Patents by Inventor Tyler Arthur Stevenson

Tyler Arthur Stevenson 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).

  • Methods for the preparation of tris-aryl-o-hydroxyphenyl-s-triazines
    Patent number: 6242598
    Abstract: A process for preparing 2-(2,4-dihydroxyphenyl)-4.6-diaryl-s-triazines in three steps starting with cyanuric chloride is described. Step 1 involves the nucleophilic (basic) displacement of one chlorine atom with a phenolic moiety. Step 2 involves a Friedel-Crafts reaction using a Lewis acid catalyst (preferably aluminum chloride) to replace the remaining two chlorine atoms with aryl groups such as xylyl. Finally, step 3 involves replacing the phenolic moiety with resorcinol using either a Lewis acid or protic acid catalyst or combinations thereof. Some additional processes only peripherally related to the three-step process outlined above are also described for the preparation of various s-triazine compounds. The s-triazines prepared are useful as UV absorbers for the stabilization of organic substrates against the adverse effects of actinic light.
    Type: Grant
    Filed: March 22, 2000
    Date of Patent: June 5, 2001
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Tyler Arthur Stevenson, Michael Ackerman, Pascal Hayoz, Roger Meuwly, John Francis Oswald, Christian Schregenberger
  • Compositions stabilized with red-shifted tris-aryl-s-triazines
    Patent number: 5684070
    Abstract: Tris-aryl-s-triazines of formula VI ##STR1## which contain from one to three resorcinol derived moieties have UV spectra which are red-shifted to the near UV range and provide excellent stabilization to polymeric substrates against the deleterious effects of actinic light.
    Type: Grant
    Filed: July 15, 1996
    Date of Patent: November 4, 1997
    Assignee: Ciba Specialty Chemicals Corporation
    Inventor: Tyler Arthur Stevenson
  • Red-shifted tris-aryl-s-triazines
    Patent number: 5681955
    Abstract: Tris-aryl-s-triazines of formula VI ##STR1## which contain one or more resorcinol derived moieties have UV spectra which are red-shifted to the near UV range and provide excellent stabilization to polymeric substrates against the deleterious effects of actinic light.
    Type: Grant
    Filed: July 15, 1996
    Date of Patent: October 28, 1997
    Assignee: Ciba Specialty Chemicals Corporation
    Inventor: Tyler Arthur Stevenson
  • Red-shifted tris-aryl-S-triazines
    Patent number: 5675004
    Abstract: Tris-aryl-s-triazines of formula V ##STR1## which contain from one one to three resorcinol derived moieties with at least one of said moieties substituted in the 5-position with a group such as, for example, alkyl or phenylalkyl have UV spectra which are red-shifted to the near UV range and provide excellent stabilization to polymeric substrates against the deleterious effects of actinic light.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: October 7, 1997
    Assignee: Ciba-Geigy Corporation
    Inventor: Tyler Arthur Stevenson
  • Compositions stabilized with red-shifted tris-aryl-s-triazines
    Patent number: 5648488
    Abstract: Tris-aryl-s-triazines of formula V ##STR1## which contain from one one to three resorcinol derived moieties with at least one of said moieties substituted in the 5-position with a group such as, for example, alkyl or phenylalkyl have UV spectra which are red-shifted to the near UV range and provide excellent stabilization to polymeric substrates against the deleterious effects of actinic light.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: July 15, 1997
    Assignee: Ciba-Geigy Corporation
    Inventor: Tyler Arthur Stevenson