably used. A laser scanning method by means of a laser beam includes a method of scanning on an outer surface of a cylinder, a method of scanning on an inner surface of a cylinder and a method of scanning on a plane. In the method of scanning on an outer surface of a cylinder, laser beam exposure is conducted while a drum around which a recording material is wound is rotated, in which main scanning is represented by the rotation of the drum, while sub-scanning is represented by the movement of the laser beam. In the method of scanning on an inner surface of a cylinder, a recording material is fixed on the inner surface of a drum, a laser beam is emitted from the inside, and main scanning is carried out in the circumferential direction by rotating a part of or an entire part of an optical system, while sub-scanning is carried out in the axial direction by moving straight a part of or an entire part of the optical system in parallel with a shaft of the drum. In the method of scanning on a plane, main scanning by means of a laser beam is carried out through a combination of a polygon mirror, a galvano mirror and an Fxcex8 lens, and sub-scanning is carried out by moving a recording medium. The method of scanning on an outer surface of a cylinder and the method of scanning on an inner surface of a cylinder are more suitable for high density recording because they make it easy to enhance a precision of an optical system.
 less than Developer greater than
The presensitized planographic printing plate used in the invention is subjected to imagewise exposure to harden the exposed portions of the photopolymerizable light sensitive layer, and subjected to developing treatment employing an alkaline developer to remove unexposed portions of the layer, whereby an image is formed. The developer used in the developing treatment does not substantially contain an organic solvent.
The passage above, xe2x80x9cthe developer used in the developing treatment does not substantially contain an organic solventxe2x80x9d means that the developer does not contain an organic solvent at all, or the developer contains an organic solvent in an extremely slight amount. The above expression, xe2x80x9cthe developer contains an organic solvent in an extremely slight amountxe2x80x9d means that the developer contains an organic solvent in an amount of not more than 2% by weight. Examples of the organic solvent added to the developer in an amount of not more than 2% by weight include an alcohol such as ethanol, n-propanol, isopropanol, n-butanol, isobutanol, benzyl alcohol, ethylene glycol, propylene glycol, 2-phenoxyethanol, or propylene glycol methyl ether.
The developer used in the invention is an aqueous solution with a pH of from 11.5 to less than 12.5.
The alkali agents for obtain the above pH include inorganic alkali agents such as sodium silicate, potassium silicate, ammonium silicate, sodium secondary phosphate, potassium secondary phosphate, ammonium secondary phosphate, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, ammonium borate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, and lithium hydroxide. These alkali agents may be used singly or as an admixture of two or more thereof. Among them, a mixture of potassium silicate and potassium hydroxide is preferred, wherein the potassium silicate content of the mixture is preferably 0.5 to 4.0% by weight in terms of SiO2, and the potassium silicate is preferably added to the developer to give a pH of from 11.5 to less than 12.5.
The developer may contain organic alkali agents such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine. The organic alkali agents herein referred to are different from the organic solvent described above, and the organic alkali agent content of the developer is preferably not more than 2% by weight.
The developer may optionally contain a surfactant such as an anionic surfactant, a nonionic surfactant, a cationic surfactant or an amphoteric surfactant. In the invention, the developing time is preferably from 10 to 40 seconds.
Thus, the imagewise exposed presensitized planographic printing plate is subjected to the developing treatment described above to obtain a planographic printing plate with an image. The resulting planographic printing plate is mounted on a press, and then printing is carried out. Examples of ink used at the printing include soybean oil-based ink. Examples of the soybean oil-based ink include TK HIGH ECO-SOY1, TK HIGH ECO-OS, TK ECOTWIN, CK WINECO-SOY3, and CK WINECO-SOY each produced by Toyo Ink Manufacturing Co., Ltd., and New Champion Naturalith 100 produced by Dainippon Ink Kagaku Kogyo Co., Ltd.
The soybean oil-based ink used in the invention contains soybean oil of from 1 to 20% by weight.

Method of preparing planographic printing plate


A pitch control trimming system for a canard design aircraft has the ability to reposition the center of gravity of the aircraft along the longitudinal axis. The design permits trimming of the aircraft without external trim tabs and permits flaps to be used on a canard design aircraft without a nose down or negative pitching moment occurring. The aircraft has a substantial mass associated with the aircraft preferably the power plant including engine and propeller, which is movable substantially along the longitudinal axis of the aircraft, and includes an actuator to move the mass forward and aft on the longitudinal axis to reposition the center of gravity of the aircraft.

