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1、GENERAL MOTORS ENGINEERING STANDARDS I Materials and Processes - Procedures RESISTANCE OF COATINGS TO CHEMICAL ETCHING AND DISTORTION GM9533P 1 SCOPE. This standard describes the test procedures to evaluate the sensitivity of paint coatings or films to etching, distortion or discoloration from expos
2、ure to assembly plant chemicals or severe outdoor environmental conditions, 1.1 RESTRICTED AND REPORTABLE CHEMICALS (GMlOOOM). By 1997 start of saleable vehicles, all materials supplied to this specification must comply with the require- ments listed in GMlOOOM, “Restricted and Reportable Chemicals.
3、” REFERENCED STANDARDS. GMlOOOM 9981386 998545 1 GM4653M 9981606 9985670 GM6043M 9982015 9986066 GM9625P 9985013 TEST EQUIPMENT. 3.1 Thermal Gradient Bar, the following model or equivalent BYK - CHEMIE Model 2612, 250 C, RS232 Computer, 524 S. Cherry, P.O. Box 5670, Wallingford, CT 06492, (203) 265-
4、2086. 3.2 Air-circulating electric oven. 3.3 Temperature measuring equipment (DATAPAQ system with thermocouples and thermistors or equivalent). 3.4 Pipette for application of test materials. 3.5 Clean, lint-free, nonabrasive wiping cloths. 4 TEST MATERIALS Unless otherwise indicated in the applicabl
5、e coating material specification, the coating or film shall be exposed to the following materials during basic quali- fication. Testing of additional materials may be required for specific plant applications. 4.1 ENVIRONMENTAL MATERIALS, ,“: C. d. e. f. Acid rain mixture per GM9625P at both pH 3 and
6、 4 Sulphuric acid solutions in water - 10% by weight and pH of 2.0, 3.0 and 4.0. (Adjust per GM9625P) Calcium sulphate solution in water - 0.75% by weight and adjusted to pH of 4.0 with sulphuric acid Deionized water Tap water Egg Albumin - 2% by weight in deionized water 4.2 PLANT MATERIALS. a. Car
7、 wash detergent, 9982015 (Chemfll Chemsheen or equivalent) - concentrate, 1:50 and 1:lOO dilutions with tap water b. Adhesive remover, 9981606 (Parker-Amchem Sno- Sol 13-R or equivalent) c. Grease, 9981386(Texaco Thermatex EP-1 or equiva- lent) d. Motor Oil, any commercial low-30 grade e. Windshield
8、 washer fluid, 9985670 concentrate 1:l with tap water or commercial mixed materials, full strength f. Brake Fluid, GM4653M (Delco Supreme 11, DOT 3, 9985013) g. Poly Alkaline Glycol Oil (9986066) h. Engine Coolant, GM6043M (Texaco, 9985451) 5 TEST PANELS. Panels shall be prepared using the specified
9、 processing such as film build and bake. Recommended panel size is 100 x 300 mm or larger. For tests with most materials, etching or distortion of the coating sur- face can be most easily observed on black panels. Where the primary effect is expected to be discoloration, white panels must be used. B
10、ecause of test variability and rating subjective- ness, control panels of similar current technologies should be run concurrent with the coating to be tested. Unless otherwise indicated, coated test panels or film samples shall be aged a maximum of 24 h at room temperature prior to exposure. 6 PROCE
11、DURE. For all testing, apply 0.05 mL of the specified test solutions via pipette to the test panel. Multiple solutions can be evaluated on the same panel. Spotted panels are then tested per one or more of the following methods. Unless otherwise indicated in the coating material specifica- tion, Meth
12、od 1 and 2 shall be used for testing of environmental materials, and Methods 2 and 3 for plant materials. Where environmental materials must be evaluated on coated nonme- tallic panels not suitable for gradient bar testing, Method 3 may be used 10C increments. 6.1 METHOD 1 - TEMPERATURE GRADIENT BAR
13、. See Section 6. 6.1.1 Place drops along the entire length of two 100 x 300 mm panels. Drops can be in either a straight line spaced 6.0 mm apart or in a zig-zag pattern. 6.1.2 Place panels on gradient bar that runs from 38 to 82C. Bar should be calibrated to ensure that panel heat up time is no gre
14、ater than 2 minutes for 0.090 mm thickness steel substrate. Residence time on bar must be adjusted for plastic or thick metal substrates requiring longer heat-up times (or use Method 3 10C increments). 6.1.3 Remove one panel after 15 minutes exposure at temper- ature, and the other panel after 30 mi
15、nutes exposure. JULY 1995 PAGE 1 9533P Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 06/23/2008 21:41:47 MDTNo reproduction or networking permitted without license from IHS -,-,- GM GM9533P 95 - 9006379
16、 0007297 75T m GENERAL MOTORS ENGJNEEFUNG - P?uceduFB?) RESISTANCE OF COATINGS TO CHEIWCAL ETCHING AND DISTORTION ww33P 61.4 Rinse any remaining test solution from panels, using water or compatible, nonagmssive solvent. 6.1.5 Record and report etch-free temperamm for test coating and control. 6.1.6
17、Allow panels to recover for 24 h and re-rate. 6.2 METHOD 2 - ROOM TEhPERATURE TEST. See Section 6. 6.2.1 Apply 2 spots of each test solution to coated panel. 6.2.2 Allow panels to age 24 h at room temparature. Ambient conditions must be 21 to 25C, 30 to 50% RI-I with averages recorded. 6.2.3 Rinse a
18、ny remaining test solutions from panel using water or applicable solvent and wipe dry. 6.2.4 Rate and report the affect of each test solution, com- pared to the control, per the the Scale in Section 7. 6.3 METHOD 3 - ELEVATED TEMPERATURE TEST. Follow steps outlined in Method 2. see 6 except as follo
19、ws: 6.3.1 After application of test solutions, place panels in an electric air-circulating oven that has been preheated to the specified temperature. Use 7oC, unless otherwise indicated in the applicable coating specification. 6.3.2 Condition panels in oven for 30 minutes at substrate temperature. R
20、ecord actual substrate temperature. 6.3.3 For testing of environmental materials on nonmetallic substrates which are not suitable for temperature gradient bar, run tests 50,60,70,8oC, and report etch-free temperature. 7 RATING SCALE. The following subjective rat&g scale shall be used to evaluate and
21、 report the effect of teat materials on the coating or film. In all cases, the effect on con- ids should be evaluated at the same time for comparison. 10 - Nochange 8 - Slight 6 - Moderate 4 - Pronounced 2 - Severe 8 REPORT. The following information must be provided in the report of all test result
22、s: a. Complete identitlcation of test coating and control. b. Complete identiftcation of test solutions. c. Time and verified temperature for each test. d For Method 1, etch-free temperature and comparison to control. e. For Methods 2 and 3, rating of effect and comparison to control. 9 SAFETY. This
23、 method may involve hazardous materi- als, operations and equipment. This method does not propose to address all the safety problems associated with its use. It is the responsibility of the user of this method to establish appro- priate safety and health practices and determine the applicability of
24、regulatory limitations prior to use. 10 GENERAL INFORMATION. This standard was originated by the Topcoat Task Group and approved by the Paint Materials Specification Committee in August 1991. The latest revisions include: Rev Date Description A 5195 Added 4.2, f, g, h 9533P PAGE 2 JULY 1995 Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 06/23/2008 21:41:47 MDTNo reproduction or networking permitted without license from IHS -,-,-