Patents by Inventor John D. Renwick

John D. Renwick 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).

  • Process of preparing screen stencil using diazo photosensitive compositions with acidic p-H indicator
    Patent number: 4564581
    Abstract: The invention provides photosensitive compositions useful in the production of screen printing stencils which comprise, in addition to the usual ingredients, also an indicator to show when a layer formed from the said composition has been isolubilized by exposure to actinic light.
    Type: Grant
    Filed: July 13, 1984
    Date of Patent: January 14, 1986
    Assignee: Sericol Group Limited
    Inventors: John R. Curtis, John D. Renwick
  • Photopolymerizable materials for use in producing screen printing stencils
    Patent number: 4499175
    Abstract: Aqueous compositions useful in making stencils for screen printing comprise a solution of an unsaturated prepolymer dispersed in an aqueous solution of a colloid, and a photo-initiator. Such compositions may be coated on suitable support sheets to produce photosensitive sheets useful for making stencils for screen printing by the direct, indirect, or direct/indirect methods.
    Type: Grant
    Filed: September 22, 1982
    Date of Patent: February 12, 1985
    Assignee: Sericol Group Limited
    Inventors: John R. Curtis, John D. Renwick
  • Photopolymerizable composition for producing screen printing stencils
    Patent number: 4499176
    Abstract: Aqueous compositions useful in making stencils for screen printing by the direct, indirect or direct/indirect method comprise a photopolymerizable monomer, a water-insoluble photoinitiator, a tertiary amine accelerator, a water-soluble colloid, water, and a water-miscible organic solvent.
    Type: Grant
    Filed: September 22, 1982
    Date of Patent: February 12, 1985
    Assignee: Sericol Group Limited
    Inventors: John R. Curtis, John D. Renwick