Three-layer nonwoven composite structure

Claim 1

An improved nonwoven composite structure having three melt-extruded nonwoven layers which comprises: (A) a first layer which comprises at least a portion of a first nonwoven web; (B) a second layer which comprises at least a portion of a second nonwoven web having a first surface and a second surface; and (C) a third layer which comprises at least a portion of a third nonwoven web; in which: (1) said first nonwoven web is adjacent to the first surface of said second nonwoven web and said third nonwoven web is adjacent to the second surface of said second nonwoven web; (2) said first nonwoven web is comprised of continuous and randomly deposited filaments having an average filament diameter in excess of about 7 micrometers and prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (3) said second nonwoven web is comprised of substantially continuous and randomly deposited microfibers having an average diameter of from about 0.1 to about 10 micrometers; (4) the microfibers of said second nonwoven web are prepared by melt extrusion through a die at a shear rate of from about 50 to about 30,000 sec -1 and a throughput of no more than about 6.4 kg/cm/hour of a mixture of an additive and a second thermoplastic polymer, which additive imparts alcohol repellency to the surfaces of said microfibers as a consequence of the preferential migration of said additive to the surfaces of said microfibers as they are formed, said preferential migration taking place spontaneously upon the formation of said microfibers without the need for a post-formation treatment of any kind; (5) the additive is present in said second nonwoven web in an amount which is sufficient to both impart alcohol repellency to the microfibers thereof and to substantially prevent entry into said second nonwoven web of topically applied treatment liquid; (6) said second thermoplastic polymer is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (7) said third nonwoven web is comprised of continuous and randomly deposited filaments having an average filament diameter in excess of about 7 micrometers and prepared from a third thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (8) the boundary between at least two adjacent melt-extruded nonwoven layers is indistinct in that fibers at or near the surfaces of such adjacent layers are significantly intermingled; (9) said composite structure has been pattern bonded by the application of heat and pressure; and (10) at least one of said first and third nonwoven webs has been treated by topical application of at least one agent in an amount which is sufficient to impart to the filaments of said web at least one characteristic which is different from the surface characteristics of filaments in a web not so treated, said topical treatment being carried out in a manner such that each topically applied agent is substantially restricted to the web to which it was applied.

Claim 12

A method of preparing a nonwoven composite structure having three melt-extruded nonwoven layers adjacent to each other in which each melt-extruded nonwoven layer comprises at least a portion of a nonwoven web and the boundary between any two adjacent melt-extruded nonwoven layers is indistinct in that fibers or filaments at or near the surfaces of such adjacent layers are significantly intermingled, which method comprises the steps of: (A) forming a first nonwoven web by melt extruding continuous filaments which are randomly deposited on a moving foraminous support, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (B) forming a second nonwoven web by melt extruding substantially continuous microfibers which are randomly deposited directly onto at least a portion of said first nonwoven web, said substantially continuous microfibers having an average diameter of from about 0.1 to about 10 micrometers; (C) forming a third nonwoven web by melt extruding continuous filaments which are randomly deposited directly onto at least a portion of said second nonwoven web, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (D) pattern bonding the resulting structure by the application of heat and pressure; and (E) treating at least one of said first and third nonwoven webs of the resulting pattern bonded structure by topical application of at least one agent in an amount which is sufficient to impart to the filaments of said web at least one characteristic which is different from the surface characteristics of filaments in a web not so treated, said topical treatment being carried out in a manner such that each topically applied agent is substantially restricted to the web to which it was applied; in which: (1) the microfibers of said second nonwoven web are prepared by melt extrusion through a die at a shear rate of from about 50 to about 30,000 sec -1 and a throughput of no more than about 6.4 kg/cm/hour of a mixture of an additive and a second thermoplastic polymer, which additive imparts alcohol repellency to the surfaces of said microfibers as a consequence of the preferential migration of said additive to the surfaces of said microfibers as they are formed, said preferential migration taking place spontaneously upon the formation of said microfibers without the need for a post-formation treatment of any kind; (2) the additive is present in said second nonwoven web in an amount which is sufficient to both impart alcohol repellency to the microfibers thereof and to substantially prevent entry into said second nonwoven web of topically applied treatment liquid; and (3) said second thermoplastic polymer is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides.

Claim 13

A method of preparing a nonwoven composite structure having three melt-extruded nonwoven layers adjacent to each other in which each melt-extruded nonwoven layer comprises at least a portion of a nonwoven web and the boundary between any two adjacent melt-extruded nonwoven layers is indistinct in that fibers or filaments at or near the surfaces of such adjacent layers are significantly intermingled, which method comprises the steps of: (A) forming a first nonwoven web by melt extruding continuous filaments which are randomly deposited on a moving foraminous support, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (B) forming a second nonwoven web by melt extruding substantially continuous microfibers which are randomly deposited directly onto at least a portion of said first nonwoven web, said substantially continuous microfibers having an average diameter of from about 0.1 to about 10 micrometers; (C) forming a third nonwoven web by melt extruding continuous filaments which are randomly deposited directly onto at least a portion of said second nonwoven web, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (D) pattern bonding the resulting structure by the application of heat and pressure; and (E) treating at least one of said first and third nonwoven webs of the resulting pattern bonded structure by topical application of at least one agent in an amount which is sufficient to impart to the filaments of said web at least one characteristic which is different from the surface characteristics of filaments in a web not so treated, said topical treatment being carried out in a manner such that each topically applied agent is substantially restricted to the web to which it was applied; in which: (1) the microfibers of said second nonwoven web are prepared by melt extrusion through a die at a shear rate of from about 50 to about 30,000 sec -1 and a throughput of no more than about 6.4 kg/cm/hour of a mixture of an additive and a second thermoplastic polymer, which additive imparts alcohol repellency to the surfaces of said microfibers as a consequence of the preferential migration of said additive to the surfaces of said microfibers as they are formed, said preferential migration taking place spontaneously upon the formation of said microfibers without the need for a post-formation treatment of any kind; (2) the additive is present in said second nonwoven web in an amount which is sufficient to both impart alcohol repellency to the microfibers thereof and to substantially prevent entry into said second nonwoven web of topically applied treatment liquid; and (3) said second thermoplastic polymer is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides.

