Patents by Inventor Walter J. Schrenk

Walter J. Schrenk 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: 6583930
    Abstract: A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
    Type: Grant
    Filed: December 23, 1998
    Date of Patent: June 24, 2003
    Assignee: 3M Innovative Properties
    Inventors: Walter J. Schrenk, Victor S. Chang, John A. Wheatley
  • Publication number: 20010046086
    Abstract: A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
    Type: Application
    Filed: July 24, 2001
    Publication date: November 29, 2001
    Applicant: 3M Innovative Properties Company
    Inventors: John A. Wheatley, Walter J. Schrenk
  • Patent number: 5872653
    Abstract: A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
    Type: Grant
    Filed: December 18, 1996
    Date of Patent: February 16, 1999
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Walter J. Schrenk, John A. Wheatley, Victor S. Chang
  • Patent number: 5628950
    Abstract: Methods and apparatus are provided for making multilayer plastic articles. Initially, two or more streams of diverse thermoplastic materials are provided. Layers are formed from these streams and are arranged in a layered first composite stream. The first composite stream may be directly formed into a desired configuration by a molding process or may be manipulated to form a second composite stream having an increased number of layers before being formed into the desired configuration. The resulting articles are comprised of a number of discrete and substantially continuous layers.
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: May 13, 1997
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, Ranganath K. Shastri, Herbert C. Roehrs, Ralph E. Ayres, Mark A. Barger, Jeffrey N. Bremmer
  • Patent number: 5612820
    Abstract: A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
    Type: Grant
    Filed: May 30, 1995
    Date of Patent: March 18, 1997
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, Victor S. Chang, John A. Wheatley
  • Patent number: 5568316
    Abstract: A formable multilayer reflective polymeric body which has a substantially uniform broad bandwidth reflectance over substantially the entire range of the visible spectrum to provide a substantially uniform reflective appearance is provided. The body includes at least first and second diverse polymeric materials, the body comprising a sufficient number of alternating layers of the first and second polymeric materials such that at least 40% of visible light incident on the body is reflected. A substantial majority of the individual layers of the body have optical thicknesses in the range where the sum of the optical thicknesses in a repeating unit of the polymeric materials is greater than about 190 nm, and the first and second polymeric materials differ from each other in refractive index by at least about 0.03.
    Type: Grant
    Filed: April 13, 1995
    Date of Patent: October 22, 1996
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, Charles B. Arends, Conrad F. Balazs, Ray A. Lewis, John A. Wheatley
  • Patent number: 5540878
    Abstract: A blow molded multilayer plastic article having a large number of layers is formed. First and second diverse thermoplastic streams are extruded into a coextrusion feedblock. In the feedblock the streams are divided into multiple streams and arranged into a first composite stream having a substantially uniform distribution of the layers. The first stream is fed into an interfacial surface generator in which the stream is manipulated to form a second composite stream having even more layers of substantially uniform thickness. This second stream is then formed into a preform such as by injection molding and this preform is blow molded. The second composite stream and preform are formed so that the layers of first and second materials lie generally parallel to a critical surface and possess substantial uniformity when blow molded.
    Type: Grant
    Filed: September 27, 1994
    Date of Patent: July 30, 1996
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, Ranganath K. Shastri, Herbert C. Roehrs, Ralph E. Ayres
  • Patent number: 5540978
    Abstract: An all-polymeric ultraviolet light reflective film which is lower in cost than previously used reflector materials, is weather resistant, and which does not absorb significant amounts of solar ultraviolet energy is provided. The film includes a sufficient number of alternating layers of at least first and second diverse polymeric materials which have an average percent transmission of greater than about 50% between wavelengths of 300-400 nm. A substantial majority of the individual layers of the film have optical thicknesses in the range where the sum of the optical thicknesses in a repeating unit of the polymeric materials is between about 0.15 .mu.m to about 0.228 .mu.m, and the first and second polymeric materials differ from each other in refractive index by at least about 0.03 in the wavelength range of from about 300-400 nm.
