SAE J 2020-2016 Accelerated Exposure of Automotive Exterior Materials Using a Fluorescent UV and Condensation Apparatus.pdf

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1、 _ 6$(7HFKQLFDO6WDQGDUGV%RDUG5XOHVSURYLGHWKDW7KLVUHSRUWLVSX EOLVKHGE6$(WRDGYDQFHWKHVWDWHRIWHFKQLFDO and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, LVWKHVROHUHVS

2、RQVLELOLWRIWKHXVHU SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this publication may be reproduced

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4、-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2020_201604 SURFACE VEHICLE STANDARD J2020 APR2016 Issued 1989-06 Revised 2016-04 Superseding J2020 FEB2003

5、Accelerated Exposure of Automotive Exterior Materials Using a Fluorescent UV and Condensation Apparatus RATIONALE This standard has been updated to current industry standards. 1. SCOPE 1.1 This test method specifies the operating conditions for a fluorescent ultraviolet (UV) and condensation apparat

6、us used for the accelerated exposure of various automotive exterior components. 1.2 Specimen preparation, test duration, and performance evaluation procedures are addressed by each automotive PDQXIDFWXUHUVPDWHULDOVSHFLILFDWLRQV 1.3 This SAE Standard may involve hazardous materials, operations, and e

7、quipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of whoever uses this document to consult and establish appropriate and health practices and determine the applicability of regulatory limitations prior to use. 1.4 Signifi

8、cance and Use This test method is designed to simulate extreme environmental conditions encountered on the outside of an automobile due to sunlight, heat, and to provide an acceleration of exposure for the purpose of predicting the performance of exterior automotive materials. 1.5 Unless otherwise s

9、pecified, all dimensions reported in this method are nominal. SAE INTERNATIONAL -APR2016 Page 2 of 14 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications s

10、hall apply. 2.1.1 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org ASTM E 207 Standard Test Method for Thermal EMF Test of Single Thermoelement Materials By Comparison with a Reference Thermoe

11、lement of Similar EMF-Temperature Properties ASTM E 220 Method for Calibration of Thermocouples by Comparison Techniques ASTM G 113 Standard Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials ASTM G 154 Standard Practice for Operating Fluorescent Light Apparatus

12、 for UV Exposure of Nonmetallic Materials 2.1.2 CIE Publication $YDLODEOHIURP&RPPLVVLRQ,QWHUQDWLRQDOHGH/HFODLUDJH%G0DOHVKHUEHV) -75008 Paris, France. CIE Publication No. 85 - Solar spectral irradiance (1989) 2.1.3 ISO Publication Available from American National Standards Institute, 25 West 43rd Str

13、eet, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ISO 9370 Plastics - Instrumental determination of radiant exposure in weathering testsGeneral guidance and basic test method 2.2 Related Publication The following publications are provided for information purposes only and are not a requ

14、ired part of this SAE Technical Report. 2.2.1 ASTM Publication Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org ASTM G 151 Standard Practice for Exposing Nonmetallic Materials in Accelerated Test Devices that U

15、se Laboratory Light Sources SAE INTERNATIONAL -APR2016 Page 3 of 14 3. DEFINITIONS The terminology found in ASTM G 113 may be appropriate to this procedure. 3.1 BLACK PANEL THERMOMETER, n A temperature measuring device consisting of a metal panel, having a black coating which absorbs all wavelength

16、uniformly, with a thermal sensitive element firmly attached to the center of the exposed surface. The black panel thermometer is used to control an artificial weathering device and to provide an estimate of the maximum temperature of specimens exposed to a radiant energy source. 3.2 IRRADIANCE, n Th

17、e radiant power per unit area incident on a receiver, typically reported in watts per square meter, W/m2. 3.3 IRRADIANCE, SPECTRAL, n The distribution of irradiance as a function of wavelength (W/m2/nm). 3.4 SPECTRAL POWER DISTRIBUTION (SPD), n The absolute or relative radiant power emitted by a sou

18、rce, or incident upon a receiver as a function of wavelength. 3.5 FLUORESCENT UV LAMP, n A lamp in which the irradiance from a low pressure mercury arc is transformed to a higher wavelength UV by a phosphor. The spectral power distribution of a fluorescent lamp is determined by the emission spectrum