Claim 20

A method of preparing a nonwoven composite structure having three melt-extruded nonwoven layers adjacent to each other in which each melt-extruded nonwoven layer comprises at least a portion of a nonwoven web and the boundary between at least two adjacent melt-extruded nonwoven layers is indistinct in that fibers or filaments at or near the surfaces of such adjacent layers are significantly intermingled, which method comprises the steps of: (A) forming a first nonwoven web by melt extruding continuous filaments which are randomly deposited on a moving foraminous support, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (B) placing a preformed second nonwoven web directly onto at least a portion of said first nonwoven web, said second nonwoven web having been formed by melt extruding substantially continuous microfibers which are randomly deposited, said substantially continuous microfibers having an average diameter of from about 0.1 to about 10 micrometers; (C) forming a third nonwoven web by melt extruding continuous filaments which are randomly deposited directly onto at least a portion of said second nonwoven web, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (D) pattern bonding the resulting structure by the application of heat and pressure; and (E) treating at least one of said first and third nonwoven webs of the resulting pattern bonded structure by topical application of at least one agent in an amount which is sufficient to impart to the filaments of said web at least one characteristic which is different from the surface characteristics of filaments in a web not so treated, said topical treatment being carried out in a manner such that each topically applied agent is substantially restricted to the web to which it was applied; in which: (1) the microfibers of said second nonwoven web are prepared by melt extrusion through a die at a shear rate of from about 50 to about 30,000 sec -1 and a throughput of no more than about 6.4 kg/cm/hour of a mixture of an additive and a second thermoplastic polymer, which additive imparts alcohol repellency to the surfaces of said microfibers as a consequence of the preferential migration of said additive to the surfaces of said microfibers as they are formed, said preferential migration taking place spontaneously upon the formation of said microfibers without the need for a post-formation treatment of any kind; (2) the additive is present in said second nonwoven web in an amount which is sufficient to both impart alcohol repellency to the microfibers thereof and to substantially prevent entry into said second nonwoven web of topically applied treatment liquid; and (3) said second thermoplastic polymer is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides.

Claim 21

A method of preparing a nonwoven composite structure having three melt-extruded nonwoven layers adjacent to each other in which each melt-extruded nonwoven layer comprises at least a portion of a nonwoven web and the boundary between at least two adjacent melt-extruded nonwoven layers is indistinct in that fibers or filaments at or near the surfaces of such adjacent layers are significantly intermingled, which method comprises the steps of: (A) forming a first nonwoven web by melt extruding continuous filaments which are randomly deposited on a moving foraminous support, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (B) placing a preformed second nonwoven web directly onto at least a portion of said first nonwoven web, said second nonwoven web having been formed by melt extruding substantially continuous microfibers which are randomly deposited, said substantially continuous microfibers having an average diameter of from about 0.1 to about 10 micrometers; (C) forming a third nonwoven web by melt extruding continuous filaments which are randomly deposited directly onto at least a portion of said second nonwoven web, said continuous filaments having an average filament diameter in excess of about 7 micrometers and being prepared from a first thermoplastic polymer which is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides; (D) pattern bonding the resulting structure by the application of heat and pressure; and (E) treating at least one of said first and third nonwoven webs of the resulting pattern bonded structure by topical application of at least one agent in an amount which is sufficient to impart to the filaments of said web at least one characteristic which is different from the surface characteristics of filaments in a web not so treated, said topical treatment being carried out in a manner such that each topically applied agent is substantially restricted to the web to which it was applied; in which: (1) the microfibers of said second nonwoven web are prepared by melt extrusion through a die at a shear rate of from about 50 to about 30,000 sec -1 and a throughput of no more than about 6.4 kg/cm/hour of a mixture of an additive and a second thermoplastic polymer, which additive imparts alcohol repellency to the surfaces of said microfibers as a consequence of the preferential migration of said additive to the surfaces of said microfibers as they are formed, said preferential migration taking place spontaneously upon the formation of said microfibers without the need for a post-formation treatment of any kind; (2) the additive is present in said second nonwoven web in an amount which is sufficient to both impart alcohol repellency to the microfibers thereof and to substantially prevent entry into said second nonwoven web of topically applied treatment liquid; and (3) said second thermoplastic polymer is selected from the group consisting of polyolefins, polyesters, polyetheresters, and polyamides.