Aircraft using forward motion of the main wing or wings to achieve lift, must employ a horizontal stabilizer having pivotable control surfaces called "elevators" to control the nose-up or nose-down attitude of the aircraft, otherwise known as the pitching motion of the aircraft. This horizontal stabilizer can be mounted forward or aft of the main wing.
In most conventional aircraft today, the horizontal stabilizer is in the form of the tail assembly and is mounted aft of the main wing. In the canard design aircraft, the horizontal stabilizer in the form of a forward wing is mounted forward of the main wing. The forward wing is called a canard.
Canard design aircraft have been increasing in popularity in recent years as they are, in some respect, safer than conventional aircraft in that they are virtually stall and spin proof.
In conventional aircraft, it is essential that control of the aircraft by the aft tail mounted stabilizer be retained at all times, even though the main wing itself has ceased to provide lift and is in a stall condition. This control can only be achieved by ensuring that the main wing always stalls before the tail mounted stabilizer. In the case of a canard design aircraft, the opposite holds true, and the canard must stall and lose lift before the main wing. In both cases the effect is the same; in a stall, the nose of the aircraft pitches down, restoring lost air speed and regaining lift for the main wing. However, there is a fundamental difference between these two methods of stall recovery. In the case of the aft tail mounted stabilizer, the nose drops because the main wing has stalled. With a canard design aircraft, the canard stalls, causing the nose to drop, but the main wing never stalls. Therefore the canard design aircraft is considered to be far safer because stalls and resulting spins are virtually impossible to initiate. In addition, aside from the safety aspect, canard design aircraft provide the designer with a cleaner more aerodynamic shape to work with for better performance and economy due to the absence of a tail assembly.
One particular type of canard design aircraft has both a canard and an aft tail mounted stabilizer in an attempt to obtain the benefits of both conventional design and canard design aircraft (referred to as a three surface aircraft). The present invention relates primarily to a two surface canard design aircraft, although may be applied to the three surface aircraft.
The foregoing description of the capabilities of canard design aircraft and conventional aircraft apply to conditions during normal flight. In takeoff and landing situations, canard design aircraft are generally considered to have at least one disadvantage when compared to conventional aircraft. It is desirable that speeds for takeoff and landing be as low as possible to allow aircraft to use shorter runways for landing. In order to retain good high speed characteristics and still be able to obtain sufficient lift at low speeds for takeoff and landings, flaps were developed for conventional aircraft. Flaps are pivotally mounted surfaces attached to and forming part of the main wing at the trailing edge. Their purpose is to increase lift at low speeds for take off and landing. When the flaps are lowered, the additional effect is that the center of lift of the main wing moves aft causing a nose down pitching moment. With conventional aircraft, an aft tail mounted stabilizer is designed to retain sufficient authority to control the aircraft when the main wing is stalled, and thus is able to overcome nose down pitching which results from lowering the flaps. In canard design aircraft, the canard is designed to stall before the main wing, with the result that the canard generates lesser lift and is incapable of preventing nose down pitching of the aircraft when the center of lift moves aft with deployment of the flaps. Therefore it is generally accepted that a canard designed aircraft cannot be fitted with flaps. Thus take off and landing speeds for canard design aircraft are higher than most conventional aircraft fitted with flaps.

Pitch control trimming system for canard design aircraft


Inflatable packers are provided with one or more components to improve longevity and/or functionality. One or more of the packer components utilizes reinforced materials incorporated in a manner that enables the improved longevity and/or functionality.

1. Field of the Invention
The present invention generally pertains to downhole oilfield equipment, and more particularly to improved inflatable packers.
2. Description of the Related Art
It is known that there are mainly two kinds of inflatable packers, namely, slat type and weave or cable type. The slat type inflatable packers usually have a high pressure rating and a large expansion ratio. However, in general the slat type inflatable packers are not recommended for open hole applications, especially with a high expansion, because the slats do not have enough flexibility to conform to open hole profiles with potential irregularities. As a result, the inner tube or bladder of the slat type packer may be extruded through the openings between the slats. On the other hand, weave type structures will equip the packer element with enough compliance to conform to the well bore geometry, but they have a low pressure rating and a small expansion ratio. In addition to the structural design of an inflatable packer, the mechanical performance and reliability of inflatable packers depend in part upon the mechanical properties of the materials used.
As will become apparent from the following description and discussion, the present invention overcomes the deficiencies of the previous packers and constitutes an improved packer. In one aspect of the present invention, this is accomplished by the development of hybrid structures for through-tubing multiple-settable high-expandable inflatable packer elements which utilize unique features of slat type and weave type structures to achieve a much improved performance and compliance of the packer elements in open hole environments as well as cased hole environments. In another aspect of the present invention, improvement in the field of packers may be achieved by development of inflatable packer elements with high expansion ratios, high pressure ratings, high extrusion resistance, and good shape recovery after deflation by the use of materials from the fields of fiber reinforced composites and nanotechnology, including, for example, various fiber reinforced elastomers, polymers, and/or metals, and nanofiber, nanotubes, nanoparticle modified elastomers, polymers and/or metals. Details concerning these types of materials can be found, for example, in WO0106087, U.S. Pat. No. 6,102,120, and A. B. Dalton et al., Super-Tough Carbon-Nanotube Fibres, Nature, Vol. 423, 12 Jun. 2003, p. 703 ("Dalton"). The authors in Dalton outline their process of synthesizing single-walled nanotube (SWNT) fibers into 100 meter length bundles. These fibers can then be formed into a mesh or woven into other fibers as a rubber reinforcement. Nanotechnology materials exhibit superior properties over traditional materials, including greater strength, flexibility, elongation and compliance to irregular surfaces such as those found in open hole applications.


