Patents by Inventor Paul Stahlhofen

Paul Stahlhofen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5225310
    Abstract: The invention relates to a photosensitive mixture which essentially contains an ester or an amide of a 1,2-naphthoquinonediazide sulfonic or carboxylic acid as the photosensitive compound, a phenolic resin which is soluble in aqueous-alkaline solutions and insoluble in water as the binder, and an additional speed enhancer, which corresponds to the general formula ##STR1## where X denotes a single bond, CH.sub.2, SO.sub.2, S, CO, C(CH.sub.3).sub.2, CHCC1.sub.3 or ##STR2## Biphenyldiol-(4,4'), bis-(4-hydroxyphenyl)-ketone, 2,2-bis-(4-hydroxy-phenyl)-propane or bis-(4-hydroxyphenyl)-sulfone are described as suitable compounds. The mixture is employed as photosensitive layers in recording materials suitable for the production of printing forms.The invention provides for an increased photospeed, without any disadvantages occurring in respect of the copying or printing behavior.
    Type: Grant
    Filed: June 2, 1988
    Date of Patent: July 6, 1993
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Otfried Gaschler
  • Patent number: 5149613
    Abstract: A process for producing images on a photosensitive material comprising a support and a normally positive-working photosensitive layer is disclosed. The photosensitive layer is activated by exposure to ultraviolet light and imaging is effected by means of thermal energy. A mixture comprising a compound containing at least one --C--O--C-- or --C--O--Si-- bond which can be split by acid and a compound forming a strong acid upon exposure is employed in the photosensitive layer and imaging in the activated region is carried out by means of laser or electron beams or with the aid of a thermal printer. The process of the invention is suitable for use with digital techniques and makes it possible, in a simple manner, to employ a combined procedure for imaging the photosensitive material (photocomposing).
    Type: Grant
    Filed: November 22, 1989
    Date of Patent: September 22, 1992
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Dieter Mohr
  • Patent number: 5143815
    Abstract: A light-sensitive mixture is disclosed which contains a 1,2-naphthoquinone-2-diazide-sulfonic acid ester and a binder. A reproduction material produced with this mixture is also disclosed. The naphthoquinone-diazide-sulfonic acid ester is a compound of the general formula I ##STR1## in which D is a 1,2-naphthoquinone-2-diazide-4-sulfonyl or 1,2-naphthoquinone-2-diazide-5-sulfonyl radical,R.sub.1 is hydrogen or an -OD group, andR.sub.2 is alkyl or substituted or unsubstituted aryl, preferably alkyl having 1 to 10 carbon atoms or substituted or unsubstituted phenyl.The light-sensitive mixture is highly photosensitive, has good overdevelopment resistance and is resistant to fountain solutions and petroleum hydrocarbons.
    Type: Grant
    Filed: August 24, 1988
    Date of Patent: September 1, 1992
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 5084372
    Abstract: A light-sensitive composition for the preparation of printing plates is described, which contains a water-insoluble binder which is soluble in aqueous-alkaline solutions; a light-sensitive component which is an o- or p-quinone diazide, a diazonium salt polycondensation product or a mixture ofa) a compound which eliminates an acid on exposure to light andb) a compound having at least one C--O--C group which can be split by acid; and a thermo-crosslinking compound which is a cyclical acid amide of the general formula: ##STR1## wherein R denotes a hydrogen atom or an alkyl group. The printing plates can be baked at lower temperatures than plates without a crosslinking agent, but nevertheless have a long shelf life.
    Type: Grant
    Filed: January 23, 1991
    Date of Patent: January 28, 1992
    Assignee: Hoechst Celanese Corporation
    Inventors: Shane Hsieh, Paul Stahlhofen
  • Patent number: 5070001
    Abstract: A light-sensitive mixture is disclosed which containsa) a compound having at least one acid-cleavable C-O-C bond,b) a compound which forms a strong acid on exposure andc) a binder which is insoluble in water but soluble in aqueous alkaline solutions andd) a compound having at least one polymerizable or light-crosslinkable olefinic double bond. The mixture is suitable for producing printing plates, relief copies and photoresists, becoming soluble in alkaline developers on short exposure and insoluble on prolonged exposure as a result of crosslinking.
