170622 portafill h10 news letter (final sameca)

Portafill H10

Portafill H10 Naturally occurring TiO2 extender providing improved cost efficiency of waterborne decorative paints Introduction In a society where people become more and more focused on durability, making efficient use of raw materials by the paint and coating industry is only logical. Increasing raw material prices are another aspect which puts emphasis on this aspect. One example of such a raw material is TiO2. In order to make more efficient use of TiO2, Sibelco offers PORTAFILL H10.

Portafill H is produced in Sibelco’s own quarry in Greece from carefully selected, naturally occurring, platy mineral, consisting pre-dominantly of magnesium-calcium carbonate (mineral name: huntite). The chemical composition of the raw material and final product is closely monitored and particle size kept within a narrow range. There are two products available, mainly varying in fineness and whiteness: H5 and H10.

Figure 1: Mining and production location Portafill H

Portafill H10 Portafill H10 can be characterized by the following parameters:   

Particle size Particle shape Brightness

Its ultrafine particle size of ~ 1 µm makes Portafill H10 perfectly suitable to be mixed properly with the slightly finer TiO2 particles. Combined with its platy shape, this allows Portafill H10 to open up the agglomerates of TiO2 particles, therefore making more efficient use of this key raw material for decorative paints. Due to its high brightness, the impact on the color of the final coating is small (depending on the level used in the formulation).

How does it work?

Portafill H10 is most suitable for waterborn paints formulated above CPVC, but can also be used when formulated below CPVC. Its functionality stays the same: 

Above CPVC: Opening up agglomerates because not all can be wetted completely due to low binder content.



Below CPVC: Avoiding reagglomeration of the primary TiO2 particles during the evaporation of water and film formation process afterwards.

Because better use is made of the available TiO2, it is possible to either get better properties out of the paint (such as contrast ratio), or to reduce the amount of TiO2 resulting in a cost saving.

How to use?

Portafill H10 can be added to the paint mixture like any other filler, preferably after adding the TiO2. During the dispersion phase, the particle opens up the agglomerates, as shown in Figure 2.

Figure 2: TiO2 particles mixed with Portafill H

In order to guarantee stability, Sibelco recommends the use of 0.5 – 1.0 wt-% based on the total weight of the formulation of BYK LPN 22514 (or similar). This ensures stable rheology properties of the formulation during storage tests without having negative influence on other properties.

Example 1:

Portafill H10 vs. PCC

The following table shows the formulation prepared to compare Portafill H10 to PCC: Table 1: Wall paint formulation (PVC 70%)

Ingredient

Amount [g]

Amount [g]

Amount [g]

Water

238.0

238.0

238.0

BYK LPN 22514

10.0

10.0

10.0

preservative

3.0

3.0

3.0

anti-foam agent

2.0

2.0

2.0

HEC- thickener

4.0

4.0

4.0

Titanium dioxide

75.0

75.0

75.0

PCC

65.0

PCC

123.0

Portafill H10

65.0

Talcum

80.0

80.0

80.0

Calcium carbonate

205.0

205.0

205.0

Calcium carbonate

140.0

82.0

140.0

Styrene Acrcylic binder (52%)

172.0

172.0

172.0

Hydrofobically modified polyacetal/polyether thickener Water

3.0

3.0

3.0

20.0

20.0

20.0

Total

1017.0

1017.0

1017.0

Evaluated were:     

Viscosity profile Colour Wet scrub resistance Contrast ratio Gloss

50000

60000

40000

50000

Viscosity [mPa.s]

Viscosity [MPa.s]

Viscosity profile

30000 20000 10000

40000 30000 20000 10000

0

0 0

20 Shear rate

PCC (1)

PCC (2)

40

60

0

[s-1]

20 Shear rate

Portafill® H10

PCC (1)

Figure 3: Rheology profile after preparation

PCC (2)

40

60

[s-1] Portafill® H10

Figure 4: Rheology profile after 1 day

Figure 3 and Figure 4 show that the viscosity is slightly higher when using Portafill H10, caused by its platy structure. At higher shear rates, the difference becomes negligible. The higher viscosity at lower shear rate provides an additional cost saving opportunity, as it can be compensated for by lowering the amount of thickener in the formulation.

Colour Table 2: Whiteness results

Whiteness

PCC (1)

PCC (2)

Portafill® H10

Brightness L on white (300 µm wet)

96.2

96.5

96.0

Replacing 1:1, Portafill H10 is very close in whiteness to the PCC. Doubling the amount of PCC leads to a higher whiteness, mainly because the whiteness of the synthetic product exceeds the whiteness of the natural Portafill H10.

Wet Scrub resistance Table 3: Wet scrub resistance results

Scrub resistance

PCC (1)

PCC (2)

Portafill® H10

µm

29

27

29

ISO EN 13300

3

3

3

(6d @ 25 °C, 1d @ 50 °C)

The scrub resistance is very similar, so no negative side effects.

Gloss Table 4: Gloss results

Gloss

PCC (1)

PCC (2)

Portafill® H10

85° (300 µm)

3.8

3.9

3.4

With Portafill H10, an even matter finish can be obtained than already achieved by PCC.

Contrast ratio 100,0 99,0 98,0 PCC (1) 97,0

PCC (2)

96,0

Portafill® H10

95,0 94,0 150 µm wet

200 µm wet

300 µm wet

Figure 5: Contrast ratio

Figure 5 shows that Portafill H10 is clearly outperforming PCC when looking at contrast ratio at a similar loading level, and even outperforms PCC when this loading level is doubled. This makes Portafill H10 a more efficient TiO2 extender than PCC.

Summarizing: there are three options for implementing Portafill H10: 





Replacing PCC 1:1, which results in: o Improved contrast ratio; o Improved whiteness; o Improved matting efficiency; o Similar wet scrub resistance; o Slightly higher viscosity at low shear rate (which allows cost optimization by reduction of rheology additive).

Replacing PCC with less Portafill H10, which is expected to result in: o Similar contrast ratio; o Similar whiteness; o Similar matting efficiency; o Similar wet scrub resistance; o More equal viscosity at low shear rate.

Using less TiO2, which is expected to result in: o Similar contrast ratio; o Similar whiteness; o Similar matting efficiency; o Similar wet scrub resistance; o Slightly higher viscosity at low shear rate (which allows cost optimization by reduction of rheology additive).

Other examples Other examples are available upon request, such as:   

Portafill H5 vs. aluminium silicate Portafill H10 vs. hydrous kaolin Portafill H5 vs. calcined kaolin

Conclusion Portafill H10 has proven to be a suitable extender for TiO2. Key points:    



Naturally occurring product (no chemical or heat treatment involved); Good whiteness; Due to platy particle shape very suitable to separate TiO2 agglomerates and then keep the primary particles from reagglomerating during the drying process; Allowing reduction of TiO2 content and/ or thickening additive, while maintaining important paint properties such as: o Viscosity; o Colour; o Wet scrub resistance; o Contrast ratio; o Gloss.

Cost efficient alternative to various other TiO2 extenders.

Contact: For additional commercial and/or technical information, please contact: Sandra Baía Business Unit Manager YOUR PARTNER FOR CHEMICALS

SAMECA - Produtos Químicos, S.A. Rua Faria Guimarães, 345 4000-207 Porto Tlf: 00351 225 074 000 Tlm: 00351 939 720 986

www.sameca.pt sbaia@sameca.pt