WO1994007808A1 - Matiere de coulee pour fabriquer des feuilles ceramiques crues et moulages ceramiques ainsi realises - Google Patents

Matiere de coulee pour fabriquer des feuilles ceramiques crues et moulages ceramiques ainsi realises Download PDF

Info

Publication number
WO1994007808A1
WO1994007808A1 PCT/EP1993/002584 EP9302584W WO9407808A1 WO 1994007808 A1 WO1994007808 A1 WO 1994007808A1 EP 9302584 W EP9302584 W EP 9302584W WO 9407808 A1 WO9407808 A1 WO 9407808A1
Authority
WO
WIPO (PCT)
Prior art keywords
casting compound
meth
weight
acrylate
compound according
Prior art date
Application number
PCT/EP1993/002584
Other languages
German (de)
English (en)
Inventor
Friedrich Hessel
Ute STÜRMER
Andreas Roosen
Joseph Thevissen
Helmut Rinno
Hans Trabitzsch
Original Assignee
Hoechst Aktiengesellschaft
Röhm Gmbh
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 Hoechst Aktiengesellschaft, Röhm Gmbh filed Critical Hoechst Aktiengesellschaft
Priority to JP6508666A priority Critical patent/JPH08501766A/ja
Priority to EP93921844A priority patent/EP0663893A1/fr
Publication of WO1994007808A1 publication Critical patent/WO1994007808A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/63424—Polyacrylates; Polymethacrylates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/632—Organic additives
    • C04B35/634—Polymers
    • C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C04B35/6344—Copolymers containing at least three different monomers

