ADD MONDO MINERALS TO YOUR IDEAS Improved Surface Resistance of Matt Wall Paint with Mondo Minerals Talc Technical Bulletin 1207
CONTENTS INTRODUCTION 2 TALC GRADES TESTED 3 TEST METHODS WATER RESISTANCE 4 WATER/ETHANOL RESISTANCE 4 CLEANING AND STAIN RESISTANCE 4 DIRT REPELLENCY DRY EXPOSURE 4 FORMULATIONS 5 RESISTANCE RESULTS WITH DIFFERENT TALC GRADES WATER RESISTANCE 6 WATER/ETHANOL RESISTANCE 7 CLEANING AND STAIN RESISTANCE 8 DIRT RESISTANCE 9 GLOSS MEASUREMENTS 10 CONCLUSIONS 11 INTRODUCTION Matt surfaces are a trend at the moment on the decorative paint market. However, these types of coating get dirty easily and are difficult to clean due to their open and /or rough structure. As a rule, the higher the amount of filling (high PVC), the lower the gloss levels. The aim of this study was to show that it is possible for high PVC wall paints to have good surface resistance despite being matt. Talc has a platy particle form and a very hydrophobic surface, which makes it very resistant to water and many other substances. But not all talcs are similar. There are many talc grades available that are blends of talc and some other, more hydrophilic, by-minerals. The purpose of this study was to investigate the effect of different talc types on the resistance properties of matt wall paint. The resistance properties studied were: water, water/ethanol, stain resistance to achieve easy-to-clean properties, and dirt pick-up resistance. Four different talc grades were tested in this respect: Firstly, a guide formulation was developed. Then the different talc grades were added into this formulation, and the resistance tests were carried out after letting the different films cure for one week. FINNTALC M30SL from Mondo Minerals B.V. FINNTALC M40SL from Mondo Minerals B.V. CHLORITIC TALC with 90 % talc and 10 % chlorite CHLORITIC TALC with 50 % talc and 50 % chlorite 2 Technical Bulletin 1207 Matt Wall Paint
TALC GRADES TESTED Two pure talc grades from Mondo Minerals B.V. and two talc-chlorite grades with different talc-chlorite ratios were evaluated. The properties of the talc grades are given in Table 1. PROPERTY UNIT FINNTALC M30SL FINNTALC M40SL CHLORITIC TALC (10 % chlorite) CHLORITIC TALC COMPOSITION OF TALC talc = 97 %, residual chlorite and MgCO 3 talc = 97 %, residual chlorite and MgCO 3 talc = 90 %, chlorite = 10 % talc = 50 %, chlorite = 50 % ISO BRIGHTNESS % 84.3 83.5 88.1 81.7 DIN WHITENESS % 85.2 84.5 89.0 83.3 OIL ABSORPTION g /100 g 33 32 24 26 PSD BY SEDIGRAPH < 40 µm w % 100 98 100 100 < 30 µm w % 97 93 97 97 < 20 µm w % 87 74 84 88 < 10 µm w % 48 22 49 62 < 5 µm w % 23 4 22 35 < 2 µm w % 9 3 10 13 < 1 µm w % 5 2 6 3 D50 µm 10 14 10 8 Table 1: Properties of talc grades tested Photo 1: Natural weathering of coatings Technical Bulletin 1207 Matt Wall Paint 3
TEST METHODS For all the following tests, the formulations were applied on glass panels with a wet thickness of 150 μm. WATER RESISTANCE To assess the water resistance of the coating after one week of curing, a large drop of water was applied on the film of paint and then covered by a watch glass in order to prevent evaporation. The damage caused by the water was assessed after 15 min, 30 min, 1 h, 2 h, 4 h and 24 h. WATER / ETHANOL RESISTANCE To assess the water and ethanol resistance of the coating after one week of curing, a large drop of a 50 / 50 mix of water and ethanol was applied on the film of paint and then covered by a watch glass in order to prevent evaporation. The damage caused by the mixture was assessed after 15 min, 30 min, 1 h, 2 h, 4 h and 24 h. CLEANING AND STAIN RESISTANCE Two types of stains were tested: coffee and green highlighter pen. A few drops of coffee were applied on the paint as well as a few stripes of green highlighter. They were cleaned afterwards and the possible remaining stains were assessed visually. For the formulations with different talcs, the resistance to stains was also assessed using a colorimeter (L, a, b measurement). The difference between the cleaned stain colour (2) and the white colour (1) were calculated using the following formula: = (L 2 L 1 ) 2 + (a 2 a 1 ) 2 + (b 2 b 1 ) 2 DIRT REPELLENCY DRY EXPOSURE An amount of 0.02 g of hydrophilically modified carbon black (Special Black 100) was added on each paint film. After 15 minutes the test panels were then slightly inclined and 5 ml of water was dispensed in order to wash away the carbon black powder. Dust repellency was then assessed by evaluating how much carbon black remained on the paint film. Photo 2: Water resistance determination of paints 4 Technical Bulletin 1207 Matt Wall Paint
