1、 Reference number ISO 19252:2008(E) ISO 2008INTERNATIONAL STANDARD ISO 19252 First edition 2008-12-15 Plastics Determination of scratch properties Plastiques Dtermination du comportement la rayure ISO 19252:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe
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6、 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2008 All rights reservedISO 19252:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitio
7、ns. 2 4 Principle. 4 5 Apparatus 4 6 Test specimens . 6 7 Procedure 7 8 Expression of results . 10 9 Test report . 14 Annex A (informative) Photographic illustrations of different types of scratch behaviour . 16 Annex B (informative) Test machine 17 Bibliography . 18 ISO 19252:2008(E) iv ISO 2008 Al
8、l rights reservedForeword 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 ISO technical committees. Each member body interested in a subj
9、ect 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 closely with the International Electrotechnical Commission (IE
10、C) 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. Draft International Standards adopted by the technical committ
11、ees 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 document may be the subject of patent rights. ISO shall not be
12、held responsible for identifying any or all such patent rights. ISO 19252 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 2, Mechanical properties. INTERNATIONAL STANDARD ISO 19252:2008(E) ISO 2008 All rights reserved 1 Plastics Determination of scratch properties IMPORTANT
13、The electronic file of this document contains colours which are considered to be useful for the correct understanding of the document. Users should therefore consider printing this document using a colour printer. 1 Scope 1.1 This International Standard specifies a method for determining the scratch
14、 properties of plastics under defined conditions. The method involves making a scratch by moving a hard instrument (scratch tip) of specified geometry under specified conditions of load and speed across the surface of a test specimen and then assessing the result. 1.2 The method is used to investiga
15、te the behaviour of specified types of specimen under the scratch conditions defined and for classifying the type of scratch of specimens within the limitations inherent in the test conditions. It can also be used to determine comparative data for different types of material by means of a so-called
16、scratch map in which the types of scratch behaviour for each set of test conditions of test load and test speed are determined using the basic method of constant-load testing, and also by means of the so-called critical normal load (see 3.8) determined using an alternative method of linearly increas
17、ing load testing. 1.3 The method is suitable for use with uncoated and unlacquered thermoplastic moulding materials and thermosetting moulding materials. 1.4 The method specifies the preferred dimensions for the test specimen and the preferred scratch-tip geometry. 2 Normative references The followi
18、ng referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 291, Plastics Standard atmospheres for conditioning and
19、testing ISO 294-1, Plastics Injection moulding of test specimens of thermoplastic materials Part 1: General principles, and moulding of multipurpose and bar test specimens ISO 3167:2002, Plastics Multipurpose test specimens ISO 10724-1:1998, Plastics Injection moulding of test specimens of thermoset
20、ting powder moulding compounds (PMCs) Part 1: General principles and moulding of multipurpose test specimens ISO 19252:2008(E) 2 ISO 2008 All rights reserved3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 scratch damage made by a hard instrum
21、ent (scratch tip) when moved across a test specimen surface under specified conditions of tip geometry, test load and test speed (see Figure 1) NOTE The term “surface”, as used in this definition, applies to the macroscopic surface and not the microscopic surface. R 1 2Key 1 test specimen 2 scratch
22、tip P test load v test speed Figure 1 Schematic representation of a scratch (see 3.1) 3.2 test load P load applied by the scratch tip perpendicularly to the test specimen during the test NOTE It is expressed in newtons. 3.3 test speed v relative rate of displacement between the scratch tip and the t
23、est specimen during the test NOTE It is expressed in millimetres per second. 3.4 scratch force F shorizontal force between the scratch tip and the test specimen at any given moment during the test NOTE It is expressed in newtons. ISO 19252:2008(E) ISO 2008 All rights reserved 3 3.5 scratch-tip displ
24、acement d vertical displacement of the scratch tip relative to the test specimen surface at any given moment during the test NOTE It is expressed in micrometres. 3.6 scratch distance s horizontal distance travelled by the scratch tip relative to the test specimen at any given moment during the test
25、NOTE It is expressed in millimetres. 3.7 scratch behaviour type of deformation of the material under the action of the scratch tip NOTE Scratch behaviour is classified into three types: ploughing (p), wedge formation (w) and cutting (c), as defined in 3.7.1 to 3.7.3. 3.7.1 ploughing p scratch behavi
26、our in which the scratch force and scratch-tip displacement are constant over the scratch distance during the test (see Figure 2) NOTE 1 The surface of the scratch is smooth along its whole length rather than rough. NOTE 2 A small, inherent level of episodic signal oscillation (of amplitude less tha
27、n 3 N in the scratch force and 10 m in the tip displacement) is acceptable. 3.7.2 wedge formation w scratch behaviour in which the scratch force and/or scratch-tip displacement oscillate, resulting in a corresponding increase in the actual distance travelled by the scratch tip during the test (see F
28、igure 2) NOTE The surface of the scratch exhibits a continuous serrated or wedge-like pattern, and stick-slip occurs. 3.7.3 cutting c scratch behaviour in which the scratch force and/or scratch-tip displacement vary randomly, resulting in a corresponding increase in the actual distance travelled by
29、the scratch tip during the test (see Figure 2) NOTE During the test, chips are cut from the surface. 3.8 critical normal load P cminimum normal load at which wedge formation or cutting, whichever occurs first, takes place at a given test speed NOTE It is expressed in newtons. ISO 19252:2008(E) 4 ISO
