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1、- qoob33q 0004=lL2 50-f I GENERAL MOTORS ENGINEERING STANDARDS I Materials and Processes - Paint I PRiMER, POWDER, NONCONDUCTIVE POROSITY SEALING FOR SMC 9984834 1 SCOPE. This specification covers the requirements for a nonconductive powder porosity sealing primer for use on SMC plastics. In the cas
2、es where electrostatic application of subsequent coatings is desired, this primer may be applied over a conductive primer or m-mold coating. The powder primer shall provide a smooth, adhesion promoting surface which will not inhibit electrostatic application of subsequent coatings. The primer must h
3、ave the ability to fill minor surface imperfections in the substrate and act as a banier to prevent popping of topcoats during subsequent bakes. 1.1 This primer is part of a total painted product system and must meet requirements set forth in the specifications for other materials with which it is n
4、sed. This specification shall be used in conjunction with the Approved Paint on Plastics Systems (APOPS), which lists approved substrate, cleaning, priming and topcoat combinations. 2 REFERENCED STANDARDS. GM4353M 9984801 GM4365M ASTM D1921 GM9524P ASTM D345 1 3 REQUIREMENTS. 3.1 Surface Preparation
5、. Powerwash per 9984801. Any deviation must be approved by the involved GM Paint Engineering Deparunent. 3.2 Application. Apply at dry fihn thickness as specified per supplier recomm UlddOllS. 3.3 Bake. Preheat temperatures or bake conditions shall not exceed those identified in Figure 1 of GM4365M.
6、 Surface of the part must be within the range of time and temperature specified by the primer supplier for cure. Tie in oven and ambient temperature must be regulated to meet this require- ment without exceeding over/under bake specifications. 3.4 Appearance. Must meet the requirements of GM4353M wi
7、th the following exceptions: 3.4.1 This primer may be sanded 100% provided that adequate fti thickness is retained to ensure porosity sealing characteristics. 3.4.2 Since film build requirements may differ for powder coatings, the 101 m limitation is an inappropriate identifica- tion of excessive re
8、coats for this technology. 3.5 Performance. This material must meet the requirements of GM4365M with the following modifications: 3.5.1 Supplier shall identify particle size and distribution per ASTM D1921. 3.5.2 Mass percent solids and WC content shall be deter- mined using ASTM D3451. 3.5.3 For te
9、sts 1 through 4 identified in Table 1 and tests 1 through 4.7, and 8 in Table 2 test conditions shall include the following: Normal film / Normal bake (N/N) Lowfilm/Highbake(L/H) HighChn/Lowbalce(H/L) Normal film / ELPO bake (N/E) 3.5.4 Solvent Penetration test per GM9524P shall be per- formed at pr
10、imer thickness specified by the supplier. 3.5.5 The following requirements in GM4365M are not applicable to this specification: 3.1.5 (Viscosity), 3.1.6 (Resi- sistivity) and 3.1.7 (Conductivity). 3.6 Approval. When testing is satisfactorily completed per the above requirements, approval to this spe
11、cification will be given. For full specific system approval refer to the Qualifica- tion Procedures Section in the APGPS. 3.7 Sanding. Primed patts may be sanded to remove dirt or minor imperfections. However, all sanding dust must be removed from the parts before shipping. If paits are wet sanded,
12、deionized water must be used for final rinse. 4 SOURCE SHIPMENT RESPONSIBILITY. It will be the responsibility of the supplier to insure that the material is not exposed to temperatures during shipment which would cause the material to fail to meet any of the requirements of this specification. 5 INl
13、llAL SOURCE APPROVAL No shipment shall be made by any supplier until representative initial production samples have been approved by engineering as meeting the requirements of this specification. 5.1 Completed copies of the GM Material Safety Data Sheet and Critical Material Register (available from
14、 the engineering department or laboratory), or equivalent, must be submitted with any new submissions or where a composition change has occurred. 6 INSPECTION AND REJECTION. All shipments of material or parts under contract or purchase order mannfac- tured to this specification shall be equivalent i
15、n every respect to the initial samples approved by engineering. There shall be no changes in either formulation or manufacturing processes permitted without prior notification and approval by engi- neering. Lack of notification by the supplier constitutes grounds for rejection of any shipment. While
16、 samples may be taken from incoming shipments and checked for conformance to this specification, the supplier shall accept the responsibili- ty for incoming shipments meeting this specification without dependence upon purchaser s inspection. 7 APPROVED SOURCES. Engin&g qualification of an approved s
17、ource is required for this specification. only sources listed in the GM Corporate Materials File under this MARCH 1991 PAGE 1 9984834 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 20:42:22 MD
18、TNo reproduction or networking permitted without license from IHS -,-,- - 7006377 0004733 Y4b 1 GENERAL MOTORS ENGINEERING STANDARDS 1 Materials and Processes - Paint 1 PRIMER, POWDER, NONCONDUCTIVE POROSITY SEALING FOR SMC 9984834 specification number have been qualified by engineering as 8 GENERAL
19、 INFORMATION. This is a newly issued meeting the requirements of this specification. Sources are specification approved by the Paint Materials Specification available through the on-line MATSPC System. committee in October 1990. 9984834 PAGE 2 MARCH 1991 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 20:42:22 MDTNo reproduction or networking permitted without license from IHS -,-,-