ISO 4574:2019 pdf free.Plastics – PVC resins for general use – Determination of hot plasticizer absorption.
7 Procedure
7.1 Preliminary regulation of thermostat
Weigh, to the nearest 0,1 g, 600 g of the DOP (see Clause 5) and place in the bowl (6.1.1) of the mixer. Set the mixer to operate at a rotational frequency of 60 min-11).Regulate the thermostat (6.1.2) so that the temperature of the DOP Is stabilized at 75 ± 0,2 °C. Verify the temperature with the thermometer ().
Pour the DOP out of the bowl, clean the bowl and the beater (61.3) and dry them.
7.2 Measurement of mass of DOP absorbed by the cotton wool
Carry out a test with a piece of cotton wool having a mass of 0,100 ± 0,002 g, but without resin, according to the conditions indicated in ISO 4608:1998, 5.1.
Determine the mass, in grams, of DOP absorbed by the cotton wool.
7.3 Determination
Into each of 12 centrifuge tubes (&3)’ insert, using moderate pressure, a piece of cotton wool (6) of mass 0,100 ± 0,002 g. Weigh each tube with the piece of cotton wool to the nearest 001 g.
Weigh, to the nearest 0,1 g, 600 g of the DOP and place in the bowl of the mixer. Operate the mixer at a rotational frequency of 60 m1n1 for at least 15 mm. Stop the mixer and verify that the temperature of the DOP is 75 ± 0,2 °C.
While the DOP is being conditioned, weigh, into one of the vessels (1) to the nearest 0,1 g, 300 g of the polymer to be tested. When the temperature of the DOP has reached 75 ± 0,2 °C, carry out the three following operations simultaneously:
— place the polymer in the mixer;
— restart the mixer at a rotational frequency of 60 mm12)
— start the timer (6.11).
NOTE When using the mixer referred to in the note of 61.5, simultaneously start measuring the torque.
After mixing for 1 mm and without stopping the mixer, remove a sample of about 5 g of the mixture by means of an aluminium scoop (6.10) and place it in one of the centrifuge tubes already prepared. Place the tube in its sheath (fiA) and allow it to cool; if necessary, place it in solid carbon dioxide (6.12) to cool it quickly.
Take other samples in the same way, starting when the mixture passes from its pasty state to the moist premix state, and at intervals of time based on visual changes in the mixture, hut in every case at a mixing time of 30 mm. Then stop the mixer.
‘l’he use of the mixer referred to in the note of 61.5 allows the samples to be taken at appropriate times as observed by torque measurement. When the torque begins to increase, the samples should be taken with a frequency proportional to the rate of increase of torque until the torque is stabilized.
Weigh the tubes containing the samples to the nearest 0,01 g.
Replace the tubes in their sheaths and place them in the centrifuge holders. Operate the centrifuge (&2) at an acceleration of 2,5 x 10 ms2 to 3,0 x 10 m s2 for 60 mm. Other conditions may be used if they have been shown to produce equivalent results. The centrifuge may he cooled. The centrifuging must be completed within 60 to 90 mm after the removal of the samples from the mixture.
Remove the tubes from their sheaths, wipe them carefully to remove any DOP which may be on the outside of the tubes, and weigh them to the nearest 0,01 g.ISO 4574 pdf download.