Patents by Inventor Hsueh M. Li

Hsueh M. Li 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: 5145943
    Abstract: Fusible polyimide powders are prepared by the process of this invention. An amic acid amine is first prepared by treating (n+1) moles of a bis(aminophenyl)methane with n mole of aromatic tetracarboxylic anhdride to produce an aromatic amic acid prepolymer. This prepolymer is then mixed with an unsaturated carbocyclic monoanhydride and the mixture heated to form a reactive end-capped polyamic acid precursor. The resulting composition is thermally treated in order to partially imidize the precursor. The resulting fusible polyimide powder is finally separated.
    Type: Grant
    Filed: December 17, 1990
    Date of Patent: September 8, 1992
    Assignee: Ethyl Corporation
    Inventors: Hsueh M. Li, John Y. Lee
  • Patent number: 5105001
    Abstract: Novel substituted phosphazene compounds are disclosed having the formula ##STR1## wherein w, x, y and z are integers the sum of which is from 3 to 6 with the proviso that w is at least 1 but equal to or less than (w+x+y+z)-1, x is from 1 to 5, y and z are from 0 to 2;R.sub.1 and R.sub.2 are the same or different and are C.sub.1 to C.sub.6 linear or branched alkyl;R.sub.3 is an unsubstituted or substituted aryl and n is 0 or an integer from 2 to 6; Q is --O--, ##STR2## --NR-- or --S--; Ar is ##STR3## R' and R" are the same or different and are C.sub.1 to C.sub.6 linear or branched alkyl, with the proviso that R" can also be hydrogen, wherein R.sub.1 and R.sub.2 are the same or different C.sub.1 to C.sub.4 linear or branched alkyl group and n is 0 or an integer from 2 to 6. These compounds display good solubilities in both organic and aqueous systems. Accordingly, they act as antioxidants in adhesive, sealant and coating compositions.
    Type: Grant
    Filed: September 18, 1990
    Date of Patent: April 14, 1992
    Assignee: Ethyl Corporation
    Inventors: Dixie E. Goins, Hsueh M. Li
  • Patent number: 5039776
    Abstract: Fusible polyimide powders are prepared by the process of this invention. An amic acid amine is first prepared by treating equimolar amounts of a 2,2-bis[4-(aminophenoxy)phenyl]-hexafluoropropane with an unsaturated carbocyclic monoanhydride. The amic acid amine is then mixed with an aromatic tetracarboxylic dianhydride and the mixture heated to form a polyimide precursor. A chemical dehydrating agent is added in an amount sufficient to substantially, fully imidize the precursor. The resulting fusible polyimide powder is finally separated.
    Type: Grant
    Filed: May 14, 1990
    Date of Patent: August 13, 1991
    Assignee: Ethyl Corporation
    Inventors: Hsueh M. Li, Adam Nugent, Jr.
  • Patent number: 4973661
    Abstract: This invention discloses a process where a portion of an amine terminated polyamic acid intermediate is end-capped with an aromatic monoanhydride additionally substituted with a free carboxylic acid and a carboxylic ester. The polyamic acids of this invention are readily converted to high molecular weight polyimides.
    Type: Grant
    Filed: May 26, 1989
    Date of Patent: November 27, 1990
    Assignee: Ethyl Corporation
    Inventors: Burnell Lee, Hsueh M. Li
  • Patent number: 4956450
    Abstract: This invention discloses a process where a portion of an amine terminated polyamic acid intermediate is end-capped with an aromatic monoanhydride additionally substituted with a free carboxylic acid or ester thereof. The polyamic acids of this invention are readily converted to high molecular weight polyimides which may contain a small amount of amide groups.