Definitions

  • the present invention relates to a casting compound containing ceramic powder, binder and dispersion medium which is suitable for producing green ceramic films by the film casting process.
  • the film casting process essentially provides for the dispersion of fine powder in a dispersion medium, with binder and plasticizer also expediently being added at the same time.
  • the casting compound formed in this way is poured onto a moving carrier surface and forms a layer there with a layer thickness that is as uniform as possible.
  • a more or less flexible film is obtained which can be further processed into green molded parts by cutting, punching, embossing or stacking, the molded parts are then subsequently subjected to a sintering process.
  • Organic solvents or solvent mixtures are usually used as the dispersion medium for the preparation of ceramic casting compounds for shaping by the film casting process.
  • Organic solvents such as trichlorethylene, toluene, MEK, ethanol or methanol are either easily flammable or their mass use is sometimes unsafe for health reasons.
  • the object of the invention was to provide a water-based casting compound which has good water processability, i.e. which does not tend to agglomerate during its production and does not form any disruptive bonds with the mixing and pouring units, and which at the same time ensures that the green film formed therefrom has a satisfactory storage and further processing capability, i.e. Under no circumstances should embrittlement and cracks appear in the green film during storage and transport to the processing units.
  • it must always be ensured that the green film formed from the casting compound has sufficient redispersibility in order to return the waste material as recyclate to the manufacturing process of the green film and thus to maintain the economical production of ceramic molded parts.
  • a casting compound of the type mentioned essentially contains water as a dispersion medium and that it contains, as a binder, an emulsion copolymer which comprises 95 to 75% by weight of esters of acrylic and / or methacrylic acid and is 5 to 25 wt .-% of ⁇ ,? -ethylenically unsaturated carboxylic acids, in an amount of 2.0 to 10 wt .-%, based on the total weight of the casting composition, the emulsion copolymer in Form of microspheres with an average particle size, expressed as weight average d w , in the range from 75 to 150 nm.
  • esters of acrylic or methacrylic acid are methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethyl (meth) acrylate, Glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, tert-butyl (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide and (meth) acrylonitrile, while mentioning as ⁇ , ß-ethylenically unsaturated carboxylic acids in addition to acrylic acid and methacrylic acid also crotonic acid, maleic acid, itaconic acid or their half esters can be used.
  • the particle size distribution of the microspheres of the emulsion copolymer should preferably be narrow, in particular the quotient of the weight-average particle size d w and the number-average particle size d n should be a value of less than 1.3.
  • the particle size distribution d w / d n is a measure for assessing the uniformity of dispersion particles. It is defined as the quotient of the weight average of the particle diameter d w and its number average d n . If the particles are completely uniform, the quotient can assume the value 1, inconsistencies result in numerical values greater than 1 (see UEWoods et al., Journal of paint technology, Vol. 40, No. 527 (1968), page 545).
  • the particle size can be measured by known methods, for example by electron microscopy (SHMaron et al., Journal of applied Physics Vol. 23, (1952), p. 900).
  • the emulsion copolymers suitable as binders should preferably have a glass transition temperature T g in the range from -10 to + 10 ° C. Your minimum film forming temperature (MFT) should be between 0 and 5 ° C.
  • the acid content of the emulsion copolymers is preferably between 15 and 25 mol%.
  • the binder suitable for the casting composition according to the invention can contain, in addition to the emulsion copolymer, further water-soluble binders up to a maximum amount of 2% by weight, based on the total weight of the casting composition.
  • Water-soluble binders can contain both ionic polymers such as polyacrylic / methacrylic acid salts, copolymers such as polyacrylic / methacrylic ester / acid mixtures, cellulose derivatives or similar and non-ionic products such as polyvinyl alcohol, polyacrylamide or cellulose ether.
  • a good solubility of the binder results in good redispersibility, which at the same time results in a high sensitivity to moisture in the green film and can therefore have a negative effect on the physical properties of the green film, in particular on storage behavior.
  • a binder with a low sensitivity to moisture is selected, serious problems with the redispersion of waste material can result and the production shifts towards inefficiency.
  • a high solids content in the casting compound is important for achieving a high green density, but a high solids content also inevitably leads to viscosity and processing problems.
  • a higher drying temperature can adversely affect the redispersion behavior.
  • Good re-dispersibility of the green sheets must be provided for the reprocessing of film waste.
  • the binder should preferably be present in an amount of 3.0 to 6.0% by weight.
  • Glycerin, mono- or diethylene glycol or polyethylene glycol may also be present as plasticizers in the casting composition according to the invention, the plasticizing agents mentioned being present in the casting composition in an amount of 0 to 2.0% by weight, based on the total weight of the casting composition.
  • Suitable ceramic materials that are suitable for the casting compound according to the invention are metal oxides or non-oxides, which usually play a role in the production of ceramic molded parts for technical applications.
  • the ceramic powders can be used both alone and in mixtures.
  • Particularly typical ceramic powders include the oxides, carbides, nitrides, borides and sulfides of lithium, potassium, beryllium, magnesium, Boron, aluminum, silicon, copper, calcium, strontium, barium, zinc, cadmium, gallium, indium, titanium, zircon, bismuth or manganese.
  • the said ceramic powders can be contained in the casting compound in amounts of 70 to 85% by weight, preferably 75 to 80% by weight, based in each case on the total weight of the casting compound.
  • the dispersion medium for the casting compound according to the invention is essentially water and is used in an amount in the range from 15 to 20% by weight, based on the total weight of the casting compound. Smaller amounts of alcohol, higher-quality alcohol or silicones can be added to the dispersion medium as defoamers, smaller amounts of up to 0.5% by weight, preferably up to 0.1% by weight, based on the total weight of those used, according to the invention Casting compound to be understood.
  • a dispersant is added to stabilize the ceramic powder particles in solution to prevent sedimentation.
  • Salts of ⁇ , ⁇ -ethylenically unsaturated carboxylic acids, ionic and nonionic surfactants or carboxylic acid mixtures can be used as dispersants.
  • the casting compound according to the invention offers particular advantages in achieving a uniform film surface.
  • the H O content of the casting composition according to the invention is low in comparison with the literature, which at the same time results in a high solids content, and that nevertheless a readily processable composition can be obtained.
  • the casting compound according to the invention produces ceramic films with a high green density and thus a low sintering shrinkage.
  • Hostapal BV 50% sulfuric acid half ester of an ethoxylated
  • the result is an emulsion copolymer of methyl methacrylate, butyl acrylate and methacrylic acid / acrylic acid in a weight ratio of 35:65:10 and with a weight-average particle size of 120 nm and a particle size distribution d w / d n of 1.18.
  • ⁇ (ammonium polyacrylate, e.g. Dolapix CA, manufacturer Zschimmer and Schwarz,
  • ® rotational viscometer Haake RV 50, Fa. Häake
  • the slip is cast on a laboratory film casting machine, dried in a drying channel with preheated air up to 90 ° C in the counterflow principle.
  • the green film obtained (0.8 mm thick) is characterized by the green density. For this purpose, 3 test pieces are punched out of the film, precisely measured and weighed, and the green density is thus determined geometrically.
  • the surface of the film can be characterized by viewing it against the light. Specks or holes can be easily recognized.
  • test pieces are punched out of the green film obtained, measured and sintered at 1600 ° C. to form a dense body. The sintering shrinkage is determined by measuring the ceramic parts obtained.
  • a piece of green film is mixed with the amount of water from the original slip mixture and ground in a mortar. After 3 minutes, the slip obtained is poured out. If a lump-free film with comparable flexibility to the original film is created, it is recyclable. If a lumpy or brittle film is formed, it cannot be recycled.
  • Example 1 According to Example 1, a green sheet was obtained which had a green density of 2.40 g / cm 3 .
  • the green film was free of specks and was easy to recycle.
  • the sintering shrinkage was 19.5%.
  • Example 1 an emulsion copolymer was prepared which contained the same monomer units as in Example 1, but in a weight ratio of 50: 50: 3.
  • the green sheet produced with this emulsion copolymer in accordance with Example 1 had a spotty surface and was not recyclable.
  • Example 1 an emulsion copolymer of the same composition was produced, but with a weight-average particle size of 200 nm.
  • the slip produced with this emulsion copolymer in accordance with Example 1 showed a high tendency to dilatancy, which means increasing viscosity with increasing shear; therefore this slip could not be processed further.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

