Method for producing spunbonded materials with improved tensile strength
AssigneeMontell North America Inc.
InventorHee Ju Yoo
Life of this patent
Estimating the term…
Abstract
A spunbonded material having improved tensile strength is made by (1) continuously extruding a propylene homopolymer or random propylene/ethylene copolymer having a melt flow rate of about 3 to about 30 g/10 min at a temperature above 500.degree. F. through a spinneret to form discrete filaments, (2) drawing the filaments to molecularly orient the polymer filaments, and (3) depositing the filaments in a substantially random manner onto a carrier belt to form a web. The propylene polymer contains an additives package that includes an organic phosphite, a hindered phenol compound, calcium stearate, and, optionally, a hydrotalcite compound.
Claims3
A process for making a spunbonded material comprising:
- (a) Adding to a propylene polymer material selected from the group consisting of (i) a propylene homopolymer and (ii) a random copolymer of propylene and ethylene having an ethylene content of less than 10% by weight, having a melt flow rate of about 3 to about 30 g/10 min, additives consisting essentially of:
- (i) about 250 parts to about 2500 parts of a pentaerythritol diphosphite,
- (ii) about 250 parts to about 2500 parts of a hindered phenol compound,
- (iii) about 100 parts to about 1500 parts of calcium stearate, and, optionally
- (iv) about 5 to about 500 parts of a hydrotalcite compound,
- all parts being per million parts of the propylene polymer material,
- (b) continuously extruding the propylene polymer material through a spinneret at a temperature greater than 500.degree. F. to form discrete filaments,
- (c) drawing the filaments to molecularly orient the polymer filaments, and
- (d) depositing the filaments in a substantially random manner onto a carrier belt to form a web.
Dependencies are inferred from the claim text.