    Type: Grant
    Filed: October 23, 1987
    Date of Patent: December 3, 1991
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 5017462
    Abstract: The invention describes a photosensitive composition, a copying material prepared from this composition and the production of negative relief copies, in which a photosensitive material containing a photosensitive compound comprising an ester or an amide of a 1,2-quinonediazide sulfonic acid or carboxylic acid, a binder and an s-triazine of the general formula I ##STR1## wherein R.sub.1 may be an alkyl or aryl group andR.sub.2 may be an alkoxy or aryloxy group or an amino group which has one or two alkyl, cycloalkyl or aryl substitutents,is exposed imagewise under a negative original, thereafter heated and, after cooling, exposed without an original or, optionally, under a positive original and then developed by means of an aqueous-alkaline developer.
    Type: Grant
    Filed: December 4, 1989
    Date of Patent: May 21, 1991
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 5008175
    Abstract: A light-sensitive composition for the preparation of printing plates is described, which contains a water-insoluble binder which is soluble in aqueous-alkaline solutions; a light-sensitive component which is an o- or p- quinone diazide, a diazonium salt polycondensation product or a mixture of(a) a compound which eliminates an acid on exposure to light and(b) a compound having at least one C--O--C group which can be split by acid; and a thermo-crosslinking compound which is a cyclical acid amide of the general formula: ##STR1## wherein R denotes a hydrogen atom or an alkyl group. The printing plates can be baked at lower temperatures than plates without a crosslinking agent, but nevertheless have a long shelf life.
    Type: Grant
    Filed: February 16, 1990
    Date of Patent: April 16, 1991
    Assignee: Hoechst Celanese Corporation
    Inventors: Shane Hsieh, Paul Stahlhofen
  • Patent number: 4990429
    Abstract: The invention describes a photosensitive composition, a copying material prepared from this composition, and a process for the production of negative relief copies, in which a photosensitive composition or a photosensitive material, respectively, is used, that comprises a support and a photosensitive composition coated onto the support and comprising a photosensitive 1,2-quinonediazide or a photosensitive mixture, a binder that is soluble in aqueous-alkaline solutions and an s-triazine of the general formula I ##STR1## wherein R denotes akyl, allyl, alkoxy, alkoxycarbonyl, alkoxycarbonylakkenyl, each having from 1 to 4 carbon atoms in the alkyl or alkenyl group, aryloxy, halogen or a nitro group andn stands for 1 to 3.The material is exposed imagewise under a negative original, thereafter heated and, after cooling, exposed without an original or optionally under a positive original, then developed by means of an aqueous-alkaline developer and optionally baked.
    Type: Grant
    Filed: October 18, 1989
    Date of Patent: February 5, 1991
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Hans W. Frass
  • Patent number: 4983478
    Abstract: A burn-in gumming composition for irradiated and developed offset printing plates comprises water and a water-soluble polymer or copolymer for protecting the plate surface during the burning-in step and during long-term storage. The polymer or copolymer used contains sulfonic acid groups and/or alkali metal sulfonate or ammonium sulfonate groups.
    Type: Grant
    Filed: September 27, 1989
    Date of Patent: January 8, 1991
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Dieter Mohr
  • Patent number: 4889789
    Abstract: A photosensitive composition which substantially comprises a binder which is insoluble in water and soluble in aqueous-alkaline solutions, a photosensitive 1,2-naphthoquinone-diazide or a photosensitive mixture comprised of a compound which splits off acid upon exposure to light and a compound containing at least one acid-cleavable C-O-C group, and a thermally crosslinking compound comprising a urea or urethane-formaldehyde condensation product is disclosed. Also disclosed is a copying material prepared from this composition. The material has a good shelf life and can be processed as a positive or negative-working material, and also according to the photocomposing method. For development customary developer solutions are used.
