Laminated fabric for airbag
View Patent ↗A laminated fabric of an elastomeric copolyetherester-based film laminated to a manmade fiber substrate fabric and having a stiffness of from about 5 to 80 Newtons measured according to test method ASTM D4032-94 is described which demonstrates a desirable combination of stiffness and foldability, non-blocking (non self-sticking), air impermeability and resistance to heat aging.
1. An air bag comprised of a laminated fabric, said laminated fabric comprising an elastomeric film which has been prepared by a casting or extrusion process and which is laminated to manmade fiber substrate fabric,
wherein the elastomeric film is comprised of at least 70% by weight of a copolyetherester (A) having a multiplicity of recurring long-chain ester units and short-chain ester units joined head-to-tail through ester linkages, said long-chain ester units being represented by the formula:
and said short-chain ester units being represented by the formula:
wherein:
a) G is a divalent radical remaining after the removal of terminal hydroxyl groups from a poly(alkylene oxide)glycol having a number average molecular weight of about 400-4000;
b) R is a divalent radical remaining after removal of carboxyl groups from a dicarboxylic acid having a molecular weight less than 300;
c) D is a divalent radical remaining after removal of hydroxyl groups from a diol having a molecular weight less than about 250;
wherein the copolyetherester contains about 25-80 weight percent short-chain ester units, and
wherein the laminated fabric has a stiffness of from about 5 to 80 Newtons measured according to test method ASTM D4032-94.
2. The air bag of claim 1 , wherein the elastomeric film is comprised of at least 90% by weight of the copolyetherester (A).
3. The air bag of claim 1 wherein the laminated fabric does not block.
4. The air bag of claim 1 wherein the laminated fabric has an air permeability of less than 1 liter per square decimeter per minute under a test pressure differential of 500 pascal.
5. The air bag of claim 1 wherein the elastomeric film has been extruded directly onto the manmade fiber substrate fabric.
6. The air bag of claim 1 , wherein the elastomeric film contains about 0.2-20 weight percent of an ethylene-based copolymer additive.
7. The air bag of claim 6 , wherein the elastomeric film contains about 4-12 weight percent of an ethylene-based copolymer additive.
8. The air bag of claim 6 wherein said ethylene-based copolymer additive comprises at least 60 weight percent of ethylene monomer, and about 5 to about 15 weight percent of an alpha,beta-unsaturated C3-C8 carboxylic acid monomer, where about 10 to 99.5% of the carboxylic acid groups in the copolymer are neutralized with metal ions selected from the group of sodium, potassium, zinc, calcium, magnesium, lithium, aluminum, nickel, and chromium.
9. The air bag of claim 8 wherein about 10 to 99.5% of the carboxylic acid groups in the copolymer are neutralized with metal ions selected from the group of sodium, potassium, and lithium.
10. The air bag of claim 8 wherein the ethylene-based copolymer additive includes one or more softening comonomers copolymerizable with the ethylene comonomer, said softening comonomer being present in an amount of less than 25 weight percent relative to the weight of the ethylene-based copolymer.
11. The air bag of claim 1 wherein the manmade fiber substrate fabric is comprised of at least 85% by weight of nylon polymer.
12. The air bag of claim 11 wherein the substrate fabric comprises polyamide yarn with a decitex range from 110 to 940.
13. The air bag of claim 1 further comprising an adhesive for laminating the elastomeric film to the fabric.
14. The air bag of claim 13 wherein the adhesive is from the group of polyurethane, polyetherurethane, ethylene copolymers, and silicones.