L'invention concerne une matière de coulée contenant de la poudre céramique, des liants et un milieu de dispersion, qui se prête à la fabrication de feuilles céramiques crues, selon le procédé de coulage de feuilles. Cette matière de coulée contient comme milieu de dispersion essentiellement de l'eau et comme liant un copolymère d'émulsion constitué d'entre 95 et 75 % en poids d'esters d'acide acrylique et/ou d'acide méthacrylique et d'entre 5 à 25 % en poids d'acides carboxyliques insaturés α,β-éthyléniquement, dans une quantité comprise entre 2,0 et 10 % en poids, par rapport au poids total de la matière de coulée. Selon l'invention, le copolymère d'émulsion se présente sous forme de microsphères ayant une granulométrie moyenne, exprimée en moyenne de poids dw, de l'ordre de 75 à 150 nm.
PCT/EP1993/002584 1992-10-06 1993-09-23 Matiere de coulee pour fabriquer des feuilles ceramiques crues et moulages ceramiques ainsi realises WO1994007808A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP6508666A JPH08501766A (ja) 1992-10-06 1993-09-23 グリーンセラミックシートを製造するための水性注型組成物およびそれより製造される造形されたセラミック製品
EP93921844A EP0663893A1 (fr) 1992-10-06 1993-09-23 Matiere de coulee pour fabriquer des feuilles ceramiques crues et moulages ceramiques ainsi realises

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4233518.3 1992-10-06
DE4233518A DE4233518C1 (de) 1992-10-06 1992-10-06 Wäßrige Gießmasse zur Herstellung von grünen Keramikfolien und daraus hergestellte Keramikformteile

Publications (1)

Publication Number Publication Date
WO1994007808A1 true WO1994007808A1 (fr) 1994-04-14

Family

ID=6469715

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1993/002584 WO1994007808A1 (fr) 1992-10-06 1993-09-23 Matiere de coulee pour fabriquer des feuilles ceramiques crues et moulages ceramiques ainsi realises

Country Status (4)

