Quimica Amtex S.A. have been certified with this quality standard ISO 9002 – 1994 since August 1997.

In order to make the best possible decision about which type of SODIUM CARBOXYMETHYL CELLULOSE (Gelycel) accommodates itself to the necessities of the customer , one should take into account factors like the type of agitation or mixing system available (in order to define particle size in the dispersion ) , stability of the product (to define its DS) , the final application of the product (to know what purity it should have or which DS is the most indicated) , function of the product as a binder ,thickener or colloid protector in the system (to establish its viscosity ), etc. One of the factors to be considered in the application of Gelycel is its viscosity . Due to the fact that Gelycel is a product with non-Newtonian flow characteristics and a thixotropic comportment , it is very important to take into account - when making the viscosity measurements - the following factors :

Type of viscosity meter
It is recommended to make the measurement using rotational viscosity meters of the Brookfield type . It is necessary to specify the type of viscosity meter used because depending on the type of equipment used (LV, RV, etc) a different torque is applied to the sample being measured and the spindles have different geometry. This leads to varying values of viscosity by doing the evaluations on different equipment (LV, RV, etc) using the same sample .

Spindle/RPM
Each spindle possesses its own geometry characteristic . Additionally the geometry of the spindles used with LV viscometers is different to the geometry of the spindles used with the RV series . Added to this , the Gelycel is a non-Newtonian fluid , or in other words, the viscosity value obtained depends on the RPM used in the measurement. These factors mean that when a viscosity measurement of Gelycel is made , it is convenient to indicate the number of spindle used and the speed (RPM) with which the product viscosity is evaluated .

Solid contents :
The viscosity of Gelycel is directly proportional to the solids content , which is to say, the higher the solids content of the Gelycel, the higher the viscosity value obtained will be. This is why it is convenient to indicate at what concentration the viscosity measurement is made. The same reason applies to the fact that one should indicate if the evaluation has been made on a dry base or a wet base .

Temperature
The viscosity is inversely proportional to the temperature, which is to say , the higher the temperature , the lower the viscosity measurement obtained . Our measurements are carried out at 25ºC. If you make your measurements at temperatures different to 25ºC we would be pleased if you could let us know by informing our technical assistant.

We will now describe in a general way , the viscosity evaluation method that is used in our installations

*Calculate the humidity in a general form.
*Weigh the quantity of Gelycel required to prepare 500 grams of solution. For example, if you wish to prepare 500 grams of a 2% Gelycel solution and the humidity of the CMS is 5% , the quantity of Gelycel to be weighed will be :

*Weigh the quantity of water necessary to obtain 500 grams of solution. To do this you proceed in the following manner:

Weight of water, gr= 500 – weight of Gelycel  Weight of water,  ml = 489.4 gm (grams) Note : 1 gram of water = 1 ml volume

Place the agitator in the water and raise to approximately 1,000 rpm.

Agitate until de Gelycel is completely dissolved

Simultaneously choose the spindle and the RPM with which you wish to fulfil the evaluation .

Start the viscometer and rotate for one minute

Take the viscosity reading after one minute of rotation

Viscosity Range, Cps.

Spindle No.

RPM

Factor

100 Maximum

1

60

1

100 – 200

1

30

2

200 – 1000

2

30

10

1000 – 4000

3

30

40

4000 – 20000

4

30

200

20000 – 50000

4

12

500

50000 – 100000

4

6

1000