VISCOGEL S4 is a new high performing rheological additive organoclay,effective for solvent-borne systems of low to medium polarity. It gives the formulations remarkable pseudoplastic and thixotropic properties.VISCOGEL S4 allows for higher film deposits, better levelling and sag control. It also prevents pigments settling in long-term storage conditions.VISCOGEL S4 is a highly purified grade of montmorillonite , and the absence of impuritiesallows for more efficient dispersions and higher transparency levels.VISCOGEL S4 requires a polar activator to maximise its efficiency.

PSEUDOPLASTICITY AND THIXOTROPY

The apparent viscosity of a fluid decreases as the shear rate increases, due to the breaking of the internal structure bonds that are determined by molecular interactions.When the shear force is removed, the molecular interactions are re-established and the initial gelstructure reforms. The initial viscosity is recovered over time, this delay in recovery being proportionalto the thixotropy of the system.A pseudoplastic fluid, where the initial conditions are immediately recovered, would give very good anti-saggingbut very bad levelling characteristics.A long thixotropic recovery time would show unsatisfying sagging control but very good levelling characteristics.

COMPARING TESTS

VISCOGEL S4 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- Polar activator- Titanium dioxide- Soya lecithin- Cobalt dryer- Zirconium dryer- Calcium dryer- Anti skinning agent

VISCOGEL S4

Graph 1:Representation of the viscosity curve of a paint prepared with VISCOGEL S4 and a competitive material.

Paint, incorporating VISCOGEL S4, 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 S4are also shown to be excellent.

THIXOTROPIC BEHAVIOUR

Viscogel S4

Ref.

Vis

co

sit

y

Shear rate

Industrial Paint (aromatic based)- Short oil alkyd- Xilene- Organoclay- Polar activator- 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 S4 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 S4 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 S4 and the reference material is shown in figure 1.

The thixotropic properties of VISCOGEL S4 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.

LEVELLING

Fig.1

Tab. 1 : Table showing results obtained with varying concentrations of VISCOGEL S4, using the aliphatic and aromatic based formulations.

(1 mil = 25,4 micron)

STANDARD

VISCOGEL S4

Reference

3

3

2

2

1

8

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

9 10

5 5 7

7 7 7

5 5 5

0 3 31 0 0 0

VISCOGEL S4

Reference

VISCOGEL S4

Reference

0.5 12

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

Aliphatic based formulations Aromatic based formulations

0.5

0.25

0.25

10

10

7

1210

11

7

1210

11

8

0.125

0.1258 8 8

5 5 7

(1 mil = 25,4 micron)

STANDARD

VISCOGEL S4

Reference

3

3

2

2

1

20

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

1

VISCOGEL S4

Reference

VISCOGEL S4

Reference

0.5 20

CONC. (%) SAGGING (mils)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 10

10 10 10

40

20

40

1020

40

40

40

40

2020

40

80

40

80

2040

Tab. 2 : Table showing levelling results obtained with varying concentrations of VISCOGEL S4, using the aliphatic and the aromatic�������������������

Aliphatic based formulations Aromatic based formulations

SETTLING

Paints manufactured using VISCOGEL S4 will give the required viscosity, as can be demonstrated by the high viscosityobtained in a pre-gel. The viscosities were obtainable with lower concentrations of VISCOGEL S4 (Test 1) andactivating the pre-gel with mild shear forces (Test 2).

VISCOSITY

Test 1:Table showing pre-gel viscosity results obtained with varying concentrations of VISCOGEL S4 in WhiteSpirit and in Xilene.

Over time, in storage, there is a tendency with some paints for the heavy particles to settle. VISCOGELS4 considerably reduced this and allows the paint to be stored for a longer period and/or at highertemperature without any risks.In order to evaluate the settling characteristics of paints made with VISCOGEL S4, ageing tests havebeen carried out according to the following procedure.Paints (aliphatic and aromatic based) manufactured with VISCOGEL S4 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 pre-gel analysis data shows that as the organoclay concentration decreases the gel viscosity varies as follows:

The pre-gel has been made according to the following procedure:

In White Spirit:- VISCOGEL S4 has been dispersed in White Spirit at 25°C and at the speed of 4000 rpm.- The polar activator is then added and the pre-gel mixed at the speed of 6000 rpm.- VISCOGEL S4 concentration is varied from between the ranges of 2-3%.

In Xilene:- VISCOGEL S4 has been dispersed in Xilene at 25°C and at the speed of 3500 rpm.- The polar activator is then added and the pre-gel mixed at the speed of 3500 rpm.- VISCOGEL S4 concentration is varied from between the ranges of 2-3%.

Graphs 2 and 3: Variation of VISCOGEL S4 and the reference viscosity as the concentration in White Spirit and in Xilene increases

Rif.

VISCOGEL S4

ORGANOCLAY(%)

VISCOGEL S4

3,0

2,7

2,5

2,4

2,0

4560

2800

2500

1400

1200

REFERENCE

2200

1400

900

0

0

Viscosity (cps) Viscosity (cps)

White Spirit

VISCOGEL S4

586

508

445

336

260

REFERENCE

120

92

43

0

0

Viscosity (cps) Viscosity (cps)

Xilene

5000

4000

3000

2000

1000

0

2 2,2 2,4 2,6 2,8 3

Vis

co

sit

y (

cp

s)

Concentration (%)

Viscogel S4

Ref.

White Spirit Xilene

5000

4000

3000

2000

1000

0

2 2,2 2,4 2,6 2,8 3

Vis

co

sit

y (

cp

s)

Concentration (%)

Viscogel S4

Ref.

60006000

STANDARD CRYSTALLINE IMPURITIES(%)

VISCOGEL S4 <1

4-5Reference

VISCOGEL S4 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 S4 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 S4 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 S4 and the reference material analysis, by X-Ray diffraction, have been recorded in thefollowing table.

IMPURITIES

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 following table shows how the VISCOGEL S4 gel viscosity in White Spirit and in Xilene changes as the shear force����������

The pre-gel has been made according to the following procedure:

In White Spirit:- VISCOGEL S4 has been dispersed in White Spirit at 25°C, at the concentration of 3% and mixed at the speed of 4000 rpm�������- Polar activator is then added and the pre-gel mixed at various speeds form 600-6000 rpm.

Test 2:Table showing pre-gel viscosity results obtained with varying the shear force in White Spirit.

In Xilene- VISCOGEL S4 has been dispersed in Xilene at 25°C, at the concentration of 3% and mixed at the speed of 3500 rpm.- Polar activator is then added and the pre-gel mixed at various speeds from 1000 to 3500 rpm

Shear force(rpm) VISCOGEL S46000 4560

4280

3820

3640

3420

REFERENCE2200

1820

1340

1020

850

3280 300

5000

4000

2000

1000

600

Viscosity (cps)VISCOGEL S4

3500 586

476

381

299

REFERENCE120

87

-

-

2500

1500

1000

Viscosity (cps)

White Spirit Xilene

Graph 4 and 5: Variation of the VISCOGEL S4 and its reference viscosity in White Spirit and in Xilene as the shear forcedecreases.

5000

4000

3000

2000

1000

0

0 2000

Vis

co

sit

y (

cp

s)

Shear force (rpm)

4000 6000

Viscogel S4

Ref.

100

00 1000

Vis

co

sit

y (

cp

s)

2000 3000

Viscogel S4

Ref.

White Spirit Xilene

200

300

400

500

600700

4000

Shear force (rpm)

Shear force(rpm)