1

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33

SK

ANDINAVISKA

LA

CK

TEKNIKERS FöRB

UN

D

Few words from the President

I am now well underway as SLF president and have enjoyed my first few months at work! Although I am officially in pension it feels great to have re-connected with my paint colleagues with the aim of building the SLF to be a stronger and even better association.The SLF board had a telephone meeting on 14 May. It was my first contact with all board members. The budget and plans for 2013 were approved by all. Among the plans for 2013 are to reconstruct the SLF homepage, improve the content and delivery of our journal, review our role in the CSI, create an SLF domain with own email and cloud data storage, and start organ-isation of the SLF congress. I am of course not doing this by myself and have a very good team of people supporting me.The SLF congress organising com-mittee will consist of me, Peter Weissenborn, Peter Feher, Carina Stjernman, Anna-Karin Gunnars-son, Martin Lamken and Tony Reinler. We can confirm that the Congress will be held in Gothen-burg in mid-September 2015. We are currently taking in offers from suitable hotels/locations in Gothen-burg. The committee will meet on 25 June to decide exact date and location. If any SLF member would like to help, have any ideas or sug-gestions for the congress then please contact me.

I will also work more closely with Simon Greve, our editor of Färg och Lack Scandinavia, with the aim to improve the content of the jour-nal. We have also decided to de-crease the number of issues to four per year with publication date every quarter. Distribution of the journals in Sweden has not worked well the past year and we have now changed to the routines for this. I would also like more input to the journal for all members, especially reports and photos from national meetings.

In September we plan to transfer our current CSI secretariat to an-other CSI organisation. The annual CSI meeting will be held in Japan and I am sure there will be much discussion about the future roll of CSI and its benefits for members. The Australian organisation has proposed a more simple form of membership without the need of expensive annual meetings, a posi-tion which I intend to support.If any member would like to dis-cuss any SLF matter with me please feel free to send me an email at slf.president@slfpaint.org or telephone +46735936301.With this issue I hope you are either soon taking holidays, are on holi-days or returning from holidays. I will you wish all relaxing summer and good sunny and warm weather. I am looking forward to my sum-mer walks in Halmstad, perhaps I may see you there!

Laszlo Guitman, SLF President16 June 2013

ISSN 0106-7559

MEDLEMSBLAD FÖR SKANDINAVISKALACKTEKNIKERS FÖRBUND – SLF

INNEHÅLL SidFew words from the president 3Modefied colloidal silica for enhancement of dirt pick-up resistance i Deco paints 4NMLF, Bedritsbesøk Norner 16Silican-nanocomposites 17Industrinyt 21

PRESIDENTLaszlo GuitmanBäckagårdsvägen 50SE-302 74 Halmstad Telefon: +46735936301Mail: slf.president@slfpaint.org

GENERALSEKRETÆR/ANSVARLIG UDGIVERPeter WeissenbornSherwin-Williams Sweden ABP.O.Box 2016SE-19502 MärstaSwedenpeter.weissenborn@sherwin.com+46 381 262 60

CHEFREDAKTØRSimon GrevePhoenix PaintDK - 5900 RudkøbingTelefon +45 6251 2828Fax +45 6251 2727Mobile +45 3167 7958Mail: simon@phoenix-paint.dk

ANNONCER:Simon Greve

OMSLAGSBILD:Trykkeriet.net

4

MODIFIED COLLOIDAL SILICA FOR ENHANCEMENT OF

DIRT PICK-UP RESISTANCE IN DECO PAINTS.

Authors: de LAME Céline and CLAEYS Jean-Marie, CoRI, Belgium

GREENWOOD Peter and LAGNEMO Hans, Eka Chemicals,

A business Unit within AkzoNobel, Sweden

SUMMARY

For several years, the interest for nanotechnologies in the paint and coating industry is

growing. Several researches carried out in CoRI have shown that by the use of nanoparticles

such as colloidal silica, nanoTiO2, nanoceria, the mechanical and protective properties of

water based systems (epoxy 2K, acrylics, UV) are strongly improved. Moreover, at that time,

an important demand exists for multifunctional coatings e.g. protective and decorative

coatings with anti-soiling and self-healing properties. In the past, it has been proved that the

anti-soiling properties of some mineral paints could be modified by the use of modified

colloidal silica in place of a part of the silicate binder.

In this study, the effect of the addition of silane modified colloidal silica dispersions in white

deco paints and water based lacquers has been investigated regarding to their dirt pick-up

resistance (iron oxide and carbon black contaminations), their hiding power and their behavior

after outdoor exposure.

It has been highlighted that the use of Bindzil CC301 to improve the dirt pick-up resistance

(DPU) or the anti-soiling properties of water based white deco paints is successful; the mode

of addition of colloidal silica – premix or post addition – does not affect the enhancement of

the anti-soiling properties and finally the extent of DPU improvement depends on the

nanoparticles content. The action of colloidal silica on the anti-soiling properties is resin and

PVC dependent. The reduced dirt pick-up of the paints with nanoSiO2 is probably related to

surface energy modification. It has been observed that the wetting of the dirtying solutions is

less pronounced when nanosilica has been added to the paint. Moreover, the hiding powers of

these paints are affected by the addition of colloidal silica. Very surprisingly, the paint opacity

tends to increase with the nanosilica content. It can be assumed that the addition of Bindzil

CC301 could change or modify the degree of dispersion of TiO2 and then affect positively the

paint opacity.

INTRODUCTION

For several years, the interest for nanotechnologies in the paint and coating industry is

growing. Several researches carried out in CoRI have shown that by the use of nanoparticles

such as colloidal silica, nanoTiO2, nanoceria, the mechanical and protective properties of

water based systems (epoxy 2K, acrylics, UV) are strongly improved. Moreover, at that time,

an important demand exists for multifunctional coatings. For example, protective and

decorative coatings with anti-soiling, self-healing properties. In the past, it has been proved

that the anti-soiling properties of some mineral paints could be modified by the use of

modified colloidal silica in place of a part of the ethyl silicate binder. The greater dirt pick-up

resistance of such systems has been related to a modification of the surface tension and to

reduced water permeability of the dry film in presence of colloidal silica. The internal stresses

of those systems were also strongly reduced by the use of colloidal silica in place of the

silicate binder and then better adherence of those mineral paints on concrete has been reached.

