comparative study on bright fillers performed with a ... · comparative study on bright fillers...

Author: Siegfried Heckl Translation: Wilhelm Bachmann Approval: May 2008

VM / Dr. Alexander Risch _____________________

Comparative Study on

Bright Fillers Performed

with a Polyester Containing

Hydroxyl Groups

R H E O L O G Y

VM

-2/0

5.2

00

8/0

61

409

80

HOFFMANN MINERAL GmbH · P.O. Box 14 60 · D-86619 Neuburg (Donau) · Phone (+49-84 31) 53-0 · Fax (+49-84 31) 53-3 30 Internet: www.hoffmann-mineral.com · eMail: [email protected]

Seite 1

Summary

In this study, the rheological behavior of the product groups Sillitin, Sillikolloid and Aktisil was compared with other common fillers used in the paints and lacquers industry. The study looked at isotropic and anisotropic fillers as well as Neuburg Siliceous Earth. All measurements were performed using a rotation viscometer with infinitely variable settings. The viscosity of the products was measured and depicted according to the concentration and shear rate. Viscosity characteristics (structure viscosity, dilatancy, thixotropy, rheopexy and yield point) were separately evaluated.

shear rate 500 1/s

15 20 25 30 35 40 45 50 55

filler concentration in % by wt.

10

100

1000

10000viscosity in mPas (log)

Sillitin Z 86

quartz powder

unground clay

ground clay

kieselguhr

Fig. 1

Fig. 1 shows that the rheological behavior of Neuburg Siliceous Earth is in between of its mineral components (silica and kaolin). It is interesting to note that the particle structure of fillers permits no prediction on their rheological behavior. Particle size distribution and the particle surface generally have a larger influence on rheological behavior than the crystalline structure of the filler. Viscosity of the surface-treated (coated) Neuburg Siliceous Earth, the Aktisil types, does not differ significantly from their base material Sillitin Z 86. One exception is Aktisil MAM, which exhibits considerably lower viscosity throughout. This difference is due to the use of Silitin V 88 as a base material. In terms of its viscosity factor, Aktisil MAM shows the lowest value of all Aktisil types.

Seite 2

Contents

1. Preliminaries 2. Objectives 3. Methods 3.1 Raw Material Characteristics 3.2 Creation of Dispersion 3.3 Apparatus and Measurement Methods 4. Rheological Tests 4.1 Viscosity Curves 4.1.1 Isotropic Fillers 4.1.2 Anisotropic Fillers 4.1.3 Neuburg Siliceous Earth 4.1.3.1 Sillitin and Sillikolloid 4.1.3.2 Aktisil 4.2 Rheological Effects 4.2.1 Isotropic Fillers 4.2.2 Anisotropic Fillers 4.2.3 Neuburg Siliceous Earth 4.2.3.1 Sillitin and Sillikolloid 4.2.3.2 Aktisil

Seite 3

1 Preliminaries

Manufacturers of coatings, adhesives and sealing compounds are faced with an ever

increasing range of fillers for every type of application area. When paints, plastics and rubber were first developed, fillers were mainly used to cheapen

expensive polymers. This purely economic aspect is still of importance today. However, increased ecological and quality awareness has resulted in products of greater complexity, with increasing specialization and higher demands being placed on coatings, adhesives and sealing compounds. Consequently, the requirements placed on the fillers for these products have increased. Fillers are no longer used just to cheapen recipes, but also to improve their physical and/or optical characteristics. Fillers, when surface-treated with silanes or other substances, are now used specifically as a means of improving properties.

2 Objectives

A comparative study on the bright fillers was performed with a polyester containing hydroxyl

groups. Our aim is to present research departments with a means of deciding which filler to use on the basis of its rheological behavior.

Typical representatives of individual fillers classes were chosen in order to study the

broadest possible spectrum of filler types. The shear range was adapted to the conditions normally encountered in practice.

