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1、- 9006379 0002024 209 I GENERAL MOTORS ENGINEERING STANDARDS I Materials and Processes - Paint PRIMER - PLASTISOL, CHIP RESISTANT 9981738 1 SCOPE. This specification covers the requirements for a thermosetting, solvent-borne chip resistant primer that is applied by airless spraying and is subsequent
2、ly topcoated with acrylic enamel or acrylic lacquer color coats. This material is intended to provide a smooth, chip resistant coating over previously applied primers (such as dip, spray or cathodic E-coat). It is intended to protect lower body sheet metal surfaces that are subjected to severe grave
3、l impact from coating failures to the substrate that would cause premature corrosion. cycles. Lacquer topcoats are permitted to exhibit slight cracking at fracture sites, but no cracking in other areas. 4 SUPPLEMENTAL INFORMATION. 2 REFERENCED STANDARDS. GM4356M GM9509P ASTM D1186 ASTM D1474A ASTM D
4、2246 ASTM D3170 ASTM D3363 4.1 Application and Bake. The material must be capable of being applied from all common conventional spray equip- ment. Nominal bakes for these anti-chip primers is 30 minutes at 163 C for high bake materials and 30 minutes at 121 C for low bake materials. Baking within th
5、e range allowed by these process specifications shall have no effect on product durability. The suppliers must provide complete data showing the viscosity-temperature relationship and circula- tion stability characteristics of the material. 3 REQUIREMENTS. See GM4356M for additional re- quirements n
6、ot listed in this specification. The requirements listed below shall be met on all critical surfaces of the part or as designated by the applicable product engineering docu- ments. These requirements shall be determined on the baked anti-chip primer. 4.2 Sanding. The anti-chip primer may be sanded p
7、rior to application of topcoat to remove dirt or minor imperfections. However, all sanding dust must be removed from parts before subsequent topcoating. 3.1 Film Thickness (ASTM D1186): Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .300400 pm Target .
8、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350 pm 3.2 Adequacy of Cure (GM9509P). Ten double rubs with xylene or a supplier recommended solvent shall cause no appearance change, softening of film or a significant color transfer to cloth. 4.3 P
9、anel Preparation. All anti-chip panels are to be pre- pared with the top 15 cm having the total paint system without anti-chip and the bottom 15 cm having the totai paint system with anti-chip. General guidelines for the qualification procedure are given in the introductory section of these paint pr
10、oduct specifications. A detailed description of the test panel and qualification requirements for the specific materials is covered in this specification. The engineering group responsi- ble for coordinating the material development should always be contacted prior to preparation of panels and initi
11、ation of tests to determine if the test program should deviate in any way from the specified GM4356M and plant applications. 3.3 Hardness (ASTM D1474A. ASTM D3363): Pencil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Information only Tukon . . . . . . . . . . . . . .
12、 , . . . . . . . . . . . . . . . _. . _ . . . . information only 4.3.1 A sufficient number of panels should be prepared to accommodate all required tests. However, some tests may be combined on the same panels. Pre-treatment and priming of panels will be established at the beginning of test programs
13、. All bakes refer to substrate temperature in gas fired ovens. 3.4 Chip Resistance (ASTM D3170 plus GM Ratings): Acrylic Enamel Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 min Acrylic Lacquer Systems . . . . . . . . . . . . _ . . _ . _ . . . . . . . . _ _ . .7 min 4.3.2
14、All bake cycles are described in Tables 1 and 2. Film builds will be nominal for each material, except the anti-chip primer. It will include 3 thicknesses, the target value as recommended by the supplier, and the target value f 100 m. NOTE: No failures to substrate will occur. 4.3.3 Refer to Table 3
15、 for fti builds and bakes necessary for each test requirement. 3.5 Gravelometer plus Thermal Crack Cycle (ASTM 5 GENERAL INFORMATION. This specification was D2246, ASTM D3170). No evidence of cracking, blistering, last revised in January 1986 by CPC and was completely color change or other deleterio
16、us effects may occur after 15 revised by the Automotive Paint Committee in March 1988. MARCH 1988 PAGE 1 9981738 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 21:36:54 MDTNo reproduction or n
17、etworking permitted without license from IHS -,-,- U 9006379 0002025 I145 U I GENERAL MOTORS ENGINEERING STANDARDS I Materials and Processes - Paint PRIMER - PLASTISOL, CHIP RESISTANT 9981738 Thiikness NOnllSl Under over TABLE 1 - BAKE Primer Surfacer Lacquer Topcoat (ttE?as) Temp lime Temp 0 (minut
18、es) m 30 163 30 163 30 150 30 1M 45 175 42 175 Test Gravelolnacr Gravelometcr plus Thermal Crack Cycle Tape Adhesion Humidity plus Tape Adhesion Sag Rcsisrancc Florida Expure 3 Mollrhs plus Tape Adhesion Florida !Zxpurc 3 Months plus Gmvel-r T Film Build TABLE 2 - BAKE I Primer Surfacer Enamel Topco
19、at Time Temp Time Temp (minutes) (Cl (minutes) 0 NOlTliSl 30 163 30 120 UtldCr I 30 150 30 115 Over 45 175 45 135 TABLE 3 - TESTS Anti-Chip Normal Wet-On-Wet Notmal wet-on-wet Normal Wet-On-Wet Normal Normal Normal High High High LOW LOW LOW wet-on-wet wet-on-wet Wa-On-Wet wet-on-wet wet-on-wet Wet-
20、On-Wa Wet-On-Wa Wet-On-Wa Wet-On-Wa NOl-lld Normal LOW Wet-on-wet Wet-On-Wa wet-On-wet NOrmal N0llll.d LOW Normal High Wet-On-We4 Wet-On-Wa Wu-on-Wa Wa-On-Wet iKn-On-Wa Normal SOnnai Ivn-On-Wa Wa-on-wet Bake T Primer Surfacer Fibn BuiM Normal NOrmal Notmal Normal NOtTiXd Normal NOlTMl Noxmal Normal
21、Normal Normal %rtml Normal SOrmal NOmal NOlTDl NOrmal Normal fi% Normal ?;Onnal :z? Over NOrrmi under Over Nonnsl Under Over Normal Uadn Over Normal Under Over Normal Sod T Film SUM TC NOlTtlSl Normal Normal ii-i= Normal NOKtMl Normai almal Nrmal Normal iE2 Nolmal Normal Normal Normnl Normal Normal
22、nat Normal Normal Normal Normal Nod Normal ?lortnd 9981738 PAGE 2 MARCH 1988 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 21:36:54 MDTNo reproduction or networking permitted without license from IHS -,-,-