    Type: Grant
    Filed: May 11, 1994
    Date of Patent: July 30, 1996
    Assignee: The Dow Chemical Compny
    Inventor: Walter J. Schrenk
  • Patent number: 5486949
    Abstract: A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the first and second polymeric materials in a first plane which is different from the refractive index mismatch between the first and second polymeric materials in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
    Type: Grant
    Filed: November 26, 1990
    Date of Patent: January 23, 1996
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, John A. Wheatley, Victor S. Chang
  • Patent number: 5448404
    Abstract: A formable multilayer reflective polymeric body which has a substantially uniform broad bandwidth reflectance over substantially the entire range of the visible spectrum to provide a substantially uniform reflective appearance is provided. The body includes at least first and second diverse polymeric materials, the body comprising a sufficient number of alternating layers of the first and second polymeric materials such that at least 40% of visible light incident on the body is reflected. A substantial majority of the individual layers of the body have optical thicknesses in the range where the sum of the optical thicknesses in a repeating unit of the polymeric materials is greater than about 190 nm, and the first and second polymeric materials differ from each other in refractive index by at least about 0.03.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: September 5, 1995
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, Charles B. Arends, Conrad F. Balazs, Ray A. Lewis, John A. Wheatley
  • Patent number: 5389324
    Abstract: Methods and apparatus for generating, and then precisely controlling, layer thickness gradients in multilayered polymeric reflective bodies are provided. The creation of such gradients is useful in tailoring multilayer bodies to reflect and/or transmit desired wavelengths of light. Both thermal and mechanical methods, as well as combinations thereof, are used.
    Type: Grant
    Filed: June 7, 1993
    Date of Patent: February 14, 1995
    Assignee: The Dow Chemical Company
    Inventors: Ray A. Lewis, David M. Wisniewski, Ravi Ramanathan, Walter J. Schrenk
  • Patent number: 5380479
    Abstract: Methods and apparatus are provided for making multilayer plastic articles. Initially, two or more streams diverse thermoplastic materials are provided. Layers are foraged from these streams and are arranged in a layered first composite stream. The first composite stream may be directly formed into a desired configuration by a molding process or may be manipulated to form a second composite stream having an increased number of layers before being formed into the desired configuration. The resulting articles are comprised of a number of discrete and substantially continuous layers.
    Type: Grant
    Filed: November 9, 1992
    Date of Patent: January 10, 1995
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, Herbert C. Roehrs, Ranganath K. Shastri, Ralph E. Ayres, Mark A. Barger, Jeffrey N. Bremmer
  • Patent number: 5360659
    Abstract: The present invention provides a two-component infrared reflecting film which reflects light in the infrared region of the spectrum while suppressing second, third and fourth order reflections in the visible spectrum. The film comprises alternating layers of first (A) and second (B) diverse polymeric materials having a six layer alternating repeat unit with relative optical thicknesses of about .778A.111B.111A.778B.111A.111B. The polymeric materials differ from each other in refractive index by at least about 0.03.
    Type: Grant
    Filed: May 24, 1993
    Date of Patent: November 1, 1994
    Assignee: The Dow Chemical Company
    Inventors: Charles B. Arends, Walter J. Schrenk, Ray A. Lewis, Ravi Ramanathan, John Wheatley
  • Patent number: 5316703
    Abstract: A method for the production of a lamellar reflective polymeric body is provided and includes the steps of providing a first stream of a first heat plastified polymeric material and a second stream of a second heat plastified polymeric material, and encapsulating discrete portions of the first polymeric material in the second polymeric material by coextruding the polymeric materials to form a plurality of ribbon-like layers of the first polymeric material within a matrix of the second polymeric material to form the reflective polymeric body. The layers of the first polymeric material are arranged to have their major interfaces aligned substantially parallel to the major surfaces of the body such that at least 30% of light incident on the body is reflected. The ribbon-like layers may be further divided into a series of platelet-like layers to produce layers which are discontinuous in all major planar dimensions by passing the ribbon-like layers through a reciprocating feed plate or valve.
    Type: Grant
    Filed: January 19, 1993
    Date of Patent: May 31, 1994
    Assignee: The Dow Chemical Company
    Inventor: Walter J. Schrenk
  • Patent number: 5278694
    Abstract: A multilayered reflective body which is thermoformable and capable of being fabricated into films, sheets and a variety of parts while maintaining a uniform reflective appearance is provided. The reflective polymeric body includes at least first and second diverse polymeric materials of a sufficient number of alternating layers of the first and second polymeric materials such that at least 30% of the light incident on the body is reflected. A substantial majority of the individual layers of the body have an optical thickness of not more than 0.09 micrometers or not less than 0.45 micrometers, and adjacent layers of the first and second polymeric materials differ from each other in refractive index by at least about 0.1. The reflective body may be fabricated into sheets, mirrors, noncorroding metallic appearing articles and parts, reflectors, reflective lenses, and the like.