A method for provisioning a mobile device with a secret to be used as a basis for generating One-Time passwords includes receiving a first request using a first communications method. The first request includes a mobile device identifier. The method also includes sending a credential message using a second communications method. The credential message includes an authentication credential. The method also includes receiving a second request using a third communications method different from the second communications method. The second request includes information based upon the authentication credential sent by the provisioning service. The method also includes sending the secret if the authentication credential in the credential message corresponds to the information based upon the authentication credential in the second request.

A common step in deciding whether to grant a request for access to data or services in a network is to authenticate the requesting user. Authentication is the process of establishing or confirming one or more characteristics associated with a user or a request. For example, authentication may include confirming a user's identify or confirming that a request is generated by a particular device. In computer networks, authentication commonly involves the use of passwords. Knowledge of a password is assumed to warrant that the user is authentic. Typically, a user is initially assigned or selects a password, and upon each subsequent use the user must provide the password. A password is considered a first authentication factor because it is something the user knows that presumptively no one else knows.
Since passwords are vulnerable to hackers, security can be improved by adding a second authentication factor. Second authentication factors generally include something the user has (as opposed to something the user knows). Second authentication factors preferably include credentials that can be generated systematically and verified efficiently. Common sources of second authentication factors include smart cards, tokens, and other similar security devices that may be referred to generally as security tokens.
A security token can include one or more secrets that may be shared with an authentication service. The token can use the secret as the basis for generating credentials such as One-Time Passwords (OTPs). An OTP can be a number or alphanumeric string that is generated once and is not reused. The token can generate an OTP and the user can send the OTP to an authentication service. The authentication service generates an OTP using its copy of the secret. The user is authenticated if the OTP determined by the authentication service matches the OTP provided by the user.
Secrets can be stored in numerous different types of devices and used as the basis for generating OTPs. As examples, secrets may be stored in personal computers, notebook computers, cell phones, and other devices. One challenge faced by authentication services is how to provide secrets to these types of devices in a secure and user friendly manner. Users prefer provisioning methods that are user friendly, while authentication services require provisioning methods that are secure. Unlike security tokens, that are typically provisioned with a secret during manufacture, these devices are usually not provisioned with a secret until after purchase by a user. There is a tradeoff between security and usability when using conventional methods of provisioning devices. Secure methods are generally not user friendly, and user friendly methods are generally not secure. This is because secure methods typically require multiple levels of user input for authentication, while user friendly methods require little or no user input for authentication. Authentication to acquire a secret generally requires confirmation that the request is associated with a particular device. For example, a mobile device such as a cell phone may be required to provide information that confirms it generated a request for a secret.
Thus, there is a general need in the art for improved methods and apparatus for provisioning devices with secrets.

Methods and apparatus for provisioning devices with secrets


Peptide nucleic acids and analogues of peptide nucleic acids are used to form duplex, triplex, and other structures with nucleic acids and to modify nucleic acids. The peptide nucleic acids and analogues thereof also are used to modulate protein activity through, for example, transcription arrest, transcription initiation, and site specific cleavage of nucleic acids.

