Low and ultra low density butyl constrained layer patches
The present disclosure relates to use of a sound and vibration damping system for use in automotive, appliance and other applications. Specifically, the sound and vibration damping system includes an elastomeric layer prepared from a low density butyl based composition and a constraining layer. The low density butyl based composition comprises at least one polybutene, at least one butyl rubber and light weight fillers. The sound and vibration damping system of the present disclosure has a specific gravity less than 1.0 and a loss factor of not more than 0.4 at 20° F., 40° F. and 70° F. for frequencies of 200 Hz, 400 Hz and 800 Hz.
1. A vibration and sound damping system comprising:
an elastomeric layer, and
a metallic constraining layer,
wherein the elastomeric layer is prepared from an uncured, low density butyl composition with a specific gravity from 0.75 to 0.9, and
wherein the system has a damping loss factor of less than 0.4 at 20° F., 40° F. and 70° F. for frequencies of 200 Hz, 400 Hz and 800 Hz.
2. The vibration and sound damping system of claim 1 , wherein the metallic constraining layer comprises aluminum.
3. The vibration and sound damping system of claim 1 further comprising a substrate layer comprising at least one from the group of wood, glass, metal, and a polymer.
4. The vibration and sound damping system of claim 1 , wherein the low density butyl composition comprises:
at least one synthetic rubber,
at least one polybutene, and
a plurality of light weight fillers.
5. The vibration and sound damping system of claim 4 , wherein the at least one synthetic rubber is selected from the group consisting of different grades of butyl rubber, partially cross-linked butyl rubber, co-polymers of isobutylene and isoprene, and combinations thereof.
6. The vibration and sound damping system of claim 4 , wherein the at least one synthetic rubber is present in amounts of about 100 parts by weight, based on 793 parts by weight of the low density butyl composition.
7. The vibration and sound damping system of claim 4 , wherein the at least one polybutene is a low molecular weight polybutene present in amounts of about 261 parts by weight, based on 793 parts by weight of the density butyl composition.
8. The vibration and sound damping system of claim 4 , wherein the plurality of light weight fillers are present in an amount of about 186 parts by weight, based on 793 parts by weight of the low density butyl composition.
9. The sound and vibration damping system of claim 1 , wherein the low density butyl composition further comprises at least one from the group of tackifiers, molecular weight broadening agents, anti-oxidants, rheology modifying fillers, pigments, dispersion aides, and combinations thereof.
10. The vibration and sound damping system of claim 1 , wherein the low density butyl composition further comprises a tackifier present in an amount of about 46 parts by weight, based on 793 parts by weight of the low density butyl composition.
11. The vibration and sound damping system of claim 1 , wherein the low density butyl composition further comprises a weight broadening agent present in an amount of about 33 parts by weight, based on 793 parts by weight of the low density butyl composition.
12. The vibration and sound damping system of claim 1 , wherein the low density butyl composition further comprises, in an amount of about 14 parts by weight, based on 793 parts by weight of the low density butyl composition, at least one from the group of anti-oxidants, dispersion aides, pigments, and combinations thereof.
13. The vibration and sound damping system of claim 1 , wherein the low density butyl composition further comprises a rheology modifying filler selected from the group of fumed silica, precipitated silica, cellulose fibers, kaolin clay, and combinations thereof.
14. The vibration and sound damping system of claim 1 , wherein the system exhibits a density less than 1.0 g/cc.
15. The vibration and sound damping system of claim 1 , wherein the system exhibits a density from 0.65 to 1.0 g/cc.