VISCOGEL SD is a new high performing rheological additive organoclay,effective for solvent-borne systems of low to medium polarity. It gives the formulationsremarkable pseudoplastic and thixotropic properties.VISCOGEL SD allows for higher film deposits, better levelling and sag control. Italso prevents pigments settling in long-term storage conditions.VISCOGEL SD is a highly purified grade of montmorillonite , and the absence ofimpurities allows for more efficient dispersions and allowing the full potential of thepigments used to develop.

PSEUDOPLASTICITY AND THIXOTROPYThe apparent viscosity of a fluid decreases as the shear rate increases, due to the breaking of the internalstructure bonds that are determined by molecular interactions.When the shear force is removed, the molecular interactions are re-established and the initial gestructure reforms. The initial viscosity is recovered over time, this delay in recovery being proportional to the thixotropy of the system.A pseudoplastic fluid, where viscosity recovery is very fast, would give very good anti-sagging but very badlevelling characteristics.A long thixotropic recovery time would show unsatisfying sagging control but very good levelling characteristics.

COMPARING TESTS

VISCOGEL SD has been systematically compared to other organoclays used in low to medium polar solvent-bornesystems. The purpose of these tests was to evaluate the most significant properties shown by a rheological additivein a widely used aliphatic white enamel and in an industrial paint, formulated as follows:

White Enamel (aliphatic based)- Medium oil alkyd- Mineral spirits- Organoclay- Titanium dioxide- Soya lecithin- Cobalt dryer- Zirconium dryer- Calcium dryer- Anti skinning agent

VISCOGEL SD

Graph 1: Viscosity curve of a paint prepared with VISCOGEL SD and a competitive material

Paint, incorporating VISCOGEL SD, shows ideal thixotropic properties when compared to competitive materials.

The viscosity recovery is very efficient when the shear force is removed. This controlled recovery behaviour givessuperb anti-sagging and levelling results as indicated in the test data. The anti-settling properties of VISCOGEL SDare also shown to be excellent.

THIXOTROPIC BEHAVIOUR

Viscogel SD

Ref.

Vis

co

sit

y

Shear rate

Industrial Paint (aromatic based)- Short oil alkyd- Xilene- Organoclay- Titanium dioxide- Barium Sulphate- Soya lecithin- Cobalt dryer- Zirconium dryer- Calcium dryer- Anti skinning agent

The anti-sag test used allowed for different film thickness of paint to be applied to a standard contrast chart and thendried in a vertical plan. The paint made with VISCOGEL SD indicated more efficient control thus allowing thicker filmsto be applied to vertical surfaces. These enhanced results are due to the optimum pseudoplastic and thixotropic propertiesthat VISCOGEL SD gives the system.The sagging tests have been carried out for the aliphatic and aromatic based formulations at room temperature, usingthe contrast charts, dried in a vertical position. This paint test has been repeated several times and at various timeintervals. The initial test was conducted after manufacture then again after one hour and then 24 hours.

SAGGING

The comparison chart between VISCOGEL SD and the reference material is shown in figure 1.

The thixotropic properties of VISCOGEL SD allow for excellent levelling of the paint in a aliphatic and aromatic basedsystem. The levelling properties remove the brush marks and other surface irregularities and thus increases the glossobtainable and other surface requirements.

LEVELLING

Fig.1

Tab. 1 : Table showing results obtained with varying concentrations of Viscogel SD, using the aliphatic and aromatic based formulations.

(1 mil = 25,4 micron)

STANDARD

VISCOGEL SD

Riferimento

3

3

2

2

1

20

CONC. (%) LEVELLING (mils)Initial After 1h After 24h

1

VISCOGEL SD

Riferimento

VISCOGEL SD

Riferimento

0.5 20

CONC. (%)Initial After 1h After 24h

0.5

0.25

0.25

40

10

20

20

40

10

20

20

80

20

40

0.125

0.12510 10 20

10 10 10

40

20

40

100

40

40

40

40

200

40

80

40

80

200

Tab. 2 : Table showing results obtained with varying concentrations of Viscogel SD, using the aliphatic and aromatic based formulations.

LEVELLING (mils)

(1 mil = 25,4 micron)

CAMPIONE

VISCOGEL SD

Riferimento

3

3

2

2

1

8

CONC. (%) SAGGING (mils)Initial After 1h After 24h

8 9

5 6 7

7 7 8

5 5 6

0 3 51 0 0 3

VISCOGEL SD

Riferimento

VISCOGEL SD

Riferimento

0.5 11

CONC. (%) SAGGING (mils)Initial After 1h After 24h

Aliphatic based formulations

0.5

0.25

0.25

10

9

6

12

10

9

6

12

10

9

6

0.125

0.1257 7 7

5 6 6

Aromatic based formulations

Aliphatic based formulations Aromatic based formulations

SETTLING

VISCOGEL SD has been shown to give very efficient results in paints at very low concentrations. This is shown inthe tables of pre-gel results obtained (Test 1 and Test 2)

VISCOSITY

Test 1:Table showing pre-gel viscosity results obtained with varying concentrations of Viscogel SD, in a mixtureof (1:1) White Spirit/Medium Oil resin and in a mixture of (1:1) Xilene/Short Oil resin.