FORMULATIONS In order to select a suitable guide formulation for matt wall paint with good performance results, formulations with different PVCs and different talc content were prepared and the resistance properties of these formulations were tested. The formulation with 7.5 % talc content and at a PVC of 70 % showed the best performance, and thus it was selected for the testing of the different talc types. A small amount of silicone additive (Silres BS) was added to the guide formulation with the different talc grades to see if the resistance properties could be further improved. The guide formulations are shown in Table 2. BASIC FORMULATION FORMULATION WITH SILICONE ADDITIVE BINDER MOWILITH LDM 1871 12.94 12.94 SOLVENT WATER 29.01 29.01 ADDITIVES LUPON 895 0.32 0.32 CALGON N 0.75 0.75 NATROSOL 250 HR 0.32 0.32 SCHWEGO FOAM 6351 0.32 0.32 SILRES BS 333 1.05 ACRYSOL RM8 0.25 0.25 PIGMENTS AND FILLERS 5 MICRON CaCO 3 26.97 25.92 2 MICRON CaCO 3 7.55 7.55 PCC CaCO 3 3.24 3.24 TiO 2 10.78 10.78 DIFFERENT TALC GRADES 7.55 7.55 TOTAL 100.00 100.00 GLOSS 60 3.1 3.1 GLOSS 85 2.6 2.6 Table 2: Guide formulations to test the resistance properties of different talc grades Technical Bulletin 1207 Matt Wall Paint 5
RESISTANCE RESULTS WITH DIFFERENT TALC GRADES WATER RESISTANCE Table 3 shows the performance results of the coatings made with different talcs in terms of resistance to water damage. Images showing the damage done to the paint film by water after 24 hours of exposure are also shown in Table 3. Table 4 shows the performance results of the coatings in terms of resistance to water damage when Silres BS 333 silicone additive was used. FINNTALC M30SL FINNTALC M40SL CHLORITIC TALC CHLORITIC TALC 15 min whitening whitening whitening whitening 30 min whitening whitening whitening whitening 1 h whitening whitening whitening blistering 2 h whitening whitening blistering blistering 4 h whitening whitening blistering blistering and wrinkling 24 h whitening whitening blistering and cracking wrinkling and a little cracking Table 3: Water resistance results for the formulations with different talc grades and photos of the films after 24 h exposure S FINNTALC M30SL S FINNTALC M40SL S CHLORITIC TALC S CHLORITIC TALC 15 min whitening whitening blistering blistering 30 min whitening whitening blistering blistering 1 h whitening whitening blistering blistering 2 h whitening whitening blistering blistering 4 h whitening whitening blistering blistering 24 h whitening whitening cratering cratering Table 4: Water resistance results for the formulations with Silres BS 333 with different talcs and photos of films after 24 h exposure As can be seen, FINNTALC grades provide better resistance to water damage than the two talc-chlorite grades. Even if the addition of Silres BS 333 enhanced the water resistance of the formulations made with talc-chlorite, the samples made with the FINNTALCS performed better. It can thus be said that less silicone additive is needed with FINNTALCS to improve the surface resistance compared with the talc grades containing chlorite. 6 Technical Bulletin 1207 Matt Wall Paint
WATER / ETHANOL RESISTANCE Table 5 shows the performance results of the coatings made with different talcs in terms of water / ethanol damage and displays the pictures of the damage done by the water / ethanol mixture after 24 hours of exposure. Table 6 shows the same performance when Silres BS 333 was used. FINNTALC M30SL FINNTALC M40SL CHLORITIC TALC CHLORITIC TALC 15 min whitening whitening whitening whitening 30 min whitening whitening whitening whitening 1 h whitening whitening cracking wrinkling and cracking 2 h whitening whitening cracking wrinkling and cracking 4 h whitening whitening cracking cracking 24 h whitening whitening cracking cracking Table 5: Water / ethanol resistance results for the formulations with different talc grades and photos of the films after 24 h exposure S FINNTALC M30SL S FINNTALC M40SL S CHLORITIC TALC S CHLORITIC TALC 15 min whitening whitening cracking cracking 30 min whitening whitening cracking cracking 1 h whitening whitening cracking cracking 2 h cracking whitening cracking cracking 4 h cracking cracking cracking cracking 24 h cracking cracking cracking cracking Table 6: Water / ethanol resistance results for the formulations with Silres BS 333 with different talc grades and photos of the films after 24 h exposure The coatings made with the two FINNTALCS provided better resistance to water / ethanol damage than the talc-chlorite grades. The overall resistance of the coatings to the water / ethanol mix seemed to be reduced by the addition of Silres BS 333. Technical Bulletin 1207 Matt Wall Paint 7
