# US 12,759,261 B2 · Multilayer nonwoven structure

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- Number: US 12,759,261 B2
- Document ID: US12759261B2
- Status: Granted
- Kind: B2
- Application number: 18/292,572
- Filed: 2022-08-02
- Published: 2025-03-13
- Granted: 2026-10-13
- Earliest claimed: 2021-08-04
- Assignees: Borealis AG
- Applicants: Borealis AG
- Inventors: Jingbo Wang; Markus Gahleitner; Klaus Bernreitner; Henk Van Paridon; Gustaf Tobieson; Wilhelmus Henricus Adolf Sars; Anita Luyten; Pascal Wust; Onur Uzun
- Web page: https://patentgrep.com/patent/US12759261B2

## CPC

- B32B 5/269: {characterised by at least one non-woven fabric layer that is a melt-blown fabric next to a non-woven fabric layer that is a spunbonded fabric}
- B01D 39/163: {sintered or bonded}
- B32B 5/022: {Non-woven fabric}
- B32B 7/027: Thermal properties
- C08F 10/06: Propene
- D04H 1/4291: Olefin series
- D04H 1/4374: using different kinds of webs, e.g. by layering webs
- D04H 1/56: in association with fibre formation, e.g. immediately following extrusion of staple fibres
- D04H 3/16: with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
- B01D 2239/0618: Non-woven
- B01D 2239/0622: Melt-blown
- B01D 2239/0627: Spun-bonded
- B01D 2239/065: More than one layer present in the filtering material
- B01D 2239/1291: Other parameters
- B32B 2250/03: 3 layers
- B32B 2250/20: All layers being fibrous or filamentary
- B32B 2250/40: Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
- B32B 2262/0253: Polyolefin fibres
- B32B 2307/30: having particular thermal properties
- B32B 2307/718: Weight, e.g. weight per square meter
- D10B 2321/022: polypropylene
- D10B 2501/04: Outerwear; Protective garments
- D10B 2505/04: Filters
- D10B 2509/026: Absorbent pads; Tampons; Laundry; Towels
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B)
- D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES

## Abstract

A nonwoven fabric (NF) comprising a multilayer structure that comprises: i) at least one meltblown layer (M) comprising melt blown fibers (MBF) comprising a first propylene polymer (PP1) having: a) an amount of 2,1-regiodefects in the range from 0.0 to 0.1 mol-%; and b) a melting temperature Tm in the range from 155 to 170° C., ii) at least one spunbonded layer (S) comprising spunbonded fibers (SBF) comprising a second propylene polymer (PP2) having: a) an amount of 2,1-regiodefects in the range from 0.4 to 1.5 mol-%; and b) a melting temperature Tm in the range from 145 to 160° C. wherein the melting temperature of the first polypropylene polymer Tm (PP1) is at least 5.0° C. higher than that of the second first polypropylene polymer Tm (PP2).

## Claims

### Claim 1

A nonwoven fabric (NF), comprising a multilayer structure that comprises:
i) at least one melt blown layer (M) comprising melt blown fibers (MBF) comprising a first propylene polymer (PP1) having:
a) an amount of 2,1-regiodefects, as determined by 13C-NMR spectroscopic analysis, in the range from 0.0 to 0.1 mol-%; and
b) a melting temperature Tm, determined by differential scanning calorimetry (DSC), in the range from 155 to 170° C., ii) at least one spunbonded layer(S) comprising spunbonded fibers (SBF) comprising a second propylene polymer (PP2) having:
a) an amount of 2,1-regiodefects, as determined by 13C-NMR spectroscopic analysis, in the range from 0.45 to 1.5 mol-%; and
b) a melting temperature Tm, determined by differential scanning calorimetry (DSC), in the range from 145 to 160° C.,
wherein the second propylene polymer (PP2) has been polymerized in the presence of a single site catalyst,
wherein the melting temperature of the first polypropylene polymer Tm (PP1) is at least 5.0° C. higher than that of the second first polypropylene polymer Tm (PP2), and
wherein the nonwoven fabric has a hydrohead of at least 100 mbar.

### Claim 2 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the total grammage of the one or more melt blown layers (M), determined according to ISO 536:1995, is in the range from 0.8 to 30 g/m2, and/or the total grammage of the one or more spunbonded layers(S), determined according to ISO 536:1995, is in the range from 5.0 to 100 g/m2.

