1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58apparent viscosity using the Severs rheometer ICS 83.080.20Plastics Poly(vinyl chloride) pastes Det
2、ermination of BRITISH STANDARDBS ISO 4575:2007BS ISO 4575:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 September 2007 BSI 2007ISBN 978 0 580 60303 7Amendments issued since publicationAmd. No. Date CommentsCompliance with a British S
3、tandard cannot confer immunity from legal obligations.National forewordThis British Standard is the UK implementation of ISO 4575:2007. The UK participation in its preparation was entrusted to Technical Committee PRI/82, Thermoplastic materials.A list of organizations represented on this committee c
4、an be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Reference numberISO 4575:2007(E)INTERNATIONAL STANDARD ISO4575Third edition2007-05-01Plastics Poly(vinyl chloride) pas
5、tes Determination of apparent viscosity usingthe Severs rheometer Plastiques Ptes de poly(chlorure de vinyle) Dtermination de la viscosit apparente au rhomtre Severs BS ISO 4575:2007ii iiiContents Page Foreword iv 1 Scope . 1 2 Principle. 1 3 Apparatus 1 4 Procedure 4 4.1 Choice of test pressures an
6、d die 4 4.2 Introduction of the paste and control of the temperature 4 4.3 Regulation of the test pressure. 4 4.4 Determination 4 5 Calculations. 5 5.1 Calculation of flow rates 5 5.2 Calculation of shear rates and apparent viscosities. 5 6 Expression of results . 6 7 Test report . 8 Annex A (inform
7、ative) Formul for non-Newtonian fluids 9 Bibliography . 10 BS ISO 4575:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through IS
8、O technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates c
9、losely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. D
10、raft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this do
11、cument may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 4575 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9, Thermoplastic materials. This third edition cancels and replaces the second edition (ISO 4
12、575:1985), which has been technically revised. BS ISO 4575:20071Plastics Poly(vinyl chloride) pastes Determination of apparent viscosity using the Severs rheometer 1 Scope This International Standard specifies a method for determining the apparent viscosity, at high shear, of poly(vinyl chloride) (P
13、VC) pastes prepared from PVC paste polymers and plasticizers, using the Severs rheometer. It applies in particular to “standard pastes” prepared in accordance with ISO 4612 or ISO 11468. 2 Principle A sample of the paste is placed in a Severs rheometer and the jacket set to a defined temperature. Th
14、e flow rate of the paste through a calibrated die is measured at different pressures. The shear rate and apparent viscosity are calculated for each flow rate corresponding to each of the pressures applied. Optionally, a graph of apparent viscosity as a function of the shear rate can be prepared. 3 A
15、pparatus 3.1 Severs rheometer, of capacity 500 ml to 1 000 ml, of one of the two basic designs shown in Figure 1, and consisting essentially of the following components: 3.1.1 Measuring vessel, for example a stainless-steel or bronze cylinder with polished internal surfaces to which can be fixed bot
16、h a base having an orifice in which can be placed a die, and a cover which can be connected to the source of pressure or to the atmosphere. The whole shall be airtight. 3.1.2 Jacket, connected to a system for temperature control which allows the contents of the body of the measuring vessel to be mai
17、ntained at a temperature of (23 0,5) C. 3.1.3 Non-deformable die, for example of stainless steel or PTFE, consisting of a cylindrical tube which can be fitted in airtight fashion to the bottom of the measuring vessel. The outer and internal surfaces of the tube shall be polished. The die is defined
18、by the diameter and the height of the tube. Two dies, A and B, are specified in the application of this International Standard. The dimensions of the dies are given in Table 1. Table 1 Dimensions of the dies Dimensions in millimetres Dimension Die A Die B Radius of tube 1,5 0,05 1,5 0,05 Height 45 0
