EP0663893A1 - 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

Info

Publication number
EP0663893A1
EP0663893A1 EP93921844A EP93921844A EP0663893A1 EP 0663893 A1 EP0663893 A1 EP 0663893A1 EP 93921844 A EP93921844 A EP 93921844A EP 93921844 A EP93921844 A EP 93921844A EP 0663893 A1 EP0663893 A1 EP 0663893A1
Authority
EP
European Patent Office
Prior art keywords
casting compound
meth
weight
acrylate
compound according
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.)
Withdrawn
Application number
EP93921844A
Other languages
German (de)
English (en)
Inventor
Friedrich Hessel
Ute STÜRMER
Andreas Roosen
Joseph Thevissen
Helmut Rinno
Hans Trabitzsch
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.)
Hoechst AG
Roehm GmbH Darmstadt
Original Assignee
Hoechst AG
Roehm GmbH Darmstadt
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 AG, Roehm GmbH Darmstadt filed Critical Hoechst AG
Publication of EP0663893A1 publication Critical patent/EP0663893A1/fr
Withdrawn legal-status Critical Current

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 Oxide Ceramics (AREA)
  • Compositions Of Macromolecular Compounds (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.
EP93921844A 1992-10-06 1993-09-23 Matiere de coulee pour fabriquer des feuilles ceramiques crues et moulages ceramiques ainsi realises Withdrawn EP0663893A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4233518A DE4233518C1 (de) 1992-10-06 1992-10-06 Wäßrige Gießmasse zur Herstellung von grünen Keramikfolien und daraus hergestellte Keramikformteile
DE4233518 1992-10-06
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

Publications (1)

Publication Number Publication Date
EP0663893A1 true EP0663893A1 (fr) 1995-07-26

Family

ID=6469715

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93921844A Withdrawn EP0663893A1 (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)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE59706045D1 (de) * 1997-08-13 2002-02-21 Siemens Ag Verfahren zum Herstellen einer isolierenden Komponente für eine Hochtemperatur-Brennstoffzelle und Hochtemperatur-Brennstoffzelle
WO2000043328A1 (fr) * 1999-01-20 2000-07-27 Siemens Aktiengesellschaft Matiere a couler ceramique aqueuse, procede de preparation et d'utilisation de ladite matiere
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
DE19940653A1 (de) 1999-08-26 2001-03-01 Franz Koppe Verfahren zur Herstellung eines Körpers aus Porzellan
DE60008830T2 (de) * 1999-10-05 2005-01-13 Rohm And Haas Co. Verfahren zur Herstellung von keramischen Zusammensetzungen
JP3823759B2 (ja) * 2000-06-29 2006-09-20 株式会社村田製作所 セラミックスラリー組成物の製造方法
DE10043202A1 (de) * 2000-09-01 2002-03-28 Epcos Ag Keramikschlicker, Verfahren zur Herstellung einer keramischen Grünfolie und Verwendung des Verfahrens
DE10326040A1 (de) 2003-06-10 2004-12-30 Robert Bosch Gmbh Verfahren zur Herstellung von keramischen Grünfolien für keramische Bauteile
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
KR100587461B1 (ko) * 2004-06-17 2006-06-09 전자부품연구원 그린 쉬트용 슬러리 조성물 및 그로부터 제조되는 그린 쉬트

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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

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* 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
KR920000160B1 (ko) * 1984-03-15 1992-01-09 니혼 세끼유 가가꾸 가부시끼가이샤 세라믹용 수용성 공중합체성 결합제의 제조방법
US4968460A (en) * 1986-03-07 1990-11-06 Basf Aktiengesellschaft Ceramics
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
US5278250A (en) * 1989-11-04 1994-01-11 Del-Ichi Ceramo Co., Limited Process for preparing organic binder

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 9001, Derwent Publications Ltd., London, GB; AN 90-005252 & JP *
DATABASE WPI Week 9001, Derwent Publications Ltd., London, GB; AN 90-005252 & JP,A,1 289 804 (MIZUTANI PAINT) 21. November 1989 s *
DATABASE WPI, Woche 9001, Derwent Publications Ltd., London (GB); AN 90-005252 *
PATENT ABSTRACTS OF JAPAN vol. 015, no. 373 (C-0689)19. September 1991 & JP,A, 03 150 257 (DAIICHI) 26. Juni 1991 s *
PATENT ABSTRACTS OF JAPAN, Band 15, Nr. 373 (C-0689), 10. September 1991 *
See also references of WO9407808A1 *

Also Published As

Publication number Publication date
JPH08501766A (ja) 1996-02-27
DE4233518C1 (de) 1994-08-25
WO1994007808A1 (fr) 1994-04-14

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