Tacky allergen trap and filter medium, and method for containing allergens
View Patent ↗An allergen trap is provided. The allergen trap includes a woven or nonwoven substrate having at least one strata. The trap is impregnated with or otherwise treated with a tacky adhesive by which allergens may be trapped. An example of an allergen is a dust mite. The tacky adhesive, in turn, may be treated with a miticide or activated carbon.
1. A filtration medium comprising:
(a) a nonwoven airlaid multilayer substrate having a basis weight of from about 35 gsm to about 500 gsm comprising, based on the total weight of the substrate, from about 30 weight percent to about 95 weight percent matrix fibers and from about 5 weight percent to about 70 weight percent of a binder comprising
(A) a first layer comprising synthetic matrix fibers and having a top surface and a bottom surface,
(B) a second layer having a top surface and a bottom surface, the second layer comprising cellulosic matrix fibers and binder with the top surface of the second layer contacting the bottom surface of the first layer,
(b) optionally, a dusting layer of latex on the bottom surface of the second layer having an outer surface, and
(c) a pressure sensitive adhesive.
2. A filtration medium of claim 1 , further comprising a scrim having a basis weight of from about 8 gsm to about 200 gsm, wherein the scrim is positioned in contact with the bottom surface of the second layer or the outer surface of the dusting layer.
3. The filtration medium of claim 1 , wherein the binder for the matrix fibers is a bicomponent fiber, a latex or a mixture thereof.
4. The filtration medium of claim 1 , wherein the synthetic fibers of the first layer are staple synthetic fibers, bicomponent fibers or a mixture thereof.
5. The filtration medium of claim 1 , wherein the synthetic fibers of the first layer are bicomponent fibers.
6. The filtration medium of claim 1 , wherein the synthetic fibers of the first layer are eccentric bicomponent fibers.
7. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is present to a greater extent in the second layer comprising cellulosic fibers and binder than in the first layer containing synthetic fibers.
8. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is applied to the top surface of the first layer.
9. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is a waterborne adhesive that selectively migrates to the second layer comprising cellulosic fibers so that the top surface of the first layer does not exhibit significant tack.
10. The filtration medium of claim 1 , wherein the substrate has a basis weight of from about 35 gsm to about 250 gsm, the substrate comprising, based on the total weight of the substrate, from about 75 weight percent to about 95 weight percent matrix fibers and from about 5 weight percent to about 25 weight percent of a binder.
11. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is present as an add on that provides a basis weight for the filtration medium that is from about 10 percent to about 31 percent greater than the basis weight of the substrate.
12. The filtration medium of claim 1 , wherein at least a portion of the matrix of fibers are impregnated with the pressure sensitive adhesive.
13. The filtration medium of claim 2 , wherein the scrim comprises a spunbond material, a meltblown material, a wetlaid or airlaid nonwoven material, a textile, a woven or nonwoven synthetic material.
14. The filtration medium of claim 1 , wherein the substrate contains from about 50 weight percent to about 95 weight percent matrix fibers and from about 5 weight percent to about 50 weight percent of a binder.
15. The filtration medium of claim 1 , wherein the substrate has a density of from about 0.035 g/cm 3 to about 0.10 g/cm 3 .
16. The filtration medium of claim 1 , wherein the material further comprises a release layer adhered to the pressure-sensitive adhesive.
17. The filtration medium of claim 16 , wherein the release layer is paper, fiber, metal foil, polymeric film, or a combination thereof.
18. The filtration medium of claim 16 , wherein the release layer is a polymeric film that is one of polyolefin, polyethylene, polyester, and plasticized vinyl films.
19. The filtration medium of claim 16 , wherein the release layer is either a woven or nonwoven fiber which has been treated on a surface with a release agent.
20. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is present in an amount from about 5 gsm to about 300 gsm.
21. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is coextensively contiguous with a major interior or exterior surface of the substrate.
22. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is coextensively contiguous with the one or more selected areas of the substrate.
23. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is an acrylate, a polyurethane, a poly-alpha-olefin, a silicone, or a self-tacky or tackified natural or synthetic rubber.
24. The filtration medium of claim 1 , wherein the pressure sensitive adhesive is an essentially no-tacky adhesive tackified with a resin.
25. The filtration medium of claim 24 , wherein the pressure sensitive adhesive is a substantially non-tacky acrylate tackified with a rosin ester, an aliphatic resin, or a terpene resin.