Country Link
EP (1) EP0663893A1 (fr)
JP (1) JPH08501766A (fr)
DE (1) DE4233518C1 (fr)
WO (1) WO1994007808A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0897196A1 (fr) * 1997-08-13 1999-02-17 Siemens Aktiengesellschaft Procédé de fabrication d'un composant isolant pour une pile combustible fonctionnant à haute température et pile à combustible
WO2000043328A1 (fr) * 1999-01-20 2000-07-27 Siemens Aktiengesellschaft Matiere a couler ceramique aqueuse, procede de preparation et d'utilisation de ladite matiere
EP1090890A3 (fr) * 1999-10-05 2002-01-02 Rohm And Haas Company Procédé de préparation de compositions céramiques
WO2002018300A1 (fr) * 2000-09-01 2002-03-07 Epcos Ag Barbotine de ceramique et procede de production d"une feuille ceramique verte
CN1125794C (zh) * 1999-02-05 2003-10-29 北京航空材料研究院 陶瓷复合粉体合成方法
US6790907B2 (en) * 2000-06-29 2004-09-14 Murata Manufacturing Co. Ltd. Ceramic slurry composition and manufacturing method therefor
WO2004110954A1 (fr) 2003-06-10 2004-12-23 Robert Bosch Gmbh Procede pour produire des feuilles vertes ceramiques destinees a des composants ceramiques
CN1321090C (zh) * 2004-04-09 2007-06-13 中国航空工业第一集团公司北京航空材料研究院 复合陶瓷粉体的酶催化凝胶反应合成方法
US7713896B2 (en) 2004-04-14 2010-05-11 Robert Bosch Gmbh Method for producing ceramic green compacts for ceramic components

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19940653A1 (de) * 1999-08-26 2001-03-01 Franz Koppe Verfahren zur Herstellung eines Körpers aus Porzellan
KR100587461B1 (ko) * 2004-06-17 2006-06-09 전자부품연구원 그린 쉬트용 슬러리 조성물 및 그로부터 제조되는 그린 쉬트

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4329271A (en) * 1980-12-15 1982-05-11 Gte Products Corporation Flexible ceramic tape and method of making same
EP0237273A1 (fr) * 1986-03-07 1987-09-16 BASF Aktiengesellschaft Céramique
WO1988007505A1 (fr) * 1987-04-01 1988-10-06 Ceramics Process Systems Solution liante polymerisable pour des coulis de particules hautement charges, a faible viscosite et procedes de fabrication derivee d'articles
US4836966A (en) * 1984-03-15 1989-06-06 Isoo Shimuzu Binder for ceramics
JPH01289804A (ja) * 1988-05-17 1989-11-21 Mizutani Paint Kk 水分散型樹脂組成物
JPH03150257A (ja) * 1989-11-04 1991-06-26 Daiichi Seramo:Kk 射出成形用組成物およびそれからの焼結体
EP0511429A1 (fr) * 1989-11-04 1992-11-04 Dai-Ichi Ceramo Co., Limited Composition pour compactage par injection, pour la préparation des corps frittés

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4329271A (en) * 1980-12-15 1982-05-11 Gte Products Corporation Flexible ceramic tape and method of making same
US4836966A (en) * 1984-03-15 1989-06-06 Isoo Shimuzu Binder for ceramics
EP0237273A1 (fr) * 1986-03-07 1987-09-16 BASF Aktiengesellschaft Céramique
EP0428177A2 (fr) * 1986-03-07 1991-05-22 BASF Aktiengesellschaft Céramique
WO1988007505A1 (fr) * 1987-04-01 1988-10-06 Ceramics Process Systems Solution liante polymerisable pour des coulis de particules hautement charges, a faible viscosite et procedes de fabrication derivee d'articles
JPH01289804A (ja) * 1988-05-17 1989-11-21 Mizutani Paint Kk 水分散型樹脂組成物
JPH03150257A (ja) * 1989-11-04 1991-06-26 Daiichi Seramo:Kk 射出成形用組成物およびそれからの焼結体
EP0511429A1 (fr) * 1989-11-04 1992-11-04 Dai-Ichi Ceramo Co., Limited Composition pour compactage par injection, pour la préparation des corps frittés

