SURFACE COATING COMPOSITION

Abstract

The present invention relates to a composition which containsa wax (W), a silicone oil (S), a binder (B), one or more pigment(s) and/or filler(s) (PF1) of an average particle size of 0.1 to 1.0 m in a total amount of 8.0 to 55 wt. %, one or more pigment(s) and/or filler(s) (PF2) of an average particle size of more than 1.0 to 10 m in a total amount of 5.0 to 40 wt. %, and one or more pigment(s) and/or filler(s) (PF3) of an average particle size of more than 10 to 40 m in a total amount of 3.0 to 30 wt. %, in each case relative to the solids content of the composition, PF1, PF2 and PF3 being different from each other, and to a coating which can be obtained from this composition. The invention further relates to the use of the composition according to the invention as a moulding or coating compound.

Claims

1. A composition containing a wax (W) a silicone oil (S) a binder (B) one or more pigment(s) and/or filler(s) (PF1) of an average particle size of 0.1 to 1.0 m in a total amount of 8.0 to 55 wt. %; one or more pigment(s) and/or filler(s) (PF2) of an average particle size of above 1.0 to 10 m in a total amount of 5.0 to 40 wt. %; and one or more pigment(s) and/or filler(s) (PF3) of an average particle size of above 10 to 40 m in a total amount of 3.0 to 30 wt. %; in each case relative to the solids content of the composition, PF1, PF2 and PF3 being different from each other.

2. The composition according to claim 1, having a pigment-volume concentration according to EN ISO 4618-1 of 20% to 65%.

3. The composition according to claim 1, also containing a structuring filler.

4. The composition according to claim 3, wherein the structuring filler has an average particle size of more than 40 m.

5. The composition according to claim 3, wherein the content of structuring filler relative to the solids content of the composition is 0.10 to 3.0 wt. %.

6. The composition according to claim 1, wherein the following relation (I) is met
1.5.Math.average particle size(PF1)<
average particle size(PF2)<
50.Math.average particle size(PF1)(I)

7. The composition according to claim 1, wherein the following relation (II) is met
1.5.Math.average particle size(PF2)<
average particle size(PF3)<
40.Math.average particle size(PF2)(II).

8. The composition according to claim 1, wherein the relative amount by weight of pigment(s) and/or filler(s) of an average particle size of 0.10 to 1.0 m is greater than the relative amount by weight of pigment(s) and/or filler(s) of an average particle size of more than 1.0 to 10 m, and/or the relative amount by weight of pigment(s) and/or filler(s) of an average particle size of more than 1.0 to 10 m is greater than the relative amount by weight of pigment(s) and/or filler(s) of an average particle size of more than 10 to 40 m, in each case relative to the solids content of the composition.

9. The composition according to claim 1, wherein the wax has a static initial contact angle of water after 1 min equilibration that is greater than the static initial contact angle of water of the binder after 1 min equilibration.

10. The composition according to claim 3, wherein the wax has a static initial contact angle of water after 1 min equilibration that is at least 5 greater than the static initial contact angle of water of the binder after 1 min equilibration.

11. The composition according to claim 1, wherein the composition is a moulding or coating compound.

12. The composition according to claim 11, wherein the composition is a paint or render.

13. A coating on a substrate surface, said coating containing a wax (W) a silicone oil (S) a binder (B) one or more pigment(s) and/or filler(s) (PF1) of an average particle size of 0.1 to 1.0 m in a total amount of 8.0 to 55 wt. %; one or more pigment(s) and/or filler(s) (PF2) of an average particle size of more than 1.0 to 10 m in a total amount of 5.0 to 40 wt. %; and one or more pigment(s) and/or filler(s) (PF3) of an average particle size of more than 10 to 40 m in a total amount of 3.0 to 30 wt. %; in each case relative to the solids content of the composition, PF1, PF2 and PF3 being different from each other.

14. Use of a composition according to claim 1 as a moulding or coating compound.

15. The use according to claim 14, wherein the moulding or coating compound is a paint or render.

Description

[0136] FIG. 1 shows the coating surface of a composition according to the invention additionally containing hollow glass beads at 20 magnification (light microscope).

[0137] FIG. 2 shows the coating surface of a composition according to the invention additionally containing hollow glass beads at 10 magnification (light microscope).

MEASUREMENT METHODS

Wax Melting Point:

[0138] ISO EN 11357-3

Contact Angle and Surface Energy and Polar and Dispersive Component Thereof

[0139] Water and diiodomethane were used as test substances for the contact angle. The droplet size was 2 l to 4 l in each case.