CLEANING AND STAIN RESISTANCE Table 7 displays the resistance of different talc grades to coffee and highlighter pen stains. The performance is shown in the photos taken after cleaning and in the total colour difference measured between the original white paint film and the paint film after exposure and cleaning the stains. FINNTALC M30SL FINNTALC M40SL CHLORITIC TALC CHLORITIC TALC CLEANED PAINT FILMS AFTER COFFEE STAIN TEST COFFEE 4.15 3.29 5.89 2.39 CLEANED PAINT FILM AFTER HIGHLIGHTER PEN STAIN TEST HIGHLIGHTER 8.1 5.62 4.23 5.71 Table 7: Coffee and green highlighter pen stain resistance of the paints with different talc grades. Photos of the cleaned paint films after the stain exposure test. The colour difference was measured between the original paint film and the cleaned paint film after the exposure tests. The results above show that FINNTALC grades provide better resistance to the coffee and pen stains. The coffee stain marks are barely visible on the paint film with FINNTALC grades, while on the paint film with talc-chlorite the stain is more visible after cleaning. It should also be noted that the paint film with the talc-chlorites with a chlorite content of 50 % was partly washed away during cleaning process, which affected the colour measurements. Also in the pen stain resistance test the paint films with the talc-chlorites were damaged by the cleaning, so it was difficult to make an accurate evaluation of the highlighter pen stain resistance of these paint films. Table 8 displays the stain resistance of different talc grades for the paint films containing Silres additive. S FINNTALC M30SL S FINNTALC M40SL S CHLORITIC TALC S CHLORITIC TALC CLEANED PAINT FILMS AFTER COFFEE STAIN TEST COFFEE 6.01 6.78 7.19 8.71 CLEANED PAINT FILM AFTER HIGHLIGHTER PEN STAIN TEST HIGHLIGHTER 8.62 8.29 9.69 9.52 Table 8: Coffee and green highlighter pen stain resistance of the different talc grades for the paint films containing Silres BS 333. Photos of the cleaned paint films after the stain exposure test. The colour difference was measured between the original paint film and the cleaned paint film after the exposure tests. 8 Technical Bulletin 1207 Matt Wall Paint
The coatings formulated with Silres BS 333 showed similar behaviour to the coatings without a silicone additive. Visually, all the coatings seemed to have the same stain resistance properties. As happened previously, the coatings made with the talc-chlorites were damaged during the cleaning process so it was difficult to assess the stain resistance performance accurately. With the colour measurements, it seemed that the coatings formulated with the FINNTALC talcs gave better results than the coatings formulated with the talc-chlorites. However, because the latter were damaged, the measurements made on the samples with talc-chlorites could be inaccurate. DIRT RESISTANCE Pictures of the dry exposure dust repellency test are shown in Table 9 for the samples without Silres BS 333 and in Table 10 for the samples with Silres BS 333. FINNTALC M30SL FINNTALC M40SL CHLORITIC TALC CHLORITIC TALC Table 9: Wet exposure results for formulations without Silres BS 333 (the dust trace is circled in blue). S FINNTALC M30SL S FINNTALC M40SL S CHLORITIC TALC S CHLORITIC TALC Table 10: Wet exposure results for formulations with Silres BS 333 (the dust trace is circled in blue). For both films containing FINNTALC M40SL, it could be observed that part of the carbon black powder was not washed away by the water. For the formulations without Silres BS 333, larger areas of carbon black particles were left on the films with the talc-chlorite grades than on the films with FINNTALCS. This suggested that the dust resistance was better for the paints with FINNTALCS. For the formulations with Silres BS 333, it was more difficult to see differences between the different panels. During the tests it was noticed that the water drops ran faster on the films with the FINNTALC grades than on the films with the talc-chlorite grades. The water droplets also flattened more on the paint films where talc-chlorite talcs were used. This indicates that the dust repellency was better when FINNTALCS were used in the formulations. Technical Bulletin 1207 Matt Wall Paint 9