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 9001, Derwent World Patents Index; AN 90-005252 *
PATENT ABSTRACTS OF JAPAN vol. 015, no. 373 (C - 0689) 19 September 1991 (1991-09-19) *
See also references of EP0663893A1 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0897196A1 (fr) * 1997-08-13 1999-02-17 Siemens Aktiengesellschaft Procédé de fabrication d'un composant isolant pour une pile combustible fonctionnant à haute température et pile à combustible
WO2000043328A1 (fr) * 1999-01-20 2000-07-27 Siemens Aktiengesellschaft Matiere a couler ceramique aqueuse, procede de preparation et d'utilisation de ladite matiere
US6521686B1 (en) 1999-01-20 2003-02-18 Siemens Aktiengesellschaft Aqueous ceramic casting material, method for producing said casting material and use of the same
CN1125794C (zh) * 1999-02-05 2003-10-29 北京航空材料研究院 陶瓷复合粉体合成方法
EP1090890A3 (fr) * 1999-10-05 2002-01-02 Rohm And Haas Company Procédé de préparation de compositions céramiques
US6790907B2 (en) * 2000-06-29 2004-09-14 Murata Manufacturing Co. Ltd. Ceramic slurry composition and manufacturing method therefor
WO2002018300A1 (fr) * 2000-09-01 2002-03-07 Epcos Ag Barbotine de ceramique et procede de production d"une feuille ceramique verte
WO2004110954A1 (fr) 2003-06-10 2004-12-23 Robert Bosch Gmbh Procede pour produire des feuilles vertes ceramiques destinees a des composants ceramiques
CN1321090C (zh) * 2004-04-09 2007-06-13 中国航空工业第一集团公司北京航空材料研究院 复合陶瓷粉体的酶催化凝胶反应合成方法
US7713896B2 (en) 2004-04-14 2010-05-11 Robert Bosch Gmbh Method for producing ceramic green compacts for ceramic components

Also Published As

Publication number Publication date
EP0663893A1 (fr) 1995-07-26
DE4233518C1 (de) 1994-08-25
JPH08501766A (ja) 1996-02-27

Similar Documents

Publication Publication Date Title
DE4233518C1 (de) Wäßrige Gießmasse zur Herstellung von grünen Keramikfolien und daraus hergestellte Keramikformteile
DE3801326A1 (de) Verfahren zur herstellung einer keramiksuspension
DE3874480T2 (de) Schichtfoermige gruene keramik.
JP3823759B2 (ja) セラミックスラリー組成物の製造方法
EP0588171B1 (fr) Procédé de transformation de poudres céramiques sensibles à l'eau en une poudre granulée apte à l'écoulement
JP3119837B2 (ja) 水で清浄化可能な銀組成物
DE4316924C2 (de) Gießmasse zur Herstellung von grünen Keramikfolien enthaltend Polyvinylalkohol-Fettsäureester als Dispergiermittel, Verfahren zur Herstellung von grünen Keramikfolien und eines keramischen Substrats
EP1854772B1 (fr) Procédé de préparation des feuilles en matière céramique crue avec de l'alcool polyvinylique acétalisé
DE60008830T2 (de) Verfahren zur Herstellung von keramischen Zusammensetzungen
DE2812014C3 (de) Nicht wäßrige Polymerisatplastisol- oder -organosoldispersionen
DE69206645T2 (de) Suspensionzusammensetzung und daraus hergestellten gesinterten Teil
DE69304897T2 (de) Verfahren zur Herstellung eines wässerigen schlickers enthaltend ein feuchtigkeitsbeständiges Aluminiumnitridpulver
DE69021663T2 (de) Wasserlösliches Zellulose-Bindemittel zum Foliengiessen von Keramik.
EP0441219B1 (fr) Barbotine pour la réalisation de feuilles céramiques en cru et leur utilisation
US5368795A (en) Use of ethylene/vinyl acetate polymer binders as drying pressing aids for ceramic powders
DE69213334T2 (de) Verfahren und Zusammensetzung zum Binden keramischer Pulver
CN110922194A (zh) 陶瓷浆料及其制备方法
DE69003717T2 (de) Verfahren zur Herstellung teilchenförmiger keramischer Materialien.
DE19928918B4 (de) Keramischer Schlicker und Verfahren zur Herstellung keramischer Grünkörper mit dem Schlicker
DE4431363A1 (de) Ionisch leitende Keramik
DE3809350A1 (de) Verfahren zur erhoehung der brennschwindung von keramischen foliengiessmassen
DE3724108C2 (fr)
EP3368204A1 (fr) Dispersion métallique à stabilité accrue
DE4003198A1 (de) Giessmasse zur herstellung keramischer gruenfolien und ihre verwendung
DE3149796C2 (fr)

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): JP US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 1993921844

Country of ref document: EP

ENP Entry into the national phase

Ref country code: US

Ref document number: 1995 406987

Date of ref document: 19950404

Kind code of ref document: A

Format of ref document f/p: F

WWP Wipo information: published in national office

Ref document number: 1993921844

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 1993921844

Country of ref document: EP