### Claim 3 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the first propylene polymer (PP1) and/or the second propylene polymer (PP2) are propylene homopolymers or propylene ethylene copolymers wherein the ethylene content, as determined by 1H-NMR spectroscopic analysis, is less than 0.5 mol-%.

### Claim 4 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the first propylene polymer (PP1) has at least one of the following properties:
a) a melt flow rate (MFR2), measured according to ISO 1133 at 230° C. and 2.16 kg in the range from 450 to 200 g/10 min; and
b) a molecular weight distribution (Mw/Mn), determined by Gel Permeation Chromatography, in the range from 2.5 to 5.0.

### Claim 5 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the second propylene polymer (PP2) has at least one of the following properties:
a) a melt flow rate (MFR2), measured according to ISO 1133 at 230° C. and 2.16 kg in the range from 5.0 to 50 g/10 min; and
b) a molecular weight distribution (Mw/Mn), determined by Gel Permeation Chromatography, in the range from 2.0 to 4.5.

### Claim 6 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the second propylene polymer (PP2) has a xylene cold soluble content (XCS) determined according to ISO 16152, in the range from 0.1 to 2.0 wt.-%.

### Claim 7 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the first propylene polymer (PP1) has been visbroken.

### Claim 8 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the second propylene polymer (PP2) has been visbroken.

### Claim 9 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the first propylene polymer (PP1) has been polymerized in the presence of:
a) a Ziegler-Natta catalyst (ZN-C) comprising compounds (TC) of a transition metal of Group 4 to 6 of IUPAC, a Group 2 metal compound (MC) and an internal donor (ID), wherein said internal donor (ID) is a non-phthalic compound
b) optionally a co-catalyst (Co), and
c) optionally an external donor (ED).

### Claim 10 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the multilayer structure comprises the following layers in the given order:
at least one spunbonded layer(S) comprising spunbonded fibers(S);
at least one melt blown layer (M) comprising melt blown fibers (M); and
at least one spunbonded layer(S) comprising spunbonded fibers(S),
wherein each instance of the spunbonded layer(S) may be the same or different and each instance of the melt blown layer (M) may be the same or different.

### Claim 11 (depends on 10)

A process for producing the nonwoven fabric (NF) according to claim 10, comprising:
a) producing the first spunbonded layer (S1) by depositing spunbonded fibers (SBF) through a spinneret,
b) optionally producing at least one further spunbonded layer(S) by depositing spunbonded fibers (SBF) on the first spunbonded layer (S1) obtained in step a) through at least one further spinneret, thereby obtaining a multilayered structure comprising two or more spunbonded layers(S) in sequence,
c) producing the first melt blown layer (M1) by depositing melt blown fibers (MBF) on the first spunbonded layer (S1) obtained in step a) or on the outermost spunbonded layer(S) obtained in step b) through an extruder, thereby obtaining a multilayered structure comprising one or more spunbonded layer(s) (S) and a melt blown layer (M) in sequence,
d) optionally producing at least one further melt blown layer (M) by depositing melt blown fibers (MBF) on the first melt blown layer (M1) obtained in step c) through at least one further extruder, thereby obtaining a multilayered structure comprising one or more spunbonded layer(s) (S) and two or more melt blown layer(s) (M) in sequence,
e) producing the second spunbonded layer (S2) by depositing spunbonded fibers (SBF) through a spinneret on the first melt blown layer (M1) obtained in step c) or on the outermost melt blown layer (M) obtained in step d), thereby obtaining a multilayered structure comprising one or more spunbonded layer(s) (S), one or more melt blown layer(s) (M), and one spunbonded layer(S) in sequence, and
f) optionally producing at least one further spunbonded layer(S) by depositing spunbonded fibers (SBF) on the second spunbonded layer (S2) obtained in step e) through at least one further spinneret, thereby obtaining a multilayered structure comprising one or more spunbonded layer(s) (S), one or more melt blown layer(s) (M), and two or more spunbonded layer(s) (S) in sequence.

### Claim 12 (depends on 1, 11)

The nonwoven fabric according to claim 1, obtainable via the process of claim 11.

### Claim 13 (depends on 1)

An article, comprising the nonwoven fabric (NF) according to claim 1, wherein the article is selected from filtration medium (filter), diaper, sanitary napkin, panty liner, incontinence product for adults, protective clothing, surgical drape, surgical gown, and surgical wear.

