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1、 ENGINEERING STANDARDS Material Specification General GM2753M Sound Barrier Patch Copyright February 2003 General Motors Corporation All Rights Reserved February 2003 Originating Department: North American Engineering Standards, Records and Documentation Page 1 of 3 1 Scope This specification descri
2、bes an adhesively attached sheet-form sound barrier material used to cover and acoustically seal body interior holes to prevent noise intrusion. 1.1 General Description. This material is a dense, flexible, impermeable sheet of uniform thickness. It is either self-adhering or coated with a pressure s
3、ensitive adhesive to provide permanent attach- ment to painted body interior panels. It is used to cover and acoustically seal body holes. This is a trim shop installed item and is not intended for installation prior to paint bake operations. 1.1.1 There are two material types with different applica
4、tions as described below: Type I. To be used on horizontal surfaces. Type II. To be used on vertical and over- head surfaces. 1.1.1.1 The acoustical performance of parts made of this material depends upon the mate- rials surface density (mass/area), impermeabil- ity, and completeness of the seal ove
5、r the body hole. 1.1.1.2 The material is provided in various draw- ing-specified part sizes with the adhesive sur- face protected by a release liner. 2 References Note: Only the latest approved standards are ap- plicable unless otherwise specified. 2.1 Normative. ASTM D624 FMVSS 302 SAE J1351 SAE J1
6、756 2.2 GM. GM9010P GM9200P GM9505P GMW3001 GMW3059 3 Requirements Tests shall be conducted at standard conditions, 22 ? 3?C and 50 ? 5% RH unless otherwise speci- fied. 3.1 The values of some properties and perform- ance parameters (e.g., tensile strength, tear strength) may depend upon direction a
7、long the material sample. Therefore, it may be necessary to perform some tests both parallel and perpen- dicular to machine direction in order to determine true min and max values for conformance to re- quirements of this specification. 3.2 Acoustical Performance. The noise reduction performance of
8、this sound barrier material is de- fined and controlled by material mass per unit area. The mass per unit area will be 3.2 kg/m2 with toler- ances as defined in Table 1. Table 1: Tolerances Part Weight (g) Tolerance in Mass/Area 0-60 +50 %/-10% 61-199 +20 %/-10% 200-over +10 %/-10% 3.3. Color. The b
9、arrier material shall be black. Any anti-blocking, anti-transfer film which is perma- nently attached to the barrier materials shall also be black or clear. 3.4 Adhesion. 3.4.1 Adhesive Contact (wet-out). Progressively apply a patch, 50 x 100 mm min, to a clear glass plate taking care to avoid air e
10、ntrapment. Roll twice with a 2 kg roller. Examine adhesive contact. Wet-out must be 90% minimum. 3.4.2 Peel Resistance. Adhere a 25 x 100 mm min length strip of material to a painted test panel with surface representative of production body finish to which adhesion is intended. Leave 1 end loose so
11、that a clamp can be attached. Allow 5 minutes dwell time. Pull 90 degrees to surface at rate of 300 mm/minute. Satisfactory peel values for both Types I and II are given below: Type I.10 N minimum Type II50 N minimum GM2753M GM ENGINEERING STANDARDS Copyright February 2003 General Motors Corporation
12、 All Rights Reserved Page 2 of 3 February 2003 3.4.3 Heat Resistance, 85? ?C. Adhere a 25 x 100 mm strip of material to a painted test panel (as in 3.4.2) with 50 mm of strip overhanging the edge of the test panel. Place in inverted horizontal position (90 degree peel) in oven and expose to 85?C for
13、 24 h. Maximum distance from edge of panel to bond line is 5 mm. 3.4.4 Heat Resistance, 100? ?C. Adhere a 50 x 50 mm piece of material to a painted test panel (as in 3.4.2) so that the entire patch surface is in contact with the panel. Place panel in vertical position in oven and expose to 100?C for
14、 24 h. No displace- ment of the patch may occur. 3.5 Environmental Exposure (GM9505P, Cycle H). Adhere 25 x 100 mm or larger sample to painted test panel (as in 3.4.2). Expose to 3 cycles of GM9505P, Cycle H. The material must not harden appreciably nor leach oils. Adhesion after exposure must meet
15、requirements of 3.4.2. 3.6 Flammability (FMVSS 302). The material with release liner removed (but not bonded to a test panel) shall not burn or transmit a flame front across its surface at a rate of more than 101.6 mm/minute when tested in accordance with FMVSS 302 as received and after accelerated
16、aging (GM9200P). However, if the material stops burning before it has burned for 60 s from the start of timing and has not burned more than 50.8 mm from the point where the timing was started, it shall be considered as having met this requirement. 3.7 Stiffness/Conformability/Memory. Apply a 25 x100
17、 mm strip of material to a horizontal surface so that a 25 x 50 mm portion overhangs the edge. Deflect the overhung portion downward to a vertical position and immediately release it. Allow 4 h to elapse and measure the vertical distance from original surface to the overhung end of the strip. The sa