The tests examined how Neuburg Siliceous Earth, with its particular structure (natural

combination of corpuscular, crypto-crystalline and amorphous silica and lamellar kaolinite), performed against various filler classes. The whole spectrum of Neuburg Siliceous Earth, from Sillitin V 85 to Sillikolloid P 87, including the puriss types and surface-treated Aktisil types was examined.

Seite 4

3 Methods

3.1 Raw Material Characteristics Tables 1 to 4 show the most important physical characteristics of fillers for paint manufacturers. The data are only guidelines values. The fillers have been classified according to structure groups in order to simplify presentation as follows:

Determination of Brightness Brightness values Y and Z were determined once according to DIN 53 163 by means of a spectrophoto-

meter: light type D 65/10, observation angle d/8 (Mini-Scan from Hunterlab). Brightness value Y was also

determined using a three-range tester: light type C, observation angle 45/0 (D 25-9 from Hunterlab). Isotropic Fillers These fillers can be mainly characterized by their cubic to spherical structure. When combined with the polymer matrix, no process-related preferred structural planes are exhibited under operating conditions.

Oil absorpt-

Particle

Brightness

pH

Price index*

Filler ion value

g/100g

size

d50 in m Y

(45/0) Y

(DIN 53 163) Z

(DIN 53 163)

value Sillitin Z 86 = 1.0

chalk 18 2.0 88 85 85 9 0.2

calcite 18 1.5 94 92 95 9 0.8

barytes 12 1.1 95 93 99 --- 1.5

calcined clay 80 4.0 90 94 98 6.5 1.5

Silica 132 6.0 88 94 100 10.0 5.1

quartz powder 31 3.0 90 88 93 7 0.9

Table 1 * based on German prices 1993

Isotropic Fillers (chalk, calcite, barytes, calcined clay, Silica, quartz powder) fillers with largely even three-dimensional particle structure. Anisotropic Fillers (talc, clay, mica, wollastonite) fillers with fibrous or plate-shaped (lamellar) structure. Neuburg Siliceous Earth (Sillitin, Sillikolloid, Aktisil) forms its own group, but can be broadly classified under the isotropic fillers as the plate-shaped kaolinite cannot align due to interspersed silica particles.

Seite 5

Anisotropic Fillers Polymers filled with anisotropic minerals more or less exhibit directional dependence in terms of their physical properties where shear forces occur during processing.

Oil absorpt-

Particle

Brightness

pH

Price index*

Filler ion value

g/100g

size

d50 in m Y

(45/0) Y

(DIN 53 163) Z

(DIN 53 163)


coarse talc 32 87 87 86 92 9.3 2.0

fine talc 40 79 79 80 84 9.5 1.6

unground clay 55 - - 77 75 4.5 1.4

ground clay 39 87 87 89 90 4.0 2.6

mica 48 79 79 80 80 8.4 3.6

wollastonite 32 88 88 91 96 9.8 2.3

Table 2 * based on German prices 1993 Neuburg Siliceous Earth Sillitin and Sillikolloid Neuburg Siliceous Earth is classified according to particle size and brightness. The letters in the product

name (V, N, Z and P) refer to the particle size distribution; the figures to the brightness Y (45/0).

Oil absorpt-

Particle

Brightness

pH

Price index*

Filler ion value

g/100g

size

d50 in m Y

(45/0) Y

(DIN 53 163) Z

(DIN 53 163)


Sillitin V 85 45 3.0 85 83 79 8.0 0.8

Sillitin N 82 45 2.3 82 80 71 8.0 0.8

Sillitin N 85 ** 45 2.3 85 84 79 8.0 0.9

Sillitin Z 86 ** 50 1.8 86 84 79 8.2 1.0

Sillitin Z 89 ** 50 1.8 89 89 89 8.5 1.2

Sillikolloid P 82 50 1.6 82 79 70 8.2 1.6

Sillikolloid P 87 ** 50 1.6 87 85 80 8.2 1.6


** also available as puriss version

Seite 6

Puriss versions As a result of careful processing the grit content is maintained at an exceptionally low level. This considerably reduces the abrasive effect of this series of products, thereby protecting the manufacturer's processing equipment (e.g. airless sprayers). The remaining technical characteristics are identical to those of the base materials. The puriss versions are particularly recommended for very thin lacquer coatings. The results have not been included in the graphics as they are identical to the standard types. Aktisil The Aktisil types are activated Sillitins, produced by modifying the surface of the raw material by a variety of special coatings. In this study only those Aktisil types (based on Sillitin Z 86) suitable for aqueous systems free from binding agents have been considered:

