# US 10,870,937 B2 · Melt-blown webs without shots and with improved barrier properties > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,937 B2 - Document ID: US10870937B2 - Status: Granted - Kind: B2 - Application number: 16/451,936 - Filed: 2019-06-25 - Published: 2019-10-24 - Granted: 2020-12-22 - Earliest claimed: 2014-12-15 - Assignees: Borealis AG - Applicants: Borealis AG - Inventors: Joachim Fiebig; Henk Van Paridon; Jingbo Wang; Markus Gahleitner; Wilhelmus Henricus Adolf Sars; Antti Tynys - Web page: https://patentgrep.com/patent/US10870937B2 ## CPC - D04H 1/56: in association with fibre formation, e.g. immediately following extrusion of staple fibres - A41D 13/1209: {Surgeons' gowns or dresses} - A61B 46/40: {Drape material, e.g. laminates; Manufacture thereof} - A61F 13/51: characterised by the outer layers of the pads (A61F13/20 takes precedence) - C08F 8/50: Partial depolymerisation - C08K 5/098: Metal salts of carboxylic acids - C08K 5/103: with polyalcohols - C08K 5/3435: Piperidines - D01F 1/10: Other agents for modifying properties - D01F 6/06: from polypropylene - D04H 1/4291: Olefin series - D04H 1/544: Olefin series - D04H 3/007: Addition polymers - D04H 3/16: with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion - C08F 4/651: Pretreating with non-metals or metal-free compounds - C08F 4/6546: {organo-magnesium compounds} - C08F 2810/10: including a reactive processing step which leads, inter alia, to morphological and/or rheological modifications, e.g. visbreaking - D10B 2321/022: polypropylene - 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) - A41D: OUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS - D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES ## Abstract Melt-blown webs having no shots and improved barrier properties, whereby the melt-blown webs are made out of a so-called “controlled rheology” propylene (CR-PP), which was visbroken without any peroxide. ## Claims ### Claim 1 A method of preparing a melt-blown web which is free of shots, the method comprising blowing a molten polypropylene composition from an extruder die tip onto a conveyer or take-up screen, wherein the polypropylene composition comprises (A) a propylene polymer and (B) optionally a polymeric nucleating agent, wherein the polypropylene composition has (i) a melt flow rate MFR2 (230° C./2.16 kg) measured according to ISO 1133 of 20 to 5000 g/10min and (ii) a melting temperature Tm between ≥130° C. and ≤170° C. and (iii) a molecular weight distribution (MWD)>2 (iv) wherein the propylene polymer 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), b) optionally a co-catalyst (Co), and c) optionally an external donor (ED), and (v) wherein the polypropylene composition has been visbroken without the use of peroxides. ### Claim 2 (depends on 1) The method of preparing a melt-blown web according to claim 1, wherein the propylene polymer is a propylene homopolymer. ### Claim 3 (depends on 1) The method of preparing a melt-blown web according to claim 1, wherein the polypropylene composition has been visbroken by using a hydroxylamine ester, a sulphur compound, or by purely thermal degradation. ### Claim 4 (depends on 3) The method of preparing a melt-blown web according to claim 3, wherein the polypropylene composition has been visbroken by using a hydroxylamine ester. ### Claim 5 (depends on 1) The method of preparing a melt-blown web according to claim 1, wherein the polypropylene composition is free of phthalic compounds as well as their respective decomposition products. ### Claim 6 (depends on 1) The method of preparing a melt-blown web according to claim 1, wherein the melt-blown web is characterized by the following ratios: (a) a molecular weight (Mw) ratio of Mw of the web to Mw of the polypropylene composition Mw(web)/Mw(PP)<1 and (b) a molecular weight distribution (MWD) ratio of MWD of the web to MWD of the polypropylene composition MWD(web)/MWD(PP)<1. ### Claim 7 (depends on 6) The method of preparing a melt-blown web according to claim 6, wherein the melt-blown web is characterized by the following ratios: (a) a molecular weight (Mw) ratio of Mw of the web to Mw of the polypropylene composition Mw(web)/Mw(PP) is ≤0.90, and (b) a molecular weight distribution (MWD) ratio of MWD of the web to MWD of the polypropylene composition MWD(web)/MWD(PP) is ≤0.95. ### Claim 8 (depends on 7) The method of preparing a melt-blown web according to claim 7, wherein the melt-blown web is characterized by the following ratios: (a) a molecular weight (Mw) ratio of Mw of the web to Mw of the polypropylene composition Mw(web)/Mw(PP) is ≤0.85, and (b) a molecular weight distribution (MWD) ratio of MWD of the web to MWD of the polypropylene composition MWD(web)/MWD(PP) is ≤0.90. ### Claim 9 (depends on 7) The method of preparing a melt-blown web according to claim 7, wherein the melt-blown web is characterized by the following ratios: (a) a molecular weight (Mw) ratio of Mw of the web to Mw of the polypropylene composition Mw(web)/Mw(PP) is ≤0.80, and (b) a molecular weight distribution (MWD) ratio of MWD of the web to MWD of the polypropylene composition MWD(web)/MWD(PP) is ≤0.85. ### Claim 10 (depends on 1) The method of preparing a melt-blown web according to claim 1, wherein the internal donor (ID) is selected from the group consisting of optionally substituted malonates, maleates, succinates, glutarates, cyclohexene-1,2-dicarboxylates, benzoates, derivatives thereof and mixtures thereof; and the molar ratio of co-catalyst (Co) to external donor (ED) [Co/ED] is 5 to 45. ### Claim 11 (depends on 1) The method of preparing a melt-blown web according to claim 1, wherein the Ziegler-Natta catalyst (ZN-C) is produced by a process comprising the steps of a) a1) providing a solution of at least a Group 2 metal alkoxy compound (Ax) being the reaction product of a Group 2 metal compound (MC) and a monohydric alcohol (A) comprising in addition to the hydroxyl moiety at least one ether moiety optionally in an organic liquid reaction medium; or a2) a solution of at least a Group 2 metal alkoxy compound (Ax′) being the reaction product of a Group 2 metal compound (MC) and an alcohol mixture of the monohydric alcohol (A) and a monohydric alcohol (B) of formula ROH, optionally in an organic liquid reaction medium; or a3) providing a solution of a mixture of the Group 2 alkoxy compound (Ax) and a Group 2 metal alkoxy compound (Bx) being the reaction product of a Group 2 metal compound (MC) and the monohydric alcohol (B), optionally in an organic liquid reaction medium; or a4) providing a solution of Group 2 alkoxide of formula M(OR1)m(OR2)mX2−n−m or mixture of Group 2 alkoxides M(OR1)n′X2−n′and M(OR2)m′X2−m′, where M is Group 2 metal, X is halogen, R1 and R2 are different alkyl groups of C2 to C16 carbon atoms, and 0≤n<2, 0≤m<2 and n+m+(2−n−m)=2, provided that both n and m≠0, 0