18、g shall be 25 mm minimum. 3.8 Flexibility. Wrap a strip of the patch material 180 degrees around a 2 mm diameter mandrel so that adhesive surfaces meet. The strip must not crack. 3.9 Repositionability. Material applied to a test panel for 1 minute must release cleanly for reposi- tioning and then be
19、 capable of re-adhesion per specification requirements. 3.10 Die-Cut Ability. Material must be capable of being cleanly die-cut to special shapes. 3.11 Nontransfer and Staining. Adhere a patch to a metal test panel. Cover with lightest color of cur- rently available production seat belt webbing so t
20、hat entire patch and its edges are covered by the belt material. More than one strip of webbing may be required. Completely cover the webbing with another metal panel and apply a load of 7 kPa based upon the area of the patch. 3.11.1 Place the assembly in an 85?C oven for 24 h. After cooling to room
21、 temperature, remove the weight and metal cover plate. 3.11.2 Remove the webbing from the noise control patch. The webbing must separate cleanly from the patch. No significant staining or transfer of patch material to the webbing is permitted as agreed upon between supplier and user. 3.12 Solids Con
22、tent, (GM9010P). The solids con- tent shall be 98% minimum by weight. 3.13 Tear Strength, (ASTM D624, Die C). The tear strength shall be 1.7 kN/m minimum. 3.14 Odor (SAE J1351). The material must have an individual odor scale rating number of 3 or lower when tested per SAE J1351, as evaluated by a p
23、anel of six people. 3.15 Fogging (SAE J1756). Photometric Proce- dure: Bath temperature of 95?C; cooling tempera- ture of 38?C; 6 h test time; 16 h post conditioning time. The amount of fog when measured with a 60 degree glossmeter shall have a rating of 60 units or more. Samples that result in a re
24、sidue that forms a transparent film, discernible droplets, or any visual signs of crystallinity, shall be judged to have not passed this requirement. 3.16 Release Liner Removal. The release liner paper or film must be readily removed from the sealer without tearing or delamination of the part or rel
25、ease liner. Removal must be accomplished with a force not to exceed 4 N per 100 mm width. 3.17 Blocking. A stack of 10 patches is heated in an oven at 60?C for 72 h while under a uniformly applied load of 7 kPa. The test samples are re- moved from the oven, allowed to cool to room tem- perature, and
26、 the weight removed. The samples shall be easily separated and shall not stretch, lose shape, or stick to each other when pulled apart. Parts may not be dusted with talc or any other ma- terial in order to meet this requirement. 3.18 Storage Stability. The shelf life of the mate- rial shall be 180 d
27、ays at a temperature not to ex- ceed 35?C. Shelf life of material commences upon receipt of material from the manufacturer. Material must meet all performance requirements after storage and no blocking may occur. 4 Manufacturing Process Not applicable. -,-,- GM ENGINEERING STANDARDS GM2753M Copyrigh
28、t February 2003 General Motors Corporation All Rights Reserved February 2003 Page 3 of 3 5 Rules and Regulations 5.1 All materials supplied to this specification must comply with the requirements of GMW3001, Rules and Regulations for Material Specifications. 5.2 All materials supplied to this specif
29、ication must comply with the requirements of GMW3059, Re- stricted and Reportable Substances for Parts. 5.3 Initial Source Approval. No shipment shall be made by any supplier until representative initial production samples have been approved by engi- neering as meeting the requirements of this speci
30、- fication. 5.3.1 Completed copies of the Material Safety Data Sheet meeting GM information requirements must be submitted with any new submissions or when- ever a composition change has occurred. 5.4 Inspection and Rejection. All shipments of material or parts under contract or purchase order manuf
31、actured to this specification shall be equiva- lent in every respect to the initial samples approved by engineering. There shall be no changes in ei- ther formulation or manufacturing processes per- mitted without prior notification and approval by engineering. Lack of notification by the supplier c
32、onstitutes grounds for rejection of any shipment. While samples may be taken from incoming ship- ments and checked for conformance to this speci- fication, the supplier shall accept the responsibility for incoming shipments meeting this specification without dependence upon purchasers inspection. 6
33、Approved Sources Engineering qualification of an approved source is required for this specification. Only sources listed in the GM Corporate Material File under this speci- fication number have been qualified by engineering as meeting the requirements of this specification. Sources are available thr
34、ough the on-line MATSPC System. 7 Coding System This material specification shall be referenced in other documents, drawings, VTS, CTS, etc. as follows: GM2753M 8 Release and Revisions 8.1 Release. This newly issued standard has been revised from FBMS 9-84 by BOC-Lansing. 8.2 Revisions. Rev Date Description (Organization) B FEB 1998 Add Type II. Revise 3.4.4, 3.14 and 3.15 (GMNA) C FEB 2003 Editorial Revision (GMNA) -,-,-