### Claim 14 (depends on 7)

The nonwoven fabric according to claim 7, wherein the first propylene polymer (PP1) fulfils either of inequation (I) or inequation (II):
7.
<
(
MFR
⁡
(
final
)
)
/
(
MFR
⁡
(
initial
)
)
<
30.
(
I
)
wherein MFR (final) is the melt flow rate MFR2 (230° C.) determined according to ISO 1133 after visbreaking and MFR (initial) is the melt flow rate MFR2 (230° C.) determined according to ISO 1133 before visbreaking; and
1.3
<
(
MWD
⁡
(
initial
)
)
/
(
MWD
⁡
(
final
)
)
<
2.
(
II
)
wherein MWD (final) is the molecular weight distribution (Mw/Mn), determined by Gel Permeation Chromatography, after visbreaking and MWD (initial) is the molecular weight distribution (Mw/Mn), determined by Gel Permeation Chromatography, before visbreaking.

### Claim 15 (depends on 8)

The nonwoven fabric (NF) according to claim 8, wherein the second propylene polymer (PP2) fulfils either of inequation (III) or inequation (IV):
5.
<
(
MFR
⁡
(
final
)
)
/
(
MFR
⁡
(
initial
)
)
<
20.
(
III
)
wherein MFR (final) is the melt flow rate MFR2 (230° C.) determined according to ISO 1133 after visbreaking and MFR (initial) is the melt flow rate MFR2 (230° C.) determined according to ISO 1133 before visbreaking; and
1.05
<
(
MWD
⁡
(
initial
)
)
/
(
MWD
⁡
(
final
)
)
<
1.5
(
IV
)
wherein MWD (final) is the molecular weight distribution (Mw/Mn), determined by Gel Permeation Chromatography, after visbreaking and MWD (initial) is the molecular weight distribution (Mw/Mn), determined by Gel Permeation Chromatography, before visbreaking.

### Claim 16 (depends on 1)

The nonwoven fabric (NF) according to claim 1, wherein the single site catalyst comprises:
(i) a metallocene complex of the general formula (V)
wherein each X independently is a sigma-donor ligand,
L is a divalent bridge selected from —R′2C—, —R′2C—CR′2—, —R′2Si—, —R′2Si—SiR′2—, —R′2Ge—, wherein each R′ is independently a hydrogen atom or a C1-C20-hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table or fluorine atoms, or optionally two R′ groups taken together can form a ring,
each R1 are independently the same or can be different and are hydrogen, a linear or branched C1-C6-alkyl group, a C7-20-arylalkyl, C7-20-alkylaryl group or C6-20-aryl group or an OY group, wherein Y is a C1-10-hydrocarbyl group, and optionally two adjacent R1 groups can be part of a ring including the phenyl carbons to which they are bonded,
each R2 independently are the same or can be different and are a CH2-R8 group, with R8 being H or linear or branched C1-6-alkyl group, C3-8-cycloalkyl group, C6-10-aryl group,
R3 is a linear or branched C1-C6-alkyl group, C7-20-arylalkyl, C7-20-alkylaryl group or C6-C20-aryl group,
R4 is a C (R9)3 group, with R9 being a linear or branched C1-C6-alkyl group,
R5 is hydrogen or an aliphatic C1-C20-hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table;
R6 is hydrogen or an aliphatic C1-C20-hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 of the periodic table; or
R5 and R6 can be taken together to form a 5 membered saturated carbon ring which is optionally substituted by n groups R10, n being from 0 to 4;
each R10 is same or different and may be a C1-C20-hydrocarbyl group, or a C1-C20-hydrocarbyl group optionally containing one or more heteroatoms belonging to groups 14-16 of the periodic table;
R7 is H or a linear or branched C1-C6-alkyl group or an aryl or heteroaryl group having 6 to 20 carbon atoms optionally substituted by one to three groups R11,
each R11 are independently the same or can be different and are hydrogen, a linear or branched C1-C6-alkyl group, a C7-20-arylalkyl, C7-20-alkylaryl group or C6-20-aryl group or an OY group, wherein Y is a C1-10-hydrocarbyl group,
(ii) a co-catalyst system comprising a boron containing co-catalyst and/or an aluminoxane co-catalyst, and
(iii) a silica support.