US5645057A — Meltblown barrier webs and processes of making sa…

Claim 1

Independent Claim 105 words

A face mask for covering a portion of the face of a wearer of the mask, said face mask comprising: an absorbent facing layer for contacting a portion of the face of a wearer of the mask; a cover layer; and an inner filtration layer sandwiched between said cover layer and said absorbent layer, said filtration layer having a basis weight of less than ten grams per square meter and comprising a plurality of thermoplastic microfine fibers having an average fiber diameter of less than 1.5 microns which were melt blown from a polymer having a melt flow rate greater than about 1000 g/10 min.

Claim 2

Dependent Claim 105 words

A face mask for covering a portion of the face of a wearer of the mask, said face mask comprising: an absorbent facing layer for contacting a portion of the face of a wearer of the mask; a cover layer; and an inner filtration layer sandwiched between said cover layer and said absorbent layer, said filtration layer having a basis weight of less than ten grams per square meter and comprising a plurality of thermoplastic microfine fibers having an average fiber diameter of less than 1.5 microns which were melt blown from a polymer having a melt flow rate greater than about 1000 g/10 min.

Claim 3

Dependent Claim 29 words

The face mask according to claim 1, wherein said filtration layer comprises a plurality of thermoplastic microfine fibers having an average fiber diameter between about 0.5 and 1.5 microns.

Claim 4

Dependent Claim 29 words

The face mask according to claim 1, wherein said filtration layer comprises a plurality of thermoplastic microfine fibers having an average fiber diameter between about 0.8 and 1.3 microns.

Claim 5

Dependent Claim 23 words

The face mask according to claim 1, wherein said filtration layer has a basis weight between 1 and 5 grams per square meter.

Claim 6

Dependent Claim 31 words

The face mask according to claim 1, wherein said thermoplastic microfine fibers are formed from a polymer selected from the group consisting of polyolefins, polyesters, polyamides, and copolymers and blends thereof.

Claim 7

Dependent Claim 21 words

The face mask according to claim 1, further comprising means for removably attaching the mask to the face of the wearer.

Claim 8

Dependent Claim 28 words

The face mask according to claim 1, wherein said thermoplastic microfine fibers are formed of a polymer having a melt flow rate of greater than 1,200 g/10 min.

Claim 9

Dependent Claim 13 words

The face mask according to claim 1, wherein said thermoplastic polymer is polypropylene.

Claim 10

Dependent Claim 22 words

The face mask according to claim 1, wherein the change in pressure drop across said filtration layer is from 0.3 to 0.8.

Claim 11

Dependent Claim 17 words

The face mask according to claim 1, wherein said outer cover layer is a hydrophobic nonwoven web.

Claim 12

Dependent Claim 16 words

The face mask according to claim 1, wherein said absorbent layer is a hydrophilic nonwoven web.

Claim 13

Dependent Claim 39 words

The face mask according to claim 1, wherein said face mask comprises a plurality of discrete thermal bonds about the periphery thereof bonding the absorbent layer, the filtration layer and the cover layer to form a coherent laminate fabric.

Claim 14

Dependent Claim 126 words

A face mask for covering a portion of the face of a wearer of the mask, said face mask comprising: an absorbent facing layer for contacting a portion of the face of a wearer of the mask; a hydrophobic cover layer; and an inner filtration layer having a basis weight of 1 to 5 grams per square meter and comprising a plurality of microfine microfibers having an average fiber diameter of 0.5 to 1.5 microns formed from a polypropylene having a melt flow rate of greater than 1,000 g/10 min., said filtration layer exhibiting a pressure drop across said filtration layer from 0.3 to 0.8, said filtration layer sandwiched between and bonded to said cover layer and said absorbent layer to form a coherent face mask.

Claim 15

Dependent Claim 126 words

A face mask for covering a portion of the face of a wearer of the mask, said face mask comprising: an absorbent facing layer for contacting a portion of the face of a wearer of the mask; a hydrophobic cover layer; and an inner filtration layer having a basis weight of 1 to 5 grams per square meter and comprising a plurality of microfine microfibers having an average fiber diameter of 0.5 to 1.5 microns formed from a polypropylene having a melt flow rate of greater than 1,000 g/10 min., said filtration layer exhibiting a pressure drop across said filtration layer from 0.3 to 0.8, said filtration layer sandwiched between and bonded to said cover layer and said absorbent layer to form a coherent face mask.

Claim 16

Dependent Claim 106 words

A process for the manufacture of a face mask for covering a portion of the face of a wearer of the mask, the process comprising: forming from a polymer having a melt flow rate greater than about 1000 g/10 min. a meltblown web having a basis of weight of less than 10 grams per square meter and comprising a plurality of thermoplastic microfine meltblown fibers having an average fiber diameter of less than 1.5 microns; sandwiching said meltblown nonwoven web between opposing nonwoven webs to form a laminate fabric; and bonding said opposing nonwoven webs and said meltblown web together to form a coherent laminate fabric.

