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1、- 9006379 0004bbO 51T - I GENERAL MOTORS ENGINEERING STANDARDS Materials and Processes - Paint TOPCOAT SYSTEM, B&C, POWDER CLEARCOAT 9964196 1 SCOPE. This specification covers the performance and qualification requirements for exterior basecoat/clearcoat 3.1.3 Maximum Film Build. For two-tones and r
2、epairs, apply systems comprised of high solids basecoat and high bake the minimum amount of film build required for hiding and lev- eling. Total topcoat film build must not exceed 350 um or 4 se- powder clearcoat enamel. Nominal volume solids as sprayed are 40% for the basecoat and 100% for the clea
3、rcoat. quential bakes unless otherwise authorized for a specific technology. 1.1 The basecoats are covered as components under specifica- tion 9984505 and are similar to the materials used in the 9984065 and 9984103 specifications. Clearcoats in this specifi- cation can be used only on rigid or semi
4、rigid substrates and are covered as components under specification 9984240. The base- coat&arcoat enamel is part of the total paint system which must meet Corporate goals for appearance and durability. 32 APPEARANCE. The material must meet or exceed Corpo- rate specikations for gloss, DGI, orange pe
5、el and uniformity as designated in GM4348M and GM4364M. 3.3 IDENTlFICATIoN. Identification requirements for pow- der clearcoat is dit%rent than for liquid clearcoats as follows: 2 REFERENCED STANDARDS. GM4348M GM962OP 9984517 GM435OM 9984065 ASTM D153 GM4364M 9984101 ASTM D1186 GM4367M 9984103 ASTM
6、D1895 GM9508P 9984240 ASTM D1921 GM9533P 9984505 ASTM D3451 3 REQUIREMENTS. Mawials submitted for quaWcation to this specification must meet all the material, performan- and pmcessabiity requirement of GM4367M. only variations, exceptions, or requirements specific to this type of basecoav clearcoat
7、system are included herein. Gnce qualified to these requirements, routine testing of parts is covered by specification GM4350M. 3.3.1 Particle Sixe. Significant differences in particle size may effect the handling and appearance of powder coatings. Supplier shall identify particle size and distribut
8、ion per ASTM D1921. El- Counting halysis is the preferred methodology. 33.2 V&tile Content. Although clearcoats are nominally 100% solids at room temperature, some volatiles may emanate during the bal&g process. Mass percent solids and volatile con- tent shall be detexmined using ASTM D345 1, Sectio
9、n 8. 33.3 Density and Specific Gravity. Apparent density and its Bulk factor shall be determined in accordance with ASTM D1895. For specific gravity determinations use ASTM D153 or with modifications described in ASTM D3451. 33.4 Flow and Sintering Characteristics. Using a gradient bar oven at targe
10、t film builds determine tbe time verses temperature profties for flow and sintering properties. (A specification pro- cedure on this will be forthcoming.) 3.1 FILM THICKNESS (ASTM Dl186). All durabiity and appearance requirements must be met within the range specified for the technology and indicate
11、d in Table 1. Individual colors may have narrower ranges for optimum appearance. Individual colors may also have higher minimum film builds than the technology minimum due to hiding or ultraviolet opacity. The acceptable range for a color or specific pigmentation will be es- tablished during the lab
12、oratory workability phase of “ Annual Color” testing with agreed-upon primer or surfacer colors. 3.4 GRAVELOMETER (Brittleness GM9508P Method A). The minimum ratings indicated below are required for paint on metallic substrates under all conditions of bakes within the bake latitude chart provided by
13、 the suppler and at maximum total al- lowable film thiclmess per 3.1. Ratings over plastic substrates are expected to be one rating higher. Conditions Chip Rating 3.1.1 Fti build requirements for Zones DE may be superced- ed by engineering release for specific vehicle lines. Gther op- tions may incl
14、ude basecoat only or color-keyed primer instead of BCKC. TABLE 1 - FILM BUILD REQUIREMENTS Primarg SeCOlldarg Coatings DurablAppear Durab/Appear (Zones A, B, C) (Zones D, E) Basecoat Range 12-30 pm 8-U) pn Basecoat Target per workability per engineexing Clearcoat Range 75-100 pm 50-85 pm Clearcoat T
15、arget 85 w 70 ctm 3.1.2 Appearance zones are specified in GM4364M and spe- cifically identified by carlines in the PAD documents. 3.5 TOPCOAT PIGMENTXl”ION TESTING (GM962OP). All new topcoat colors or pigmentation changes made for annual color programs must meet the specified requirements prior to p
16、roduction implementation. 3.6 ETCH RESISTXNCE. Coatings approved underthis speci- fication are expected to provide the customer with a finish that will prevent or minimize environmental etch and water-spot damage to the extent that wamanty costs and customer dissatis- faction resulting from this def
17、ect are nil. Since environmental conditions vary from site-to-site and from year-to-year, compar- isons with control materials are our current method of defining JULY 1992 PAGE 1 9984196 Copyright General Motors North America Provided by IHS under license with GM Licensee=IHS Employees/1111111001, U
18、ser=Japan, IHS Not for Resale, 06/23/2008 19:59:25 MDTNo reproduction or networking permitted without license from IHS -,-,- - 900b379 OOO ibbL 456 m I GENERAL MOTORS ENGINEERING STANDARDS TOPCOAT SYSTEM, BC/CC, POWDER CLEARCOAT 9964196 etch resistance. The responsible engineer must be consulted pri
