Patents Assigned to Porvair Limited
  • Gloves
    Patent number: 4888829
    Abstract: Flexible form fitting seamless gloves made from an elastomeric polyurethane material containing fiber reinforcements. The material forming the back of the hands of the gloves has a thickness of 0.05 to 0.45 mm a water vapor permeability of 75 to 200, a hydrostatic head of 300 to 700 cm of water, a tensile tear factor of 0.20 to 1.20, and initial modulus at 25% elongation of less that 0.35 kg/cm and a elongation at break of at least 200%.
    Type: Grant
    Filed: October 27, 1988
    Date of Patent: December 26, 1989
    Assignee: Porvair Limited
    Inventors: George J. Kleinerman, John M. Woodcock
  • Air freshener unit
    Patent number: 4735626
    Abstract: New dynamic air freshener unit comprises a porous synthetic polymer support impregnated with a fragrance. The synthetic polymer support is one produced by:(a) bonding together small particles of solid polymer;(b) coagulating polymer solutions in a non-solvent for the polymer; or(c) expanding a thermoplastic or thermosetting plastic by means of a blowing agent; to form a porous body.The unit is especially useful in vacuum cleaners.
    Type: Grant
    Filed: July 6, 1987
    Date of Patent: April 5, 1988
    Assignees: Reckitt & Colman Products Limited, Porvair Limited
    Inventors: Brian R. Smith, Arthur W. R. Balkham
  • Production of porous materials
    Patent number: 4157424
    Abstract: An improved microporous polymer material is made by coagulating, e.g. in water, a polymer solution containing dispersed microscopic particles of a removable filler soluble in a coagulating liquid.
    Type: Grant
    Filed: November 23, 1971
    Date of Patent: June 5, 1979
    Assignee: Porvair Limited
    Inventor: David L. Boutle
  • Water vapor permeable microporous sheet materials and their method of manufacture
    Patent number: 4090010
    Abstract: There is disclosed a process in which both non-solvent e.g., water and filler particles e.g., microscopic sodium chloride are added in certain proportions to a polymer solution e.g., polyurethane in dimethylformamide preferably at elevated temperature and coagulated by immersion in non-solvent. This results in a more rapid coagulation time than when solvent or filler alone are used and also results in a microporous product of improved properties and novel pore structure.
    Type: Grant
    Filed: June 11, 1973
    Date of Patent: May 16, 1978
    Assignee: Porvair Limited
    Inventors: Eric Albert Warwicker, David Price
  • Method of making water vapor permeable polymer sheet material
    Patent number: 4028451
    Abstract: Coagulation apparatus for producing thick microporous polyurethane sheet material by passing a layer of polymer solvent composition beneath a close spaced plate with liquid non-solvent fed to the gap between the plate and the surface to produce controlled initiation of the coagulation.
    Type: Grant
    Filed: February 5, 1975
    Date of Patent: June 7, 1977
    Assignee: Porvair Limited
    Inventor: Eric Albert Warwicker
  • Shoe uppers
    Patent number: 3982335
    Abstract: A shoe upper having in place of the upper leather thereof a fleeceless water vapor permeable microporous sheet of elastomeric polyurethane material having a thickness of about 0.8 - 1.8 mm. and having an extension at break of at least 200%.
    Type: Grant
    Filed: October 12, 1971
    Date of Patent: September 28, 1976
    Assignee: Porvair Limited
    Inventors: Victor Ralph Cunningham, David Leonard Boutle
  • Water vapor permeable sheet material
    Patent number: 3968292
    Abstract: There is disclosed a water vapor permeable shoe upper material having at least three layers, the density, thickness and structure of the layers having a defined novel relationship whereby an improved cut tear to stiffness relationship is achieved.
    Type: Grant
    Filed: July 22, 1974
    Date of Patent: July 6, 1976
    Assignee: Porvair Limited
    Inventors: Arthur William Pearman, Steven James Wright
  • Artificial leather sheet material
    Patent number: 3968293
    Abstract: A water vapor permeable artificial leather material is disclosed which consists essentially of tough microporous elastomeric polymer material free from fibrous reinforcement having a thickness of at least 0.8 mm and a microporous appearance modifying surface layer or finish.
    Type: Grant
    Filed: October 11, 1973
    Date of Patent: July 6, 1976
    Assignee: Porvair Limited
    Inventors: Victor Ralph Cunningham, David Leonard Boutle