[0140] Since a direct measurement of a wax surface is not possible in some circumstances, since the wax can crystallise out as it hardens and therefore a measurement is not possible or the wax can be too soft, a mixture of 3.85 wt. % wax and 96.15 wt. % of the binder specified below relative to the solids content was produced, and a corresponding coating created. The contact angle measurements were taken on this surface.

[0141] Silicone oils are normally viscous liquids, and therefore a direct measurement at the surface thereof likewise normally is not possible. A mixture of 1.13 wt. % silicone oil and 98.87 wt. % of the binder specified below relative to the solids content was therefore produced, and a corresponding coating created. The contact angle measurements were taken on this surface.

[0142] An aqueous dispersion based on a copolymer formed of acrylic and methacrylic acid esters having a solids content of 46 wt. % and a Brookfield viscosity of approximately 7000 mPa.Math.s according to DIN EN ISO 2555 (spindle 4; 20 rpm; 23 C.), obtainable as Mowilith LDM 7724 from Celanese, was used as binder.

[0143] The static contact angle was determined after 2 days of drying at 23 C. and 50% relative humidity. After application of the water droplet or diiodomethane droplet, 60 sec were allowed to pass before the measurement was taken.

[0144] The contact angle at the three-phase contact line between solid, liquid and gas was determined using the G1 contact angle measuring device from Krss. At least five droplets at different points were measured on each specimen.

[0145] The surface energy was determined by the Owens, Wendt, Rabel and Kaelble method as follows (source: Krss AG).

[0146] According to OWENS, WENDT, RABEL and KAELBLE, the surface tension of each phase can be divided into a polar and a dispersive component:

.sub.l=.sub.l.sup.P+.sub.l.sup.D(equation 1)

.sub.s=.sub.s.sup.P+.sub.s.sup.D(equation 2)

OWENS and WENDT based their equation on interfacial tension

.sub.sl=.sub.s+.sub.l2({square root over (s.sup.D.Math..sub.l.sup.D)}+{square root over (.sub.s.sup.P.Math..sub.l.sup.P)})(equation 3)

and combined it with the YOUNG equation

.sub.s=.sub.sl+.sub.l.Math.cos (equation 4)

[0147] The two authors solved the equation system with the aid of contact angles of two liquids with known dispersive and polar component of the surface tension. Equations 3 and 4 are combined and the resultant equation is adapted to the general linear equation by conversion.

=mx+b(equation 5)

[0148] The adapted equation is as follows:

[00001]$\begin{array}{cc}\underset{\underset{}{}}{\frac{\left(1+\cos .Math..Math.\right).Math.{}_l}{2.Math.\sqrt{{}_l^D}}}=\underset{\underset{m}{}}{\sqrt{{}_s^P}}.Math..Math.\underset{\underset{x}{}}{\sqrt{\frac{{}_l^P}{{}_l^D}}}+\underset{\underset{b}{}}{\sqrt{{}_s.Math.D}}& \left(\mathrm{equation}.Math..Math.6\right)\end{array}$

[0149] With a linear regression of the plotting of y against x, .sub.s.sup.P is given from the square of the line gradient m and .sub.s.sup.D is given from the square of the ordinate portion b.

[0150] The surface energies are specified in mN/m.

[0151] Mixtures formed of the pure, above-mentioned binder and the wax and/or silicone oil used in the examples described below will be examined first.

[0152] To this end, the compositions from Table 1 were prepared with a wet layer thickness of 200 m and were dried as detailed above, and the contact angle after 3 min equilibration time of the droplet on the surface with water and diiodomethane, the surface energy (OFE), and the dispersive component (DA) and polar component (PA) of the OFE were determined.

[0153] The specified amounts in table 1 of the PE wax relate to an aqueous dispersion with a solids content of 35 wt. %, and those of the binder relate to an aqueous dispersion with a solids content of 46 wt. %. The silicone oil is present in the form of a cure compound.

TABLE-US-00001 TABLE 1 Contact angle [] Diiodo- DA PA DA/ Water methane OFE* DA* PA* [%] [%] PA Binder 73.4 53.3 40.4 32.4 8.0 80.2 19.8 4.0 Binder + 91.7 54.2 33.5 31.9 1.6 95.3 4.7 20.2 5 wt. % wax binder + 88.4 44.4 38.9 37.3 1.6 96.0 4.0 23.9 0.5 wt. % silicone oil Binder + 89.3 47.4 37.3 35.7 1.6 95.8 4.2 22.8 4.5 wt. % wax + 0.5 wt. % silicone oil Binder + 89.9 47.8 37.0 35.5 1.6 96.0 4.0 24.0 5 wt. % wax + 0.5 wt. % silicone oil *Unit [mN/m]

[0154] The significant increase of the contact angle of water can be seen for the addition of wax and/or silicone oil.