GLOSS MEASUREMENTS For matt wall paints the gloss at an 85 degree angle should be below 5. The gloss levels were measured for the PVC 70 coatings, containing 7.5 % talc, with and without Silres BS 333. The gloss values are shown in Figure 1. 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 FTM30SL without Silres FTM40SL without Silres CHLORITIC TALC (10 % CHLORITE) without Silres CHLORITIC TALC (50 % CHLORITE) without Silres FTM30SL with Silres FTM40SL with Silres CHLORITIC TALC (10 % CHLORITE) with Silres CHLORITIC TALC (50 % CHLORITE) with Silres Gloss 60 Gloss 85 Figure 1: Gloss measurements From Figure 1 can be seen that the gloss levels were clearly below 5 for the paints containing no Silres. With the talc-chlorites the gloss levels are higher with Silres than without Silres. The reason may be that Silres has less affinity with the talc-chlorite and therefore migrates to the surface, giving higher gloss values. 10 Technical Bulletin 1207 Matt Wall Paint
CONCLUSIONS The aim of this study was to investigate the effect of different talc types on the surface resistance properties of matt wall paint. The formulation with high PVC was developed and formulated with four different talc grades. The formulation with a PVC of 70 % containing 7.5 % talc showed the best overall resistance performance, so it was selected to test the different talc qualities. A small amount of silicone additive (Silres BS 333) was added to the test formulation to see if the resistance properties were improved. The guide formulations are given in Table 1. Four different talc grades were tested: two of them were highly pure talc grades from Mondo Minerals (FINNTALC M30SL and FINNTALC M40SL) and two were talc grades with different amounts of chlorite from another supplier. The samples were tested for water, water / ethanol and stain resistance (coffee and highlighter). Dirt pick-up was also evaluated. The paints with FINNTALC grades performed much better than the talc grade containing chlorite on all resistance properties tested. In particular the resistance to water and ethanol were much better with FINNTALC than with the talc grades containing chlorite. Also the coffee and highlighter pen stain resistance was better with FINNTALC compared with more hydrophilic talc-chlorite. It was difficult to evaluate the stain resistance by colour difference measurement for the talc-chlorite grades because they were damaged during the process of washing the stains. The poor resistance of the talc-chlorite to water used in washing was the reason for the damage in the cleaning. In terms of visual evaluation it can be said that the FINNTALC grades tested had a higher resistance to surface cleaning than the talc grades containing chlorite. This study has shown that with FINNTALC grades it is possible to improve the surface resistance in high PVC and matt paints. The silicone additive that was added to the guide formulations did not affect the performance of the FINNTALC grades, but improved the resistance properties of the talc-chlorite grades. Due to its excellent barrier properties, FINNTALC can compete with additives like silicones and waxes that are usually used to make paint film more hydrophobic in this type of paint. Using FINNTALC is therefore a cheaper solution than using silicones or waxes. Photo 3: Water droplets on hydrophobic talc Technical Bulletin 1207 Matt Wall Paint 11
MONDO MINERALS B.V. Kajuitweg 8 1041 AR Amsterdam The Netherlands E-mail: info@mondominerals.com www.mondominerals.com The information contained in this Technical Bulletin relates only to the specific tests designated herein and does not relate to the use of our products in combination with any other material or in any process. The information provided herein is based on technical data that Mondo Minerals believes to be reliable, however Mondo Minerals makes no representation or warranty as to the completeness or accuracy thereof and Mondo Minerals assumes no liability resulting from its use for any claims, losses, or damages of any third party. Recipients using this information must exercise their own judgement as to the appropriateness of its use, and it is the user s responsibility to assess the materials suitability (including safety) for a particular purpose prior to such use. V2-032017