- Aktisil EM (coated with epoxy group silane)

- Aktisil MM (coated with mercapto group silane)

- Aktisil MAM (coated with methacryl silane)

- Aktisil VM 56 (coated with vinyl silane)

- Aktisil PF 224 (coated with stearic acid and stearyl amine)

- Aktisil PF 231 (coated with stearic acid)

Oil absorpt-

Particle

Brightness

pH

Price index*

Filler ion value

g/100g

size

d50 in m Y

(45/0) Y

(DIN 53 163) Z

(DIN 53 163)


AKTISIL EM 50 1.8 86 84 78 8.5 2.5

AKTISIL MM 50 1.8 86 84 78 7.3 2.3

AKTISIL MAM 40 3.3 88 88 87 7.9 3.8

AKTISIL VM 56 50 1.8 86 83 77 7.8 1.8

AKTISIL PF 224 50 1.8 86 84 75 6.1 2.5

AKTISIL PF 231 50 1.8 86 84 77 6.4 2.9


Seite 7

3.2 Creation of Dispersion The filler was dispersed with a rotation speed of 10 to 15 m/s for 20 minutes using a laboratory mixer. The dispersion was then stored for 24 hours to enable it to recover its anomalous viscosity characteristics (thixotropy and structural viscosity). The flow curves were then recorded following a brief homogenization phase. 3.3 Apparatus and Measurement Methods The measurements were made with a rotation viscometer comprising the following components: Rheometer Measuring Apparatus Viscolab LM Rotation Rheometer Viscolab LC 10 Flow Curve Programmer Viscolab FP 10 x-y Recorder PM 8043 Manufacturer: Physica Meßtechnik GmbH &. Co. KG, Stuttgart (FRG) Different measurement systems were used, depending on the viscosity of the samples. Table 5 shows the measurement ranges determined.

Measurement system

recommended viscosity range in Pas shear rate in 1/s shear stress in

Pa

MS-Z1 DIN (double slit measurement system)

0,001 - 1 4,97 - 3979 0,676 - 67

MS-Z2 DIN 0,02 - 15 1,291 - 1033 1,958 - 195

MS-Z3 DIN 0,118 - 100 1,291 - 1033 11,42 - 1140

MS-Z4 DIN 0,672 - 500 1,291 - 1033 65,01 - 6500

Table 5 The proportion of filler in the dispersion was increased until loss of flow occurred (breaking up of flow in measuring vessel). The filler amount was increased in 10% stages and at 5% stages where its proportion in the dispersion was higher.

The test temperature was (23 ± 0.1) C. The flow curves were plotted without pre-shearing (no incremental stages) with: increasing shear rate up to 500 s

-1

and

decreasing shear rate of 500 to 0 s

-1

with a linear change of 4.17 s-2

The viscosity curves were evaluated at a shear rate interval of 8.9 to 500 s

-1. The measurements were

performed twice with the measurement system being refilled each time. Only the flow curves with increasing shear rate (upward curve) were used to evaluate viscosity. The downward curve was used to determine hysteresis (thixotropy and rheopexy), as well as the yield point.