In this study, the effect of the addition of Bindzil CC301 in white deco paints has been

investigated regarding to their open time, their hardness evolution, their dirt pick-up

resistances (iron oxide and carbon black contaminations). The hiding powers of some paints

Modified colloidal silica for enhancement of dirt pick-up resistance in Deco paints

55

containing colloidal silica in varying amounts have also been determined. Infra red

spectroscopy as well as scanning electron microscopy have been used to characterize the dry

film surfaces in order to understand the unexpected results.

EXPERIMENTAL RESULTS

The influence of the addition of Bindzil CC301 in several white deco paints has been

investigated in terms of different properties such as open time, hardness, dirt pick-up

resistance and hiding power. The open time and hardness have been evaluated on paints

whose formulas are listed in table 1, the dirt pick-up resistances on paints given in table 2 and

hiding power determinations on those given in tables 2 and 3. For these two last properties

several amounts of colloidal silica have been investigated.

Table 1: Paint composition (HG 10)

Weight (g)

Ref HG HG 10

Components

REF 2.4% CC301

1 Water 5.34 5.34

2 Disperbyk 190 1.15 1.15

3 Envirogem AD01 0.35 0.35

4 Acticide MBS 0.038 0.038

5 Tiona 595 24 24

6 Coapur XS 52 0.66 0.66

7 Primal HG 1000 57.01 57.01

8 Texanol 2.36 2.36

9 Coapur XS 52 0.91 0.91

10 NHS 300 3 3

11 Acticide MBS 0.285 0.285

12 Water 4.90 2.5

13 Bindzil CC301 0 2.4

TOTAL 100 100

Table 2: Paint composition (FP 2019/1 – post addition)

Weight (g)

FP 2019/1 FP 2019/1 a FP 2019/1 b FP 2019/1 c

Components

REF 10% CC301 15% CC301 25% CC301

1 Water 9.25 8.33 7.86 6.94

2 Orotan 731 1.3 1.17 1.105 0.975

3 Tego Foamex 810 0.1 0.09 0.085 0.075

4 Aquaflow NLS-205 0.4 0.36 0.34 0.3

5 Kronos 2190 23 20.7 19.55 17.25

6 Hydrocarb OG 5.6 5.04 4.76 4.2

7 Sillitin Z 89 3.4 3.06 2.89 2.55

8 Tego Airex 902 W 0.1 0.09 0.085 0.075

TOTAL 43.15 38.84 36.68 32.36

9 Water 15.50 9.00 6.20 0.00

10 Dowanol DPnP 1.00 0.90 0.85 0.75

11 Alberdingk AC 2019 VP 31.70 28.53 26.95 23.78

12 Bindzil CC301 0.00 8.77 12.75 19.41

13 Aquaflow NLS-205 1.80 1.62 1.53 1.35

TOTAL 93.15 87.66 84.95 77.65

6

containing colloidal silica in varying amounts have also been determined. Infra red

spectroscopy as well as scanning electron microscopy have been used to characterize the dry

film surfaces in order to understand the unexpected results.

EXPERIMENTAL RESULTS

The influence of the addition of Bindzil CC301 in several white deco paints has been

investigated in terms of different properties such as open time, hardness, dirt pick-up

resistance and hiding power. The open time and hardness have been evaluated on paints

whose formulas are listed in table 1, the dirt pick-up resistances on paints given in table 2 and

hiding power determinations on those given in tables 2 and 3. For these two last properties

several amounts of colloidal silica have been investigated.

Table 1: Paint composition (HG 10)

Weight (g)

Ref HG HG 10

Components

REF 2.4% CC301

1 Water 5.34 5.34

2 Disperbyk 190 1.15 1.15

3 Envirogem AD01 0.35 0.35

4 Acticide MBS 0.038 0.038

5 Tiona 595 24 24

6 Coapur XS 52 0.66 0.66

7 Primal HG 1000 57.01 57.01

8 Texanol 2.36 2.36

9 Coapur XS 52 0.91 0.91

10 NHS 300 3 3

11 Acticide MBS 0.285 0.285

12 Water 4.90 2.5

13 Bindzil CC301 0 2.4

TOTAL 100 100

Table 2: Paint composition (FP 2019/1 – post addition)

Weight (g)

FP 2019/1 FP 2019/1 a FP 2019/1 b FP 2019/1 c

Components

REF 10% CC301 15% CC301 25% CC301

1 Water 9.25 8.33 7.86 6.94

2 Orotan 731 1.3 1.17 1.105 0.975

3 Tego Foamex 810 0.1 0.09 0.085 0.075

4 Aquaflow NLS-205 0.4 0.36 0.34 0.3

5 Kronos 2190 23 20.7 19.55 17.25

6 Hydrocarb OG 5.6 5.04 4.76 4.2

7 Sillitin Z 89 3.4 3.06 2.89 2.55

8 Tego Airex 902 W 0.1 0.09 0.085 0.075

TOTAL 43.15 38.84 36.68 32.36

9 Water 15.50 9.00 6.20 0.00

10 Dowanol DPnP 1.00 0.90 0.85 0.75

11 Alberdingk AC 2019 VP 31.70 28.53 26.95 23.78

12 Bindzil CC301 0.00 8.77 12.75 19.41

13 Aquaflow NLS-205 1.80 1.62 1.53 1.35

TOTAL 93.15 87.66 84.95 77.65

77

Table 5: Persoz hardness

REF HG HG 10 Drying time at

room temperature Reference system 2.4% CC301

1 day 27 sec 36 sec

7 days 47 sec 60 sec

15 days 65 sec 79 sec

As it can be seen in table 5, the addition of colloidal silica induces a hardness increase which

is already pointed out after only 1 day of drying at room temperature. This hardness

reinforcement is maintained for longer drying times.