19、or to the start of submission to verify which specific con- trol(s) is to be used. 3.6.1 Field Performance. Ultimate field performance is deter- mined from surveys of production vehicles. In order to assess a new technology prior to production, controlled exposure studies will be made on large panel
20、s or parts at select sites, including Jacksonville FL. Etch resistant paint systems must demonstrate a miniium improvement of 3 rating units batter, following 14 weeks exposure at the Jacksonville site, than tire best 9984065 technology or be equal rating to the best 9984157 or 9984170 technology wh
21、en using a 12 point scale. NOTE Since actual outdoor conditions vary from year-to-year, controls must al- ways be run concurrently. 3.6.2 Laboratory Tests per GM9533P. There must be a signifi- cant visual decrease in etch severity and/or a minimum of 5C increase in etch-free temperature compared to
22、9984065 materi- als, and equal or better performance compared to 9984170 or 9984157 materials. NOTE: These tests are to be used in con- junction with field exposure.5 and other supplier vaklations to demonstrate performance as no laboratory tests to date reliably dupIicate outdoor en-.) 3.7 PRGCESSA
23、BILlTY REQUIREMENTS. Cleamoats cov- ered under this speci6cation are intended to be appiied dry-on- wet over the basecoat after a heated flash. UnRss the approved technology has been specifically evaluated and approved for this process, clearcoat must not be applied over a fully baked basecoat. Whil
24、e processing equipment is unique for the powder clearcoat, material-process interrelationship requimments are similar to those required in GM4367M except as noted 3.7.1 Flash. Typical flash times are 1 minute between basecoM coats, 3 minutes minimum heated flash between basecoat and clearcoat. Flash
25、 time between clearcoat coats coats and prior to the oven entrance is not critical to the powder clearcoat. Each supplier shall demonstrate process latitude for their material with respect to the heated flash issue in the determination of ma- terial/process interrelationships. 3.72 Bake. The nominal
26、 bake for these enamels is 25 minutes at 120 to 135 C surface temperature. Supplier shall provide bake time and temperature charts showing the bake processing window wherein all performance requirements are met. 3.7.3 Heat-up Rate. Supplier shall demonstrate the effect that heat-up rates will have o
27、n appearance of the final coating. Also, supplier will demonstrate whether an interrupted bake, as may occur at breaks or shift change, effects appearance attributes. 3.7.4 Gel Tiiack Free. Detemnne the amount of time need- ed to achieve a tack &e surface when temperature is at the target bake. This
28、 may be accomplished using ASTM D3451. section 14. 3.7.5. Final Line Repair. The repair basecoats may be uncata- lyxed OEM mamriaR or acid catalyzed 9984505 high solids basecoats. The repair clearcoats may be catalyzed 9984517 ma- terials or separate clears as specified in 9984101. Nominal re- pair
29、bake is 20 minutes 82 C min unIess qualified to lower temperature.s. 3.7.6 Package Stability. To address unique characteristics of the powder clearcoat s bulk handling needs, package stability with respect to heat and moisture exposure shall be established per ASTM D345 1, Section 9, modified as nec
30、essary to simulate shipping procedures. 4 SOURCE SHIPMENT RESPONSIBILITY. It will be the responsibility of the supplier to insure that the material is not exposed to tempemmres during shipment which would cause the mated to fail to meet any of the requirements of this SpCCiKCSiOlL 5 INITIAL SOURCE A
31、PPROVAL. 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 Gtical Mated Register (available from the engineering
32、department or labomory), or quivalent, must be submitted with any new submissions or where a composition change has oL2mred. 6 INSPECIlON AND RWECllON. AJI shipments of mate&d or parts under contract or purchase order manufacmmd to this specification shall be equivalent in every respect to the initi
33、al samples approved by engineering. There &all be no changes in either formulation or manufacturing processes pet&ted without prior notification and approval by engineering. Lack of notification by the supplier constitutes grounds for rejection of any shipment. Whiie samples may be taken from incomi
34、ng shipments and checked for conformance to this specification, the supplier shall accept the responsibility for incoming shipments meeting this specitkation without dependence upon purchaser s inspection. In addition the supplier shall be responsible for submitting a CERTIPICATE OF ANALYSIS with ea
35、ch batch of material arriving at a plant. This document shall be prepared and provide data in accordance with tbe requirements detailed in GM4389M. 7 APPROVED SOURCES. Engineering qualification of an approved source is required for this specification. only sources listed in the GM Corporate Material
36、s File under this specification number have been qualified by engineering as meeting the requirements of this s-cation. Sources are available through the on-line MATSPC System. 6 GENERAL INFORMATION. This &dkations was originated by NAO Paint Operations in June 1992. 9984196 PAGE 2 JULY 1992 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 19:59:25 MDTNo reproduction or networking permitted without license from IHS -,-,-