Seite 8

4. Rheological Tests

4.1 Viscosity Curves Sillitin Z 86 is used for comparison in all graphics. 4.1.1 Isotropic Fillers Fig. 2 clearly illustrates the special position of barytes due to its high specific gravity and low demand on bonding agents. While other fillers have a maximum filling capacity of 50 % by weight, viscosity in heavy spar emulsions is hardly affected at this level. However, as many paints are now sold by volume rather than weight, the higher filling capacity of the heavy spar recipes is only of limited advantage. Most filler emulsions show a much greater fall in viscosity up to 100 s

-1

compared to the 200 to 500 s-1 range

(see Fig. 3). This is less pronounced in the case of calcined clay and calcite. Sillitin Z 86 has a somewhat higher shear rate to viscosity ratio, probably due to the special structure of the Neuburg Siliceous Earth. Diatoma-ceous earth is shown at its maximum filling level of 35 % by weight.

Fig. 2

Fig. 3

shear rate 500 1/s

15 20 25 30 35 40 45 50 55

fil ler concentration in % by wt.

1

10

100

1000


Sillitin Z 86 kieselguhr calcite quartz powder

chalk bary tes calcined clay

fi l ler concentration 40 % by wt.

0 100 200 300 400 500

shear rate in 1/s

10

100

1000


Sillitin Z 86 quartz powder chalk calcite

bary tes calcined clay kieselguhr (35 %)

Seite 9

4.1.2 Anisotropic Fillers The anisotropic fillers return widely diverging results (Fig. 4). Mica has nearly the same viscous effect as Sillitin Z 86. Wollastonite produces the lowest increase in viscosity throughout the entire concentration range. The other anisotropic fillers, fine talc, as well as unground and ground clay, produce considerably higher vis-cosity levels, compared to Neuburg Siliceous Earth. Similar results were obtained for the viscosity to shear rate, as shown in Fig. 5.

Fig. 4

Fig. 5

shear rate 500 1/s

15 20 25 30 35 40 45 50 55


10

100

1000


Sillitin Z 86 unground clay ground clay mica f ine talc wollastonite


0 100 200 300 400 500

shear rate in 1/s

10

100

1000

10000


Sillitin Z 86 unground clay ground clay

mica f ine talc wollastonite

Seite 10

4.1.3 Neuburg Siliceous Earth The particle structure of the Neuburg Siliceous Earth is a key factor in terms of its application characteristics. The Neuburg Siliceous Earth disperses very easily and, in contrast to purely lamellar fillers such as talc or clay, does not agglomerate. 4.1.3.1 Sillitin and Sillikolloid The concentration-related viscosity curves of the different types of Neu-burg Siliceous Earth are shown in the following diagrams (Figs. 6 and 7). Comparison of the individual curves reveals some unexpected effects. Products of the same particle size range, but of different brightness, have clearly differing curves which are frequently closer to the next particle size fraction. The differences between the V and N types are very conspicuous. Apparent is the greater thickening effect of Sillikolloid P 87, of which polymers can only be filled to 40 % by weight.

Fig. 6

Fig. 7

shear rate 500 1/s

15 20 25 30 35 40 45 50 55


10

100

1000


Sil l i tin Z 86

Sill i tin V 85

Sill i tin V 88

Sill i tin N 82

Sill i tin N 85

shear rate 500 1/s

15 20 25 30 35 40 45 50 55

fi l ler concentration in % by wt.

10

100

1000


Sil l i tin Z 86

Sil l i tin Z 89

Sil l ikolloid P 87

Sil l ikolloid P 82

Seite 11

Fig. 8 shows the different types of Neuburg Siliceous Earth according to shear rate at a filler concentration of 40 % by weight. All materials show a definite increase in viscosity at shear rates lower than 100 s

-1.

4.1.3.2 Aktisil Common to all the Aktisil types EM, MM, MAM and VM 56 coated with organic silanes is that the silane is

nearly completely bonded at the filler surface1. During hardening of the coat (drying), Aktisil's molecular

groups react with the binding agent. If silanes were first added when formulating the coating the silanes could then remain free to "roam" in the coating, leading to adhesion problems with the threshold surface (coating substrate). In addition to this, silane could lead to surface defects (e.g. fish-eyes). Figs. 9 and 10 show that the Aktisil types have a somewhat lower viscosity level than the base material Sillitin Z 86. Aktisil MAM, whose base material is Sillitin V 88, behaves in the same manner.

