Polypropylene fibers and fabrics

Patent metadata

Field	Value
Publication number	US-10174442-B2
Application number	US-201514843306-A
Country	US
Kind code	B2
Filing date	Sep 2, 2015
Priority date	Dec 3, 2012
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

This invention relates to polypropylene fibers and fabrics containing polypropylene fibers, the fibers comprising propylene polymers comprising at least 50 mol % propylene, said polymers having: a) a melt flow rate (MFR, ASTM 1238, 230° C., 2.16 kg) of about 10 dg/min to about 25 dg/min; b) a dimensionless Stress Ratio/Loss Tangent Index R2 [defined by Eq. (8)] at 190° C. from about 1.5 to about 30; c) an onset temperature of crystallization under flow, Tc,rheol, (as determined by SAOS rheology, 190° C., 1° C./min, where said polymer has 0 wt % nucleating agent present), of at least about 123° C.; d) an average meso run length determined by 13C NMR of at least about 55 or higher; and e) optionally, a loss tangent, tan δ, [defined by Eq. (2)] at an angular frequency of 0.1 rad/s at 190° C. from about 14 to about 70.

First claim

What is claimed is:

1. A nonwoven fabric comprising polypropylene fibers having a denier per filament (dpf) value of 0.3 to 5 dpf, wherein said polypropylene fibers comprise a visbroken propylene polymer composition comprising at least 50 mol % propylene, said polymer composition having:
a) a melt flow rate (MFR, ASTM 1238, 230° C., 2.16 kg) of 10 to 25 dg/min;
b) a dimensionless Stress Ratio/Loss Tangent Index R 2 [defined by Eq. (8) below] at 190° C. from 1.5 to 30;

R
2

=

(

SR
⁡

(

500
⁢

⁢

s

-
1

)

⁢

η
o

tan
⁢

⁢

δ
⁡

(

0.1
⁢

⁢
rad
⁢

/

⁢
s

)

)

/
248

(
8
)

where η o [Eq. (1) below] is in Pa s;

η
o

=

∑

j
=
1

M

⁢

λ
j

⁢

G
j

(
1
)

c) an onset temperature of crystallization under flow, T c,rheol , (as determined by SAOS rheology, 1° C./min, where said polymer has 0 wt % nucleating agent present), of at least 123° C.;
d) an average meso run length determined by 13 C NMR of at least 55 or higher; and
e) a peak melting temperature Tmp of at least 160° C.

2. A nonwoven fabric according to claim 1 , said nonwoven fabric being obtainable by spun-bonding with a production line speed of at least 400 m/min.

3. A nonwoven fabric according to claim 1 , wherein said fabric has a fabric tensile anisotropy as defined herein of less than 3.0 when produced at a production line speed of 900 m/min.

4. A laminate nonwoven fabric comprising a first nonwoven and a second nonwoven, each of said first and second nonwovens being independently selected from spunbonded nonwovens and meltblown nonwovens, wherein at least one of said nonwovens comprises a nonwoven fabric according to claim 1 .

5. A nonwoven fabric according to claim 1 , obtainable by spunbonding with a line speed of at least 600 m/min.

6. A laminate fabric comprising a nonwoven fabric according to claim 1 and at least one or more further fabric layers, said one or more further fabric layers being selected from body fluid impermeable layers and body fluid permeable layers.

7. A nonwoven according to claim 1 , wherein the fibers comprise a yarn comprising a plurality of polypropylene filaments having a dpf value of from 0.3 to 5 dpf.

8. A nonwoven fabric according to claim 1 , having a fabric basis weight in the range of 5 to 70 gsm.

9. A nonwoven fabric according to claim 1 , said nonwoven fabric is obtainable by spunbonding with a production line speed of at least 400 m/min.

10. A nonwoven according to claim 1 , wherein the fibers comprise monofilaments of 0.3 to 5 denier.

11. An article comprising a one or more nonwoven fabrics according to claim 1 .

12. A diaper comprising one or more nonwoven fabrics according to claim 1 .

Assignees

• Exxonmobil Chemical Patents Inc
• Reifenhaeuser Masch

Inventors

• Macdonald Jeanne Marie
• Doufas Antonios K
• Sarrazin Jerome
• Ferry William Michael
• Kulkarni Rahul Ravindra
• Thurman Derek Wade
• Mitchell Cynthia Ann
• Frey Detlef
• Schlag Peter
• Geus Hans-Georg
• Cinquemani Claudio

Classifications

• Y10T428/2904

  Staple length fiber · CPC title

• D01F6/06 Primary

  from polypropylene · CPC title

• C08L23/10

  Homopolymers or copolymers of propene · CPC title

• Y10T442/608

  Including strand or fiber material which is of specific structural definition · CPC title

• C08L2203/12

  used for fibers · CPC title