This invention is directed to compounds that form triple-stranded structures with single-stranded and double-stranded nucleic acids. It is further directed to the use of such compounds to cause strand displacement in double-stranded nucleic acids. The invention further is directed to processes for modifying double-stranded nucleic acid utilizing such strand displacement. Such processes for modifying double-stranded nucleic acids include cleavage of the nucleic acid strand or strands. In particular, such cleavage includes sequence specific cleavage of double-stranded nucleic acids using a nuclease which normally is nonsequence specific. Such process also include transcription inhibition or arrest as well as transcription initiation. The processes of the invention are effected, in particular, with compounds that include naturally-occurring nucleobases or other nucleobase-binding moieties covalently bound to a polyamide backbone.
The function of a gene starts by transcription of its information to a messenger RNA (mRNA) which, by interaction with the ribosomal complex, directs the synthesis of a protein coded for by the mRNA sequence. The synthetic process is known as translation. Translation requires the presence of various co-factors and building blocks, the amino acids, and their transfer RNAs (tRNA), all of which are present in normal cells.
Transcription initiation requires specific recognition of a promoter DNA sequence by the RNA-synthesizing enzyme, RNA polymerase. In many cases in prokaryotic cells, and probably in all cases in eukaryotic cells, this recognition is preceded by sequence-specific binding of a protein transcription factor to the promoter. Other proteins which bind to the promoter, but whose binding prohibits action of RNA polymerase, are known as repressors. Thus, gene activation typically is regulated positively by transcription factors and negatively by repressors.
Most conventional drugs function by interaction with and modulation of one or more targeted endogenous proteins, e.g., enzymes. Typical daily doses of drugs are from 10xe2x88x925-10xe2x88x921 millimoles per kilogram of body weight or 10xe2x88x923-10 millimoles for a 100 kilogram person. If this modulation instead could be effected by interaction with and inactivation of mRNA, a dramatic reduction in the necessary amount of drug necessary likely could be achieved, along with a corresponding reduction in side effects. Further reductions could be effected if such interaction could be rendered site-specific. Given that a functioning gene continually produces mRNA, it would thus be even more advantageous if gene transcription could be arrested in its entirety.
Synthetic reagents that bind sequence selectively to single-stranded and especially to double-stranded nucleic acids are of great interest in molecular biology and medicinal/chemistry, since such reagents may provide the tools for developing gene-targeted drugs and other sequence-specific gene modulators. Until now oligonucleotides and their close analogues have presented the best candidates for such reagents.
Oligodeoxyribonucleotides as long as 100 base pairs (bp) are routinely synthesized by solid phase methods using commercially available, fully automatic synthesis machines. Oligoribonucleotides, however, are much less stable than oligodeoxyribonucleotides, a fact which has contributed to the more prevalent use of oligodeoxyribonucleotides in medical and biological research directed to, for example, gene therapy and the regulation of transcription and translation. Synthetic oligodeoxynucleotides are being investigated for used as antisense probes to block and eventually breakdown mRNA.
It also may be possible to modulate the genome of an animal by, for example, triple helix formation using oligonucleotides or other DNA recognizing agents. However, there are a number of drawbacks associated with oligonucleotide triple helix formation. For example, triple helix formation generally has only been obtained using homopurine sequences and requires unphysiologically high ionic strength and low pH. Whether used as antisense reagents or a triplexing structures, unmodified oligonucleotides are unpractical because they have short in vivo half-lives. To circumvent this, oligonucleotide analogues have been used.
These areas for concern have resulted in an extensive search for improvements and alternatives. For example, the problems arising in connection with double-stranded DNA (dsDNA) recognition through triple helix formation have been diminished by a clever xe2x80x9cswitch backxe2x80x9d chemical linking whereby a sequence of polypurine on one strand is recognized, and by xe2x80x9cswitching backxe2x80x9d, a homopurine sequence on the other strand can be recognized. See, e.g., McCurdy, Moulds, and Froehler, Nucleosides, in press. Also, helix formation has been obtained by using artificial bases, thereby improving binding conditions with regard to ionic strength and pH.
In order to improve half-life as well as membrane penetration, a large number of variations in polynucleotide backbones has been undertaken. These variations include the use of methylphosphonates, monothiophosphates, dithiophosphates, phosphoramidates, phosphate esters, bridged phosphoramidates, bridged phosphorothioates, bridged methylenephosphonates, dephospho internucleotide analogs with siloxane bridges, carbonate bridges, carboxymethyl ester bridges, acetamide bridges, carbamate bridges, thioether, sulfoxy, sulfono bridges, various xe2x80x9cplasticxe2x80x9d DNAs, xcex1-anomeric bridges, and borane derivatives. The great majority of these backbone modifications have decreased the stability of hybrids formed between a modified oligonucleotide and its complementary native oligonucleotide, as assayed by measuring Tm values. Consequently, it is generally believed in the art that backbone modifications destabilize such hybrids, i.e., result in lower Tm values, and should be kept to a minimum.