Pigment-Volume Concentration

[0155] The pigment-volume concentration (EN ISO 4618-1) indicates the volume ratio between pigments/fillers and the binder in the coating film.

[0156] The additives likewise contained in the formulation were not taken into consideration in the calculation. Solvents and water also are no longer contained in the hardened film and are have thus also been omitted. The wax and silicone oil, if provided, were not taken into consideration in the calculation.

Silicone Oil Viscosity

DIN 53015

FTIR (Absence of Symmetrical SiOC Stretching Vibration

[0157] The measurement was carried out using a Perkin-Elmer Spectrum 100 FTIR spectrometer with Universal ATR Accessory. The absence of the symmetrical SiOC stretching vibration at 94-970 cm.sup.1 indicates the absence of alkoxy side chains.

Average Particle Size

[0158] In the present application the pigments and fillers are characterised on the basis of their average particle size. This is realised by determining the particle size distribution. The value dx here means the proportion in % (x) of the particles that have a diameter smaller than d. This means that the d20 value represents the particle diameter at which 20 wt. % of all particles are smaller than this diameter. The d50 value is consequently the volume-average median value, i.e. 50 vol. % of all particles are smaller than this particle size. In the present invention the particle size is specified as volume-average median value d50. In order to determine the volume-average median value d50, a Mastersizer 3000 laser diffraction particle size analyser from Malvern Instruments Limited, U.K. was used. The method and instrument are known to a person skilled in the art and are routinely used in order to determine particle sizes of fillers, pigments and other particulate materials.

[0159] The measurement was performed in water. The sample was dispersed by means of a high-speed agitator and ultrasound.

[0160] The average particle size corresponds to the d50 value.

Bulk Density

[0161] The bulk density was determined in accordance with ISO 697.

Coefficient of Friction

[0162] The dynamic coefficient of friction (.sub.R) was determined in analogy with ISO 8295:1995 and ASTM D1894-11. An Altek Slip tester was used. A film with a wet layer thickness of 200 m was formed on Lenetta film and dried for 3 days at room temperature. Three specimens (150240 mm.sup.2) were cut in the application direction and held at 23 C. for at least 16 h in a thermostatically controlled environment. The test was also performed at this temperature. The sample was placed on the measuring table in such a way that the application direction of the coating matched the movement direction of the slide. The slide was made of stainless steel. The weight of the slide was 1.00 kg. The slide was then moved over the table at a constant speed (127 mm/min). The profile of the force over time was recorded. The mean force necessary to move the slide was determined as described in paragraph 9.2 of ISO 8295:1995. The dynamic coefficient of friction was then calculated as described in ISO 8295:1995 as

[00002]${}_R=\frac{F_f}{w.Math.g}$

wherein F.sub.f is the dynamic frictional force in Newtons, w is the weight of the slide in kilograms, and g is the gravitational constant 9.81 m.sup.2/s.

EXAMPLES

Used Materials:

Binder:

[0163] Aqueous dispersion based on a copolymer formed of acrylic and methacrylic acid esters having a solids content of 46 wt. %, a Brookfield viscosity of approximately 7000 mPa.Math.s according to DIN EN ISO 2555 (spindle 4; 20 rpm; 23 C.) obtainable as Mowilith LDM 7724 from Celanese.

[0164] Titanium dioxide, average particle size=0.25 m (example of PF1)

[0165] Calcium carbonate, average particle size2.5 m (example of PF2)

[0166] Sheet silicate, average particle size25 m (example of PF3)

[0167] Cristobalite, average particle size14 m (example of PF3)

Hollow Glass Beads:

[0168] average particle size=50 m

Wax:

[0169] Polyethylene wax with a melting range from 91 to 99 C., a density of 1.00 g/cm.sup.3 and a viscosity of 25-50 mPa.Math.s (DIN 53019 1.921 s1). Dispersion with a solids content of 35 wt. %

Silicone Oil

[0170] Alkoxy-group-free dimethylpolysiloxane having a viscosity of 90 mm.sup.2/s and a molecular weight of 6100 g/mol.

[0171] The following compositions were prepared.

