Spunbonded non-woven fabric and laminate

Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including a foamed layer or component

Reexamination Certificate

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Details

C442S381000, C442S382000, C442S400000, C442S401000, C442S417000, C524S423000, C524S425000, C524S451000, C524S462000, C524S582000, C524S588000

Reexamination Certificate

active

06759357

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a spunbonded non-woven fabric and to a laminate thereof comprising one or more webs of such spunbonded non-woven fabric, wherein the spunbonded non-woven fabric is made of fibers obtained by spinning a polypropylene resin composition comprising a polypropylene resin and a lubricant, which lubricant comprises a vinylidene fluoride/hexafluoropropylene copolymer and one or more inorganic compounds.
BACKGROUND OF THE INVENTION
While there have been used as the polypropylene resin for the raw material for non-woven fabric those which are produced using a Ziegler catalyst or a solid titanium catalyst, the polypropylene resins produced using such a catalyst, which have wider molecular weight distribution, are apt to suffer from fluctuation in the flow rate of the molten resin upon extrusion from a spinning nozzle into filament and are inferior in the spinning performance. They have also a narrow permissible range of temperature for spinning.
On the other hand, polypropylene resins having narrower molecular weight distribution produced using a single-site catalyst, such as metallocene catalyst or so on, are subject to occurrence of surface roughness and are difficult to process into a formed product exhibiting better appearance, though they are superior in the spinning performance together with permission of attaining finer filament, as compared with the polypropylene resins having wider molecular weight distribution obtained using Ziegler catalyst. For example, when an extrusion spinning is carried out to spin into a filament using a polypropylene resin which has higher melt flow rate and which is generally recognized to have a better moldability, the resulting spun filament may often suffer from occurrence of rough surface of the filament due to occurrence of melt-fracture, causing thus an inferior appearance. When extrusion-molded into film or sheet, inferior appearances, such as rough surfaces, irregular thickness and white clouding, may often be brought about.
It has heretofore been known, that extrusion-molded articles exhibiting better appearances are produced by incorporating a lubricant in a polypropylene resin to improve its moldability. There has, however, not been known, that the appearance of a polypropylene resin produced by polymerization using a single-site catalyst is considerably improved by incorporating therein a lubricant component comprising a vinylidene fluoride/hexafluoropropylene copolymer and one or more inorganic compounds.
Also, it has not been known, that non-woven fabric made of more finer long filaments can be produced efficiently by incorporating therein a lubricant comprising a vinylidene fluoride/hexafluoropropylene and an inorganic compound and that fibers exhibiting scarce adherent finger touch are obtained thereby.
The object of the present invention is to provide a spunbonded non-woven fabric and a laminated product thereof, wherein the fabric is made of fibers produced from a polypropylene resin composition used as the raw material and exhibits better appearance with scarce occurrence of surface roughness together with scarce adherent finger touch and with superior hand feel due to permission of realizing more finer filament thickness and wherein the fibers can be produced efficiently without suffering from breaking of spun filaments.
DISCLOSURE OF THE INVENTION
The present invention consists in the following spunbonded non-woven fabric and laminate thereof:
(1) A spunbonded non-woven fabric made of fibers which comprise a polypropylene resin and have fiber finenesses in the range from 0.8 to 2.8 denier, wherein the said fabric has an average friction factor (MIU) of 0.1 to 0.3, a thickness uniformity of not higher than 0.8, a waterproof performance of at least 60 mm H
2
O and a gas permeability of not higher than 480 ml/cm
2
/sec.