Dirtpick­upresistanceThe dirt pick-up resistances have been evaluated from an internal test method developed by

CoRI. It is based on the surface aspect modification (color measurement) of coated panels

after their soiling by means of red iron oxide or carbon black water based solutions (1

weight% in water) and surface cleaning by means of running water. The dirtying solutions

contain only water and pigment particles without any other dispersing or wetting agents; they

are applied on the paint surface by means of a spray. These two powders based on iron oxide

and carbon black have been retained for their hydrophilic and hydrophobic character

respectively. Moreover, they tend to stick to the coated surfaces where the soiling solution has

been in contact.

The different paints (table 2) have been applied on fibrocement substrates in two layers by

means of a brush. The drying time between the two layers was 24h at room temperature. After

2 weeks of drying at ambient temperature, the paint surfaces were contaminated by means of

red iron oxide and carbon black water-based solutions (see fig.1). Contaminated surfaces are

let to dry during 24h before being gently washed with a soft towel under running water.

Secondly, the paint surfaces are cleaned with water and soap. The dirt pick-up resistances

have been evaluated from the surface color modifications (L*a*b* measurements before and

after the contamination) of the coated panels and are expressed in terms of deltaE (ΔE)

calculated from L*,a*,b* values.

Figure 1: Soiled paint surfaces (iron oxide and carbon black)

The surface aspects of the soiled paint surfaces (table 2) after their washing by means of water

and water/soap are presented in figure 2

8

FP2019/1Reference

FP2019/1

10%CC301

FP2019/1a

25%CC301

FP2019/1c

15%CC301

FP2019/1b

Figure 2: Surface aspects after the DPU test.

It has to be noted that the wetting properties of the dirtying solutions on the paint surface

depend on the paint composition and on the pigment volume concentration. In the case of the

considered mate paint (table 1), it has been observed that, in presence of nanosilica particles,

the water based soiling solution droplets spread more on the paint surface. Similar

observations have also been made for the satin paint (table 2).

The evolutions of deltaE determined on FP 2019/1 paints after the washing of the soiled

surfaces with running water or with soapy water are shown in figures 3 and 4 respectively

(IO-iron oxide CB-carbon black contaminations).

From these two figures, it is clear that the use of Bindzil CC301 in this paint formulation is

positive for the dirt pick-up resistance. A strong reduction of dE is pointed out in presence of

25% in weight of colloidal silica when the surfaces were soiled with carbon black solution.

An effect is also seen with iron oxide as contaminant but it is not so spectacular. In this

Figure 3: dE after running water surface cleaning (IO iron

oxide, CB carbon black) in function of Bindzil CC301 – post

addition‐amountforFP2019/1paints

Figure4:dEaftersoapywatersurfacecleaning(IOironoxide,

CBcarbonblack)infunctionofBindzilCC301–postaddition‐

amountforFP2019/1paints

99

evaluation, 10% of Bindzil CC301 is already efficient to make the paint surface less sensitive

to dirtying.

HidingpowerThe hiding powers have been determined according to ISO 6504-3 standard "Determination

of hiding power - Part 3: Determination of contrast ratio of light-coloured paints at a fixed

spreading rate". This standard describes a method for determining the opacity (by contrast

ratio measurement) given by paint films of white or light colours of tristimulus value Y

greater than 25, applied at a spreading rate of 20 m²/l to a black and white chart or to

colourless transparent polyester foil. In the latter case, the tristimulus value Y is measured

subsequently over black and white glass panels. The results of the hiding power

determinations as well as densities, dry contents and PVC's are listed in table 6.

Table 6: Density, dry content, hiding power and PVC-TiO2 for the studied paints

Paint Description Density Dry content

(%)

Hiding

power

(m²/l)

PVC

(%) PVC-TiO2

(%)

2019/1

2019/1a

2019/1b

2019/1c

Ref - matte

CC301 – 10%

CC301 – 15%

CC301 – 25%

1.337

1.354

1.353

1.375

50.182

51.938

52.317

54.048

8.60

9.12

9.57

9.70

38.56

41.76

43.34

46.37

24.04

22.79

22.17

20.98

2019/ba

2019/bc

CC301 – 10% (premix)

CC301 – 25% (premix)

1.352

1.372

51.836

53.954

9.03

9.52

41.76

46.37

22.79

20.98

2019/2

2019/2a

2019/2b

2019/2c

Ref - satin

CC301 – 10%

CC301 – 15%

CC301 – 25%

1.269

1.277

1.283

1.298

47.165

48.189

48.822

50.554

8.24

8.73

8.42

8.37

29.56

33.07

34.82

38.18

18.43

17.51

17.05

16.17

For the paints listed in tables 2 and 3, some results are unexpected; use of Bindzil CC301

induces for some paint an increase of their hiding power. Indeed the addition of Bindzil

CC301 in those paints results in a reduction of TiO2 concentration due to a dilution of the

pigment content by the colloidal silica. Then, it could be expected that the paint opacity will

be lowered proportionally to the added amount of colloidal silica.

DISCUSSION

The use of colloidal silica in this kind of deco paints affects strongly some properties such as

open time, Persoz hardness development, dirt pick-up resistance and hiding power:

- the open time of the liquid paint is enlarged for the considered paint;

- the Persoz hardness is increased, even after only 1 day of drying. The reinforcement is

maintained after the complete film formation;

- the dirt pick-up resistance of paint films is improved. This effect is more pronounced

when carbon black solution is used as soiling agent;

- in some cases, depending on the paint composition and on the PVC, the opacity of the

dried films is also enhanced.