[0172] R1: Formulation II from EP 0 546 421 (hydrophobic faade paint with a PVC (pigment volume concentration) of approximately 80%)

[0173] R2: Commercially available hydrophilic dispersion silicate paint with a PVC of approximately 82%)

[0174] All values in wt. %

TABLE-US-00002 TABLE 2 EG1 EG2 EG3 EG4 EG5 A1 A2 A3 B1 C1 R1 R2 Water 13 14 4 20 31 19 14.5 17 19.5 18.5 Binder 40 40 49 33 22 40 40 40 40 40 Wax 5.0 5.0 5.0 5.0 5.0 5.0 5.0 Silicone oil 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 16 16 16 16 16 16 16 16 16 16 CaCO.sub.3 10 10 10 10 10 10 10 10 10 Sheet silicate 9 9 9 9 9 9 9 9 9 Cristobalite 16 Hollow glass beads 1.0 1.0 1.0 1.0 1.0 Additives.sup.1) 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 PVC [approx. %] 45 36 40 50 60 36 36 36 36 45 Contact angle water 87.3 85.9 82.8 85.2 84.7 85.9 78.5 80.1 74.1 75.4 122.2 50.1 [] Contact angle 57.7 58.3 58.3 63.7 59.6 56.1 66.8 61.6 64.0 62.1 85.1 26.6 diiodomethane [] OFE.sup.2) 33.02 33.18 34.31 31.15 33.07 34.17 32.89 34.06 36.11 36.16 14.98 61.42 DA.sup.2) 29.92 29.55 29.54 26.46 28.83 30.83 24.70 27.63 26.25 27.38 14.96 45.92 PA.sup.2) 3.11 3.63 4.77 4.68 4.25 3.34 8.19 6.44 9.86 8.78 0.02 15.51 R 0.17 0.12 0.16 0.14 0.18 0.17 0.17 0.17 0.30 0.35 0.17 0.25 .sup.1)in particular dispersant, thickener, anti-foaming agent, biocide .sup.2)unit [mN/m] EG = according to the invention, A, B, C = reference

[0175] The coefficient of friction was significantly reduced by the filler combination according to the invention, as can be seen from the comparison of EG2 (0.12) and A3 (0.17). In addition, the polar component of the surface energy is reduced by the pigment/filler combination according to the invention by almost half. Both compositions have the same PVC (36) and have the same binder content. They differ merely in that EG2 contains the pigment/combination according to the invention and A3 does not.

[0176] The use of glass beads (EG1/EG3/EG4/EG5) indeed increases the coefficient of friction. However, the glass beads produce a microstructure on the surface, as can be seen from FIG. 1 and FIG. 2. On smooth surfaces, water that is draining off often runs off over only a few paths. Here, deposits can be formed along these paths. Due to a microstructure produced by means of glass beads, water that is running off is directed into different paths, whereby deposits of this kind can be significantly reduced.

[0177] The re-drying of the compositions according to the invention was determined on the basis of the following tests.

[0178] To this end, samples with a wet layer thickness of 200 m were created on Lenetta film and dried for 2 days at room temperature. The surface was 414 cm.sup.2.

[0179] The coated Lenetta film was suspended from above and tared.

[0180] The film was then sprayed from a distance of approximately 35 cm with approximately 85 g/m.sup.2 distilled water. Re-drying was observed for 30 min, and the weight was recorded every 5 min. The test was performed at a standard climate of 23 C./50% rel. humidity.

TABLE-US-00003 EG 1 with EG 2 R1 HGB without HGB R2 [g] [%] [g] [%] [g] [%] [g] [%] Start 3.71 100.0 3.64 100.0 3.75 100.0 3.51 100.0 5 3.29 88.7 2.21 60.7 2.1 56.0 2.20 62.7 10 2.82 76.0 1.52 41.8 1.39 37.1 1.74 49.6 15 2.34 63.1 1.01 27.7 0.96 25.6 1.25 35.6 20 1.91 51.5 0.65 17.9 0.56 14.9 0.91 25.9 25 1.45 39.1 0.36 9.9 0.27 7.2 0.57 16.2 30 1.05 28.3 0.14 3.8 0.1 2.7 0.30 8.5 HGB = hollow glass beads

[0181] As the above table shows, the re-drying behaviour of the compositions according to the invention is significantly improved. The start drying speed is already significantly increased, as can be seen from the values at 5 and 10 minutes. In addition, the remaining water amount after 30 minutes is also significantly reduced.

[0182] The course over time of the amount of water remaining on or in the surface is shown in FIGS. 3 (weight/time) and 4 (wt. %/time).