    Type: Grant
    Filed: April 4, 1988
    Date of Patent: December 26, 1989
    Assignee: Hoechst Aktiengsellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 4889788
    Abstract: The invention describes a photosensitive composition, a copying material prepared from this composition, and a process for the production of negative relief copies, in which a photosensitive composition or a photosensitive material, respectively, is used, that comprises a support and a photosensitive composition coated onto the suppoort and comprising a photosensitive 1,2-quinonediazide or a photosensitive mixture, a binder that is soluble in aqueous-alkaline solutions and an s-triazine of the general formula I ##STR1## wherein R denotes akyl, allyl, alkoxy, alkoxycarbonyl, alkoxycarbonylakkenyl, each having from 1 to 4 carbon atoms in the alkyl or alkenyl group, aryloxy, halogen or a nitro group andn stands for 1 to 3. The material is exposed imagewise under a negative original, thereafter heated and, after cooling, exposed without an original or optionally under a positive original, then developed by means of an aqueous-alkaline developer and optionally baked.
    Type: Grant
    Filed: July 27, 1988
    Date of Patent: December 26, 1989
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Hans W. Frass
  • Patent number: 4885230
    Abstract: A burn-in gumming composition for irradiated and developed offset printing plates comprises water and a water-soluble polymer or copolymer for protecting the plate surface during the burning-in step and during long-term storage. The polymer or copolymer used contains sulfonic acid groups and/or alkali metal sulfonate or ammonium sulfonate groups.
    Type: Grant
    Filed: September 6, 1988
    Date of Patent: December 5, 1989
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Dieter Mohr
  • Patent number: 4786581
    Abstract: A gumming solution is disclosed for use in the burning-in of irradiated and developed offset-printing plates. The gumming solution contains (a) water, (b) at least one hydrophilic polymer, and (c) at least one component derived from an organic acid. Component (b) comprises, for example, N-polyvinyl-pyrrolidone-(2) or polyacrylic acid, and component (c) comprises a water-soluble organic carboxylic acid, sulfonic acid, or phosphonic acid which has at least two acid functions and which is selected from the group consisting of benzene carboxylic acids, benzene sulfonic acids, benzene phosphonic acids, and alkane phosphonic acids, or one of the salts thereof (for example, disodium-benzene-1,3-disulfonate, mellitic acid, or methane-diphosphonic acid.) A process for the production of an offset-printing plate, using the aforesaid gumming solution in the burning-in of the plate, is also disclosed.
    Type: Grant
    Filed: February 9, 1987
    Date of Patent: November 22, 1988
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Loni Schell
  • Patent number: 4717640
    Abstract: A light-sensitive mixture containing a light-sensitive compound or a light-sensitive combination of compounds, the solubility of which is increased upon exposure, and a binder made from a polymer which has units of alkenylsulfonylaminocarbonyloxystyrenes or cycloalkenylsulfonylaminocarbonyloxystyrenes and which is insoluble in water and soluble in aqueous alkali. Moreover, a recording material is described which is particularly used in the production of printing plates coated with a light-sensitive layer of the indicated mixture. The printing form obtained after exposure and development of the material can be baked at temperatures ranging from 180.degree. C. to 250.degree. C. without forming difficult to remove deposits on the non-image areas of the plate. As a result, a printing form is produced, which has a particularly high resistance and yields a large print run.
    Type: Grant
    Filed: December 11, 1985
    Date of Patent: January 5, 1988
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 4642282
    Abstract: A light-sensitive mixture is disclosed which contains a binder comprising a polycondensation product of a phenol corresponding to the formula ##STR1## wherein R.sub.1 is a hydrogen atom, an alkyl group or a hydroxy group,R.sub.2 is a hydrogen atom, an alkyl group, a hydroxy group or an acetyl group, andR.sub.3 is a hydrogen atom or a halogen atom, an alkyl group, an alkoxy group, a carboxyl group or a carboxylic acid ester group,and a compound corresponding to the formulaROCH.sub.2 --X--CH.sub.2 OR,whereinR is a hydrogen atom, a methyl group, an ethyl group or an acetyl group andX is a phenylene group or a binuclear aromatic group.The mixture yields printing plates which have a high resistance to developing solutions and which show a low degree of soiling upon baking.