To explain those properties modifications in presence of Bindzil CC301 in water based

dispersion paints, several assumptions can be made:

- the nanosilica particles tend to migrate to the surface of the paint film during the film

formation inducing an enrichment of its surface by silica which results in a change of

the surface tension and of the surface composition of the dried films. Those surface

10

modifications could affect some paint properties such as open time, hardness and dirt

pick-up resistance;

- those nanoparticles could also act as dispersing agent for different pigments and in

particular for TiO2. An optimal dispersion of the TiO2 aggregates into the dry films

will affect strongly the hiding power and paints opacity will be improved. The

nanoparticles could also act as a spacing agent for the polymeric particles and then

slow down the coalescence process causing an enlargement of the open time.

Infrared spectroscopy analysis as well as electron microscopy examinations have been

performed in order to confirm the assumptions made above.

In order to determine surface composition and by this way to evaluate the silica enrichment,

IR analysis have been performed on paint with Bindzil CC301 at variable incident angles. By

adjusting this angle, the depth of penetration of the IR beam into the samples is controlled(1,2)

.

By using high incident angle (80°), surface monolayer composition can be determined, the

grazing angle probe is generally used when very low level contamination needs to be

analyzed (nanometer thickness levels). The 45° probe is optimal for analysis of thin films

greater than 1 µm in thickness. The resulting spectra taken at these two incident angles are

given in figure 3.

In presence of Bindzil CC301, modifications of the IR spectrum in the 1200 cm-1

region is

pointed out; this region is characteristic of the absorption bands of Si-O-Si, Si-O-C and Si-OH

species(3)

. FTIR spectrum (see fig.4) taken on Bindzil CC301 shows absorption bands arising

from asymmetric vibration of Si-O (1090 cm-1

), asymmetric vibration of Si-OH (950 cm-1

)

and symmetric vibration of Si-O (795 cm-1

). Those values are in accordance to those listed in

literature. The absorption bands between 800 and 1260 cm-1

are described as superimposition

of various SiO2 peaks, Si-OH bonding and peaks due to residual organic groups(3)

. These IR

analysis show that a greater amount of silica is present in surface monolayers of the paint with

Bindzil CC301 compared to the amount found more deeply into the film. A part of the

colloidal silica migrates to the paint surface during the film formation inducing formation of a

more concentrated silica based components layer on the top of the paint film. This enrichment

of the paint surface by silica is most probably at the origin of the modification of properties

such as open time, hardness development, dirt pick-up resistance.

2000 1800 1600 1400 1200 1000 800 600

20

30

40

50

60

70

80

90

100

Tra

nsm

issio

n

Wavenumber (cm-1)

80°

45°

COO-

Si-O-Si

Si-O-C

Si-OH

Figure3:FTIRspectratakenonHG10(seetable1)

4000 3500 3000 2500 2000 1500 1000

0

10

20

30

40

50

60

70

80

1085

953

800

% tra

nsm

issio

n

Wavenumber (cm-1)

3383

Figure4:BindzilCC301FTIRspectrum

The presence of colloidal silica at the film surface has been confirmed by SEM examinations.

Free films of paints listed in table 2 (FP2019/1 and 1c) have been broken in liquid nitrogen in

order to visualize the surface silica layer or enrichment in the film cross section from SEM

observations.

1111

Surface examinations have clearly shown that the surface aspect is strongly modified in

presence of Bindzil CC301 (see fig.5). In this case, the paint surface is covered by microsized

flakes looking like glass pieces and not forming a continuous layer.

When cross sections are analyzed (see fig. 6), a thin layer whose aspect differs from the one

of the bulk is seen on the top of paint film in presence of Bindzil CC301. As pointed out

during surface examinations, the covering of the surface by this very thin layer of silica based

components is not continuous and is irregular in thickness. The structure of this layer has

been investigated more deeply (see fig. 7), its surface seems to be coated with nanoparticles

attached together.

Figure 5: SEM observations – paint surfaces (see table 2)

Figure6:Crosssectionsobservationsofpaintfilmslistedintable2

12

Figure 7: Cross sections observations of paints with Bindzil CC301

OpentimeFilm formation of water-based dispersion paint results from the coalescence of the polymer

particles(4)

. During water evaporation, the polymer particles approach each other, are

deformed and the polymer macromolecular chains forming the polymer particles have to

interdiffuse to form ideally a continuous dry film. The different steps of the coalescence

process are mostly governed by surface tension. The film formation - coalescence of the

particules - occurs only if capillary forces (proportional to the surface tension of the

dispersion medium) are higher than the deformation forces (related to the mechanical

properties of the polymer) and progress laterally (exterior to interior) and vertically (top to

bottom). This particular progression mode promotes the formation of a thin skin of dry

polymer on the top of the paint. This thin skin is at the origin of the defects appearing during

paint application. An increase of the open time of the water-based paints could be induced by

a lowering of the surface tension during the coalescence or by other phenomenon slowing

down the film formation process.

To evaluate the role of colloidal silica in the coalescence process, the surface tension of

several paints during their drying has been measured. Paints without colloidal silica, with

Bindzil CC301 and with an additive (add.1) suitable to improve the open time have been

characterized (see figure 8). As it can be seen in

this figure, the dynamic surface tension is not

affected by the use of Bindzil CC301. The surface

tension profile during the paint drying is similar

to the one observed for the paint without additive.

On the other hand, the second additive (add.1)

modifies strongly the surface tension profile; it

keeps the surface tension low enough for a longer

time resulting in a significant enlargement of the

open time. Then, it is evident that, in presence of

Bindzil CC301, the open time improvement is not

related to a surface tension effect. Another

mechanism takes probably place during the film

formation to slow down the process and to prevent Figure 8: Surface tension in function of drying

time

1313

the closing of the paint surface; the nanosilica particles act as spacing agent or spacer

between polymeric particles. This behavior allows a regulation of the drying process without

skin formation at the surface of the paint film. Bindzil CC301 has a steric hindrance effect

during the coalescence of the polymeric particles; it inhibits a rapid film formation and allows

an enlargement of the open time.

HardnessPendulum hardness is measured by the damping produced as the pendulum swings from side

to side on the paint surface to be characterized. Then, it is related to the damping properties of

organic surface. A lower stiffness will result in deeper indentation of the ball into the material

resulting in a greater rate of decrease of the oscillations and finally, a lower hardness. It is also

known(5)

that the hardness value determined by means of pendulum can be influenced by a

“skin effect” or hard outer surface, while the bulk of the film is relatively soft.