Over time, in storage, there is a tendency with some paints for the heavy particles to settle. VISCOGELSD considerably reduced this and allows the paint to be stored for a longer period and/or at highertemperature without any significant syneresis or pigment settling.In order to evaluate the settling characteristics of paints made with VISCOGEL SD, ageing tests havebeen carried out according to the following procedure.Paints (aliphatic and aromatic based) manufactured with VISCOGEL SD and the reference paints werekept at 60°C for two weeks. This test simulates a storage time of approximately 8-12 months. Theresults obtained are shown in figure 2.

Fig.2

The gel has been made according to the following procedure:

In White spirit/medium oil resin:- VISCOGEL SD has been dispersed in the blend White Spirit/Medium Oil resin at 25°C and at the speed of 2000 rpm.- VISCOGEL SD concentration is varied from between the ranges of 2-3%.

In Xilene/Short Oil resin:- VISCOGEL SD has been dispersed in the blend Xilene/Short Oil resin at 25°C and at the speed of 3500 rpm.- VISCOGEL SD concentration is varied from between the ranges of 2-3%.

Graphs 2 and 3: Variation of the VISCOGEL SD and the reference viscosity as the concentration in White Spirit/medium oil resin����Xilene/Short oil resin increases

Rif.

VISCOGEL SD

ORGANOCLAY(%)

VISCOGEL SD

3,0

2,7

2,5

2,4

2,0

252

232

206

180

147

REFERENCE

140

112

95

0

0

Viscosità (cps) Viscosità (cps)

White Spirit

VISCOGEL SD

456

400

380

310

261

REFERENCE

264

217

163

120

0

Viscosità (cps) Viscosità (cps)

Xilene

250

200

150

100

50

0

2 2,5 3 3,5

Vis

co

sit

y (

cp

s)

Concentration (%)

Viscogel SD

Ref.

White Spirit Xilene

500

400

300

200

100

0

2 2,5 3 3,5

Vis

co

sit

y (

cp

s)

Concentration (%)

Viscogel SD

Ref.

600300

STANDARD IMPUREZZE(%)

VISCOGEL S4 <1

4-5Riferimento

The highly efficient purification process step that is a characteristic of VISCOGEL SD gives a light off white powdercolour giving a very light opaque pre-gel colour. This allows full optimisation of the pigments used.The degree of whiteness of paint prepared with VISCOGEL SD has been compared to that observed in paint preparedwith a reference material. The test has been carried out as follows:the paint has been spread on a test chart, allowed to dry and then exposed to diurnal, halogen and fluorescent light.The white degree has been measured with a spectrophotometer by comparison with a standard. Delta is the measureddifference between the sample and the standard. The lower the difference between the sample and the standard thehigher the degree of whiteness. The table shows how VISCOGEL SD performs against the standard, thus giving a higherlevel, of whiteness in paints, compared to the reference material. This table also shows that a higher gloss and betterhiding properties can be obtained by using VISCOGEL SD.

COLOUR

As the rheological additives do not provide all the paint rheological properties, because of thecomplexity of the interactions between the components contained in the system, buyers andusers should make their own assessment of our product under their own conditions and for

their own requirements.

via Leonardo da Vinci, 21 - 57123 LivornoTel. +39 0586 434000-Fax +39 0586 410852E-mail: info@bentec.it - www.bentec.it

- The Hegman test has been carried out using the gel prepared according to the procedure described at the Test 1 (withthe addition of a 1% concentration)- The Hegman test is carried out as follows:the product is placed on the deepest part of the groove and drawn along the gauge using the scraper. The positionwhere a large number of particles appears indicates the measurement. This operation is usually repeated after 2, 5 and7 minutes since the moment after optimum dispersion of the organoclay has taken place.

Test 2:VISCOGEL SD dispersion times in the blend 1:1 White Spirit/Medium Oil resin and in the blend 1:1 Xilene/ShortOil resin at the decreasing concentration levels.

(1 mil = 25,4 micron)

STANDARD

VISCOGEL SD

Riferimento

3

3

2

2

1

5

CONC. (%) HEGMAN TEST (Hegman)2 min

6 7

4 5 6

6 7 7

5 6 6

7 7 81 6 7 7

VISCOGEL SD

Riferimento

VISCOGEL SD

Riferimento

3 6

CONC. (%)

White Spirit Xilene

3

2

2

5

7

6

7

6

8

7

8

6

8

7

1

18 8 8

7 7 8

DISPERSION VELOCITY

5 min 7 minHEGMAN TEST (Hegman)

2 min 5 min 7 min

STANDARD DELTA

VISCOGEL SD 4,42

5,34Riferimento

VISCOGEL SD is more efficiently purified to remove most of the impurities than in the reference material. This refiningtechnique allows for a higher concentration of the montmorillonite, giving a higher concentration of active reaction sites.The pre-gels prepared by dispersing the VISCOGEL SD in White Spirit and Xilene have repeatedly been observed undera microscope and the results confirm the absence of non activated platelets sites. This plus the evidence from X-Raydiffraction tests show that in VISCOGEL SD any crystalline impurities are in a negligible concentration. This result hasnot been found in the majority of the other organoclays.The results of the VISCOGEL SD and the reference material analysis, by X-Ray diffraction, have been recorded in the

IMPURITIES