Melt-blown nonwoven fabric, and production process and apparatus for the same
It is an object of the present invention to provide a stable production process for a melt-blown nonwoven fabric comprising thin fibers and having extremely few thick fibers [number of fusion-bonded fibers] formed by fusion bonding of thermoplastic resin fibers to one another, and an apparatus for the same. The present invention relates to a melt-blown nonwoven fabric comprising polyolefin fibers and having (i) a mean fiber diameter of not more than 2.0 μm, (ii) a fiber diameter distribution CV value of not more than 60%, and (iii) 15 or less fusion-bonded fibers based on 100 fibers; a production process for a melt-blown nonwoven fabric characterized by feeding cooling air of not higher than 30° C. from both side surfaces of outlets of slits 31 from which high-temperature high-velocity air is gushed out and thereby cooling the spun molten resin; and a production apparatus for the same.
1. A melt-blown nonwoven fabric comprising polyolefin fibers and having:
(i) a mean fiber diameter of not more than 2.0 μm,
(ii) a fiber diameter distribution CV value of not more than 60%, and
(iii) 15 or less fusion-bonded fibers based on 100 fibers.
2. A melt-blown nonwoven fabric comprising propylene-based polymer fibers and having:
(i) a mean fiber diameter of not more than 2.0 μm,
(ii) a fiber diameter distribution CV value of not more than 60%, and
(iv) an α crystal fraction of less than 0.9.
3. A filter containing a layer composed of the melt-blown nonwoven fabric as claimed in claim 1 and having a 0.5 mm diameter fine particle collection efficiency of not less than 90% in the case of a basis weight of 90 g/cm 2 .
4. A nonwoven fabric laminate structure having the melt-blown nonwoven fabric as claimed in claim 1 on at least one surface of which a spun bonded nonwoven fabric is laminated, wherein a ratio of a basis weight (g/m 2 ) of the melt-blown nonwoven fabric layer to a basis weight (g/m 2 ) of the whole laminate is not more than 0.05.
5. Sanitary goods comprising the nonwoven fabric laminate structure as claimed in claim 4 .
6. A battery separator containing a layer composed of the melt-blown nonwoven fabric as claimed in claim 1 .
7. A filter containing a layer composed of the melt-blown nonwoven fabric as claimed in claim 2 and having a 0.5 mm diameter fine particle collection efficiency of not less than 90% in the case of a basis weight of 90 g/cm 2 .
8. A nonwoven fabric laminate structure having the melt-blown nonwoven fabric as claimed in claim 2 on at least one surface of which a spun bonded nonwoven fabric is laminated, wherein a ratio of a basis weight (g/m 2 ) of the melt-blown nonwoven fabric layer to a basis weight (g/m 2 ) of the whole laminate is not more than 0.05.
9. Sanitary goods comprising the nonwoven fabric laminate structure as claimed in claim 8 .
10. A battery separator containing a layer composed of the melt-blown nonwoven fabric as claimed in claim 2 .