GB1453258A - Process for the production of stable dispersions - Google Patents

Process for the production of stable dispersions

Info

Publication number
GB1453258A
GB1453258A GB2031275A GB2031275A GB1453258A GB 1453258 A GB1453258 A GB 1453258A GB 2031275 A GB2031275 A GB 2031275A GB 2031275 A GB2031275 A GB 2031275A GB 1453258 A GB1453258 A GB 1453258A
Authority
GB
United Kingdom
Prior art keywords
prepared
components
dispersions
stable dispersions
mixer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB2031275A
Other languages
English (en)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer AG
Original Assignee
Bayer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bayer AG filed Critical Bayer AG
Publication of GB1453258A publication Critical patent/GB1453258A/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
    • C08G18/3225—Polyamines
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/0838—Manufacture of polymers in the presence of non-reactive compounds
    • C08G18/0842—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents
    • C08G18/0861—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents in the presence of a dispersing phase for the polymers or a phase dispersed in the polymers
    • C08G18/0871—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents in the presence of a dispersing phase for the polymers or a phase dispersed in the polymers the dispersing or dispersed phase being organic
    • C08G18/0876—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents in the presence of a dispersing phase for the polymers or a phase dispersed in the polymers the dispersing or dispersed phase being organic the dispersing or dispersed phase being a polyol
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/2805—Compounds having only one group containing active hydrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/409—Dispersions of polymers of C08G in organic compounds having active hydrogen

Landscapes

  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Polyurethanes Or Polyureas (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Colloid Chemistry (AREA)
  • Paints Or Removers (AREA)
GB2031275A 1975-03-27 1975-05-14 Process for the production of stable dispersions Expired GB1453258A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19752513815 DE2513815C3 (de) 1975-03-27 1975-03-27 Verfahren zur Herstellung von stabilen Dispersionen

Publications (1)

Publication Number Publication Date
GB1453258A true GB1453258A (en) 1976-10-20

Family

ID=5942648

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2031275A Expired GB1453258A (en) 1975-03-27 1975-05-14 Process for the production of stable dispersions

Country Status (17)

Country Link
JP (1) JPS51114497A (de)
AT (1) AT342305B (de)
BE (1) BE829123A (de)
BR (1) BR7503066A (de)
CA (1) CA1068840A (de)
CH (1) CH614455A5 (de)
DD (1) DD118102A5 (de)
DE (1) DE2513815C3 (de)
DK (1) DK218375A (de)
ES (1) ES437721A1 (de)
FR (1) FR2305466A1 (de)
GB (1) GB1453258A (de)
IT (1) IT1035736B (de)
LU (1) LU72484A1 (de)
NL (1) NL171592C (de)
SE (1) SE414501B (de)
SU (1) SU741801A3 (de)