(2) A spunbonded non-woven fabric made of fibers obtained by spinning a polypropylene resin composition comprising
99.995-99.7% by weight of a polypropylene resin having a molecular weight distribution (Mw/Mn) of 1 to 3.5, determined by a gel permeation chromatography (GPC), and a melt flow rate of 0.01 to 300 g/10 min., determined according to ASTM D 1238 at 230° C. under a load of 2.16 kg, and
0.005-0.3% by weight of a lubricant comprising 70 to 100% by weight of a vinylidene fluoride/hexafluoropropylene copolymer and 0 to 30% by weight of one or more inorganic compounds.
(3) A spunbonded non-woven fabric as defined in the above (1) or (2), wherein the polypropylene resin is that produced by a polymerization process using a single-site catalsyt.
(4) A spunbonded non-woven fabric made of fibers obtained by spinning a polypropylene resin composition comprising
99.995-99.7% by weight of a polypropylene resin having a molecular weight distribution (Mw/Mn) of 1 to 3.5, determined by a gel permeation chromatography (GPC), and a melt flow rate of 0.01 to 300 g/10 min., determined according to ASTM D 1238 at 230° C. under a load of 2.16 kg, and
0.005-0.3% by weight of a lubricant comprising 70 to 100% by weight of a vinylidene fluoride/hexafluoropropylene copolymer and 0 to 30% by weight of one or more inorganic compounds, the said inorganic compounds being selected from the group consisting of talc, calcium carbonate, silicon oxide and barium sulfate.
(5) A spunbonded non-woven fabric made of fibers obtained by spinning a polypropylene resin composition comprising
99.995-99.7% by weight of a polypropylene resin having a molecular weight distribution (Mw/Mn) of 1 to 3.5, determined by a gel permeation chromatography (GPC), and a melt flow rate of 0.01 to 300 g/10 min., determined according to ASTM D 1238 at 230° C. under a load of 2.16 kg, and
0.005-0.3% by weight of a lubricant comprising 70 to 100% by weight of a vinylidene fluoride/hexafluoropropylene copolymer and 0 to 20% by weight of talc, 0 to 10% by weight of calcium carbonate and 0 to 10% by weight of silicon oxide.
(6) A spunbonded non-woven fabric made of fibers obtained by spinning a polypropylene resin composition comprising
99.995-99.7% by weight of a polypropylene resin having a molecular weight distribution (Mw/Mn) of 1 to 3.5, determined by a gel permeation chromatography (GPC), and a melt flow rate of 0.01 to 300 g/10 min., determined according to ASTM D 1238 at 230° C. under a load of 2.16 kg, and
0.005-0.3% by weight of a lubricant comprising 89 to 91% by weight of a vinylidene fluoride/hexafluoropropylene copolymer, 5 to 7% by weight of talc, 1.5 to 2.5% by weight of calcium carbonate and 1.5 to 2.5% by weight of silicon oxide.
(7) A non-woven fabric laminate comprising one or more webs of a spunbonded non-woven fabric as claimed in any one of claims 1 to 6 and one or more webs of one or more melt-blown non-woven fabrics.
(8) The non-woven fabric laminate as defined in the above (7), wherein it has a three-layered structure of spunbonded non-woven fabric/melt-blown non-woven fabric/spunbonded non-woven fabric.
THE BEST MODE FOR EMBODYING THE INVENTION
The spunbonded non-woven fabric according to the present invention is one which is made of fibers having a content of polypropylene resin as a main component and fiber finenesses in the range from 0.8 to 2.8 denier, preferably from 0.8 to 2.5 denier, wherein the said fabric has an average friction factor (MIU) in the range from 0.1 to 0.3, preferably from 0.1 to 0.29, a thickness uniformity not higher than 0.8, preferably not higher than 0.75, a waterproof performance of at least 60 mm H
2
O, preferably at least 63 mm H
2
O, and a gas permeability of not higher than 480 ml/cm
2
/sec, preferably not higher than 460 ml/cm
2
/sec.
The spunbonded non-woven fabric according to the present invention, which has the material properties given above, may preferably be made of a raw material consisting of a polypropylene resin composition as will be detailed in the following, though it may not be restricted to such polypropylene resin composition so long as the material properties are in the range defined above.
The fiber fineness value mentioned above is that d

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