19、,5 22,5 0,5 3.1.4 Piston (if necessary), of rigid plastic material with a diameter slightly less than that of the measuring vessel to prevent the fluid, under pressure, from passing directly through the die in the case of pastes which cavitate. (Its use also simplifies the cleaning of the instrument
20、.) A sketch of the piston is given in Figure 2. BS ISO 4575:20072 Key 1 temperature-regulating fluid out 6 cylinder 2 lid 7 jacket 3 PTFE washer 8 die clamp 4 clamped joint 9 temperature-regulating fluid in 5 threaded joint 10 die Figure 1 Diagram showing the basic principles of two types of Severs
21、rheometer Dimensions in millimetres Figure 2 Piston BS ISO 4575:200733.1.5 Pressurizing device, consisting of a cylinder of pressurized nitrogen, an expansion chamber with pressure gauges, and a number of valves. An example is shown in Figure 3. Key C valve H Severs rheometer D valve I die E pressur
22、ized-nitrogen inlet valve J expansion chamber F valve to atmosphere K nitrogen cylinder G pressure gauges (with different scales) L pressure reduction valve Figure 3 Example of pressurizing device 3.2 Beakers, of capacity about 50 ml. 3.3 Timer, accurate to 0,1 s. 3.4 Balance, accurate to 0,5 g. 3.5
23、 Thermometer, capable of measuring a temperature of (23 0,5) C. BS ISO 4575:20074 4 Procedure 4.1 Choice of test pressures and die Depending on the test paste and its intended use, choose at least four pressures in the following list of preferred numbers: 100 kPa, 160 kPa, 250 kPa, 400 kPa, 630 kPa,
24、 1 000 kPa, 1 600 kPa, 2 500 kPa 1). Conduct a test with die A and a pressure of 2 500 kPa. From the measured flow rate qm(see 5.1), calculate as indicated in 5.2 the corresponding shear rate: if the shear rate is more than 1 000 s1, tests shall be carried out with die A; if the shear rate is less t
25、han or equal to 1 000 s1, tests shall be carried out with die B. 4.2 Introduction of the paste and control of the temperature Position the base together with the appropriate die (see 3.1.3) and introduce the paste to be tested into the measuring vessel (3.1.1). If necessary, place the piston (3.1.4)
26、 on the paste. Bring the temperature of the paste to (23 0,5) C by circulating water maintained at that temperature in the jacket (3.1.2) (generally 5 min is sufficient). Screw down the lid and connect it to the pressurizing device (3.1.5). 4.3 Regulation of the test pressure Start the tests at the
27、lowest pressure. Regulate the pressure to 10 kPa according to the device used. In the case of the example given in Figure 3, proceed in the following manner: Close valves E and F, open valves C and D, and operate the pressure reduction valve L progressively until the pressure reading on the gauge ha
28、ving the higher scale range (C) is practically equal to the desired value. Then read the pressure on the gauge having the lower scale range (D) and carefully regulate the pressure to the desired value to the nearest 10 kPa. Operate in the same way when regulating the other test pressures, but withou
29、t opening valve D for pressures above its maximum gauge reading. 4.4 Determination 4.4.1 Weigh three 50 ml beakers (3.2) to the nearest 0,5 g. Clean the exit orifice of the die and open valve E to admit nitrogen under pressure to the rheometer. Under pressure, the paste will pass through the die. Ma
30、ke sure that the pressure does not vary; regulate, if necessary, by operating the pressure reduction valve L. Place a weighed beaker under the emerging paste stream and at the same time start the timer (3.3). When the mass of paste obtained is at least 10 g, remove the beaker and stop the timer simu
31、ltaneously; note the time of flow t1in seconds to the nearest 0,1 s. (If the amount is insufficient at the end of 2 min, abandon the test at this pressure and carry it out under greater pressure.) 1) 1 kPa = 1 kN/m2BS ISO 4575:20075Repeat the measurements with the other two weighed beakers in turn,
