Method for producing polypropylene nonwoven fabric

1. A method for producing a polypropylene nonwoven fabric comprising the steps of:

step 1: spinning a metallocene polypropylene resin to produce filaments;

step 2: cooling the spun filaments at a temperature of 10 to 20° C.; and

step 3: bonding the cooled filaments together at 150 to 165° C. to form a nonwoven fabric,

wherein the metallocene polypropylene resin has:

a weight average molecular weight of 100,000 to 150,000,

a molecular weight distribution (PDI) of 2.0 to 2.5,

a melt index (MI) of 20 to 28 g/10 min measured at 230° C. under a load of 2.16 kg according to ASTM D1238,

a melting point of 150 to 155° C., and

a xylene soluble (XS) content of 2% by weight or less.

2. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein the metallocene polypropylene resin has a weight average molecular weight of 100,000 to 110,000.

3. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein the metallocene polypropylene resin has a PDI of 2.3 to 2.4.

4. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein the metallocene polypropylene resin has a MI of 22 to 28 g/10 min.

5. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein the metallocene polypropylene resin has a xylene soluble (XS) content of 1.5% by weight or less.

6. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein the metallocene polypropylene resin is prepared by using a compound represented by the following Chemical formula 1 as a catalyst:

in Chemical formula 1,

R 1 and R 2 are each independently phenyl, or phenyl substituted with C 1-20 alkyl;

R 3 and R 4 are each independently C 1-20 alkyl;

A is carbon, silicon, or germanium;

M is zirconium, or hafnium, and

X is halogen, or C 1-20 alkyl.

7. The method for producing a polypropylene nonwoven fabric according to claim 6 , wherein the compound represented by the chemical formula 1 is the following compound:

8. The method for producing a polypropylene nonwoven fabric according to claim 7 , wherein the compound represented by the chemical formula 1 is supported on a support.

9. The method for producing a polypropylene nonwoven fabric according to claim 8 , wherein the support is at least one carrier selected from the group consisting of silica, silica-alumina and silica-magnesia.

10. The method for producing a polypropylene nonwoven fabric according to claim 9 , wherein the support contains an oxide, a carbonate, a sulfate, or a nitrate.

11. The method for producing a polypropylene nonwoven fabric according to claim 6 , wherein in Chemical formula 1, R 1 and R 2 are each independently phenyl substituted with tert-butyl, R 3 and R 4 are ethyl, A is silicon, and X is chloro.

12. The method for producing a polypropylene nonwoven fabric according to claim 6 , wherein the catalyst further includes a cocatalyst.

13. The method for producing a polypropylene nonwoven fabric according to claim 12 , wherein the cocatalyst is at least one selected from the group consisting of silica, silica-alumina, and an organic aluminum compound.

14. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein step 2 is performed at a temperature of 12 to 20° C.

15. The method for producing a polypropylene nonwoven fabric according to claim 1 , wherein the polypropylene nonwoven fabric has a water pressure resistance of 150 mmH 2 O or more.