《ISO-305-1990.pdf》由会员分享，可在线阅读，更多相关《ISO-305-1990.pdf（7页珍藏版）》请在三一文库上搜索。
1、INTERNATIONAL STANDARD IS0 305 Second edition 1990-04-01 Plastics - Determination of thermal stability of poly(vinyl chloride), related chlorine-containing homopolymers and copolymers and their compounds - Discoloration method Plastiques - 06termination de la stabilit.5 thermique du poly(chlorure de
2、 viny/e), des homopolym - squares of side 15 mm and thickness approxi- mately 1 mm, for method B. They shall be punched out from the sheets to be tested. 3.2 The number of test specimens required is the expected time of the test in minutes divided by 5. If the stability of the compound is very high,
3、 remove the test specimens every 10 to 15 minutes instead of every 5 minutes during the first stage of heating, before the appearance of discoloration, Thus, the number of test specimens used can be less than that specified above. 1 Copyright International Organization for Standardization Provided b
4、y IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:23:23 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 305:1990(E) 3.3 If the material to be tested is an extrusion or moulding material in granule, powder or pellet
5、 form, this shall be sheeted on a roll-mill under the condi- tions specified in the material specification, or as agreed upon between the interested parties (IS0 293:1986, Plastics - Compression moulding test specimens of thermoplastic materials, may be help- ful in this respect). 3.4 If the materia
6、l to be tested is In the form of a paste (plastlsol), it shall be gelled to give a well fused sheet: the test specimens shall be punched out from the sheet thus obtained. Dlmenslons in mllllmetres a5+0,5 z D -. $9 NOTES Figure 1 - Alumlnium block 1 If the surface finish of specimens (particularly th
7、ose made from unplasticized materials) prepared by milling does not ensure sufficient contact with the aluminium block and cylinder, press-polishing of the specimens is recommended as an optional additional step. 5.1.4 Alumlnlum cylinders, with a diameter of 15 mm + 0,5 mm and a height of 30 mm. 2 W
8、arming of the milled unplasticized sheets will permit test specimens to be cut without shattering. 4 Test temperature 5.1.5 Timing device, for example a stopwatch, with an accuracy of 0,5 min or better. The test temperature shall be that stated in the ma- terial specification or as agreed upon betwe
9、en the Interested partles; In the latter case, the temper- ature shall be chosen so that the test duration is In the range 60 min to 120 min. If there is no specifica- tlon or agreement, a temperature of 180 “C shall be used. 5.2 Procedure 5.2.1 Prepare a sufficient number of test tubes (51.2) and p
10、lace an aluminium block (5.1.3) in each tube; then insert a test specimen and cover it with an aluminium cylinder (5.1.4). 5 Method A: Oil-bath method 5.1 Apparatus 5.2.2 Place the test tubes vertically in the oil bath (5.1.1) that has been brought to within 0,5 “C of the specified or agreed tempera
11、ture, and start the tlm- ing device (5.1.5). 5.1-l Thermostatically controlled oil bath, capable of maintaining the temperature within + 0,5 “C in the range 120 “C to 200 “C, fitted with a suitable stirrer and a suitable device for holding a convenient number of test tubes immersed to a depth of 60
12、mm to 70 mm. 5.2.3 Every 5 min take a test tube from the bath. Remove the test specimen from the tube and allow it to cool, using slight pressure, if necessary, to prevent deformation. Number the test specimens consecutively. 5.1.2 Glass test tubes, of the following dimensions: 5.2.4 Fasten the test
13、 specimens on a card with a - external dlameter: 18 mm note of the exposure time in minutes of each speci- men and the test temperature. WARNING - In order to make handllna of the test tubes, which are covered with hot 011, safer after they have been removed from the oil bath, an optional dralnage a
14、nd handling tlme can be agreed upon be- tween the Interested partles, Use tongs or another sultable device to hold the tubes when tipping out the alumlnlum blocks. - length: 150 mm minimum. 5,1.3 Alumlnlum blocks, as shown in figure 1. Copyright International Organization for Standardization Provide
15、d by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:23:23 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 305:1990(E) 6 Method B: Oven method 6.1.3 Tlmlng device, for example a stopwatch, with an accuracy of 0,5 m
16、in or better. 6.1 Apparatus 6.2 Procedure 6.1.1 Forced-air-clrculatlon oven, having the fol- lowing additional features: 6.2.1 Prepare, for each exposure time envisaged, a specimen support (6.1.2) of sufficient size to hold one specimen of each of the different compositions under test. 6.1.1.1 The t
17、emperature of the oven shall be controlled by a thermostat capable of maintaining it to within checks are made at 5 min Intervals. It may also be done by inserting, at the test temperature, a rack with 8 to 10 specimens from the same sample dis- tributed over the test area and exposing them until an
18、 early stage of discoloration is reached. The for- mulation shall be such as to cause a sharp change in colour within 45 min to 60 min under the test conditions. A non-uniform temperature distribution, as indicated by differences in the colours of the ex- posed specimens, shall be corrected before p
19、ro- ceeding with the test. 6.1.1.5 The inside of the oven shall be free of con- tamination and surface deposits. Use stainless-steel oven liners to reduce corrosion due to extended ex- posure to decomposition gases. 6.1.2 Specimen supports, made of new, clean alu- mlnium foil laid on a removable ove
20、n rack (grllle). If an oven equipped with a rotating specimen-holder is employed, the specimens shall be supported so that no appreciable elongation or necking down of the test specimens occurs during the test, since this would alter the specimen dimensions, and espe- cially the thickness. In this c
21、ase, the uniformity of the oven temperature shall be checked with the speci- men holders mounted on the rotating device. 6.2.7 Fasten the test specimens on a card with a note of the exposure time in minutes of each speci- men and the test temperature. 7 Expression of results Note the times, in minut
22、es, from the start of the test to - the first observed change in colour and - the end of the test. NOTE 3 In cases of dispute, when greater precision is required, it is recommended that test specimens be com- pared by means of an agreed colour scale or by means of a photometer. 8 Precision The preci
23、sion of this test method is not known be- cause inter-laboratory data are not available. This method may not be suitable for use in specifications or in case of disputed results until these data are available. 9 Test report The test report shall include the following informa- tion: a) a reference to
24、 this International Standard; 3 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:23:23 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 305:1990(E)
25、 b) the method used (A or 6); c) all details necessary for the complete identiffca- tion of the sample, including the composition of the compound and the method of preparation of the test specimens (for example thermal treat- ment): d) the test temperature; - the first observed change in colour and
26、- the end of the test; f) the date of the test. The test report shall be accompanied by a piece of an untreated test specimen and the complete series of treated test specimens fastened on a card (It is essential that this be stored in the dark). e) the times, in minutes, from the start of the test t
27、o Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:23:23 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 305:1990(E) UDC 678.743.22:536.4 Descript
28、ors: plastics, polyvinyl chloride, copolymers, thermal tests, determination, thermal stablllty, dlscoloratlon. Price based on 4 oaaes Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/27/2007 04:23:23 MDTNo reproduction or networking permitted without license from IHS -,-,-