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4374209A (en) 1980-10-01 1983-02-15 Interchem International S.A. Polymer-modified polyols useful in polyurethane manufacture
EP0072096A1 (de) * 1981-08-11 1983-02-16 Imperial Chemical Industries Plc Mit Polymeren modifizierte Polyole, ein Verfahren zu ihrer Herstellung, ihre Verwendung bei der Herstellung von Polyurethan-Produkten, sowie die so hergestellten Produkte
US4417002A (en) 1981-07-09 1983-11-22 Kabel-Und-Gummiwerke Ag Foam manufacture
US4452923A (en) * 1981-10-28 1984-06-05 Imperial Chemical Industries Plc Polymer-modified polyols
EP0187333A2 (de) * 1985-01-08 1986-07-16 Miles Inc. Verfahren zur Herstellung von Polyharnstoff-und/oder Polyhydrazodicarbonamid-Dispersionen und ihre Weiterverarbeitung zu Polyurethanen.
EP0188766A1 (de) * 1985-01-08 1986-07-30 Bayer Ag Stabile Dispersionen von Polyharnstoffen und/oder Polyhydrazodicarbonamiden in höhermolekularen, mindestens eine Hydroxylgruppe aufweisenden Hydroxylverbindungen, ein Verfahren zu ihrer Herstellung und ihre Verwendung zur Herstellung von Polyurethankunststoffen
EP0250977A1 (de) * 1986-06-25 1988-01-07 The Dow Chemical Company Mit harten, stabförmigen Mikro-Füllstoffen verstärkte Polyurethane sowie Verfahren zu deren Herstellung
US4757093A (en) * 1987-05-21 1988-07-12 Reeves Brothers, Inc. Flame retardant melamine containing polyurethane foam
US4757094A (en) * 1987-05-21 1988-07-12 Reeves Brothers, Inc. Melamine cured polyurethane foam with improved properties
DK153796B (da) * 1980-02-14 1988-09-05 Interchem Int Sa Fremgangsmaade til fremstilling af et polyurethanskum.
GB2221217A (en) * 1988-07-28 1990-01-31 Mobay Corp Process for the production of stable dispersions,the dispersions so produced, and the use thereof in the manufacture of polyurethanes
GB2221218A (en) * 1988-07-28 1990-01-31 Mobay Corp Stable dispersions and the manufacture thereof
EP0443157A1 (de) * 1990-01-23 1991-08-28 Miles Inc. Stabile Polyhydrazodicarbonamid-Dispersionen zur Herstellung von Polyurethan-Produkten mit verbesserter Tragfähigkeit
EP0448813A1 (de) * 1990-03-07 1991-10-02 Bayer Ag Stabile Dispersionen von Polyharnstoffen und/oder Polyhydrazodicarbonamiden in höhermolekularen, mindestens eine Hydroxylgruppe aufweisenden Verbindungen, ein Verfahren zu ihrer Herstellung und ihre Verwendung zur Herstellung von Polyurethankunststoffen
US6331028B1 (en) 2000-10-17 2001-12-18 Advance Usa, Inc. Fiber-reinforced composite structure
WO2002048232A1 (de) * 2000-12-14 2002-06-20 Bayer Aktiengesellschaft Holzklebstoffen auf basis von isocyanat-terminierten prepolymeren
US6627018B1 (en) 2000-10-17 2003-09-30 Advance Usa, Llc System and method of forming composite structures
WO2006058422A1 (en) 2004-11-30 2006-06-08 Agrium Inc. Process and apparatus for coating a controlled release product in a rotating drum
US7465757B2 (en) 2004-10-15 2008-12-16 Danisco A/S Foamed isocyanate-based polymer, a mix and process for production thereof
US7682656B2 (en) 2004-06-14 2010-03-23 Agruim Inc. Process and apparatus for producing a coated product
WO2010079202A2 (en) 2009-01-09 2010-07-15 Danisco A/S A foamed isocyanate-based polymer, a mix and process for production thereof
WO2013030118A1 (en) 2011-08-26 2013-03-07 Ekompany Agro B.V. Process for producing a coated fertilizer
WO2013030127A1 (en) 2011-08-26 2013-03-07 Ekompany Agro B.V. Process for producing a coated fertilizer comprising boron
EP2809701A4 (de) * 2012-02-02 2016-01-20 Covestro Llc Polyurethanschaumstoffe mit verminderten aldehydemissionen, verfahren zur herstellung dieser schaumstoffe und verfahren zur verringerung von aldehydemissionen in polyurethanschaumstoffen
EP3023400A1 (de) 2005-08-09 2016-05-25 Agrium Inc. Dünger mit kontrollierter freisetzung mit epoxydiertem fettsäure-triglycerid-öl als ein beschichtungsadditiv
DE112013004958B4 (de) 2012-10-10 2023-01-26 Proprietect L.P. Verfahren zur Herstellung eines frei aufgeschäumten Polyurethan-Schaumstoffs mit niedriger Dichte sowie frei aufgeschäumter Polyurethan-Schaumstoff
US11926137B2 (en) 2018-09-25 2024-03-12 Proprietect L.P. Composite foam article

