Polymer particles patents

Noteable are recent studies on the generation of polymer particles as carriers for controlled drug release [333] and of cationic solid lipid micro-particles as synthetic carriers for the targeted delivery of macromolecules to phagocytic antigen-presenting cells [334]. The industrial interest, although rarely disclosed, is evident from the patents filed in the field (see, e.g., [335, 336]). 

Leng DE, Sigclko WL, Saunders FL, inventors The Dow Chemical Company, assignee. Aqueous dispersions of pla.sticized polymer particles US Patent No. 4,502.888. 1985. 

Microemulsion processes may well find applications in areas which have traditionally used emulsion polymerisation. At the present stage of research, it is mainly water-in-oil microemulsion polymerisation which offers the most possibilities and several patents have been taken out [6.5]. This process minimises certain problems encountered in classic inverted emulsions, namely instability of the latexes they produce, large polydispersity of polymer particles, and the large quantity of coagulum which increases production costs. Water-soluble (co)polymers prepared in microemulsion polymerisation can be used in various ways ... 

X. Yang and J.R. Bennett, Process for preparing porous polymer particles, US Patent 8466206, assigned to Eastman Kodak Company (Rochester, NY), June 18,2013. 

Another method developed by Hercules Inc. (9) consisted of reacting crystalline polypropylene with maleic anhydride in the presence of organic peroxide in an inert liquid organic solvent. This process is expensive because it requires the separation of solvent and excess maleic anhydride from the modified polypropylene. A similar process, detailed in patent 3,414,551, uses a fluidized bed of polymer particles instead of a solvent. 

Wemett PC (2009) Surface treated inorganic particle additive for increasing the toughness of polymers. WO Patent 2,009,077,860... 

Rolfes H, Van Der Merwe TL, Truter PA (2001) Method of making controlled release particles of complexed polymers, Google Patents. 

Woo JS, Kim HJ, Kim Y (2006) Method for the preparatin of paclitaxel sohd dispersion by using the supercritical fluid process and paclitaxel solid dispersion prepared thereby, Google Patents Yeo S-D, Kiran E (2005) Formation of polymer particles with supercritical fluids a review. J Supercrit Fluids 34(3) 287-308... 

In a procedure described in Ref. [474], sodium orthosilicate was added to the reaction medium to raise the polymer yield to 95%. The initiator was ammonium persulfate with a special emulsifier that is believed to be perfluorinated carboxylated emulsifier from 3M Corp [458]. Other initiators used are redox systems such as potassium persulfate-sodium metabisulfite or ammonium persulfate-sodium sulfite [475]. Different initiators are also of some interest because they affect the particle diameter of the emulsion. Polymer particles formed with a diameter between 0.36 and 18 pm, depending on the initiator system and the polymerization procedures, are reported [458]. In a patent of Dynamit Nobel [476], iodine-containing compounds such as ammonium iodide or isopropyl iodide are used. These compounds give rise to polymers of improved thermal stability and resistance to color deterioration. The procedure did not require the use of an emulsifier. After 150 min the internal pressure of the autoclave dropped from 2 x 10 to 3 X 10 Pa and a conversion to polymer of 86% was found. More recently Uschold [477] describes also an emulsion polymerization of PVF in high yields and having excellent color. 

Gronwald O, Leitner K, Janssen N, Weber C, Roth M, Hauber G, Falusi S, Geiger S, Berg M. Separators for electrochemical cells comprising polymer particles 2015, US patent 8999602. 

In Table VII, it will be noted that in a bulk polymerization, at a conversion of 10-20%, secondary particles form. That is, swollen polymer particles collide to form larger particles. As the process proceeds, virtually no free liquid monomer is present. Using a special autoclave, in which polymer lumps could be broken up, bulk polymerization of vinyl chloride could be carried out beyond this low conversion range [58]. This concept was improved upon in the basic patent for the Pechiney-Saint Gobain process [59]. Evidently Produits Chimique Pechiney-Saint Gobain was a... 

S. Chevigny, S. Dong, A.-C. Couffin-Hoarau, I. Bolduc, M. Berrada, and C. Thibodeau, Polysaccharide-inorganic composite particles as performance additives for super-absorbent polymers, US Patent 8563466, assigned to Archer Daniels Midland Company (Decatur, IL), October 22, 2013. 

Ugelstad, J., Ellingsen, T., Berge, A., and Helgee, B. 1986. Process for the production of magnetic polymer particles. European Patent 0 106 873. 

Polymer Solvent. Sulfolane is a solvent for a variety of polymers, including polyacrylonitrile (PAN), poly(vinyhdene cyanide), poly(vinyl chloride) (PVC), poly(vinyl fluoride), and polysulfones (124—129). Sulfolane solutions of PAN, poly(vinyhdene cyanide), and PVC have been patented for fiber-spinning processes, in which the relatively low solution viscosity, good thermal stabiUty, and comparatively low solvent toxicity of sulfolane are advantageous. Powdered perfluorocarbon copolymers bearing sulfo or carboxy groups have been prepared by precipitation from sulfolane solution with toluene at temperatures below 300°C. Particle sizes of 0.5—100 p.m result. 

FIFE is made commercially by two major processes, one leading to the so called granular polymer and the second leading to a dispersion of polymer of much finer particle size and lower molecular weight. One method of producing the latter involved the use of a 0.1 % aqueous disuccinic acid peroxide solution. The reactions were carried out at temperatures up to 90°C. It is understood that the Du Pont dispersion polymers, at least, are produced by methods based on the patent containing the above example. 

Zorbax PSM particles are made from small (80-2000 A), extremely uniform colloidal silica sol beads. In a patented polymerization process, these beads are agglutinated to form spherical particles. The size of the Zorbax PSM particles is controlled by the polymerization process, and the pore size is determined by the size of the silica sol beads. After polymerization, the silica is heated to remove the organic polymer and sinter the particles. The result is a spherical, porous, mechanically stable, pure silica particle that provides excellent chromatographic performance (Pig. 3.1). 

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