Process for the preparation of hollow microspheres
Patent 4782097 Issued on November 1, 1988. Estimated Expiration Date: 
September 23, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
September 23, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2797201 2806509 3312632 3607169 3615972 3873475 3914360 3927181 Process for production of carbon products Formation of hollow spherical articles InventorsAssigneeApplicationNo. 07/100090 filed on 09/23/1987US Classes:521/56, Particle which is expandible, process of preparing an expandible particle, or process of expanding a particle to form a cellular product521/141, Cellular vinyl alcohol polymer521/149, From oxygen containing reactant521/58, Expanding utilizing plural expansion steps521/60, Adding expanding agent subsequent to solid polymer formation521/64, Removing a liquid to form a cellular product521/87, Ingredient is aldehyde or ketone521/89, Ingredient contains a sulfur atom521/94Ingredient is a nitrogen containing compoundExaminersPrimary: Foelak, MortonAttorney, Agent or FirmInternational ClassesB01J 13/20 (20060101)B01J 13/06 (20060101) B01J 13/12 (20060101) C08J 3/14 (20060101) C08J 9/00 (20060101) C08J 9/08 (20060101) C08J 3/12 (20060101) Foreign Application Priority Data1986-10-01 CAAbstractA process for forming hollow microspheres containing carbon or a polymer which is a carbon precursor. The process comprises forming a solution in a liquid solvent of a polymer having the following properties (a) a molecular weight of at least 10,000 and a long chain structure; (b) an ability to be coagulated by or precipitated from the solution by a non-solvent for the polymer; (c) an ability to form a continuous stretchable film when coagulated or precipitated from solution; (d) a chemical structure which is infusible or capable of being rendered infusible, and (e) a high carbon yield of at least 30% by weight upon being carbonized in a non-reactive atmosphere. An insoluble particulate blowing agent is incorporated into the solution and the solution is then divided into droplets and the droplets are introduced into a liquid bath containing a suitable non-solvent for the polymer. The non-solvent causes the polymer to precipitate or coagulate rapidly and simultaneously the blowing agent is decomposed to generate a gas within the droplets so that hollow microspheres are formed. The microspheres are then optionally subjected to carbonization in a non-reactive atmosphere at high temperature to convert the polymer to carbon. Uniformly-sized relatively large hollow microspheres can be produced by this process.Other References
Field of SearchParticle which is expandible, process of preparing an expandible particle, or process of expanding a particle to form a cellular productExpanding utilizing plural expansion steps Adding expanding agent subsequent to solid polymer formation Removing a liquid to form a cellular product Cellular vinyl alcohol polymer From oxygen containing reactant | |