Claim 17

Dependent Claim 106 words

A process for the manufacture of a face mask for covering a portion of the face of a wearer of the mask, the process comprising: forming from a polymer having a melt flow rate greater than about 1000 g/10 min. a meltblown web having a basis of weight of less than 10 grams per square meter and comprising a plurality of thermoplastic microfine meltblown fibers having an average fiber diameter of less than 1.5 microns; sandwiching said meltblown nonwoven web between opposing nonwoven webs to form a laminate fabric; and bonding said opposing nonwoven webs and said meltblown web together to form a coherent laminate fabric.

Claim 18

Dependent Claim 36 words

The process according to claim 14, wherein the step of forming a meltblown web comprises forming a meltblown web comprising a plurality of thermoplastic microfine fibers having an average fiber diameter between 0.5 and 1.5 microns.

Claim 19

Dependent Claim 36 words

The process according to claim 14, wherein the step of forming a meltblown web comprises forming a meltblown web comprising a plurality of thermoplastic microfine fibers having an average fiber diameter between 0.8 and 1.3 microns.

Claim 20

Dependent Claim 31 words

The process according to claim 14, wherein the step of forming a meltblown web comprises forming a meltblown web having a basis weight between 1 and 5 grams per square meter.

Claim 21

Dependent Claim 39 words

The process according to claim 14, wherein the step of forming a meltblown nonwoven web comprises forming a meltblown nonwoven web formed of a polymer selected from the group consisting of polyolefins, polyesters, polyamides, and blends and copolymers thereof.

Claim 22

Dependent Claim 34 words

The process according to claim 14, wherein the step of forming a meltblown nonwoven web comprises forming a meltblown web from a polymer having a melt flow rate of greater than 1,200 g/10 min.

Claim 23

Dependent Claim 31 words

The process according to claim 14, wherein the step of forming a meltblown web comprises forming a meltblown web having a pressure drop across said meltblown web from 0.3 to 0.8.

Claim 24

Dependent Claim 20 words

The process according to claim 14, wherein the step of bonding said laminate fabric comprises thermally bonding said laminate fabric.

Claim 25

Dependent Claim 33 words

The process according to claim 14, wherein the step of sandwiching said meltblown layer between outer opposing layers comprises sandwiching said meltblown layer between a hydrophobic cover layer and a hydrophilic absorbent layer.

Claim 26

Dependent Claim 86 words

A process for manufacturing a meltblown barrier layer, comprising: extruding a molten thermoplastic polymer, having a melt flow rate greater than about 1000 g/10 min. through capillaries to form filamentary streams; attenuating and breaking said filamentary streams with a high velocity heated gas to form a plurality of microfine fibers having an average fiber diameter of less than 1.5 microns; and collecting said microfine fibers on a collection surface to form a nonwoven web having a basis weight of less than 10 grams per square meter.

Claim 27

Dependent Claim 86 words

A process for manufacturing a meltblown barrier layer, comprising: extruding a molten thermoplastic polymer, having a melt flow rate greater than about 1000 g/10 min. through capillaries to form filamentary streams; attenuating and breaking said filamentary streams with a high velocity heated gas to form a plurality of microfine fibers having an average fiber diameter of less than 1.5 microns; and collecting said microfine fibers on a collection surface to form a nonwoven web having a basis weight of less than 10 grams per square meter.

Claim 28

Dependent Claim 30 words

The process according to claim 23, wherein said molten thermoplastic polymer is polypropylene and said high velocity heated gas is heated to a temperature from 560° F. to 650° F.

Claim 29

Dependent Claim 24 words

The process according to claim 24, wherein said high velocity heated gas is heated to a temperature of between 575° F. and 640° F.

Claim 30

Dependent Claim 27 words

The process according to claim 24, wherein said high velocity heated gas has an air velocity of about 25 to 30 cubic feet per minute per inch.

Claim 31

Dependent Claim 21 words

The process according to claim 23, wherein said molten polymer has a melt flow rate of greater than 1,200 g/10 min.

Claim 32

Dependent Claim 20 words

The process according to claim 23, wherein said microfine fibers have an average fiber diameter between 0.5 and 1.5 microns.

Claim 33

Dependent Claim 22 words

The process according to claim 23, wherein said meltblown web has a basis weight between 1 and 5 grams per square meter.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2000-07-07	2001-01-06	2001-07-08	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2004-07-07	2005-01-06	2005-07-08	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2008-07-07	2009-01-06	2009-07-08	$7700.00	Window Closed / Lapsed

Meltblown barrier webs and processes of making same

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