By the use of colloidal silica, modification of the hardness of the water-based paints has been

highlighted. After very short drying time, a hardness improvement is already seen; its

intensity depends on paint composition and nanosilica concentration. This behavior has to be

related to the enrichment of the top of the paint film by colloidal silica causing localized PVC

increases. By this fact, the tackiness of the surface is reduced in particular when low Tg

binders are used and hardness values related to those paints CC301 are reinforced.

Dirtpick­upresistanceSeveral factors

(6,7,8) affect the dirt pick-up resistance or the easy-to-clean characteristic of

paints: the dry film surface tension, their hardness, their surface roughness, their tackiness.

This list is not exhaustive. Surface tension of the solid plays a determinant role in the easy-to-

clean properties of a surface. Depending on the surface tension of the material, water based

contaminant solutions will either wet completely this material due the superhydrophilicity

character of its surface or form spherical droplets which easily roll on the surface due to

superhydrophobic properties of the material. In these two cases, the dirt pickup resistance of

the surface will be strongly improved. The hardness or tackiness of a system is also

determinant for the adhesion of contaminants to the paint film surface. Harder is the surface;

less sensitive will be the paint surface towards the permanent attachments of soiling particles.

By the use of colloidal silica in this kind of water-based paints, it can be assumed that the

hydrophilicity character of the surface will be reinforced and then their soiling resistance

affected. In order to verify this fact, water contact angle measurements have been performed

on paints with and without Bindzil CC301; the results are displayed in figure 9. The water

contact angles are slightly reduced in presence of colloidal silica (2019/1c); the reached

values (around 60°) are not low enough

to modify the wetting characteristics of

the water-based soiling solutions. This

result is not surprising due to the fact

that, in Bindzil CC301, the colloidal

particles are surface treated by means of

organic chains. It induces a more

hydrophobic behavior of these silica

particles. Paint surface properties

modification in term of hydrophilicity is

thus not at the origin of the

reinforcement of dirt pickup resistance of

the paint with Bindzil CC301. IR and Figure9::Contactanglemeasurements(water)onpaints

with(2019/1)andwithoutBindzilCC301(2019/1c)

14

SEM analysis performed on those paints have shown an accumulation of silica based

components at the paint surface inducing in particular a hardness improvement. This silica

layer makes probably the paint film surface less tacky and less sensitive to a permanent

attachment of dirt particles. By this way, the dirt pick-up resistance of the paints with Bindzil

CC301 is reinforced. Some studies(9,10)

on nanocomposites systems have shown similar results

in terms of hardness and easy-to-clean properties. They attributed the improved properties to

an enrichment of the surface by silica particles.

HidingpowerIt is known

(11) that a major change in opacity (hiding power) of films can be produced by

varying the PVC and smaller changes by such things as pigment particle size, mixture of

pigments and extenders, type of vehicle, and the gloss of the film. It can be expected the S-

value (scattering – hiding power) of a film will increase with its pigment content (PVC). The

higher the content, the greater will be the number of pigment-vehicle interfaces at which

scattering takes place. It has been proved

experimentally for white pigments that at

lower PVC's - up to about 20% - there is an

almost linear relation between S and PVC.

At higher PVC's, the S-value reaches a

maximum and then decreases. In the case of

TiO2, the curve passes through a maximum

at a value of about 25% PVC (see fig.10).

This evolution (fig.10) of S-value in

function of PVC may be interpreted as a

packing effect. That is, when crowded

together, each particle no longer scatters light as efficiently as before inducing degradation in

opacity (reduction of the hiding power).

When the determined hiding powers of the studied paints are plotted in function of the TiO2

PVC's (fig.11), it can be seen that the hiding power evolution is similar to the one shown in

figure 10. The hiding power passes through a maximum for a value around 21% TiO2 – PVC.

In taking into account the TiO2 PVC, the reached hiding powers for the different paints

containing Bindzil CC301 could be explained in terms of crowding effect.

The hiding power of the paints without

Bindzil CC301 seems to be reduced

compared to those of paints with

nanosilica, in particular for PVC-TiO2

<20%. The measured value for the

hiding power of this system is not on

the continuous blue curve (see fig.11).

The use of Bindzil CC301 changes or

modifies probably the degree of

dispersion of TiO2 and then affect

positively the paint opacity. It is well

known that a poor degree of dispersion

resulting from either flocculation or

agglomeration causes a decrease in hiding power (11)

. It has to be noted that the role of

colloidal silica as dispersing agent has already been pointed out in a previous study(12)

; some

TEM images showing nanosilica particles around TiO2 particles are displayed.

Figure 10: S‐value in function of the PVC (from

pigmentHandbookeditedbyT.C.pattonp318)

Figure11:HidingpowerevolutioninfunctionofPVC

1515

CONCLUSIONS

To conclude, the improvement of some properties of water-based deco paints such as open

time, hardness, dirt pick-up resistance, hiding power in presence of Bindzil CC301 has to be

related to the fact that :

- Colloidal silica particles migrate to the paint surface during the film formation

inducing its enrichment by silica based components. The thin silica layer on the paint

surface has been pointed out by means of IR and SEM analysis.

- Those nanoparticles act also as dispersing agent or spacing agent for both pigment and

organic particles.

