Polyester sewing thread for airbag and preparation method thereof

Patent metadata

Field	Value
Publication number	US-9896787-B2
Application number	US-201314648552-A
Country	US
Kind code	B2
Filing date	Nov 29, 2013
Priority date	Nov 30, 2012
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

A polyester sewing thread usable for a fabric for an airbag and a cushion for an airbag is provided. The polyester sewing thread is obtained by doubling and twisting a specific polyester yarn including a plurality of polyester filaments, and bonding the polyester yarn in the manner of in-bonding, out-bonding, or in-and-out bonding. A method for producing the thread is also disclosed.

First claim

What is claimed is:

1. A polyester sewing thread for an airbag, wherein the sewing thread is a bond thread containing a ply of at least three twisted polyester yarns,
wherein the respective individual twisted polyester yarn includes a plurality of polyester filaments and has tensile strength of 7.8 g/d or more, elongation at break of 13% to 27%, dry heat shrinkage of 7% or less, boiling water shrinkage of 5% or less, and melted heat capacity of 35 J/g or more,
wherein a toughness index Y of the polyester sewing thread according to Calculation Formula 1 below is 1.0 to 4.0:
Y =( S×E )/ D   Calculation Formula 1

in Calculation Formula 1, S represents tensile tenacity N of the polyester sewing thread, E represents tensile elongation (%) of the polyester sewing thread, and D represents a total fineness (denier) of the polyester sewing thread,
wherein the dry heat shrinkage is a value obtained by measurement under condition in which a fixed load of 0.01 g/d is applied at 177° C. for 2 minutes; the boiling water shrinkage is a value obtained by performing heat treatment in boiling water at 95° C. for 30 minutes, applying a fixed load of 0.1 g/d, and measuring a yarn length change between pre-treatment and post-treatment; and the melted heat capacity is a value of melted heat capacity generated by raising the temperature of a 10 mg sample from 30° C. up to 280° C. at a heating rate of 10° C./min under a nitrogen atmosphere by using DSC equipment, and
wherein the bond thread is obtained by
providing at least three twisted polyester yarns, wherein the respective individual twisted polyester yarn includes a plurality of polyester filaments,
doubling and twisting the at least three twisted polyester yarns to give a ply of the at least three twisted polyester yarns; and
subjecting the ply to a bonding using an in-bonding, an out-bonding, or an in-and-out-bonding to give the bond thread, wherein the in-bonding is carried out by placing a bonding polymer yarn having a melting point of 160° C. to 210° C. as an internal seam of the ply of the twisted polyester yarns, followed by applying heat; the out-bonding is carried out by coating an outer side of a ply of the twisted polyester yarns with a polymer resin having a melting point of 160° C. to 210° C.; and wherein the in-and-out-bonding is carried out by performing both of the in-bonding and the out-bonding.

2. The polyester sewing thread for an airbag of claim 1 , wherein the polyester sewing thread has total fineness of 200 to 2,400 denier.

3. The polyester sewing thread for an airbag of claim 1 , wherein the polyester yarn has a denier per filament of 2.0 to 8.0 DPF, and includes 20 to 180 filaments.

4. The polyester sewing thread for an airbag of claim 1 , wherein the polyester yarn has a number average molecular weight of 100,000 to 250,000.

5. The polyester sewing thread for an airbag of claim 1 , wherein the polyester yarn has an intrinsic viscosity of 0.8 dl/g or more.

6. The polyester sewing thread for an airbag of claim 1 , wherein the polyester yarn has crystallinity of 40% to 60%.

7. The polyester sewing thread for an airbag of claim 1 , wherein the polyester yarn has an initial modulus of 40 to 120 g/d.

8. A preparation method of a polyester sewing thread for an airbag according to claim 1 , the preparation method comprising:
providing at least three twisted polyester yarns, wherein the respective individual twisted polyester yarn includes a plurality of polyester filaments,
doubling and twisting the at least three twisted polyester yarns to give a ply of the at least three twisted polyester yarns; and
subjecting the ply to a bonding using an in-bonding, an out-bonding, or an in-and-out-bonding to give a bond thread,
wherein the in-bonding is carried out by placing a bonding polymer yarn having a melting point of 160° C. to 210° C. as an internal seam of the ply of the twisted polyester yarns, followed by applying heat; the out-bonding is carried out by coating an outer side of a ply of the twisted polyester yarns with a polymer resin having a melting point of 160° C. to 210° C.; and wherein the in-and-out-bonding is carried out by performing both of the in-bonding and the out-bonding,
wherein the bonding polymer yarn has total fineness of 30 to 60 denier,
wherein the polyester yarn has tensile strength of 7.8 g/d or more, elongation at break of 13% to 27%, dry heat shrinkage of 7% or less, boiling water shrinkage of 5% or less, and melted heat capacity of 35 J/g or more, and
wherein the dry heat shrinkage is a value obtained by measurement under condition in which a fixed load of 0.01 g/d is applied at 177° C. for 2 minutes; the boiling water shrinkage is a value obtained by performing heat treatment in boiling water at 95° C. for 30 minutes, applying a fixed load of 0.1 g/d, and measuring a yarn length change between pre-treatment and post-treatment; and the melted heat capacity is a value of melted heat capacity generated by raising the temperature of a 10 mg sample from 30° C. up to 280° C. at a heating rate of 10° C./min under a nitrogen atmosphere by using DSC equipment.

9. The preparation method of claim 8 , wherein a twisting degree of the ply of the at least three twisted polyester yarns is 200 to 700 TPM.

10. The preparation method of claim 8 , wherein the in-and-out-bonding is performed by
doubling and twisting the at least three twisted polyester yarns with a bonding polymer yarn, as an internal seam, said bonding polymer yarn having a melting point of 160° C. to 210° C.;
coating an outer surface of thus obtained doubled and twisted polyester yarns with a polymer resin having a melting point of 160° C. to 210° C.; and
applying heating to the polyester yarns to obtain a bond thread.

Assignees

• Kolon Inc

Inventors

• Kim Jae Hyung
• Kim Hyung Keun
• Lee Sang Mok
• Kwak Dong Jin

Classifications

• D02G3/402

  the adhesive being one component of the yarn, i.e. thermoplastic yarn · CPC title

• D02G3/36

  Cored or coated yarns or threads ({D02G3/34, D02G3/40 take precedence}; elastic yarns or threads D02G3/32) · CPC title

• D10B2331/04

  polyesters, e.g. polyethylene terephthalate [PET] · CPC title

• D10B2505/124

  Air bags · CPC title

• B60R21/235 Primary

  characterised by their material · CPC title