Method for joining ceramic green bodies using a transfer tape and conversion of bonded green body into a ceramic body
View Patent ↗The invention relates to a ceramic green body consisting of at least two ceramic bodies that are bonded together. The invention is characterized in that the green body is produced using an adhesive tape that consists of an adhesive film located on a release liner.
1. A composite green ceramic body comprising at least two green ceramic bodies adhesively bonded to one another with an adhesive film, wherein the adhesive film is oriented and comprises copolymers of acrylates and methacrylates, but the adhesive film does not comprise ceramic powder.
2. A composite green ceramic body as claimed in claim 1 , wherein the adhesive film has a thickness of from 2 to 50 μm.
3. The composite green ceramic body as claimed in claim 2 , wherein the adhesive film has a thickness of from 5 to 25 μm.
4. A composite green ceramic body as claimed in claim 1 , wherein a mixture of derivatives of acrylic acid and/or methacrylic acid corresponding to the formula:
CH 2 =CH(R 1 ) (COOR 2 )
where
R 1 =H or CH 3 and
R 2 =a branched or unbranched alkyl chain having from 2 to 20 carbon atoms, and
olefinically unsaturated monomers having functional groups,
is used as starting material for the adhesive film.
5. A composite green ceramic body as claimed in claim 4 , wherein crosslinkers, photoinitiators, resins or mixtures thereof have been added to the adhesive film.
6. A composite green ceramic body as claimed in claim 1 , wherein crosslinkers, photoinitiators, resins or mixtures thereof have been added to the adhesive film.
7. A composite green ceramic body as claimed in claim 6 , wherein one or more additives selected from the group consisting of aging inhibitors, light stabilizers, agents to protect against ozone, fatty acids, compounding aids, and accelerators have been added to the adhesive film.
8. A method of producing the composite green ceramic body of claim 1 , comprising:
(a) applying an adhesive film to at least one region and at least one side of a first green ceramic body, said adhesive film being applied attached on one side to a release liner, wherein the adhesive film is oriented and comprises copolymers of acrylates and methacrylates, but the adhesive film does not comprise ceramic powder;
(b) removing the release liner and adhesively bonding the first green ceramic body with a second green ceramic body; and
(c) optionally, adhesively bonding one or more additional green ceramic body/bodies.
9. A method of producing a composite green ceramic body as claimed in claim 8 , wherein after applying the adhesive film and removing the release liner, the adhesive bonding of the first and second green ceramic bodies is by means of pressure.
10. A method of producing a composite green ceramic body as claimed in claim 8 , wherein the first and second green ceramic bodies are produced from green ceramic sheets with at least two green ceramic sheets adhesively bonded to one another, wherein the at least two green sheets are unmetallized, metallized or mixtures thereof.
11. A method of producing a composite green ceramic body as claimed in claim 8 , wherein processing is carried out continuously from rolls.
12. A method of sintering a ceramic which comprises:
(a) subjecting the composite green ceramic body of claim 1 to at least one heat treatment during which the polymer matrix of the green ceramic sheets is thermally decomposed and/or vaporized;
(b) decomposing the adhesive film of the composite green ceramic body; and
(c) sintering the composite green ceramic body to a ceramic.
13. The method of claim 12 , wherein there is no drying step.
14. The method of claim 13 , wherein sintering is carried out at temperatures of from 700° C. to 2000° C.