REFERENCES

1. Agilent 4100 ExoScan FTIR – Operation Manual

2. Infrared Spectroscopy in the analysis, characterization and testing coatings, John M.

Chalmers, JCT CoatingsTech, July 2005, pp. 50-59

3. FTIR, TEM and NMR investigations of silica nanoparticles, A. Beganskiene, V.

Sirutkaitis, M. Kurtinaitiene, Materials science, vol.10 n°4, 2004

4. Surface Coatings, Science and technology, edited by Swaraj Paul, pp. 521-525

5. Paint and Coating Testing Manual, 14th edition of Gardner-Sward Handbook, pp. 555-584

6. Nano keeps water and dirt at bay, I. Cabrera, B. Lohmeijer, E. Jahns, European Coatings

Journal, 03/2011, pp. 108-112

7. Raising the barriers to dirt, O. Wagner, C. Seng Yong, J. Allen, European Coatings

Journal, 10/2010, pp.32-37

8. Strategies to minimize soiling and biofouling of exterior coatings, A. Larsson, YKI,

Institute for Surface Chemistry

9. Nanocomposite dispersions for water-based coatings, F. tiarks, J. leuninger, O. wagner,

E. Jahns and H. Wiese, Surface Coatings International, May 2007, pp. 221-229

10. Evaluation of durability of nano-silica containing clear coats for automotive applications,

E. Scrinzi, S. Rossi, P. Kamarchik, F. Deflorian, Progress in Organic Coatings, vol. 71

(2011), pp. 384-390

11. PIGMENT HANDBOOK, Vol. III "Characterization and physical relationships",

Opacity, Hiding Power, and Tinting Strength. P289

12. Modified silica sols: Titania dispersants and co-binders for silicate paints, P. Greenwood,

Pigment and resin technology, 2010 vol.39 n°6

16

Norner var tidligere en del av Statoil, senere Borealis, og har siden 2007 vært et selvstendig firma som tilbyr test-ing og rådgivning, først og fremst innen plastutvikling- og produksjon. For de fleste med bakgrunn innen maling og lakk, er Norner først og fremst kjent for å tilby NORSOK-testing for offshoreindustrien, men har egentlig en enda bredere portfolio innen testing og rådgivning for polymer-industrien, ettersom dette var Norners hovedtyngdepunkt som Statoil-laboratorium frem til 2007. I dag har Norner 55 ansatte med hovedkontor i Stathelle i Telemark, et videre kontor i India, og kunder over hele verden, inkludert Aus-tralia, Brasil, Thailand og Russland. Etter at Borealis gikk ut som eiere har Energi og Miljøkapital overtatt 63% av eier-skapet, mens de resterende 37% er hos de ansatte. Norner beskriver selv sin nøkkelkompetanse som plast processing, additiver for plastindustrien, polymerer, katalysatorer og polymerisasjon. Norner bidrar som rådgivere når aktører vil starte ny satsing på produksjon av polymer eller plast og ved konkret problemløsing for å optimere kvaliteten på

spesielle plastprodukter avhengig av bruksområde. Her har Norner også gode muligheter for testing under mange for-skjellige relevante forhold. Impact testing, stretch/elonga-tion, cyclic weathering og NORSOK testing er blant tester som kan utføres hos Norner, både i utvikling av produkter og som 3. part i testing og dokumentasjon av allerede eksis-terende produkter. Selv om Norner er størst innenfor plast og polymer, tar de også oppdrag innen stål og maling. De ønsker en stabil ekspansjon utover både tekniske områder de nå har drevet innenfor, så vel som markedsområder på verdensbasis.Til sammen 10 medlemmer fra NMLF besøkte Norner 23. mai 2013, og fikk en fin innføring i deres aktiviteter, inkludert en omvisning på laboratoriene og en hyggelig avs-lutning med spørsmål og svar over et lite felles måltid.

Anette Nordskog

NMLF, Bedriftsbesøk Norner 23. mai 2013

17

SILICA-NANOCOMPOSITES – READY TO USE PRODUCTS FOR

HIGHEST SCRATCH AND ABRASION RESISTANCE IN INDUSTRIAL

AND WOOD COATINGS

Liquid silica-nanocomposites from Tego are used primarily where coatings are required to

exhibit high scratch and abrasion resistance without sacrificing transparency. Also, these

products should be easy to formulate. Furthermore, secondary properties such as barrier

effect, reduced shrinkage during curing and improved adhesion on substrates with hydroxyl

function can be achieved in various coatings systems without compromising the degree of

gloss. The properties can only be achieved by conventional means by using several layers.

Manufacture of Silica-Nanocomposites

Using a modified sol-gel process, it is possible to manufacture composites from silica

nanoparticles and organic resins which, despite being 50% w/w filled, are water clear.

Starting from water glass, spherical silica nanoparticles, approximately 20 nm in diameter and

with a very narrow size distribution, can be cultured in an aqueous environment.

These particles then have their surfaces modified to permit a stable transfer into their future

organic matrix. The results are transparent products that do not exhibit any sedimentation.

Improving properties with Silica-Nanocomposites

Silica-nanocomposites should be regarded as an additive to the binder in a coating

formulation.

In addition to the main property of scratch and abrasion resistance while maintaining

transparency, silica nanocomposites improve other properties of the coating. Thus, they

reduce shrinkage during curing and improve barrier effects.

The particles are statistically distributed in the cured film i.e. the average distribution is

identical at the surface, in the middle and at the bottom.

Diagram: Nanocomposite particle distribution in the coating

Silican-nanocomposites - ready to useproducts for highest scratch and abrasion resistance

in industrial and wood coatings

18

2

This is quite different from surface active products such as waxes or silicone oils which are

only effective at the coating/air interface and thus have a more or less temporary effect on

scratch and abrasion resistance.

Silica-nanocomposites, in contrast, offer permanent protection as they are firmly bound in the

cured film matrix. Because they are distributed throughout the whole film, the initial

recommendation is 5 to 10% weight content of nanoparticles relative to the solids of a coating

formulation.

The liquid nanocomposites from Tego also have the advantage that they only cause a slight

increase in the viscosity of the coating formulation. This is achieved by customized surface

modification of the nanoparticles.

On substrates such as glass and aluminum, the glassy nanoparticles improve adhesion. This

effect is utilized in, for example, printing on high quality glass bottles.

Silica-nanoparticles are also suitable for applications where a barrier effect is required,

especially where excellent transparency is needed. The barrier effect in an organic coating is

increased by the inorganic silica particles. Diffusion of oxygen or water vapor is thus

significantly lower when compared to an unmodified clearcoat.