The discovery of sequence specific endonucleases (restriction enzymes) was an essential step in the development of biotechnology, enabling DNA to be cut at precisely specified locations containing specific base sequences. However, although the range of restriction enzymes now known is extensive, there is still a need to obtain greater flexibility in the ability to recognize particular sequences in double-stranded nucleic acids and to cleave the nucleic acid specifically at or about the recognized sequence.
Most restriction enzymes recognize quartet or sextet DNA sequences and only a very few require octets for recognition. However, restriction enzymes have been identified and isolated only for a small subset of all possible sequences within these constraints. A need exists, especially in connection with the study of large genomic DNA molecules, in general, and with the human genome project, in particular, to recognize and specifically cleave DNA molecules at more rarely occurring sites, e.g., sites defined by about fifteen base pairs.
Efforts have therefore been made to create artificial xe2x80x9crestriction enzymesxe2x80x9dor to modify the procedures for using existing restriction enzymes for this purpose. Methods investigated include the development of oligonucleotides capable of binding sequence specifically via triple helix formation to double-stranded DNA tagged with chemical groups (e.g., photochemical groups) able to cleave DNA or with non-specific DNA cleaving enzymes and other such modifications consistent with an xe2x80x9cAchilles heelxe2x80x9d general strategy. Such methods are described by: Francois, J. C., et al. PNAS 86,9702-9706 (1989); Perrouault, L., et al. Nature 344,358-360 (1990); Strobel, S. A. and Dervan P. B. Science 249,73-75 (1990); Pei, D., Corey D. R. and Schultz P. G. PNAS 87,9858 (1990); Beal, P. A. and Dervan P. B., Science 251,1360 (1991); Hanvey, J. C., Shimizu M. and Wells R. D. NAR 18,157-161 (1990); Koob, H. and Szybalski W. Science 250,271 (1990); Strobel, S. A. and Dervan P. B. Nature #50,172 (1991); and Ferrin, L. J. and Camerini-Otero R. D. Science 254,1494-1497 (1991).
In Patent Cooperation Treaty Applications No. PCT/EP92/01220, and PCT/EP92/01219, both filed on 22nd May 1992, we described certain nucleic acid analogue compounds that have a strong sequence specific DNA binding ability. Examples of such compounds were also disclosed by us in Science 1921, 254 1497-1500. We have shown that a nucleic acid analogue of this type containing 10 bases hybridized to a non-terminal region of a double-stranded DNA and rendered the strand of DNA which was non-complementary to the nucleic acid analogue susceptible to degradation by S1 nuclease. No increased cleavage of the DNA strand complementary to the nucleic acid analogue was seen, so no cleavage of double-stranded DNA was obtained.
It is an object of the invention to provide compounds that bind DNA and RNA strands.
It is a further object of the invention to provide triple x structures between DNA or RNA strands and these compounds.
It is yet another object to provide compounds other than RNA that can bind on strand of a double-stranded polynucleotide, thereby displacing the other strand.
It is still another object to provide therapeutic, diagnostic, and prophylactic methods that employ such compounds.
In the cell, DNA exists as a double stranded structure. During certain cellular events, as for instance transcription or during cell division, portions of the double stranded DNA are transiently denatured to single strand. Further DNA can be isolated outside of a cell and can be purposefully denatured to single stranded DNA. RNA generally exist as a single stranded structure; however, in a local area of secondary structure a RNA, as for instance the stem of a stem loop structure, the RNA can exist as a double stranded structure.
We have found that certain compounds that have nucleobases attached to an aminoethylglycine backbone and other like backbones including polyamides, polythioamides, polysulfinamides and polysulfonamides, which compounds we call peptide nucleic acids or PNA, surprisingly bind strongly and sequence selectively to both RNA and DNA.
We have surprisingly found that these PNA compounds recognize and bind sequence-selectively and strand-selectively to double-stranded DNA (dsDNA). We have found that the binding to double-stranded DNA is accomplished via strand displacement, in which the PNA binds via Watson-Crick binding to its complementary strand and extrudes the other strand in a virtually single-stranded conformation. We have also surprisingly found that these PNA compounds recognize and bind sequence-selectively to single-stranded DNA (ssDNA) and to RNA.
The recognition of PNA to RNA, ssDNA or dsDNA can take place in sequences at least 5 bases long. A more preferred recognition sequence length is 5-60 base pairs long. Sequences between 10 and 20 bases are of particular interest since this is the range within which unique DNA sequences of prokaryotes and eukaryotes are found. Sequences of 17-18 bases are of special interest since this is the length of unique sequences in the human genome.