    Type: Grant
    Filed: May 26, 1989
    Date of Patent: September 11, 1990
    Assignee: Ethyl Corporation
    Inventors: Burnell Lee, Hsueh M. Li
  • Patent number: 4551317
    Abstract: Halophosphazene polymers such as linear phosphonitrilic chloride polymers are prepared in two stages by (i) heating a nitrogen source (e.g., NH.sub.3 ; NH.sub.4 Cl; etc.) with an excess of a phosphorus source (e.g., PCl.sub.5 ; PCl.sub.3 +Cl.sub.2 ; P+Cl.sub.2 ; etc.) so that hydrogen halide is evolved and halophosphazene is formed, and (ii) heating at least a portion of the halophosphazene with at least a stoichiometric amount (preferably an excess) of a nitrogen source (e.g., NH.sub.3 ; NH.sub.4 Cl; etc.) so that hydrogen halide is evolved and halophosphazene polymer of higher molecular weight is formed. Preferably, a third stage is utilized wherein the resultant halophosphazene polymer is then heated, most preferably in an inert solvent or diluent which enhances the fluidity of the reaction mixture, to increase the molecular weight of the polymer.
    Type: Grant
    Filed: April 28, 1983
    Date of Patent: November 5, 1985
    Assignee: Ethyl Corporation
    Inventor: Hsueh M. Li
  • Patent number: 4539352
    Abstract: Improved injection moldability of polyethylene terephthalates is achieved by the addition of an epoxidized plasticizer and a nucleating agent cooperative with the epoxidized plasticizer to achieve the improved moldability even when the composition is injection molded using mold temperatures of at least as low as 93.degree. C.
    Type: Grant
    Filed: August 15, 1984
    Date of Patent: September 3, 1985
    Assignee: Ethyl Corporation
    Inventors: James Y. J. Chung, Jesse D. Jones, Hsueh M. Li
  • Patent number: 4537755
    Abstract: To prepare halophosphazene oligomer enriched in cyclic trimer, a two-stage process is used. In the first stage halogen halide and ammonia are concurrently introduced into an agitated liquid reaction medium in which halophosphazene oligomer is soluble, these materials being proportioned so as to form a reaction system composed of a dilute slurry of finely divided ammonium halide particles. In the second stage phosphorus trihalide and halogen are concurrently introduced into the slurried reaction system from the first stage heated to a temperature of about 80.degree. to about 180.degree. C. In the process the quantities of the reactants introduced into the reaction medium are proportioned such that the ammonium halide:phosphorus trihalide molar ratio is between about 1:1 and about 3:1, and the phosphorus trihalide:halogen molar ratio is kept above about 0.
    Type: Grant
    Filed: December 5, 1983
    Date of Patent: August 27, 1985
    Assignee: Ethyl Corporation
    Inventor: Hsueh M. Li
  • Patent number: 4522797
    Abstract: One or a mixture of compounds of the formula:X--(PX.sub.2 .dbd.N).sub.n --POX.sub.2wherein X is a halogen atom and n is an integer, usually below about 15 is heated with a suitable phosphorus reactant such as PX.sub.5 ; PX.sub.3 +X.sub.2 ; P+X.sub.2 ; or oligomer of the formula[X--(PX.sub.2 .dbd.N).sub.n --PX.sub.3 ].sup.+ [R].sup.-wherein X is a halogen atom, R is PX.sub.6 or X, and n is an integer usually below about 15; or a mixture of two or more such phosphorus reactants so that a halophosphazene having a --PX.sub.3.sup.+ end group is formed as one of the co-products of the reaction. This co-product is a substance having the general formula[X--(PX.sub.2 .dbd.N).sub.n --PX.sub.3 ].sup.+ [R].sup.-wherein X, R and n are as defined above. The other co-product is phosphoryl trihalide, POX.sub.3. In a second stage the resultant reaction product is heated with at least a stoichiometric amount (preferably, an excess) of a nitrogen source (e.g., NH.sub.3 ; NH.sub.4 Cl; etc.
