John F Kwok

US Patent:

52160360, Jun 1, 1993

Filed:

Sep 30, 1992

Appl. No.:

7/953810

Inventors:

Ervin R. Dun - Lexington MA
John Kwok - Holden MA

Assignee:

Novacor Chemicals (International) S.A.

International Classification:

C08J 918

US Classification:

521 59

Abstract:

Foamable photodegradable suspension polymers of vinyl aromatic monomers may be prepared by dissolving a copolymer of a vinyl aromatic monomer and a vinyl ketone in the vinyl aromatic monomer and suspension polymerizing the resulting mixture. The resulting polymer may be foamed and used in the manufacture of food containers.

US Patent:

53570340, Oct 18, 1994

Filed:

Sep 8, 1992

Appl. No.:

7/941731

Inventors:

Israel D. Fridman - Belmont MA
John Kwok - Holden MA
Ronald J. Downey - Leominster MA
Speros P. Nemphos - League City TX

Assignee:

Camelot Technologies Inc. - Leominster MA

International Classification:

C08G 6308

US Classification:

528354

Abstract:

High molecular weight polylactic acid is generally produced by the polymerization of lactide. Lactide is prepared by the depolymerization of low molecular weight polylactic acid. There are difficulties in the preparation of high molecular weight polylactic acid and high purity lactide isomers due to the equilibrium between lactic acid, low molecular weight polylactic acid, high molecular weight polylactic acid, lactide and water. Further it has never been proposed to provide a continuous process to produce high molecular weight polylactic acid from lactic acid. The present invention overcomes the equilibrium problem and provides a continuous process.

US Patent:

52645924, Nov 23, 1993

Filed:

Sep 8, 1992

Appl. No.:

7/941678

Inventors:

Israel D. Fridman - Belmont MA
John Kwok - Holden MA

Assignee:

Camelot Technologies Inc. - Leominster MA

International Classification:

C07D31912

US Classification:

549274

Abstract:

Generally, polylactic acid is prepared by the ring opening polymerization of lactide. However, to obtain a high molecular weight polylactic acid it is necessary to start with a lactide having a high degree of purity. Lactide may be economically brought to the required degree of purity using melt recrystallization techniques.

US Patent:

51909847, Mar 2, 1993

Filed:

Sep 23, 1991

Appl. No.:

7/763604

Inventors:

Ervin R. Dan - Lexington MA
John Kwok - Holden MA

Assignee:

Novacor Chemicals (International) S.A. - Fribourg

International Classification:

C08J 918

US Classification:

521 59

Abstract:

Foamable photodegradable suspension polymers of vinyl aromatic monomers may be prepared by dissolving a copolymer of a vinyl aromatic monomer and a vinyl ketone in the vinyl aromatic monomer and suspension polymerizing the resulting mixture. The resulting polymer may be foamed and used in the manufacture of food containers.