The degree of gloss of the formulation is not affected by the silica-nanoparticles. Unlike

surface waxes, which are also used to increase abrasion resistance and for a higher matting

effect, the nanoparticles do not orientate at the surface but are, as already described,

distributed throughout the entire film. It is thus possible to obtain coatings with improved

hardness, scratch and abrasion resistance without having to worry about loss of gloss even at

higher dosages.

Use of silica-nanocomposites

Incorporation of the liquid composites is easy. Like standard binders, the products are

thoroughly stirred in together with the main binder at the start of the production process.

Dispersing or bead milling is unnecessary.

Moderately polar solvents such as xylene or toluene should not be used alone in formulations.

These solvents are, however, generally compatible with the silica-nanocomposites when used

in blends with polar solvents such as esters, ketones and alcohols.

19

3

Certain additives can result in incompatibilities with silica-nanocomposites. These manifest

themselves in, for example, agglomeration, flocculation or increased viscosity of the coating

formulation. A previous testing of the compatibility of nanocomposites with the formulation

ingredients is recommended.

To save laboratory time when developing coatings with silica-nanocomposites, compatibility

lists are available on request for the most used additives with NANOCRYL®, NANOPOX

®

and NANOPOL®. These lists give recommendations for the compatibility of additives with

the silica-nanocomposites in terms of short- and long-term shelf-life.

Silica-Nanocomposites for various coatings systems

Optimized silica-nanocomposites have been developed by Evonik Tego for the different

curing mechanisms in coatings.

NANOCRYL®, a range of silica-nanocomposites in various commonly used UV-curable

acrylate monomers, has been specially developed for radical-curing UV coatings.

Product Overview NANOCRYL®

Name Monomer

SiO2-

content[

% w/w]

Viscosity,

25°C

NANOCRYL® C 130

Trimethylolpropaneformal-

acrylate 50 275 mPa⋅s

NANOCRYL® C 140 Hexanedioldiacrylate 50 175 mPa⋅s

NANOCRYL® C 145 Tripropyleneglycoldiacrylate 50 200 mPa⋅s

NANOCRYL® C 150 Trimethylolpropanetriacrylate 50 3.3 Pa⋅s

NANOCRYL® C 153

Ethoxylated

trimethylolpropanetriacrylate 50 1.0 Pa⋅s

NANOCRYL® C 155 Propoxylated glycerinetriacrylate 50 1.75 Pa⋅s

NANOCRYL® C 165

Alkoxylated (4) pentaerythritol

tetraacrylate 50 2.5 Pas

Listing status of individual products available on request.

NANOPOX® materials are manufactured from epoxy resins and suitable reactive diluents.

Product Overview NANOPOX® I

Name

SiO2-

content

[% w/w]

Base

resin

EEW

[g/equiv.] Viscosity

25°C Characterization

NANOPOX®

C 450 40 DGEBA 295 60,000 aromatic

NANOPOX®

C 460 40

DGEBA/

DGEBF 290 45,000

aromatic,

crystallization-free

Listing status of individual products available on request.

These NANOPOX® products can be heat-cured anhydrously, room-temperature cured with

amines, or forced cured.

20

4

Product Overview NANOPOX® II

NANOPOX®

C 620 EEC

Cycloaliphatic epoxy resin for cationic

curing 40 4.0 Pa⋅s

Listing status of individual products available on request.

The product NANOPOX® C 620 is suitable for cationic UV curing.

NANOPOL®

is a solvent-based product which is universally applicable. It is equally suited

for use in 1-pack stoving enamels and in 2-pack PUR or UV coatings.

Product Overview NANOPOL®

Name Solvent

SiO2-

content [%

w/w]

Viscosity

25°C

NANOPOL®

C 764 Methoxypropylacetate 50 < 50 mPa⋅s

NANOPOL®

C 784 N-butylacetate 50 < 50 mPa⋅s

Listing status of individual products available on request.

For technical support please contact:

Mr. Marco Heuer

Senior Technical Service Manager Nanoresins

Evonik Tego Chemie GmbH

Telefon +49 4152 13 90 777

Mobile +49 162-2199668

marco.heuer@evonik.com

21

R2 Group A/S

R2 Group har nu indgået aftale med den indiske produ-cent, Tagros, om eksklusiv forhandling af permethrin i hele EU. Tagros er en af de få producenter, der kan tilbyde dette insekticid med godkendelse til PT08 træbeskyttelse under biocidproduktdirektivet, og dermed har R2 Group nu mu-lighed for at udstede Letter of Access (LoA) til permethrin.R2 Group har i forvejen et omfattende produktprogram in-den for biocider, men aftalen med Tagros er iflg. kommerciel direktør, Thomas L. Nielsen, et kvanteskridt i den rigtige retning. Permethrin er et insekticid, som anvendes mod ter-mitter, og netop permethrinen fra Tagros sælges i forskellige kvaliteter. Thomas L. Nielsen tilføjer i den forbindelse, at R2 Group kan levere insekticidet til kunderne inden for kort tid direkte fra forskellige lagre rundt i Europa.R2 Group har mange års erfaring inden for netop biocider, som er et af virksomhedens store fokusområder, og man sælger til kunder i hele Europa. Virksomheden arbejder p.t.blandt andet på at udvikle egne rammerecepter med perme-thrin, som vil blive godkendt under BPD, og generelt har innovation høj prioritet i R2 Group.

Chemark, Danmark

Chemark har indgået en aftale med Stahl Performance Coatiing om at repræsetere Stahl i Scandinavien.Stahl er beliggende i Holland og producerer specielle harpikser og coating inden bl.a. inden for polyuretnake-mien mv. Produkterne er specielt egnede til gulve, textiler samt plast mv.