We have further surprisingly found that the PNA compounds are able to form triple helices with dsDNA. We have found that PNA compounds are able to form triple helices with RNA and ssDNA. The resulting triplexes, e.g., (PNA)2/DNA or (PNA)2/RNA, surprisingly have very high thermal stability. It has been found that the PNA binds with a DNA or RNA in either orientation, i.e., the antiparallel orientation where the amino-terminal of the PNA faces the 3xe2x80x2 end of the nucleic acid or the parallel orientation where the amino-terminal of the PNA faces the 5xe2x80x2 end of the nucleic acid. PNAs are able to form triple helices wherein a first PNA strand binds with RNA or ssDNA and a second PNA strand binds with the resulting double helix or with the first PNA strand.
We further have found that the PNA compounds are able to form triple helices wherein a first PNA strand binds with the ssDNA or RNA or to one of the strands of dsDNA and in doing so displaces the other strand, and a second PNA strand then binds with the resulting double helix. While we do not wish to be bound by theory, it is further believed that other triple helices might be formed wherein a single PNA strand binds to two single stranded nucleic acids strands. In binding with nucleic acids both Watson-Crick and Hoogsteen bind is utilized. It is further believed that PNA might also bind via reverse Hoogsteen binding.
We have further surprisingly found that the PNA compounds form double helices with RNA and ssDNA. Such double helices are hetero duplex structures between the PNA and the respective nucleic acid. Such double helices are preferably helices formed when the PNA strand includes a mixture of both pyrimidine and purines nucleobases.
For therapeutic use of PNA compounds the targets of the PNA compounds would generally be double stranded DNA and RNA. For diagnostic use, investigations methods and reagents where DNA is isolated outside of a cell, the DNA can be denatured to single stranded DNA and use of the PNA compound would be targeted to such single stranded DNA as well as RNA.
PNA compounds useful to effect binding to RNA, ssDNA and dsDNA and to form duplex and triplex complexes are in one sense polymeric strands formed from a polyamide, polythioamide, polysulfinamide or polysulfonamide backbone with a plurality of ligands located at spaced locations along the backbone. At least some of the ligands are capable of hydrogen bonding with other ligands either on the compounds or nucleic acid ligands.
More preferred PNA compounds according to the invention have the formula:
wherein:
n is at least 2,
each of L1-Ln is independently selected from the group consisting of hydrogen, hydroxy, (C1-C4)alkanoyl, naturally occurring nucleobases, non-naturally occurring nucleobases, aromatic moieties, DNA intercalators, nucleobase-binding groups, heterocyclic moieties, and reporter ligands;
each of C1-Cn is (CR6R7), where R6 is hydrogen and R7 is selected from the group consisting of the side chains of naturally occurring alpha amino acids, or R6 and R7 are independently selected from the group consisting of hydrogen, (C2-C6)alkyl, aryl, aralkyl, heteroaryl, hydroxy, (C1-C6)alkoxy, (C1-C6)alkylthio, NR3R4 and SR5, where R6 and R7 are as defined above, and R5 is hydrogen, (C1-C6)alkyl, hydroxy-, alkoxy-, or alkylthio-substituted (C1-C6)alkyl, or R6 and R7 taken together complete an alicyclic or heterocyclic system;
each of D1-Dn is (CR6R7) where R5 and R7 are as defined above;
each of y and z is zero or an integer from 1 to 10, the
sum y+z being greater than 2 but not more than 10;
each of G1-Gn is xe2x80x94NR3COxe2x80x94, xe2x80x94NR3CSxe2x80x94, xe2x80x94NR3SOxe2x80x94 or xe2x80x94NR3SO2xe2x80x94, in either orientation, where R3 is as defined above;
each of A1-An and B1-Bn are selected such that:
(a) A is a group of formula (IIa), (IIb), (IIc) or
(IId), and B is N or R3N4; or
(b) A is a group of formula (IId) and B is CH;
where:
X is O, S, Se, NR3, CH2 or C(CH3)2;
Y is a single bond, O, S or NR4;
each of p and q is zero or an integer from 1 to 5, the sum p+q being not more than 10;
each of r and s is zero or an integer from 1 to 5, the sum r+s being not more than 10;
each R1 and R2 is independently selected from the group consisting of hydrogen, (C1-C4)alkyl which may be hydroxy- or alkoxy- or alkylthio-substituted, hydroxy, alkoxy, alkylthio, amino and halogen; and
each R3 and R4 is independently selected from the group consisting of hydrogen, (C1-C6)alkyl, hydroxy- or alkoxy- or alkylthio-substituted (C1-C6)alkyl, hydroxy, alkoxy, alkylthio and amino;
Q is xe2x80x94CO2H, xe2x80x94CONRxe2x80x2Rxe2x80x3, xe2x80x94SO3H or xe2x80x94SO2NRxe2x80x2Rxe2x80x3 or an activated derivative of xe2x80x94CO2H or xe2x80x94SO3H; and
I is xe2x80x94NHRxe2x80x2xe2x80x3Rxe2x80x3xe2x80x3 or xe2x80x94NRxe2x80x2xe2x80x3C(O)RIxe2x80x3xe2x80x3, where Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3 and Rxe2x80x3xe2x80x3 are independently selected from the group consisting of hydrogen, alkyl, amino protecting groups, reporter ligands, intercalators, chelators, peptides, proteins, carbohydrates, lipids, steroids, nucleosides, nucleotides, nucleotide diphosphates, nucleotide triphosphates, oligonucleotides, oligonucleosides and soluble and non-soluble polymers.
In the above structures wherein Rxe2x80x2, Rxe2x80x3, Rxe2x80x2xe2x80x3and Rxe2x80x3xe2x80x3 are oligonucleotides or oligonucleosides, such structures can be considered chimeric structures between PNA compounds and the oligonucleotide or oligonucleoside.
Preferred PNA-containing compounds useful to effect binding to RNA, ssDNA and dsDNA and to form triplexing structure are compounds of the formula III, IV or V:
where in:
