More info
Description / Abstract:
This specification details the material and performance
requirements for heat-fusible (bakeable) and selfadhesive,
bitumen-based, vibration damping sheets. These heat-fusible sheets
are intended for application in the assembly plant paint shop to
provide local vibration and sound damping effects to the body. They
are intended to be applied over metal with cured electrocoat (ELPO)
and baked in at least one paint shop oven. The materials are
intended for use on horizontal, vertical, or negative horizontal
(inverted) surfaces.
Material Description. Heat-fusible damping
sheets consist primarily of a bitumen-based damping layer. The
sheets may be supplied as a single layer or as a multilayer
composite. When multiple layers are involved, the following
descriptions are typical (see Table 1).
Adhesion to the substrate may be obtained through the use of a
hot-melt adhesive or a heat-fusible film, applied to the bottom
surface of the damping sheet and activated by the baking process.
Prior to the bake, adhesion to the substrate may be enhanced with a
magnetic filler in the bitumen-based layer or with a pressure
sensitive adhesive (PSA) applied to the bottom surface of the
sheet. Additional layers may be applied to the top surface of the
sheet to provide anti-blocking or stiffening.
Only the complete system that has been validated as meeting the
performance requirements of this standard shall be allowed.
Heat-Fusible Dampers for Standard Process Paint Shops
(Types 1 thru 5). Materials designated as Type 1, 2, 3 and
4 are intended for use in GM paint shops utilizing standard low or
high bake primer surfacer paints (solvent-based, water-based or
powder). The damping sheets are intended for application on the
sealer line over metal substrates with cured ELPO and baked in the
primer surfacer and topcoat ovens. All performance requirements
must be achieved after the first oven and shall not be negatively
impacted by subsequent ovens including topcoat reprocess.
Heat-Fusible Dampers for Non-compressed Integrated
Process Paint Shops (Types 1A thru 5A). These materials
correspond with Types 1 thru 5 described in 1.1.1, but are intended
for use in GM paint shops utilizing a non-baked primer process
(non-compressed integrated, waterborne). In the non-compressed
integrated process, the damping sheets are intended for application
on the sealer line over metal substrates with cured ELPO. In a
non-compressed integrated process, the damping mats are baked in a
short sealer oven, followed by a waterborne (WB) primer, heated
flash and then basecoat, 1K or 2K (1 component or 2 component)
clearcoat and topcoat oven. All performance requirements must be
achieved after the first oven and shall not be negatively impacted
by subsequent ovens including topcoat reprocess.
Remarks. These materials are not intended to be
applied in body shop (over oily metal) or in general assembly
without a bake (except Type 3/3A and Type 5/5A). The materials
specified are not intended for use in areas subject to excessive
heat such as directly above exhaust components.