30、 2008 All rights reserved4 Principle A standard test specimen is scratched by a hard tip which applies a load perpendicular to the test specimen and moves lengthwise across the surface at a constant speed along the centreline of the test specimen. During the scratch, the horizontal force between the
31、 scratch tip and the test specimen (the scratch force), the vertical displacement of the scratch tip (tip displacement) and the scratch distance are each measured continuously and recorded. The scratch force/scratch distance and tip displacement/scratch distance diagrams thus produced describe the s
32、cratch behaviour of the test specimen. Using the basic method of constant-load testing, the type of scratch behaviour can be determined for a series of test conditions (load and speed) and expressed as a so-called scratch map. Using an alternative method of linearly increasing load testing, the crit
33、ical normal load can be determined at a given test speed (see Table 1). Changes in slope and/or spikes in the scratch force/scratch distance curve indicate transitions from one type of scratch behaviour to another (e.g. from ploughing to wedge formation or to cutting). 5 Apparatus 5.1 Test machine 5
34、.1.1 General The test machine shall consist essentially of a frame with a specimen support, a scratch tip with its associated fittings, and a device for applying the load (see Annex B), and shall meet the specifications given in 5.1.2 to 5.1.8. 5.1.2 Frame The frame of the machine shall be capable o
35、f being levelled and shall not be deformed by more than 3 m under the maximum load. 5.1.3 Scratch tip The scratch tip shall be hardened to at least Rockwell HRC 64 hardness, shall be polished to a roughness of less than 0,20 m and shall not show any deformation or damage after a test. The scratch ti
36、p shall be hemispherical in shape, with an outside radius R of 0,5 mm 0,025 mm. NOTE Tips made from hardened and polished steel or tungsten carbide have been found to be satisfactory. 5.1.4 Test load The machine shall be capable of maintaining the test load within a tolerance of 1 %, for any test lo
37、ad chosen as specified in 7.2.3, and shall be capable of applying the load perpendicular to the test specimen within a tolerance of 5. 5.1.5 Test speed The machine shall be capable of maintaining the test speed within a tolerance of 1 %, except over the first and the last 10 mm of the scratch distan
38、ce, for any test speed chosen as specified in 7.2.4 and shall be capable of reaching the test speed within 10 mm and stopping within 10 mm. 5.1.6 Test specimen support The test specimen support shall be flat, smooth and free of holes in the area where the test specimen will be placed. ISO 19252:2008
39、(E) ISO 2008 All rights reserved 5 The clamping system for holding the test specimen on the support shall be attached to the test machine so that the longitudinal axis of the test specimen coincides with the line of scratch. The clamping system shall not cause any premature fracture of the test spec
40、imen, and the test specimen shall be held in such a way that it cannot slip relative to the specimen support. 5.1.7 Load indicator The load indicator shall incorporate a mechanism capable of showing the horizontal force between the scratch tip and the test specimen continuously during the test. The
41、mechanism shall be essentially free from inertia lag at the specified test speeds and shall indicate the load with an accuracy equal to or within 1 % of the actual value. 5.1.8 Scratch tip displacement gauge A mechanical or, preferably, an electronic device shall be used which incorporates a mechani
42、sm capable of indicating the vertical displacement of the scratch tip to an accuracy of 1 m or better under static conditions. The mechanism shall be essentially free from inertia lag at the specified test speeds and shall be capable of indicating the vertical displacement of the scratch tip to an a
43、ccuracy of 10 m or better continuously during the test. 5.2 Instruments for measuring the test specimen dimensions The width b of the test specimen shall be measured using a micrometer or gauge with an accuracy of 0,01 mm or better. For measuring the thickness h of the test specimen, a micrometer wi
44、th a flat circular foot reading to 0,01 mm or less shall be used. 5.3 Monitoring and inspection devices (optional) 5.3.1 Monitoring device A monitoring device, such as a video camera equipped with a recording system and a magnifying mechanism, is useful for monitoring the area around the scratch tip
45、 during the test (see 7.2.9, 8.2 and 8.4). The device shall not have any thermal effect on the specimen. 5.3.2 Scratch inspection device In addition to inspection with the naked eye, a device such as a magnifying glass, microscope, flatbed scanner or interferometer is useful for observing the appear
46、ance of the surface of the scratch after the test (see 7.2.9, 8.2 and 8.4). The device shall not have any thermal effect on the specimen. NOTE When testing using a linearly increasing load (the alternative method), an image of the surface of the scratch at the critical normal load can be generated w
47、ith the aid of computer software using, for instance, a “grey-level threshold” programme (see Figure 4). ISO 19252:2008(E) 6 ISO 2008 All rights reserved6 Test specimens 6.1 Shape and dimensions Type A multipurpose test specimens as specified in ISO 3167:2002 shall be used. 6.2 Preparation 6.2.1 Mou
48、lding Test specimens shall be directly injection-moulded in accordance with ISO 294-1 or ISO 10724-1, as appropriate, under conditions defined in the relevant standard for the material under examination. The specimens shall be suitably marked outside the test area to indicate the melt-flow direction
49、, the particular cavity from which the specimen came (when using a multi-cavity mould) as well as the side of the mould (cavity-plate side or fixed-plate side) on which a particular specimen face was formed (see e.g. ISO 10724-1:1998, Annex B). NOTE Certain types of material may show different scratch behaviour depending on the face of the specimen which is tested and/or the melt-flow direction. Strict control of all conditions during specimen preparation is essential to ensure that all test specimens
