Dual density acoustic insulation
A dual layer nonwoven acoustic insulating material having a more densified layer and a less densified layer that is comprised of shoddy fibers and other fibers.
1. An acoustic insulation material that is a nonwoven felt sheet comprised of:
a mixture of shoddy fibers, low melt binder fibers, and polyester fibers that has gone through a first needling step;
a first layer of the nonwoven felt sheet that is a layer with a certain thickness;
a second layer of the nonwoven felt sheet that is a layer comprised of the remaining thickness of the sheet;
wherein the first layer has greater density than the second layer.
2. The acoustic insulation material of claim 1 , wherein the first layer comprises 10% to 50% of the total thickness of the sheet and the second layer comprises the remainder of the thickness of the sheet.
3. The acoustic insulation material of claim 1 , wherein the greater density of the first layer is the result of a purely mechanical process during manufacturing of the material.
4. The acoustic insulation material of claim 3 , wherein the purely mechanical process that results in the greater density of the first layer is a second needling step in which Only the first layer is needled a second time.
5. The acoustic insulation material of claim 1 , wherein over 50% of the shoddy fibers are cotton fibers.
6. The acoustic insulation material of claim 1 , wherein the low melt binder fibers are low melt polyester fibers.
7. The acoustic insulation material of claim 1 , wherein the low melt binder fibers are bicomponent fibers.
8. The acoustic insulation material of claim 1 , wherein the low melt binder fibers are PET fibers.
9. The acoustic insulation aerial of claim 1 , wherein the mixture of fibers is comprised of:
35% to 60% by weight shoddy fibers;
20% to 40% by weight low melt binder fibers;
with any remaining balance of the mixture of fibers being comprised of polyester fibers.
10. The acoustic insulation material of claim 9 , wherein resin is added to the mixture of fibers until 7% to 20% by weight of the resulting mixture is comprised of resin.
11. An acoustic insulation material that is a nonwoven batt comprised of:
shoddy fibers, low melt binder fibers, and polyester fibers that have undergone an initial needle punching operation;
wherein a first region comprising one-third (⅓) to one-half (½) of the thickness of the batt has greater density than a second region comprising the remaining two-thirds (⅔) to one-half (½) of the thickness of the batt.
12. The acoustic insulation material of claim 11 , wherein the greater density of the first region in comparison to the second region is the result of a purely mechanical process during manufacture of the batt.
13. The acoustic insulation material of claim 12 , wherein the purely mechanical process resulting in greater density of the first region is a subsequent needle punching operation in which only one-third (⅓) to one-half (½) of the thickness of the batt is subjected to the subsequent needle punching operation.
14. The acoustic insulation material of claim 11 , wherein the batt is comprised of:
35% to 60% by weight shoddy fibers;
20% to 40% by weight low melt binder fibers;
with any remaining balance being comprised of polyester fibers.
15. The acoustic insulation material of claim 11 , wherein the batt is comprised of:
35% to 60% by weight shoddy fibers;
20% to 40% by weight low melt hinder fibers;
7% to 20% by weight resin;
with the remaining balance, if any, being comprised of polyester fibers.
16. An acoustic insulation material that is a nonwoven material comprised of:
a first region comprised of a first thickness of the material;
a second region comprised of a second thickness of the material;
wherein the first region is denser than the second region;
wherein the greater density of the first region is a result of a purely mechanical process during manufacturing of the nonwoven material.
17. The acoustic insulation material of claim 16 , wherein the first region is 10% to 50% of the total thickness of the nonwoven material.
18. The acoustic insulation of claim 17 , wherein the density of the first region is within the range of
675
grams
m
2
to
1
,
125
grams
m
2
.
19. The acoustic insulation of claim 17 , wherein the density of the second region is within the range of
225
grams
m
2
to
375
grams
m
2
.
20. The acoustic insulation material of claim 17 , wherein:
the density of the first region is within the range of
675
grams
m
2
to
1
,
125
grams
m
2
;
the density of the second region is within the range of
225
grams
m
2
to
375
grams
m
2
;
the material is comprised of 35% to 60% by weight shoddy fibers;
the material is comprised of 20% to 40% by weight low melt binder fibers;
the material is comprised of 7% to 20% by weight resin;
the remaining balance of the material, if any, is comprised of polyester fibers;
a majority of the shoddy fibers are recycled cotton fibers;
at least one external planar surface of the material is sprayed with a fire retardant and a resin.