Paint composition and filler for such a paint composition

Abstract

The present invention relates to a filler for a paint composition, wherein the filler comprises a calcinate having particles with an average particle size (d.sub.50, SediGraph III) in the range between 3 m and 50 m and a mullite content of 30-70 measured as mullite index. The invention is characterised in that the bulk density of the filler is >450 g/L. The invention also relates to a paint composition characterised in that it comprises a filler which has a bulk density>450 g/L and comprises a calcinate which has particles with a mean particle size (d.sub.50, SediGraph III) in the range between 3 m and 50 m and a mullite content of 30-70 measured as mullite index. Furthermore, the invention relates to uses of such a filler for the preparation of a paint composition.

Claims

1. A filler for a paint composition, the filler comprising: a calcinate having particles with an average particle size (d.sub.50, SediGraph III) in a range between 3 micrometers and 50 micrometers; and a mullite content of 30-70 measured as a mullite index, wherein a bulk density of the filler is greater than 600 grams per liter, wherein at least 50% of the particles of the calcinate have at least one flat surface, and wherein the proportion of an associated side surface of the respective particle is at least 25%.

2. The filler according to claim 1, wherein the particles of the calcinate have an average particle size (d.sub.50, SediGraph III) in a range between 5 micrometers and 45 micrometers.

3. The filler according to claim 1, wherein the filler has a bulk density in a range from 620 to 680 grams per liter.

4. The filler according to claim 1, wherein the filler has an oil absorption according to DIN EN ISO 787-5:1995-10 of less than 50 g/100 g.

5. The filler according to claim 1, wherein at least 50% of the particles of the calcinate have an edgy morphology.

6. The filler according to claim 1, wherein the particles of the calcinate have an average particle size (d.sub.50, SediGraph III) in the range between 7 micrometers and 50 micrometers.

7. The filler according to claim 1, wherein the particles of the calcinate have an average particle size (d.sub.50, SediGraph III) in the range between 8 micrometers and 40 micrometers.

8. The filler according to claim 1, wherein the filler has an oil absorption according to DIN EN ISO 787-5:1995-10 of less than 40 g/100 g.

9. The filler according to claim 1, wherein the filler has an oil absorption according to DIN EN ISO 787-5:1995-10 of less than 30 g/100 g.

10. The filler according to claim 1, wherein at least 75% of the particles of the calcinate have an edgy morphology and/or at least one flat surface, and wherein the proportion of an associated side surface of the respective particle is at least 30%.

11. The filler according to claim 1, wherein at least 80% of the particles of the calcinate have an edgy morphology and/or at least one flat surface, and wherein the proportion of an associated side surface of the respective particle is at least 40%.

12. The filler according to claim 1, wherein at least 90% of the particles of the calcinate have an edgy morphology and/or at least one flat surface, and wherein the proportion of an associated side surface of the respective particle is at least 50%.

13. The filler according to claim 1, wherein the particles have a packable substantially platelet-shaped geometry.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and embodiments of the invention will be explained with reference to the following figures and examples.

(2) In the drawings:

(3) FIG. 1a-c shows scanning electron micrograph images of filler particles described above;

(4) FIG. 2a-c shows scanning electron micrograph images of filler particles of a comparison product on the market.

DETAILED DESCRIPTION

(5) FIGS. 1a-c each show scanning electron microscope (SEM) images of filler particles according to an advantageous embodiment of this invention. FIGS. 1a and 1b show different sections of the surface on which the particles are applied at 10,000 magnification. FIG. 1c, however, shows a section of the surface, which is shown at 3000 magnification.

(6) As can be seen on the SEM images in FIGS. 1a-c, the particles of the filler essentially have an angular morphology, wherein hardly any rounded corners or edges are formed. In addition, the particles have a high proportion of planar surfaces, each of which accounts for a majority of the respective side surfaces of the particle. It can also be seen that the particle size of the particles clearly differs and results from the wide range of the mean particle size. This could contribute to the filler having a high bulk density, since the different sized angular particles with the many flat surfaces could be packed very tightly and could effectively utilize the available volume. In addition, the described morphology of the filler shown ensures good wettability with a binder, which is reflected by the low oil absorption of the particles. In connection with FIGS. 1a-c, it is pointed out that in each case a loose layer was used for the SEM images to illustrate the particles, and the arrangement of the particles relative to one another may deviate from the arrangement in the densest possible packing.

(7) As a comparison to the embodiment according to the present invention shown in FIGS. 1a-c, FIGS. 2a-c show SEM images of a filler on the market (comparative product M). This product is also calcinate particles containing a high mullite content. It can be seen that the filler particles have substantially rounded corners and edges and have virtually no flat surfaces. The recognizable surfaces essentially show a high degree of unevenness. Furthermore, the particles have a small average particle size and also the particle size band in which the particle sizes are located is narrower, which is why all particles show substantially very similar particle sizes.

(8) The substantially drop-shape or rice-grain-like shape of the particles of the comparative product shown in FIGS. 2a-c indicates that the calcination was carried out in the fluidized bed process. Larger particles appear to be agglomerates of smaller drop- or rice grain-shaped particles.

(9) In the exemplary embodiment shown, the high bulk density or the high filler content achievable in the bulk of the filler as well as in the paint composition can be explained in particular by the different morphology and the broader particle size distribution in comparison to the commercially available filler particles (see FIGS. 2a-c). In combination with the high mullite content, fillers according to the present invention can achieve the above-described advantageous properties over the prior art.

(10) The applicant reserves the right to claim all the features disclosed in the application documents as essential to the invention, provided that these are novel individually or in combination over the prior art. It is further pointed out that features which in themselves can be advantageous have also been described in the individual drawings. A person skilled in the art will immediately recognize that a particular feature described in one drawing can also be advantageous without adopting further features from this drawing. Furthermore, a person skilled in the art will recognize that advantages can also result from a combination of a plurality of features shown in individual or in different drawings.