1 Albers and Lechner Kunststoffe 81 (1991) No.5 pp. 420 ff

Fig. 8

Fig. 9


0 100 200 300 400 500

shear rate in 1/s

50

500

5000

viscosity in mPas (log)

Sil l i tin Z 86 Sil l i tin V 85

Sil l i tin V 88 Sil l i tin N 82

Sil l i tin N 85 Sil l ikolloid P 82

Sil l ikolloid P 87

shear rate 500 1/s

15 20 25 30 35 40 45 50 55


10

100

1000


Sil l i tin Z 86

Aktisil EM

Aktisil MM

Aktisil MAM

Aktisil VM 56

Seite 12

This characteristic can be seen even more clearly in Figs. 11 and 12, which show the viscosity to shear rate. However, in the lower shear rate up to 100 s

-1 all Aktisil types display around

the same considerable fall in viscosity as the base material.

Fig. 10

Fig. 11

Fig. 12

shear rate 500 1/s

15 20 25 30 35 40 45 50 55


10

100

1000


Sil l i tin Z 86

Aktisil PF 224

Aktisil PF 231


0 100 200 300 400 500

10

100

1000

10000Sillitin Z 86

Aktisil EM

Aktisil MM

Aktisil MAM

Aktisil VM 56


0 100 200 300 400 500

shear rate in 1/s

10

100

1000


Sil l i tin Z 86

Aktisil PF 224

Aktisil PF 231

Seite 13

4.2 Rheological Effects In the following chapter, variations in flow behavior of the filler dispersions from Newtonian flow were quantified. The fillers were grouped according to particle structure, as in the case of the viscosity curves. The rotation test does not permit a (physically) exact description of thixotropy, rheopexy and the yield point. For that reason, auxiliary values were defined which permit a practical comparison of quantitative deviation from Newtonian flow.

Description of methods for anomalous viscosity values: 1. Structural Viscosity Factor As well as Newtonian flow, where viscosity is independent of the shear rate, some systems exhibit

shear rate dependent flow behavior. Where viscosity decreases at an increasing shear rate this is considered to be a structurally viscous or pseudo plastic flow. Where viscosity increases with an increasing shear rate, this is termed dilatancy.

For the following assessment the structural viscosity factor (SVF) as an auxiliary value was

defined as follows:

SVF = relationship: viscosity at 50 s-1 / viscosity at 500 s

-1 (upward curve)

SVF = 1 Newtonian flow SVF < 1 dilitancy flow SVF > 1 structural viscous flow

2. Yield Point Substances with a yield point first start to flow when the external force is greater than the internal

structural forces affecting them. These substances exhibit plastic flow below the yield value. The yield point is assessed from the shear stress at a shear rate of 5 s

-1 (from the downward

curve). 3. Thixotropy and Rheopexy under external shear forces over time. The original structure recovers after a given relaxation

period. This is a reversible process. Rheopexy refers to structural reinforcement over time under the influence of external shear forces

(increase in viscosity). In the case of rheopexy, the structure strengthens over a limited time under the influence of

external shear forces (increase in viscosity).

In this assessment it should be noted that the anomalous viscosity values cannot be regarded as

absolute, but must be considered individually in relation to the viscosity of a particular system.