    Type: Grant
    Filed: September 8, 1983
    Date of Patent: June 11, 1985
    Assignee: Ethyl Corporation
    Inventors: F. Alexander Pettigrew, Hsueh M. Li, Genevieve S. Lum
  • Patent number: 4522796
    Abstract: Linear phosphonitrilic chloride polymers are produced from phosphonitrilic chloride oligomers by means of an improved process wherein a mixture of phosphonitrilic chloride oligomers enriched in linear oligomer is heated with at least a stoichiometric amount (and preferably an excess) of ammonia or ammonium chloride while concurrently removing hydrogen chloride to produce a higher molecular weight polyphosphonitrilic chloride product. Cyclic phosphonitrilic chloride oligomer may be and preferably is present in the initial oligomer. Preferably, cyclic phosphonitrilic chloride oligomer is recovered from the reaction mixture during (but more preferably after) completion of the polymerization reaction. At least a portion of the recovered cyclic oligomer may be used in a subsequent polymerization reaction.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: June 11, 1985
    Assignee: Ethyl Corporation
    Inventor: Hsueh M. Li
  • Patent number: 4522798
    Abstract: A mixture of compounds of the formulas:[X--(PX.sub.2 .dbd.N).sub.n --PX.sub.3 ].sup.+ [R].sup.-andX--(PX.sub.2 .dbd.N).sub.n --POX.sub.2wherein X is a halogen atom, R is X or PX.sub.6 or both of them, and n is an integer, usually below about 15, is heated either with no other reactant or with a suitable phosphorus reactant such as PX.sub.5 ; PX.sub.3 +X.sub.2 ; P+X.sub.2 ; or a mixture of two or more such phosphorus reactants so that a halophosphazene having a --PX.sub.3.sup.+ end group is formed as one of the co-products of the reaction. This co-product is a substance having the general formula[X--(PX.sub.2 .dbd.N).sub.n --PX.sub.3 ].sup.+ [R].sup.-wherein X, R and n are as defined above. The other co-product is phosphoryl trihalide, POX.sub.3. In a second stage the resultant reaction product is heated with at least a stoichiometric amount (preferably, an excess) of a nitrogen source (e.g., NH.sub.3 ; NH.sub.4 Cl; etc.
    Type: Grant
    Filed: September 8, 1983
    Date of Patent: June 11, 1985
    Assignee: Ethyl Corporation
    Inventors: Genevieve S. Lum, Hsueh M. Li, F. Alexander Pettigrew
  • Patent number: 4522795
    Abstract: Linear phosphonitrilic chloride polymers are produced from phosphonitrilic chloride oligomers by means of a two-stage process. In the first stage a mixture of phosphonitrilic chloride oligomers enriched in linear oligomer is heated with at least a stoichiometric amount (and preferably an excess) of ammonia or ammonium chloride while concurrently removing hydrogen chloride to produce an intermediate reaction product. In the second stage the molecular weight of the reaction product is increased by heating the product to a higher temperature than the average temperature used in the first stage. Cyclic phosphonitrilic chloride oligomer may be present in the initial oligomer. Preferably, cyclic phosphonitrilic chloride oligomer is recovered from the reaction mixture after the start of the second stage. Most preferably it is recovered after completion of the second stage. At least a portion of the recovered cyclic oligomer may be used in a subsequent first stage reaction.
    Type: Grant
    Filed: April 22, 1983
    Date of Patent: June 11, 1985
    Assignee: Ethyl Corporation
    Inventor: Hsueh M. Li
  • Patent number: 4486561
    Abstract: Improved injection moldability of polyethylene terephthalates is achieved by the addition of an epoxidized plasticizer and a nucleating agent cooperative with the epoxidized plasticizer to achieve the improved moldability even when the composition is injection molded using mold temperatures of at least as low as 93.degree. C.
