Meltblown wetlaid method for producing non-woven fabrics from natural cellulose
The present invention provides a meltblown wetlaid method for producing non-woven fabrics from natural cellulose using pulp as raw material and N-methylmorpholine N-oxide (NMMO) as solvent for dissolving into dope. The dope is then extruded out of a spinneret to form filament bundle by meltblown method. Subsequently, by means of ejecting mist aerosol of water, the filament bundle is coagulated with regeneration. Via post treatments of water rinsing, hydro-entangled needle punching, drying, winding-up and the like have been orderly applied, then final product of nonwoven fabrics with continuous filament are produced from natural cellulose.
1. A meltblown wetlaid method for producing non-woven fabrics with continuous filament from natural cellulose, comprising the steps of:
(a) selecting wood pulp as raw material;
(b) mixing the wood pulp of step (a) with N-methylmorpholine N-oxide (NMMO) as a dissolving solvent and 1,3-phenylene-bis 2-oxazoline (BOX) as a stabilizer, blending the mixture, and dissolving the mixture at a temperature of 60 to 80° C.;
(c) heating the mixture of step (b) to a temperature of 80 to 120° C. for 5 to 10 minutes to decrease the water content thereof down to 5 to 13% to form a homogenized mucilaginous dope;
(d) extruding the homogenized mucilaginous dope of step (c) out of a spinneret by the meltblown method to form a filament bundle;
(e) Coagulating the filament bundle with regeneration by ejecting mist aerosol of water; and
(f) rinsing the coaglulated filament bundle of step (e) with water; and
(g) hydro-entangled needle punching, drying, and winding-up the rinsed coaglulated filament bundle of step (f) to produce the nonwoven fabrics with continuous filament.
2. The method of claim 1 , wherein the wood pulp as raw material is wood pulp or paper pulp cellulose of staple or filament and has a cellulose content of over 65% and a degree of polymerization (DP) of from 500 to 1200.
3. The method of claim 1 , wherein the concentration of the dissolving solvent N-methylmorpholine N-oxide (NMMO) in the mixture of step (b) is from 45 to 75%.
4. The method of claim 1 , wherein the dope of step (c) has a cellulose content of from 6 to 15wt%.
5. The method of claim 1 , wherein the dope of step (c) has a viscosity of from 300 to 3000 poise.
6. The method of claim 1 , wherein the dope of step (c) has a light transmittance index of from 1.470 to 1.495.
7. The method of claim 1 , wherein the dope of step (c) has a melting index of from 200 to 1000.
8. The method of claim 1 , wherein the nonwoven fabric of step (g) has a speed of winding-up of from 2 to 200 meters per minute.
9. The method of claim 1 , wherein the nonwoven fabric of step (g) has a basis weight of from 10 to 300 g/m 2 .
10. The method of claim 1 , wherein the nonwoven fabric of step (g) has a tensile strength in mechanical direction (MD) of over 15 kgf and a tensile strength in cross direction (CD) of over 8 kgf.
11. The method of claim 1 , wherein the nonwoven fabric of step (g) has a fiber fineness of from 1 to 15 μm.
12. The method of claim 1 , wherein the nonwoven fabric of step (g) has a degree of air permeability of from 100 to 3500 cm 3 /cm 2 /min.
13. The method of claim 1 , wherein the nonwoven fabric of step (g) has a degree of water absorption of from 300 to 2000%.