Thixotropy = - A A

Vupwards downwards

sample

Seite 14

4.2.1 Isotropic Fillers Fig. 13 shows clearly that Sillitin Z 86 has a considerably higher structural viscosity factor over the whole concentration range, compared to the isotropic fillers. In the case of calcite, the structural viscosity factor remains nearly constant at increasing filler content. All other fillers exhibit a more or less strongly defined factor increase. With regard to the yield point (Fig. 14), Sillitin Z 86 has definitely higher values compared to the isotropic fillers. Calcite behaves here like the other fillers. From a filler concentration of 20 % by weight Sillitin Z 86 has a higher thixotropic value compared to the isotropic fillers (Fig. 15). Even at the highest concentration of 50 % the values obtained with Sillitin Z 86 were considerably higher than those of the isotropic fillers. The value 0 is not defined in a logarithmic presentation. For that reason measurement points taking the value 0 are shown on the x-axis. Definite thixotropy can only be demonstrated at the higher filler percentage levels. In the case of kieselguhr, thixotropy increases very rapidly: however, this is limited by its low filler level.

Fig. 13

15 20 25 30 35 40 45 50 55

filler concentration in % by

0,01

0,1

1

10

100

1000yield point in Pa

Sillitin Z 86 chalk calcite barytes

calcined clay kieselguhr quartz powder

Fig. 14

Fig. 15

15 20 25 30 35 40 45 50 55


0

1

2

3

4

5

6

7

8structural viscosity factor (SVF)

Silltitin Z 86

chalk

calcite

bary tes

calcined clay

kieselguhr

quartz powder

15 20 25 30 35 40 45 50 55


0,001

0,01

0,1

1

10

100

1000thixotropy in Pa/cm³

Sillitin Z 86

kieselguhr

calcite

quartz powder

chalk

bary tes

calcined clay

Seite 15

4.2.2 Anisotropic Fillers All fillers shown in Fig. 16 return definite increases in the structural viscosity factor at increasing filler concentration, with the exception of wollastonite. Wollastonite returns the lowest values and remains almost unchanged at increasing filler levels. Ground clay has the highest values throughout the entire concentration range. Comparison of the yield points of this group of fillers reveals a similar pattern. Ground clay has the highest yield point throughout the entire concentration range. Wollastonite, on the other hand, has definitely lower values, compared to the other fillers in this group (Fig. 17). Fig. 18 shows that Sillitin Z 86 returns higher values from a filler concentration of 20 % by weight, compared to the other fillers. Even at the highest concentration level of 50 % by weight, Sillitin Z 86 lies clearly above the anisotropic fillers. Here, too, measured value of 0 are placed on the x-axis. Thixotropy is only definitely defined at higher filler levels for the anisotropic fillers. Fine talc is not shown in this graphic presentation, as it has no thixotropy throughout the concentration range.

Fig. 16

15 20 25 30 35 40 45 50 55


0,1

1

10

100


Sillitin Z 86 fine talc unground clay ground clay mica wollastonite

Fig. 17

Fig. 18

15 20 25 30 35 40 45 50 55


0

1

2

3

4

5

6

7

8

9


Sill i tin Z 86 fine talc unground clay

ground clay mica wollastonite

15 20 25 30 35 40 45 50 55


0,001

0,01

0,1

1

10

100


Sil l i tin Z 86

unground clay

ground clay

mica

wollastonite

Seite 16

4.2.3 Neuburg Siliceous Earth 4.2.3.1 Sillitin and Sillikolloid Figs. 19 and 20 show the increase in structural viscosity factor at increasing filler concentration. The structural viscosity factor tends to increase with decreasing particle size distribution. Particle size also has an influence on flow behavior in terms of the yield point. The coarser materials such as Sillitin V and Sillitin N have lower yield points compared to Sillitin Z 86 (Fig. 21). The fine products Sillikolloid P 82 and Sillikolloid P 87 have the highest yield point of all the Neuburg Siliceous Earth types. Sillitin Z 89 also return higher values than the reference material (Fig. 22).