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2638759A1 (de) 1976-08-27 1978-03-09 Bayer Ag Loesungen von polyisocyanat-polyadditionsprodukten
DE2723293C2 (de) * 1977-05-24 1985-05-02 Bayer Ag, 5090 Leverkusen Verfahren zur Herstellung von Überzügen
PH19314A (en) * 1981-03-25 1986-03-14 Dow Chemical Co An improved process for preparing a rigid polyurethane foam
DE3330197A1 (de) * 1983-08-20 1985-02-28 Bayer Ag, 5090 Leverkusen Waermesensibilisierungsmittel, ihre herstellung und verwendung
DE4431963A1 (de) 1994-09-08 1996-03-14 Bayer Ag Verfahren zur Herstellung von elastischen Formkörpern
DE10129062A1 (de) 2001-06-15 2002-12-19 Basf Ag Verfahren zur Herstellung von hochelastischen Polyurethanschaumstoffen
DE102005001565A1 (de) 2005-01-13 2006-07-27 Bayer Materialscience Ag Holzklebstoffe
CN103562249B (zh) 2011-03-24 2015-06-17 拜耳知识产权有限责任公司 由增强的聚氨酯脲-弹性体构成的成型件及其应用
US8946313B2 (en) * 2011-12-16 2015-02-03 Bayer Materialscience Llc Hybrid PHD/PMPO polyols for polyurethane foam applications
US9683334B2 (en) 2015-05-15 2017-06-20 Covestro Llc Free-flowing coated rubber particles, methods for their production and use
US10119223B2 (en) 2016-07-15 2018-11-06 Covestro Llc Carpet and synthetic turf backings prepared from a polyether carbonate polyol
CN111303380B (zh) * 2020-03-20 2022-03-11 万华化学集团股份有限公司 一种可释放二氧化碳聚脲多元醇的制备方法和应用