each L independently selected from the group consisting of hydrogen, phenyl, heterocyclic moieties, naturally occurring nucleobases, and non-naturally occurring nucleobases;
each R7xe2x80x2 is independently selected from the group consisting of hydrogen and the side chains of naturally occurring alpha amino acids;
n is an integer greater than 1,
each k, l, and m is, independently, zero or an integer from 1 to 5;
each p is zero or 1;
Rb is OH, NH2 or xe2x80x94NHLysNH2; and
Ri is H or COCH3.
The improved binding of the PNA compounds of the invention with single-stranded RNA and DNA renders them useful as antisense agents. In addition, the binding to double-stranded DNA renders these compounds useful for gene inhibition via various mechanisms. Further, the binding to double-stranded DNA renders these compounds useful as gene activators to initiate transcription.
In one embodiment, the present invention provides methods for inhibiting the expression of particular genes in the cells of an organism, comprising administering to said organism a reagent as defined above which binds specifically to sequences of said genes.
In a further embodiment, the invention provides methods for inhibiting transcription and/or replication of particular genes or for modifying double-stranded DNA as, for instance, by inducing degradation of particular regions of double-stranded DNA in cells of an organism comprising administering to said organism a reagent an defined above.
In a still further embodiment, the invention provides methods for killing cells or virus by contacting said cells or virus with a reagent as defined above which binds specifically to sequences of the genome of said cells or virus.
A novel strategy for sequence-selective cleavage of double-stranded DNA is described. For cases were two closely positioned homo-pyrimidin stretches (of 7-10 bas s and preferably on opposite strands) can be identified, this can be done by synthesizing pairs of PNAs complementary to two parts of this DNA sequence and separated by several base pairs. These PNA molecules are then reacted with the dsDNA and the resulting complex is allowed to react with an endonuclease.
In practicing certain embodiments of the invention, the PNA compounds are able to recognize duplex DNA by displacing one strand, thereby presumably generating a hetero duplex with the other one. Such recognition can take place with dsDNA sequences 5-60 base pairs long. Sequences between 10 and 20 bases are of interest since this is the range within which unique DNA sequences of prokaryotes and eukaryotes are found. Reagents which recognize 17-18 bases are of particular interest since this is the length of unique sequences in the human genome.
The PNA compounds are able to form triple helices with dsDNA, ssDNA or RNA and double helices with RNA or ssDNA. In one embodiment of the invention, the PNA compounds form triple helices wherein a first PNA strand binds with a nucleic acid strand forming a hetero duplex and a second PNA strand then binds with the resulting hetero duplex. In other embodiments of the invention, a PNA compound or a PNA chimera compound forms triple helices wherein a single PNA strand or PNA chimera strand binds with two nucleic acid strands, with a nucleic acid strand and a PNA chimera strand or with two chimera PNA strands.
The invention further provides methods for inhibiting the action of restriction enzymes at restriction sites in nucleic acids. Such methods comprise contacting a nucleic acid with a reagent as defined above under conditions effective to bind such reagent to the nucleic acid proximal to a restriction site.
The invention further provides methods of sequencing DNA by binding the DNA with a reagent as defined above at a site proximal to a restriction site, cleaving the DNA with a restriction enzyme, and identifying the cleaved products.
The invention further provides methods for initiating transcription in cells or organisms comprising administering to the organism a reagent as defined above which initiates transcription of a gene in such cells or organisms.
The invention further provides methods for modulating binding of RNA polymerase to dsDNA by binding the dsDNA with a reagent as defined above that binds with the DNA and then exposing the complex formed thereby to a RNA polymerase.
The invention further provides methods for initiating transcription of a gene by binding the gene with a reagent as defined above that interacts with the gene to melt the double- stranded DNA of the gene and to form a transcription elongation loop.
The invention further provides methods for binding RNA polymerase to dsDNA by contacting the dsDNA with a reagent as defined above that is capable of interacting with the DNA and then exposing the complex formed thereby to a RNA polymerase. More particularly, the interaction is via binding to said dsDNA.
The invention further provides a hybrid complex for modulating transcription wherein the complex comprises dsDNA and a reagent as defined above that binds with the dsDNA, and a RNA transferase.
The invention further provides a synthetic transcription factor comprising a dsDNA and a reagent as defined above that is capable of interaction with the dsDNA. More particularly, the interaction is via binding to said dsDNA.
The invention further provides specific gene activators comprising first and second strands, as defined above, that have specific sequences that bind to selected DNA regions of the gene.
The invention further provides chimeric structures comprising PNAs and DNA or RNA. Such chimeric structures will be used in place of or in addition to a normal PNA strand to effect duplexing, triplexing, nucleic acid binding or protein binding.