    Type: Grant
    Filed: June 20, 1984
    Date of Patent: February 10, 1987
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 4639406
    Abstract: A light-sensitive copying material for the preparation of printing plates and photoresists is described, which material contains, as the light-sensitive compound, a naphthoquinone-diazide-sulfonic acid ester of the general formula I ##STR1## in which D is a 1,2-naphthoquinone-2-diazide-4-sulfonyl radical or a 1,2-naphthoquinone-2-diazide-5-sulfonyl radical, R.sub.1 is a hydrogen atom or a --COC.sub.n H.sub.2n+1 radial, and R.sub.2 is a hydrogen atom or a --CO--OC.sub.n H.sub.2n+1 radial, n being a number from 10 to 25 and the sum of the carbon atoms of R.sub.1 +R.sub.2 being n+1.The new quinone-diazides are distinguished by a higher solubility and a greater resistance to developer.
    Type: Grant
    Filed: October 20, 1981
    Date of Patent: January 27, 1987
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 4628020
    Abstract: A light-sensitive mixture comprising a light-sensitive naphthoquinone-diazide-sulfonic acid ester corresponding to the formula: ##STR1## wherein D represents a 1,2-naphthoquinone-2-diazide-5-sulfonyl or -4-sulfonyl radical; R.sub.1, R.sub.2, R.sub.3, R.sub.1 ', R.sub.2 ' and R.sub.3 ' each represent hydrogen, halogen, alkyl groups having 1 to 4 carbon atoms or radicals of the formula DO and n represents an integer from 2 to 18; not more than three DO radicals in total being present on one benzene ring. The mixture is useful for preparing printing plates or photoresists.
    Type: Grant
    Filed: January 11, 1982
    Date of Patent: December 9, 1986
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 4594306
    Abstract: This invention relates to an improvement in a light-sensitive copying material comprising a carrier and a light-sensitive copying layer which contains, as the light-sensitive compound, an o-quinone diazide sulfonic acid ester or an o-quinone diazide sulfonic acid amide, the improvement being that the layer also contains a compound with an aromatic or aliphatic hydroxy group which is capable of forming chelate compounds.
    Type: Grant
    Filed: August 17, 1984
    Date of Patent: June 10, 1986
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Rainer Beutel
  • Patent number: 4581321
    Abstract: A process for producing negative relief copies is disclosed in which a light-sensitive material, comprising (1) a light-sensitive ester or amide of a 1,2-quinone-diazide-sulfonic acid or of a 1,2-quinone-diazide-carboxylic acid and (2) a hexamethylol melamine ether is imagewise exposed, thereafter heated, and, after cooling, exposed again without an original, and subsequently developed by means of an aqueous-alkaline developer. The disclosed process permits the production of negative copies with the aid of a material which yields positive copies when it is processed in a conventional manner.
    Type: Grant
    Filed: July 2, 1984
    Date of Patent: April 8, 1986
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Paul Stahlhofen
  • Patent number: 4576901
    Abstract: A process for producing negative relief copies is disclosed in which a light-sensitive material, consisting essentially of (1) a binder which is insoluble in water and soluble in aqueous-alkaline solutions and (2) a light-sensitive ester or amide of a 1,2-benzoquinone-2-diazide-4-sulfonic acid, a 1,2-benzoquinone-2-diazide-4-carboxylic acid, a 1,2-naphthoquinone-2-diazide-4-sulfonic acid, or a 1,2-naphthoquinone-2-diazide-4-carboxylic acid, is imagewise exposed, thereafter heated and, after cooling, exposed again without an original, and subsequently developed by means of an aqueous-alkaline developer. The disclosed process permits the production of negative copies with the aid of a material which yields positive copies when it is processed in a conventional manner.
    Type: Grant
    Filed: July 2, 1984
    Date of Patent: March 18, 1986
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Paul Stahlhofen, Gerhard Mack