Ceramic and glass ceramic slips for stereolithography

1. Slip for stereolithographic preparation of ceramic or glass ceramic shaped parts, wherein said slip comprises

(a) at least one radically polymerizable monomer,

(b) at least one photoinitiator and

(c) ceramic and/or glass ceramic particles,

characterized in that said slip comprises

(d) at least one non-ionic surfactant, wherein said slip comprises as non-ionic surfactant (d)

a fatty acid ester of hydrogenated sugars with the formula R′—CO—O-sugar in which R′ is a branched or straight-chain alkyl radical with 10 to 25 carbon atoms and “sugar” means a hydrogenated sugar radical which is ethoxylated 1 to 5 times or not ethoxylated, and/or

a fatty acid ethoxylate of the general formula R″—(CO)—(OCH 2 CH 2 ) m —OH in which R″ is a branched or straight-chain alkyl radical with 10 to 25 carbon atoms and m is an integer from 2 to 20, and/or

a polyalkylene glycol ether with the general formula R—(OCH 2 CH 2 ) n —OH in which R is an alkyl radical with 10 to 20 carbon atoms and n is an integer from 2 to 25.

2. Slip according to claim 1 , wherein said slip comprises as non-ionic surfactant (d), a surfactant with a melting point of from 30° C. to 120° C.

3. Slip according to claim 1 , wherein said slip comprises as non-ionic surfactant a surfactant with an HLB value of from 3 to 16.

4. Slip according to claim 1 , wherein said slip comprises as monomer (a) at least one (meth)acrylate and/or (meth)acrylamide.

5. Slip according to claim 1 , wherein said slip comprises as component (c) ceramic particles based on ZrO 2 , Al 2 O 3 or ZrO 2 —Al 2 O 3 , or based on ZrO 2 , Al 2 O 3 , ZrO 2 —Al 2 O 3 which is stabilized in each case with HfO 2 , CaO, Y 2 O 3 , CeO 2 and/or MgO.

6. Slip according to claim 1 , wherein said slip comprises as component (c) glass ceramic particles based on leucite, apatite and/or lithium disilicate glass ceramic.

7. Slip according to claim 1 , wherein the particles of component (c) have a particle size in the range of from 10 nm to 100 μm.

8. Slip according to claim 1 , wherein said slip additionally comprises at least one surface modification agent and/or at least one additive which is selected from dyes, solvents, inhibitors, debinding accelerators, defoaming agents and/or antiskinning agents.

9. Slip according to claim 8 , wherein

the surface modification agent is selected from linear or branched carboxylic acids, formic acid, acetic acid, propionic acid, octanoic acid, isobutyric acid, isovaleric acid, pivalic acid, phosphoric acids, methyl-, ethyl-, propyl-, butyl-, hexyl-, octyl- or phenylphosphonic acid, propyltrimethoxysilane, phenyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, trimethylchlorosilane, trimethylbromosilane, trimethylmethoxysilane or hexamethyldisilazane, acidic phosphoric acid esters, dimethyl, diethyl, dipropyl, dibutyl, dipentyl, dihexyl, dioctyl or di(2-ethylhexyl) phosphate; and/or

the dye is selected from organic dyes comprising azo dyes, carbonyl dyes, cyanine dyes, azomethine, methine, phthalocyanine, dioxazine, (4-(4-nitrophenylazo)aniline or a mixture thereof; and/or

the solvent is selected from polyethylene glycols, poly-propylene glycols, PEG-PPG co-polymers, glycerol and glycerol derivatives, phthalates, PEG 200-600 g/mol, PPG 200-800 g/mol, co-PEG-PPG 200-800 g/mol and polypropylene glycol ˜400 g/mol and mixtures thereof.

10. Slip according to claim 1 comprising

5 to 65 wt.-% monomer (a);

0.001 to 1.0 wt.-% photoinitiator (b);

33 to 90 wt.-% ceramic and/or glass ceramic particles (c);

1 to 30 wt.-% non-ionic surfactant (d).

11. Process of using the slip according to claim 1 for the preparation of ceramic or glass ceramic dental restorative shaped parts comprising an inlay, onlay, veneer, crown, bridge or framework.

12. Process for the preparation of a ceramic or glass ceramic shaped part, wherein

(A) a green compact is prepared by curing a slip according to claim 1 by local introduction of radiation energy accompanied by the formation of the geometric shape of the green compact,

(B) the green compact is then subjected to a heat treatment to remove the binder (debinding), in order to obtain a white body, and

(C) the white body is sintered.

13. Slip according to claim 2 , wherein the melting point of the non-ionic surfactant (d), is in the range of 40° C. to 100° C.

14. Slip according to claim 3 , wherein the HLB value of the non-ionic surfactant is in the range of 4 to 13.

15. Slip according to claim 10 comprising

9 to 57 wt.-% monomer (a);

0.01 to 1.0 wt.-%, wt.-% photoinitiator (b);

40 to 88 wt.-% ceramic and/or glass ceramic particles (c);

2 to 15 wt.-% non-ionic surfactant (d).

16. Slip according to claim 10 comprising

10 to 40 wt.-% monomer (a);

0.1 to 1.0 wt.-% photoinitiator (b);

56 to 86 wt.-% ceramic and/or glass ceramic particles (c);

3 to 10 wt.-% non-ionic surfactant (d).

17. Slip according to claim 2 , wherein the melting point of the non-ionic surfactant (d), is in the range of 40° C. to 60° C.

18. Slip according to claim 3 , wherein the HLB value of the non-ionic surfactant is in the range of 4 to 10.