Higher order structure and binding of peptide nucleic acids


Novel strains of yeast and methods for improved ethanol production utilizing the yeast strains are disclosed. In particular, the novel yeast strains Saccharomyces cerevisae YE1358 and YE1615 provide for increased fermentation temperature tolerance, as well as tolerance to increased levels of glucose and ethanol, and thereby provide increased ethanol production as compared to ethanol industry standard strains of Saccharomyces cerevisae. The novel yeast strains also generate decreased residual glucose than the ethanol industry standard yeasts.

Increasing demand for renewable energy sources, including ethanol production, has created commercial demand for the generation of ethanol fuel sources. The process to obtain ethanol generally involves the transformation of plant matter, usually sugars, into a distilled pure ethanol product, through either a wet or dry milling processes. Wet milling methods include various soaking steps to soften grains and separate the soluble starches (from the germ, fiber and protein components) for further treatment before alcohol production methods. Dry milling methods are most commonly used for ethanol production, involving the grinding of whole plant matter into meal (without fractionating or separating the various component parts of the starch, as is done with wet milling) and forming a slurry. Subsequently, the starch components of the slurry are converted into sugars, through the use of high temperatures and enzymes, to effectuate the conversion. Upon generation of a sugar source from the plant matter, the conversion to ethanol requires the use of an ethanol-producing microorganism, such as yeasts.
The ethanol-producing microorganism utilized in the fermentation process most often involves yeast added to the mixture to convert sugars to alcohol, which is then distilled, purified, and denatured to generate the ethanol end product. (U.S. Pat. No. 4,316,956). The majority of fuel ethanol is produced by a few distinct strains of yeast. These commercial yeast strains require a high tolerance to both sugars and ethanol in order to yield sufficient ethanol concentrations.
The various processes and method steps for producing ethanol are well known by those skilled in the art and are described in various references. Ethanol production includes at least the following processes or method steps, or combinations of the same: milling, liquefaction, saccharification, fermentation and distillation. (See e.g., U.S. Pat. Nos. 5,231,017 and 4,316,956, WO 94/08027, WO 92/20777). One skilled in the art can ascertain the process for production of ethanol, including for example, whether steps are carried out simultaneously.
Numerous improvements to the ethanol production process, including both the wet and dry milling processes, have been achieved by those skilled in the art. For example: genetic modifications to ethanol-producing microorganisms (see e.g. Shi et al, J. Ind. Microbiol. Biotechnol., 36:139-47 (2009)); improving thermotolerance (see e.g. U.S. Publication No. 2005/0069998); and improved enzymatic processes and enzymes (see e.g. WO 2007/145912).
Despite improvements to methods of ethanol production, the process is complex and the significant commercial interest in ethanol creates a continued need to further improve the production process, including the ethanol-producing microorganisms utilized therein. Accordingly, improvements upon commercial yeasts strains are further necessary to enhance industrial production of ethanol. Ethanol-producing microorganisms, such as yeast, capable of improving ethanol production, as measured by the ability to produce increased ethanol yields, provide both significant economic and industrial advantages. Even slight improvements in ethanol production provide significant commercial benefits. For example, it is estimated that an increased ethanol yield of 1% (estimated as an additional 0.0271 gallons/bushel) generates a commercial value of $100 million dollars annually for the ethanol industry (estimated as $2.00/gallon ethanol).
Accordingly, enhanced methods for ethanol production involving novel, isolated ethanol-producing microorganisms, such as yeast strains, will enhance production and profitability of industrial ethanol production.

Yeast strains for improved ethanol production