19、 of the phosphor and the UV transmittance of the glass tube. 3.6 APPARATUS A more complete description of the apparatus may be found in ASTM G 154. 3.6.1 Test Chamber, constructed of corrosion-resistant materials enclosing eight fluorescent UV lamps, a heated water pan, test specimen racks, and prov

20、isions for controlling and indicating operating times and temperatures. 3.7 Lamps shall be rapid start, medium bi-pin fluorescent UV type with a length of 1200 mm, and a nominal rating of 40 W. 3.7.1 The lamps shall be one of the following types: a. UVB lamps with a peak emission of 313 nm as descri

21、bed in Table 3 of ASTM G 154. A representative spectral power distribution of this lamp is shown in Figure 1. NOTE: ,QGHYLFHVWKDWGRQRWDXWRPDWLFDOOFRQWUROLUUDGLDQFH)6 -RU)89%WSHODPSVKDYHKLVWRULFDOOEHHQXVHG . In devices that automatically control irradiance, UVB-313 lamps may be used. SAE INTERNATIONA

22、L -APR2016 Page 4 of 14 Figure 1 - UVB lamps representative spectral power distribution 3.7.2 Other fluorescent UV lamps meeting the size and electrical characteristics in 3.7 may be used by prior agreement, provided that the lamp and spectral power distribution are reported in conformance with the

23、Report section. Use of lamps other than those specified in 3.7 may result in significant differences in test results. a. UVA lamps with a peak emission of 340 nm as described in Table 1 of ASTM G 154. A representative spectral power distribution of this lamp is shown in Figure 2. Figure 2 - UVA lamp

24、s representative spectral power distribution 3.8 LAMP SPACING AND ARRANGEMENT The lamps shall be mounted in two banks of four lamps each. The lamps in each bank shall be mounted in a flat plane on 70 mm centers. 3.8.1 Lamp manufacturing techniques typically result in a slight gradient in light outpu

25、t from one end of a lamp to the other end. To compensate for this, see figure 3. SAE INTERNATIONAL -APR2016 Page 5 of 14 3.9 TEST SPECIMENS The test specimens shall be mounted in stationary racks with the plane of the surface parallel to the plane of the lamps at a distance of 50 mm from the nearest

26、 surface of the lamps. 3.10 CONDENSATION MECHANISM Water vapor shall be generated by heating a water pan extending under the entire specimen area and containing a minimum water depth of 20 mm. Specimen racks and the test specimens themselves shall constitute the side walls of the chamber. The back s

27、ide of the specimens shall be exposed to cooling effects of ambient room air. The resulting heat transfer causes water to condensate on the test surface. 3.10.1 Water Supply Supply water with an automatic control to regulate the level in the water pan shall be provided. Distilled, deionized, or pota

28、ble tap water are equally acceptable for purposes of the test, since the condensation process itself distills water onto the test surface. NOTE: Use of distilled or deionized water is recommended. Using tap water may necessitate more frequent cleaning of water pan. 3.11 CYCLE TIME A continuously ope

29、rating cycle timer shall be provided to program the selected cycle of UV periods and condensation periods. 3.11.1 Temperature Measurement Specimen temperature shall be measured by a remote sensor attached to a black panel 75 mm X 100 mm X 2.5 mm thick. The temperature sensor shall be accurate to 2 C

30、 through a range from 30 C to 100 C. The temperature indicator shall be located outside the test chamber. The black panel with the temperature sensor shall be positioned so that the sensor is subject to the same conditions as the specimens. Specimen Temperature Control-During UV exposure, the select

31、ed equilibrium temperature shall be maintained within 3 C of set-point temperature by supplying heated air to the test chamber. During condensation exposure, the selected equilibrium temperature shall be maintained within 3 C of set-point temperature by heating the water in the water pan. The UV and

32、 condensation temperature controls shall be independent of each other. 3.12 TEST CHAMBER LOCATION 3.12.1 The apparatus shall be located in an area maintained between 18 C and 27 C. Control of ambient temperature is particularly critical for proper operation of apparatus stacked one above the other,

33、because the heat generated from one unit could interfere with the operation of adjacent units. 3.12.2 The apparatus shall be located at least 300 mm from walls or other apparatus. Nearby heat sources, such as ovens or heated test apparatus, shall be avoided or shielded. 3.12.3 The room where the app