    Type: Grant
    Filed: July 14, 1983
    Date of Patent: December 4, 1984
    Assignee: Ethyl Corporation
    Inventors: James Y. J. Chung, Jesse D. Jones, Hsueh M. Li
  • Patent number: 4447408
    Abstract: Linear phosphonitrile chloride polymers are produced from linear phosphonitrilic chloride oligomers by means of a two-step proess. In the first step a mixture of linear phosphonitrilic chloride oligomer having an average degree of polymerization of at least 3 and preferably at least 4 is heated with an excess of ammonia or ammonium chloride having a relatively small particle size such that the Mean Value is within the range of from about 1 micron to about 110 microns. Cyclic phosphonitrilic chloride oligomer formed during the course of the first step is removed from the reaction mixture. After the removal of the cyclic oligomer the reaction mixture is subjected to the second step which involves heating the mixture in an inert liquid solvent (optionally in the presence of ammonia or ammonium chloride having a relatively small particle size) whereby the molecular weight of the linear phosphonitrilic chloride polymer is increased.
    Type: Grant
    Filed: December 7, 1982
    Date of Patent: May 8, 1984
    Assignee: Ethyl Corporation
    Inventor: Hsueh M. Li
  • Patent number: 4374815
    Abstract: Linear phosphonitrilic chloride polymers are produced from linear phosphonitrilic chloride oligomers by means of a two-step process. In the first step a mixture of linear phosphonitrilic chloride oligomer having an average degree of polymerization of at least 4 is heated with an excess of ammonia or ammonium chloride. Cyclic phosphonitrilic chloride oligomer formed during the course of the first step is removed from the reaction mixture. After the removal of the cyclic oligomer the reaction mixture is subjected to the second step which involves heating the mixture in an inert liquid solvent (optionally in the presence of ammonia or ammonium chloride) whereby the molecular weight of the linear phosphonitrilic chloride polymer is increased.
    Type: Grant
    Filed: October 26, 1981
    Date of Patent: February 22, 1983
    Assignee: Ethyl Corporation
    Inventor: Hsueh M. Li
  • Patent number: 4289862
    Abstract: Liquid, linear, crosslinkable phosphazene compositions and a process for their preparation are disclosed. These liquid compositions, prepared from normally solid polyphosphazene, contain the polyphosphazene in admixture with from about 1 to about 30 parts per hundred parts of polymer of a polythiol, a polyacrylate, a polymethacrylate or mixtures thereof such that the combination has a viscosity of less than 500,000 cps at 23.degree. C. These compositions are easily handled and can be crosslinked at ambient temperatures.
    Type: Grant
    Filed: July 14, 1980
    Date of Patent: September 15, 1981
    Assignee: Ethyl Corporation
    Inventors: Edwin D. Hornbaker, Hsueh M. Li
  • Patent number: 4264531
    Abstract: Substituted, linear phosphazene prepolymers and processes for their preparation are disclosed. These prepolymers are liquid at ambient temperatures and can be conveniently cured and/or foamed without the use of external heat.
    Type: Grant
    Filed: November 14, 1979
    Date of Patent: April 28, 1981
    Assignee: Ethyl Corporation
    Inventors: Hsueh M. Li, Edwin D. Hornbaker
  • Patent number: 4198381
    Abstract: In the first step of a two step process, PCl.sub.3 and Cl.sub.2 are reacted in a suitable medium. In the second step, PCl.sub.3, Cl.sub.2 and NH.sub.3 are concurrently fed into said medium while keeping the temperature at 100.degree. C. to 140.degree. C. The feeds of the reactants are controlled so that until the first 1/2 of the NH.sub.3 has been reacted the molar ratio of PCl.sub.3 :NH.sub.3 (including the PCl.sub.3 of the first step) is kept above 2. Thereafter, the feeds are adjusted so that with respect to the total amount of ammonia, said molar ratio is between 1.2 and 1.5. Linear phosphonitrilic chloride oligomers having a number average degree of polymerization from 2 to 9 are produced in high yield.
    Type: Grant
    Filed: August 21, 1978
    Date of Patent: April 15, 1980
    Assignee: Ethyl Corporation
    Inventors: Edwin D. Hornbaker, Hsueh M. Li