Nonwoven fibrous mat for MERV filter and method
AssigneeJohns Manville
InventorAlan Michael Jaffee
Life of this patent
Estimating the term…
Abstract
Wet laid, nonwoven, fibrous mats suitable for making MERV 6 or higher, filters, and methods of making the nonwoven mats filter media are disclosed. The mats include a blend comprising a major portion of glass fibers, a minor portion of man-made polymer fibers, such as polyester fibers and about 0-30 wt. percent of chemically cross linked bleached Kraft pulp the fibers, and optionally fully bleached softwood Kraft pulp, the fibers being bound together with a cured binder having a Tg in the range of about minus 30 to about 50 degrees C. The mats are pleated prior to assembling the filter in conventional manner. The only fibrous mat in the filters is wet laid fibrous nonwoven mat and the pleated filter media needs no other means of support in the filter frame.
Claims45
A method for making a fibrous, wet laid, nonwoven pleatable filter media comprising;
- a) dispersing fibers comprising different types of fibers in a fluid dispersion,
- b) subjecting the dispersion to a moving forming screen to form a wet laid fibrous web,
- c) optionally applying an aqueous resin binder to the web in sufficient amount to produce a binder level in the filter media of about 18 to about 25 wt. percent, and
- d) drying the wet web and at least partially curing the resin in the binder to form a resin bound fibrous, wet laid, nonwoven pleatable dry mat, wherein;
- i) the fiber dispersion comprises about 28 to about 40 weight percent polymer fibers, having a denier in the range of microdeniers to 6, about 40 to about 28 weight percent H glass fibers about 0.5 to about 1 inch long and about 15+/−10 wt. percent of either a chemically cross linked bleached Kraft pulp or a fully bleached softwood Kraft pulp, based on the weight of said pleatable dry mat, and
- ii) the aqueous binder comprises a mixture of water and an acrylic resin having a glass transition temperature in the range of about 5 to about 30 degrees C. whereby the resultant filter media, when pleated and formed into a pleated gaseous filter using conventional pleating and assembly techniques produces a filter meeting at least MERV 6 specifications and requires no additional means of support in the pleated gaseous filter.
A wet laid fibrous, dry nonwoven pleated filter media comprising a about 28 to about 40 weight percent H glass fibers having a length of about 0.5 to about 1 inch, about 15+/−10 wt. percent of either chemically cross linked bleached Kraft pulp fibers or fully bleached softwood Kraft pulp fibers and about 28 to about 40 percent man-made polymer fibers, having deniers from microdeniers to about 6, in said filter media, the fibers in the mat being bound together with about 18 to about 25 wt. percent of a binder derived from an acrylic latex, the acrylic latex binder having a Tg in the range of about 5 to about 30 degrees C., the filter media, after pleating in a conventional manner to form said filter media and assembled into a gaseous filter in which said filter media is unsupported and the filter meets at least MERV 6 specifications.
A filter for gases having a MERV rating of at least 6, the filter containing a filter media consisting essentially of a wet laid, dry and pleated unsupported mat filter media, said filter media comprising a blend of fibers comprising about 28 to about 40 wt. percent H glass fibers having a length of about 0.5 to about 1 inch long and about 40 to about 28 wt. percent man-made polymer fibers and about 15+/−10 wt. percent of either chemically cross linked bleached Kraft pulp fibers or fully bleached softwood Kraft pulp fibers, the fibers in said filter media being bound together with about 18 to about 25 wt. percent, based on the weight of said filter media, of a binder derived from an acrylic latex having a Tg in the range of about 5 to about 30, the pleated filter media requiring no additional means of support in the filter.
Dependencies are inferred from the claim text.