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK153796B (da) * 1980-02-14 1988-09-05 Interchem Int Sa Fremgangsmaade til fremstilling af et polyurethanskum.
US4374209A (en) 1980-10-01 1983-02-15 Interchem International S.A. Polymer-modified polyols useful in polyurethane manufacture
US4417002A (en) 1981-07-09 1983-11-22 Kabel-Und-Gummiwerke Ag Foam manufacture
US4438252A (en) 1981-08-08 1984-03-20 Imperial Chemical Industries Limited Polymer-modified polyols
EP0072096A1 (de) * 1981-08-11 1983-02-16 Imperial Chemical Industries Plc Mit Polymeren modifizierte Polyole, ein Verfahren zu ihrer Herstellung, ihre Verwendung bei der Herstellung von Polyurethan-Produkten, sowie die so hergestellten Produkte
US4452923A (en) * 1981-10-28 1984-06-05 Imperial Chemical Industries Plc Polymer-modified polyols
US4761434A (en) * 1985-01-08 1988-08-02 Bayer Aktiengesellschaft Stable dispersions of polyureas and/or polyhydrazodi-carbonamides in relatively high molecular weight, hydroxyl group-containing compounds process for the production thereof and use thereof for the production of polyurethanes
EP0187333A3 (en) * 1985-01-08 1988-01-13 Mobay Corporation Stable dispersions, process for production thereof and use in the manufacture of polyurethanes
EP0188766A1 (de) * 1985-01-08 1986-07-30 Bayer Ag Stabile Dispersionen von Polyharnstoffen und/oder Polyhydrazodicarbonamiden in höhermolekularen, mindestens eine Hydroxylgruppe aufweisenden Hydroxylverbindungen, ein Verfahren zu ihrer Herstellung und ihre Verwendung zur Herstellung von Polyurethankunststoffen
EP0187333A2 (de) * 1985-01-08 1986-07-16 Miles Inc. Verfahren zur Herstellung von Polyharnstoff-und/oder Polyhydrazodicarbonamid-Dispersionen und ihre Weiterverarbeitung zu Polyurethanen.
EP0250977A1 (de) * 1986-06-25 1988-01-07 The Dow Chemical Company Mit harten, stabförmigen Mikro-Füllstoffen verstärkte Polyurethane sowie Verfahren zu deren Herstellung
US4757093A (en) * 1987-05-21 1988-07-12 Reeves Brothers, Inc. Flame retardant melamine containing polyurethane foam
US4757094A (en) * 1987-05-21 1988-07-12 Reeves Brothers, Inc. Melamine cured polyurethane foam with improved properties
GB2221217A (en) * 1988-07-28 1990-01-31 Mobay Corp Process for the production of stable dispersions,the dispersions so produced, and the use thereof in the manufacture of polyurethanes
GB2221218A (en) * 1988-07-28 1990-01-31 Mobay Corp Stable dispersions and the manufacture thereof
EP0443157A1 (de) * 1990-01-23 1991-08-28 Miles Inc. Stabile Polyhydrazodicarbonamid-Dispersionen zur Herstellung von Polyurethan-Produkten mit verbesserter Tragfähigkeit
EP0448813A1 (de) * 1990-03-07 1991-10-02 Bayer Ag Stabile Dispersionen von Polyharnstoffen und/oder Polyhydrazodicarbonamiden in höhermolekularen, mindestens eine Hydroxylgruppe aufweisenden Verbindungen, ein Verfahren zu ihrer Herstellung und ihre Verwendung zur Herstellung von Polyurethankunststoffen
US6331028B1 (en) 2000-10-17 2001-12-18 Advance Usa, Inc. Fiber-reinforced composite structure
US6627018B1 (en) 2000-10-17 2003-09-30 Advance Usa, Llc System and method of forming composite structures
WO2002048232A1 (de) * 2000-12-14 2002-06-20 Bayer Aktiengesellschaft Holzklebstoffen auf basis von isocyanat-terminierten prepolymeren
US7056415B2 (en) 2000-12-14 2006-06-06 Bayer Aktiengesellschaft Wood adhesives
US7682656B2 (en) 2004-06-14 2010-03-23 Agruim Inc. Process and apparatus for producing a coated product
US8178161B2 (en) 2004-06-14 2012-05-15 Agrium Inc. Process and apparatus for producing a coated product
US7465757B2 (en) 2004-10-15 2008-12-16 Danisco A/S Foamed isocyanate-based polymer, a mix and process for production thereof
WO2006058422A1 (en) 2004-11-30 2006-06-08 Agrium Inc. Process and apparatus for coating a controlled release product in a rotating drum
US9878959B2 (en) 2004-11-30 2018-01-30 Agrium Inc. Process and apparatus for coating a controlled release product in a rotating drum
EP3023400A1 (de) 2005-08-09 2016-05-25 Agrium Inc. Dünger mit kontrollierter freisetzung mit epoxydiertem fettsäure-triglycerid-öl als ein beschichtungsadditiv
US10202314B2 (en) 2005-08-09 2019-02-12 Agrium, Inc. Controlled release fertilizer employing epoxidized fatty acid triglyceride oil as a coating additive
WO2010079202A2 (en) 2009-01-09 2010-07-15 Danisco A/S A foamed isocyanate-based polymer, a mix and process for production thereof
US8735460B2 (en) 2009-01-09 2014-05-27 DuPont Nutrition BioScience ApS Foamed isocyanate-based polymer, a mix and process for production thereof
US9090518B2 (en) 2011-08-26 2015-07-28 Ekompany Agro B.V. Process for producing a coated fertilizer comprising boron
US9328033B2 (en) 2011-08-26 2016-05-03 Ekompany International B.V. Process for producing a coated fertilizer
WO2013030127A1 (en) 2011-08-26 2013-03-07 Ekompany Agro B.V. Process for producing a coated fertilizer comprising boron
WO2013030118A1 (en) 2011-08-26 2013-03-07 Ekompany Agro B.V. Process for producing a coated fertilizer
EP2809701A4 (de) * 2012-02-02 2016-01-20 Covestro Llc Polyurethanschaumstoffe mit verminderten aldehydemissionen, verfahren zur herstellung dieser schaumstoffe und verfahren zur verringerung von aldehydemissionen in polyurethanschaumstoffen
EP3159364A1 (de) * 2012-02-02 2017-04-26 Covestro LLC Polyurethanschaumstoffe mit verminderten aldehydemissionen, verfahren zur herstellung dieser schaumstoffe und verfahren zur verringerung von aldehydemissionen in polyurethanschaumstoffen
US10066047B2 (en) 2012-02-02 2018-09-04 Covestro Llc Polyurethane foams with decreased aldehyde emissions, a process for preparing these foams and a method for decreasing aldehyde in polyurethane foams
DE112013004958B4 (de) 2012-10-10 2023-01-26 Proprietect L.P. Verfahren zur Herstellung eines frei aufgeschäumten Polyurethan-Schaumstoffs mit niedriger Dichte sowie frei aufgeschäumter Polyurethan-Schaumstoff
US11926137B2 (en) 2018-09-25 2024-03-12 Proprietect L.P. Composite foam article

