Process of producing a surface-modified 3-dimensional article
A process of producing a surface-modified 3-dimensional article, the process comprising the steps of providing a radiation-curable composition, building-up a 3-dimensional article by radiation-curing the radiation-curable composition layer by layer, preferably by using a stereolithography or digital light processing unit, partially removing radiation-curable composition which sticks to the surface of the 3-dimensional article, treating only a portion of the surface of the 3-dimensional article to which the radiation-curable composition is stuck with particles, applying an additional curing step to the 3-dimensional article, preferably by applying heat and/or radiation. A 3-dimensional article which can be obtained by such a process and a kit of parts comprising such a 3-dimensional article.
1. A process of producing a surface-modified 3-dimensional article, the surface-modified 3-dimensional article having the shape of a dental or orthodontic article, the process comprising the steps of:
providing a radiation-curable composition, the radiation curable composition comprising (meth)acrylate components, photo-initiator, optionally dye(s) and optionally filler(s),
building-up a 3-dimensional article by radiation-curing the radiation-curable composition layer by layer using a stereolithography or digital light processing unit,
partially removing radiation-curable composition which sticks to the surface of the 3-dimensional article, the remaining radiation-curable composition forming a layer on the surface of the 3-dimensional article,
treating only a portion of the surface of the 3-dimensional article to which the radiation-curable composition is stuck with particles in a manner enabling at least a portion of the particles to become partially embedded in the radiation-curable composition which remained on the surface of the 3-dimensional article, and
applying an additional curing step to the 3-dimensional article by applying heat or radiation to at least the treated portion of the surface of the 3-dimensional article,
the treating step being adjusted to achieve a surface roughness Ra of 1 to 20 μm.
2. The process according to the claim 1 , the thickness of the layer formed by the remaining radiation-curable composition being in a range of 1 to 500 μm.
3. The process according to claim 1 , the additional curing step being characterized by the following features alone or in combination:
applying radiation with a wavelength of 350 to 450 nm, or
applying a heating step of 30 to 120° C.
4. The process according to claim 1 , the particles being characterized by the following features alone or in combination:
average particle size: 1 to 150 μm; or
density: 2 to 6 g/cm 3 .
5. The process according to claim 1 , the material of the particles being selected from glass powder, metal oxide or hydroxide powder, and mixtures thereof.
6. The process according to claim 1 , the radiation-curable composition being characterized by the following feature:
viscosity: 1 to 400 Pas at 23° C., and a shear rate of 1 s −1 .
7. The process according to claim 1 , the treating step comprising the following steps alone or in combination:
applying the particles with a gas stream with a working pressure in the range of 0.5 to 500 kPa or with a particle flow rate in the range of 0.01 to 10 g/s; or
applying the particles by coating.
8. The process according to claim 1 , the partially removing of the radiation-curable composition being done by applying either of the following process steps alone or in combination:
rotating the 3-dimensional article to generate a mass inertial force;
using a cleaning composition;
storing the 3-dimensional article for a time sufficient to allow the radiation-curable composition to drop or flow from the surface of the 3-dimensional article; or
applying a gas stream.
9. The process according to claim 1 , the process being characterized as follows:
the radiation-curable composition comprising (meth)acrylate component(s), photo-initiator(s), filler(s) and optionally dye(s), wherein the filler(s) do not contain particles with a size above 1 μm, and having a viscosity in the range of 5 to 100 Pa*s at 23° C., and a shear rate of 1 s −1 , and
the particles used for the treating step having an average particle size in the range of 1 to 150 μm, and being selected from glass powder, metal oxide powder, hydroxide powder and mixtures thereof,
the x, y, z dimensions of the 3-dimensional article being in a range of 1 to 100 mm for each dimension.
10. A 3-dimensional article obtained or obtainable by the process described in claim 1 .
11. The process according to claim 1 , wherein the 3-dimensional article is subjected to a post-curing step under reduced pressure in the range of 1 to 100 mbar.