Fig. 19

Fig. 20

15 20 25 30 35 40 45 50 55


0,1

1

10

100


Sillitin Z 86

Sillitin V 85

Sillitin V 88

Sillitin N 82

Sillitin N 85

Fig. 21

15 20 25 30 35 40 45 50 55


1

10

100


Sillitin Z 86

Sillitin Z 89

Sillikolloid P 82

Sillikolloid P 87

Fig. 22

15 20 25 30 35 40 45 50 55


0

1

2

3

4

5

6

7

8

9


Sill i tin Z 86

Sill i tin V 85

Sill i tin V 88

Sill i tin N 82

Sill i tin N 85

15 20 25 30 35 40 45 50 55


0

1

2

3

4

5

6

7

8

9


Sil l i tin Z 86

Sil l i tin Z 89

Sil l ikolloid P 82

Sil l ikolloid P 87

Seite 17

This trend cannot be observed when comparing the thixotropy of the individual Sillitin types, as shown in Figs. 23 and 24. Here thixotropy is not dependent on the particle size distribution of the material. Sillitin V 85 is not shown in this graphic presentation, as it exhibits no thixo-tropy throughout the concentration range.

Fig. 23

Fig. 24

15 20 25 30 35 40 45 50 55

fil ler conncentration in % by wt.

0,001

0,01

0,1

1

10

100


Sil l i tin Z 86

Sill i tin V 88

Sill i tin N 82

Sill i tin N 85

15 20 25 30 35 40 45 50 55


0,001

0,01

0,1

1

10

100


Sill itin Z 86

Sill itin Z 89

Sill ikolloid P 87

Sill ikolloid P 82

Seite 18

4.2.3.2 Aktisil All the Aktisil types, with the exception of Aktisil MAM, have similar structural viscosity factors to Sillitin Z 86. Based on the coarser base material Sillitin V 88, Aktisil MAM exhibits the least deviation from Newtonian flow in terms of its structural viscosity and yield point. In this respect it differs distinctly from the other Aktisil types. The curves for Aktisil PF 231 and PF 224 clearly flatten out at the highest filler concentration levels. The yield points of the Aktisil types are lower than that of the base material. Here, too, Aktisil MAM returns the lowest value. The Aktisil PF types have similar yield points to the base material.

Fig. 25

Fig. 26

15 20 25 30 35 40 45 50 55


0,1

1

10

100


Sillitin Z 86

Aktisil EM

Aktisil MM

Aktisil MAM

Aktisil VM 56

Fig. 27

15 20 25 30 35 40 45 50 55


0,1

1

10

100


Sillitin Z 86

Aktisil PF 224

Aktisil PF 231

Fig. 28

15 20 25 30 35 40 45 50 55


0

1

2

3

4

5

6structural viscosity fator (SVF)

Sil l i tin Z 86

Aktisil EM

Aktisil MM

Aktisil MAM

Aktisil VM 56

15 20 25 30 35 40 45 50 55


1

2

3

4

5

6structural viscosity faktor (SVF)

Sil l i tin Z 86

Aktisil PF 224

Aktisil PF 231

Seite 19

Aktisil MAM is also completely different in terms of its thixotropy (Fig. 29 and 30). Unlike the other Aktisil types and the base material Sillitin Z 86, whose thixotropy increases at increasing filler concentration, Aktisil MAM exhibits a slight decrease in its thixotropy at the highest filler concentration. This effect is due to the coating agent and the particle size of the material.

Fig. 29

Fig. 30

Our technical service suggestions and the information contained in this report are based on experience and are made to the best of our knowledge and belief, but must nevertheless be regarded as non-binding advice subject to no guarantee. Working and employment conditions over which we have no control exclude any damage claims arising from the use of our data and recommendations. Furthermore, we cannot assume any responsibility for any patent infringements which might result from the use of our information.

15 20 25 30 35 40 45 50 55


0,001

0,01

0,1

1

10

100

thixotropy in Pa/cm³

Sil l i tin Z 86

Aktisil EM

Aktisil MM

Aktisil MAM

Aktisil VM 56

15 20 25 30 35 40 45 50 55


0,01

0,1

1

10

100

thixotropy in Pa/cm³

Sil l i tin Z 86

Aktisil PF 224

Aktisil PF 231

comparative study on bright fillers performed with a ... · comparative study on bright fillers...

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