ISO 2555:1989 pdf download.Plastics一Resins in the liquid state or as emulsions or dispersions一Determination of apparent viscosity by the Brookfield Test method
I Scope
ISO 2555:1989 pdf download specifies a method of determining en apparent viscosity, by the Brookfield Test method, of resins In a liquid or similar state, using one of the types of rotational viscometer described in this Standard.
The application of this method to specific products is detailed in annex A.
The viscometers, types A, B and C, permit viscosity measurements from 0,02 Pa.s (20 cP) to 60 000 Pa•s (60 x 106 cP).
2 PrInciple
A spindle, of cylindrical or related form (disc), is driven at a constant rotational frequency in the product being studied.
The resistance exerted by the fluid on the spindle, which depends on the viscosity of the product, causes a torque which is indicated by a suitable meter. This measurement may be based on tightening of a spiral spring depending on the torque, indicated by the movement of a needle on a dial.
The apparent viscosity by the Brookfield Test method is obtained by multiplying this dial reading by a coefficient which depends on the rotational frequency and characteristics of the spindle.
The products to which this International Standard is applicable are generally non-Newtonian and the measured viscosity depends on the velocity gradient to which the products are subjected during the measurement.
With these types of viscometer, the velocity gradient is not the same for every point of the spindle. Thus, for a non-Newtonian fluid, the result is not strictly the true “viscosity at a known velocity gradient” and therefore is conventionally called the apparent viscosity.
3 Apparatus
3.1 Brookfield-type viscorneter, type A, B or C, chosen according to the product to be tested and the desired precision.
The detailed working principle of this apparatus, its description and the characteristics of the three types are given in annex B.
Each viscometer conaists of:
- the viscometer body;
- seven interchangeable spindles numbered from 1 to 7 (number 1 being the largest); these spindles carry a mark that indicates the immersion level in the liquid; they are the same for the three types of viscometer; do not use spindles which show signs of corrosion or eccentricity;
- a detachable guard stirrup (type A only).
The rotational frequencies available on the different types of Brookfield viscometer are given in table 1.
NOTE一In the case of the Brookfield apparatus, the relationship be-tween the models and available frequencies and viscometer typesA, B and C are given in table 1. Other rotational frequencies within the same limits may be chosen.ISO 2555 pdf download.