    Type: Grant
    Filed: May 17, 1991
    Date of Patent: January 11, 1994
    Assignee: The Dow Chemical Company
    Inventors: John A. Wheatley, Walter J. Schrenk, Stephen E. Bales, Mark A. Barger, Charles A. Langhoff, Ravi Ramanathan
  • Patent number: 5269995
    Abstract: A process and apparatus for the coextrusion of a multilayer polymeric body is provided which incorporates protective boundary layers into the body, protecting the layers from instability and breakup during layer formation and multiplication. The process includes the steps of providing at least first and second streams of heat plastified extrudable thermoplastic material which are combined to form a composite stream having the first substreams and second substreams interdigitated. A third stream of heat plastified thermoplastic material is supplied to the exterior surfaces of the composite stream to form protective boundary layers adjacent the walls of the coextrusion apparatus through which the heat plastified polymer streams pass. Layer instability and breakup are avoided using process conditions which would otherwise adversely affect the optical and/or mechanical properties of the articles which are formed.
    Type: Grant
    Filed: October 2, 1992
    Date of Patent: December 14, 1993
    Assignee: The Dow Chemical Company
    Inventors: Ravi Ramanathan, Walter J. Schrenk, John A. Wheatley
  • Patent number: 5262894
    Abstract: A multicomponent, multilayered, highly reflective polymeric body which is thermoformable and capable of being fabricated into films, sheets and a variety of parts while maintaining a uniform reflective appearance is provided. The reflective polymeric body includes at least first, second, and third diverse polymeric materials having a sufficient number of alternating layers of the polymeric materials such that a portion of the light incident on the body is reflected. A sufficient number of the individual layers of the body have optical thicknesses of not more than 0.09 micrometers or not less than 0.45 micrometers, such that there is an absence of visibly perceived color in the body. The polymeric materials having the highest and lowest refractive indices differ from each other in refractive index by at least about 0.03. The reflective body may be fabricated into mirrors, noncorroding metallic appearing articles and parts, reflectors, reflective lenses, and the like.
    Type: Grant
    Filed: February 10, 1992
    Date of Patent: November 16, 1993
    Assignee: The Dow Chemical Company
    Inventors: John A. Wheatley, Walter J. Schrenk
  • Patent number: 5234729
    Abstract: A multilayered reflective polymeric body of alternating layers of polymers wherein at least a portion of the layers are in a folded-over relationship is provided along with a coextrusion apparatus and method of preparing the multilayer polymeric body. The reflective polymeric body includes at least first and second diverse polymeric materials having a sufficient number of alternating layers of the first and second polymeric materials such that a portion of the light incident on the body is reflected. The first and second polymeric materials differ from each other in refractive index by at least about 0.03. The reflective body is thermoformable and may be fabricated into wall panels, dishware, decorative trims, and the like, and may also find use in security applications such as credit cards, credit card emblems, or on currency.
    Type: Grant
    Filed: February 27, 1992
    Date of Patent: August 10, 1993
    Assignee: The Dow Chemical Company
    Inventors: John A. Wheatley, Walter J. Schrenk, David M. Wisniewski
  • Patent number: 5233465
    Abstract: A polymeric multilayered film which reflects wavelengths of light in the infrared region of the spectrum while being substantially transparent to wavelengths of light in the visible spectrum without the effects of visibly perceived iridescent color is provided. The polymeric multilayered infrared reflecting film comprises at least two diverse, substantially transparent polymeric materials, with the layers having an optical thickness of between 0.09 .mu.m and 0.45 .mu.m and the polymeric materials having a different index of refraction such that light is reflected in the infrared portion of the spectrum. A color masking film is associated with the polymeric film which reflects light substantially uniformly over the visible portion of the spectrum to eliminate perceived iridescent color.
    Type: Grant
    Filed: May 27, 1992
    Date of Patent: August 3, 1993
    Assignee: The Dow Chemical Company
    Inventors: John A. Wheatley, Walter J. Schrenk
  • Patent number: RE34605
    Abstract: The present invention provides an optical interference film, made of multiple layers of polymers, which reflects wavelengths of light in the infrared region of the spectrum while being substantially transparent to wavelengths of light in the visible spectrum. The optical interference film includes multiple alternating layers of at least first, second, and third diverse, substantially transparent polymeric materials A, B, and C, with the layers being of an optical thickness of between about 0.09 and 0.45 micrometers. Each of the polymeric materials has a different index of refraction, n.sub.i, and the refractive index of the second polymeric material is intermediate the respective refractive indices of the first and third polymeric materials.
    Type: Grant
    Filed: December 11, 1992
    Date of Patent: May 10, 1994
    Assignee: The Dow Chemical Company
    Inventors: Walter J. Schrenk, John A. Wheatley