Also Published As

Publication number Publication date
ATA371775A (de) 1977-07-15
SE7505598L (sv) 1976-09-28
BE829123A (fr) 1975-11-17
DE2513815C3 (de) 1979-05-23
CH614455A5 (en) 1979-11-30
DK218375A (da) 1976-09-28
NL171592C (nl) 1983-04-18
SU741801A3 (ru) 1980-06-15
NL7505666A (nl) 1976-09-29
AU8119875A (en) 1976-11-18
CA1068840A (en) 1979-12-25
JPS5216747B2 (de) 1977-05-11
FR2305466B1 (de) 1979-03-02
AT342305B (de) 1978-03-28
ES437721A1 (es) 1977-03-16
IT1035736B (it) 1979-10-20
DE2513815B2 (de) 1978-09-14
NL171592B (nl) 1982-11-16
BR7503066A (pt) 1976-09-28
LU72484A1 (de) 1976-03-17
SE414501B (sv) 1980-08-04
JPS51114497A (en) 1976-10-08
DD118102A5 (de) 1976-02-12
DE2513815A1 (de) 1976-09-30
FR2305466A1 (fr) 1976-10-22

Similar Documents

Publication Publication Date Title
GB1453258A (en) Process for the production of stable dispersions
GB1493769A (en) Process for the production of aminoplast dispersions and their use
GB1483957A (en) Diphenylmethane diisocyanate compositions
GB2072204A (en) Polymer-modified polyols useful in polyurethane manufacture
ES471044A1 (es) Procedimiento para la obtencion de dispersiones estables de productos de poliadicion y policondensacion
ES449690A1 (es) Procedimiento para la preparacion de una mezcla de di(amino-fenil)metanos y polimetilen polifenil poliamidas oligomeri- cas.
ES8304591A1 (es) Procedimiento para la obtencion de un polimerizado de poliisocianurato dispersable.
IE50890B1 (en) Polymer-modified polyols useful in polyurethane manufacture
ES8704189A1 (es) Procedimiento para la obtencion de dispersiones estables de poliureas y-o polihidrazodicarbonamidas
DE3175097D1 (en) Process for the production of polymer/polyisocyanate compositions and the use thereof for making polyurethanes
ES477660A1 (es) Procedimiento para la obtencion de materiales espumados a base de poliisocianato.
EP0187330A3 (en) Stable dispersions of polyureas and/or polyhydrazodicarbonamides in higher molecular weight, at least on hydroxyl group containing hydroxylcompounds, a process for their preparation and their use in the preparation of polyurethane plastics
IE39642L (en) Polyurethane products containing cycloaliphatic components
DE3036693A1 (de) Polyurethanhartschaum, zusammensetzung und verfahren zu dessen herstellung
DE3069565D1 (en) Method of preparing agglomerated foams
ES8406516A1 (es) Procedimiento para la obtencion de cuerpos moldeados microcelulares o espumados a base de poliurea
DE3063273D1 (en) Process for the preparation of cellular polyurethane elastomers
EP0215267A3 (en) Use of polyisocyanates or polyisocyanate mixtures as additives for aqueous dispersion paints
GB1176252A (en) Process for the production of Aqueous Polyurethane Dispersions
ES409017A1 (es) Un procedimiento para la preparacion de polimeros de poliu-retano o poliurea modificados con aceite.
GB1156340A (en) Improved Cellular Polyurethane Products and process for preparing same
ES453241A1 (es) Procedimiento para la obtencion "in situ" de dispersiones a-cuosas.
GB1242780A (en) Polyurethanes
GB1498616A (en) Process for the production of stable dispersions
KR900007897A (ko) 고탄성 발포체용 습식고정 시스템 첨가제

Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940514