34、aratus is located shall be ventilated to remove the heat and moisture produced and to maintain the temperatures specified in 5.5 3.13 7RLQVXUHUHSHDWDELOLWRIWHVWUHVXOWVPDLQWDLQDQGFDOLEUDWHWKHDSSDUDWXVWRWKHPDQXIDFWXUHUV instructions. SAE INTERNATIONAL -APR2016 Page 6 of 14 4. TEST SPECIMENS 4.1 Specim

35、en size shall be either 50 mm X 75 mm, 75 mm X 100 mm, 75 mm X 150 mm, 100 mm X 150 mm, or as agreed upon by concerned parties. NOTE: Because of the geometry of some specimen holders, the previous sizes may cause some problems if, after inspection, they are replaced in a different orientation than t

36、he original. For example, improper replacement of 75 mm X 150 mm panel into a commonly used holder can cause the end VWREHVKLHOGHG LHHSRVHGOHVVWKDQthe center 1/3). 4.1.1 For simultaneous exposures of original and repair coatings on one test specimen, 100 mm X150 mm specimens have been found useful.

37、In this situation, each coating should cover one half of the specimen and be 50 mm X 150 mm area. 4.2 Replicate specimens are desirable to provide a record of degradation at different time intervals. Retention of unexposed specimens in a controlled environment is recommended as it is difficult to ma

38、sk a specimen to prevent exposure to condensation. 4.3 For specimens of insulating materials, such as plastics or foams, maximum specimen thickness should be 30 mm to allow adequate heat transfer for condensation. Report any thickness greater than this in the test report. 4.4 To provide rigidity, fl

39、exible specimens should be attached to a backing panel made of aluminum, 0.635 mm thick, 3003 H14 alloy. 4.5 Holes in specimens larger than 2 mm and any openings larger than 1 mm around irregularly shaped specimens shall be sealed to prevent loss of water vapor. Porous specimens, such as textiles, s

40、hall be backed with a vapor barrier such as metal. 5. PROCEDURE 5.1 Mount the test specimens in the specimen racks with the test surfaces facing the lamp. When the test specimens do not completely fill the racks, the empty spaces must be filled with panels to maintain the test conditions within the

41、chamber. 5.2 The test specimens shall be exposed within an area 210 mm in height by 900 mm wide on each side of the apparatus located as shown in Figure 3. NOTE: To avoid areas of variability in the specimen exposure area, do not use the extreme right- and left-hand specimen holders on the apparatus

42、. Figure 3 - Area of most uniform UV intensity SAE INTERNATIONAL -APR2016 Page 7 of 14 5.3 Set Condensation Cooling Timer to 15 min, if applicable. Report any variations in the test report Figure 4. Figure 4 - Exposure report form SAE INTERNATIONAL -APR2016 Page 8 of 14 5.4 Initiate all exposures at

43、 the beginning of the condensation cycle. 5.5 Program the Cycle Timer to achieve the following test conditions: 8 h UV light exposure at 70 C, alternating with 4 hours condensation exposure at 50 C. 5.5.1 Operating continuously, repeating the cycle, except for servicing the instrument and inspection

44、 of specimens. Inspect specimens weekly during the condensation cycle for evidence of condensation. 5.6 In order to minimize any effect from temperature or UV light variation, specimens shall be repositioned periodically. As a minimum, specimens must be rotated horizontally once each week by (a) mov

45、ing the two extreme right-hand specimen holders to the far left of the exposure area and (b) sliding the remaining specimen holders to the right (see Figure 5). Figure 5 - Horizontal specimen holder rotation 5.7 UV Irradiance 5.7.1 UV irradiance shall be maintained within a specified range by one of

46、 the methods shown in Appendix A. 5.7.2 For UVB lamps, the irradiance level shall be 0.48 15% W/m2/nm at 310 nm (0.41 to 0.55 W/m2/nm at 310 nm). If the irradiance deviates beyond this tolerance, terminate the test until the cause of the deviation has been determined and corrected. 5.7.2.1 Other irradiance levels can be used by mutual agreement between contracting parties. SAE INTERNATIONAL -APR2016 Page 9 of 14 5.7.3 For UVA lamps, the irradiance level shall be mutually agreed upon by contracting parties. NOTE: For devices that automatically control irradiance, target irrad