32、designating the corresponding flow times t2and t3. Close the pressurized-nitrogen inlet valve E and open the valve to atmosphere F in order to arrest the flow of paste. Weigh the containers, determining the masses of paste m1, m2and m3, in grams, to the nearest 0,5 g. 4.4.2 Close the valve to atmosp
33、here F and regulate the pressure to its new value. Repeat the test under the conditions specified in 4.4.1. 4.4.3 After testing, clean the rheometer, avoiding the use of fluffy materials. 5 Calculations 5.1 Calculation of flow rates For each one of the test pressures, calculate the flow rates qm1, q
34、m2, and qm3, in grams per second, corresponding to the measurements, using the equations 111mmqt= 222mmqt= 333mmqt= where m1, m2and m3and t1, t2and t3have the same meanings as in 4.4.1. Calculate the arithmetic mean of the three values, i.e. the flow rate qm, in grams per second, corresponding to th
35、e test pressure. 5.2 Calculation of shear rates and apparent viscosities For each of the values of flow rate qm(calculated as indicated in 5.1), calculate the shear rate and apparent viscosity using the formulae shown in Table 2 (see Notes 1 and 2): Table 2 Formul for shear rate and apparent viscosi
36、ty Quantity Any die Die A Die B Shear rate, (s1) 34mqr 377mqApparent viscosity, app(Pas) 43108mrphq344 10mpq 388 10mpq BS ISO 4575:20076 where r is the radius of the cylindrical tube of the die, in centimetres; h is the height of the cylindrical tube of the die, in centimetres; p is the test pressur
37、e, in kilopascals; qmis the paste flow rate at pressure p, in grams per second (calculated as indicated in 5.1); is the density of the paste at 23 C, in grams per cubic centimetre. NOTE 1 Strictly speaking, these formulae are applicable only to Newtonian fluids. Nevertheless, they have been applied
38、to PVC pastes because they are easy to use and the values determined are sufficiently accurate for the purpose intended. The exact formul are given, for information, in Annex A. NOTE 2 The shear force is equal to and can be calculated for each test pressure using the equation = pr/2h. 6 Expression o
39、f results Indicate the apparent viscosity at each shear rate in the form of a table (see Figure 4). Plot a graph showing the apparent viscosity (ordinate) versus the shear rate (abscissa). An example of such a curve is given in Figure 4. BS ISO 4575:20077Test with Severs rheometer PVC paste “100 and
40、 50” 23= 1,22 g/cm3Die A Immediate measurement p kPa 100 400 630 1 000 qmg/s 0,32 1,40 2,38 4,44 s198 430 730 1 360 appPas 16,9 15,4 14,3 12,2 Key X shear rate, (s1) Y apparent viscosity, app(Pas) Figure 4 Examples of presentation in tabular form and graphically of results obtained using the Severs
41、rheometer BS ISO 4575:20078 7 Test report The test report shall include the following particulars: a) a reference to this International Standard; b) all details necessary for complete identification of the PVC paste polymer and plasticizer tested; c) the formula of the paste; d) the method by which
42、the paste was prepared, i.e. planetary-mixer method or dissolver method; e) the density of the paste; f) the die used; g) the conditioning time at 23 C before measurement; h) a table of the apparent viscosities at the various shear rates used; i) optionally, a graph of apparent viscosity versus shea
43、r rate. BS ISO 4575:20079Annex A (informative) Formul for non-Newtonian fluids The exact formul for non-Newtonian fluids include the term m, the reciprocal of the non-Newtonian symbol n. They are given in Table A.1. Table A.1 Exact formul for non-Newtonian fluids Quantity Any die Shear rate, (s1) (
44、)33mmqr +Apparent viscosity, app(Pas) ()431023mrphm q+in which the symbols (other than m) have the same meaning and are expressed in the same units as in 5.2. BS ISO 4575:200710 Bibliography 1 ISO 4612, Plastics Preparation of PVC pastes for test purposes Planetary-mixer method 2 ISO 11468, Plastics
45、 Preparation of PVC pastes for test purposes Dissolver method BS ISO 4575:2007blankBS ISO BSI389 Chiswick High RoadLondonW4 4AL4575:2007BSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe an
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