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US 4,807,619 AGranted
Resilient shape-retaining fibrous filtration face mask
AssigneeMinnesota Mining and Manufacturing Company
InventorsJames F. Dyrud, Harvey J. Berg, Alice C. Murray
Life of this patent
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Abstract
New molded fibrous filtration face masks that are highly resilient and shape-retaining are provided using one or more molded fibrous shaping layers, with a fibrous filtration layer disposed on one side of or between the molded fibrous shaping layers; the molded fibrous shaping layers having a total basis weight of at least 150 g/m2, and at least one of the fibrous shaping layers having an average density over the central area of the face mask of no greater than about 0.2 g/cc, such that at bends of the layer during deformation of the face mask the layer elastically deforms and tends to return to its original thickness and shape when the deforming pressure is removed.
Claims57
A resilient cup-shaped filtration face mask adapted to cover the mouth and nose of a wearer of the mask comprising:
- (a) one or more molded fibrous shaping layers that comprise fibers bonded to one another and to other included fibers at intersecting points throughout the layer;
- (b) a fibrous filtration layer disposed on one side of or between said molded fibrous shaping layers, the filtration layer removing a higher percentage of particles from a gaseous stream than the shaping layers remove;
- said molded fibrous shaping layers having a total basis weight of at least about 150 g/m.sup.2, and at least one said fibrous shaping layer having an average density over the central area of the face mask of no greater than about 0.2 g/cc, such that at bends of the layer during deformation of the face mask the layer elastically deforms and tends to return to its original thickness and shape when the deforming pressure is removed.
A resilient filtration face mask comprising:
- (a) one or more molded fibrous shaping layers that comprise bicomponent fibers having first and second components extending over the length of the fibers, the first component melting at a temperature lower than the second component and the fibers being bonded to one another and to other included fibers at intersection points throughout the layer by adhesion of the first component to the intersecting fibers;
- and
- (b) a fibrous filtration layer disposed on one side of or between said molded fibrous shaping layers, the filtration layer removing a higher percentage of particles from a gaseous stream than the shaping layers remove;
- said molded fibrous shaping layers having a total basis weight of at least about 150 g/m.sup.2, and at least one said fibrous shaping layer having a density over the central area of the face mask of no greater than about 0.2 g/cc such that at bends of the layer during deformation of the face mask the layer elastically deforms and tends to return to its original thickness and shape when the deforming pressure is removed.
1 more element
A cup-shaped filtration face mask comprising:
- (a) one or more molded fibrous shaping layers at one of which comprises bicomponent fibers that average 10 denier or larger in diameter and that have first and second components extending over the length of the fibers, the first component melting at a temperature lower than the second component and the fibers being bonded to one another and to other included fibers at intersection points throughout the layers by adhesion of the first component to the intersecting fibers;
- and
- (b) a fibrous filtration layer disposed on one side of or between said mole fibrous shaping layers, the filtration layer removing a higher percentage of particles from a gaseous stream than the shaping layers remove;
- said molded fibrous shaping layers having a total basis weight of at least about 150 g/m.sup.2 but causing less than half the pressure drop in a gaseous stream flowing through the face mask;
- and at least one fibrous shaping layer having an average density over the central area of the mask of no greater than about 0.2 g/cc such that at bends of the layer during deformation of the face mask the layer elastically deforms and tends to return to its original thickness and shape when the deforming pressure is removed;
- and the face mask exhibiting a resistance to 5-centimeter deformation of at least 5 Newtons when a probe is pressed against the apex of the mask and recovery to its original shaped after such 5-centimeter deformation.
3 more elements
A cup-shaped filtration face mask comprising:
- (a) one or more molded fibrous shaping layers at least one of which comprises at least about 75 weight-percent bicomponent fibers that average 10 denier or larger in diameter and that have first and second components extending over the length of the fibers, the first component melting at a temperature lower than the second component and the fibers being bonded to one another and to other included fibers at intersection points throughout the layers by adhesion of the first component to the intersecting fibers;
- and
- (b) a fibrous filtration layer disposed on one side of or between said molded fibrous shaping layers, the filtration layer removing a higher percentage of particles from a gaseous stream than the shaping layers remove;
- said molded fibrous shaping layers having a total basis weight of at least about 250 g/m.sup.2 but causing less than half the pressure drop in a gaseous stream flowing through the face mask;
- and at least one fibrous shaping layer having an average density over the central area of the mask of no greater than about 0.2 g/cc such that at bends of the layer during deformation of the face mask the layer elastically deforms and tends to return to its original thickness and shape when the deforming pressure is removed;
- and the face mask exhibiting a resistance to 5-centimeter deformation of at least 5 newtons when a probe is pressed against the apex of a mask and recovery to its original shape after such 5-centimeter deformation.
3 more elements
Dependencies are inferred from the claim text.