Garvson - Bjørn Thorsen

I december 2012 gick det ut ett meddelande från Björn Thorsen AS att man förvärvat Garvson AB´s aktiviteter (läs bif. brev) på den nordiska marknaden och att det officiella överlåtandet skulle ske per den 1 januari 2013. Aftalen omfatter følgende agenturer:Organik Kimya S.A (Bindemedel och additiv)Schill & Seilacher GmbH (Flamskyddsmedel och hydrofo-beringsmedel)EMS Griltech AG (Termoplastiska Co-polymerer)Bühler AG/Oxylink (Härdare)Omnova Solutions Inc., (Råvaror till golvpolish, fluorten-sider, plastråvaror)

Medens følgende forsat er i Gavssonregi:Org. Färgpigment från SUN Chemical A/S,Titandioxid ersättningspigment från FP Pigments OYsamt råvaror till den kosmetiska industrin från CLR GmbH.

Esters of soybean fatty acids have lower VOC

Styrenated sucrose esters of soybean fatty acids were success-fully synthesised by American researchers from the Depart-ment of Coatings and Polymeric Materials at North Dakota State University. The coatings’ properties were found to be comparable to a commercial styrenated alkyd while having lower VOC at comparable solids content. It was found that an increased styrene content shortens the drying time of the resin. A series of reactions were performed which varied the per-cent styrene incorporated into the resin. The drying time was significantly reduced as the styrene content increased which was a result of having more hard polystyrene chain segments. Tack-free times of ≈ 30 min were observed for resins containing high amounts of polystyrene.Cobalt and zinc reduce the drying time NMR (Nuclear Magnetic Resonance) spectroscopy indi-cated residual bisallylic hydrogens were present which are capable of further crosslinking through autoxidation after film application. The addition of cobalt and zinc driers re-duced the drying time which indicates that autoxidation is occurring.Furthermore, the styrenation reaction was extended to make water-reducible resins. These resins were crosslinked with a melamine–formaldehyde resin resulting in biobased thermosets having high solvent resistance, high hardness while retaining good flexibility.More information about this study: Journal of Coatings Technology and Research, 2013, Volume 10, Issue 4, pp 515-525.

Cytec is now Allnex

The divestiture of the Coating Resins business of Cytec In-dustries to funds affiliated with Advent International was first announced in October 2012 and completed on April 3, 2013. The adoption of the new name – Allnex – is the first step towards establishing the company’s new identity.“We are excited about our new name,” states CEO Frank Aranzana. “We believe that it reflects who we are, what we stand for, and what we want to achieve.”The search for a name began with an employee contest in November 2012 that generated more than 300 possibilities. Those names gave inspiration to a global diversity group, which brainstormed further and incorporated advice from the leading branding agency Interbrand.“Because a company name is one of the most visible aspects of its reputation, it was very important to take the time to consider the company’s identity, mission and future ambi-

Industrinyt

22

One Network. A world of solutions for paints and coatings industry.

Powerful perspective from our global Paints & Coatings expert network that provides world-class product development knowledge from formulation to commercialization

Innovative green choices oering product-based answers to green formulation challenges Visit Univar’s half-day seminar in connection with the Färg & Lack-dagen in Malmö, 27 September. E-mail your application with name & company name to coating.nordic@univareurope.com, by 2 September. www.univar.se

Coatingsad.indd 1 2012-07-31 14:13:36

tions in the selection process,” notes Frank.As a global coating resins company that offers multiple products all under one roof, Allnex is unique in the mar-ketplace. We partner with our customers, who leverage our extensive expertise and myriad of solutions to create value along the next steps in the supply chain. Allnex does more than provide products; we help improve performance. All-nex is also innovative, continually bringing new technolo-gies and new ideas to our customers and the marketplace. These characteristics result in our name Allnex and our slo-gan ‘All About Resins’.The company’s new logo was designed to reflect Allnex’s product portfolio, sustainable innovations, growth aspira-tions, and commitment to continuous improvement. Spe-cifically, the multiple colors and sizes of the droplets repre-sent Allnex’s technologies, products and talented employees. In addition, the green droplet stands for sustainability while the upward movement of the droplets and text reflects the company’s commitment to operational excellence, innova-tion and growth, both for Allnex and its customers.“We believe that Allnex is the one name that we can all stand behind and be proud of,” Aranzana adds.Additional information on aspects of Allnex’s new identify will be provided as it becomes available. In the meantime, please visit www.allnex.com to keep up to date on additions and improvements to our well-known portfolio of products and services.

Kemira sells its stake in Sachtleben to Rockwood

Kemira Oyj and Rockwood Holdings Inc. has signed an agreement, according to which Rockwood buys Kemira’s share (39 %) of the titanium dioxide joint venture Sachtle-ben GmbH.

23

Titandioxid-extenders DispergermedelKaoliner med hög vithet EmulgatorerKalcinerad kaolin Delaminerad kaolin VätmedelSilika – Silikater Fluortensider SkumdämpareModifierade silikasoler ATH, AluminiumhydroxidFörtjockningsmedel Magnesiumhydroxid ZinkboratFree flowing agents Expanderbar grafit MolybdaterPigment Melamin –cyanuratRostskyddspigment - fosfat – boratGlasmikrosfärer PolyolerKeramiska mikrosfärer Fettsyror Dimersyror

Kemi-Intressen AB, Box 2018, 169 02 Solna, SverigeTelefon +46 8 629 63 30 Fax +46 8 529 63 35www.kemiintressen.com

Minerals & extenders

• kaolin• calcium carbonate• mica• microspheres

Additives

• biocides• siccatives• coalescents• micronized waxes• plasticizers• silicones• rheology modifiers• defoamers

Binders/Resins

• alkyds, acrylics, epoxy• PVA, PVB and PVC-resins• CAB, CAP• silicon resins• polyols

Pigments

• TiO2

• iron oxides• effect pigments

+370 5 236 3660

+370 5 236 3660

+370 5 236 3660

+7 812 438 1680

+46 40 16 75 00

+45 49 25 05 80

+47 66 81 60 20

+358 9 251 51 60

www.imcd.se

IMCD

info@imcd.se

24

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w.tr

ykke

riet.n

et

INNOVATION TROUGH EXPERIENCE

www.westerlins.com