Coated fabric products

Abstract

An air bag coated with a cured organopolysiloxane composition, characterized in that the air bag is top coated with an antifriction coating comprising at least one solid lubricant dispersed in an organic polymer binder.

Claims

1. An air bag coated with a cured organopolysiloxane composition, wherein the cured organopolysiloxane composition is directly top coated with an antifriction coating comprising a siloxane polyether wetting agent, an epoxysilane adhesion promoter, non-ionic surfactant, aluminum trihydrate, and solid lubricant comprising talc and polytetrafluoroethylene, wherein the solid lubricant is dispersed in an urethane polymer binder, wherein the antifriction coating comprises 5 to 30% of the talc on a dry coat weight basis; 20 to 90% of the solid lubricant, including the talc, on a dry coat weight basis; 3 to 50% of the urethane polymer binder on a dry coat weight basis; and 5 to 55% of the aluminum trihydrate on a dry coat weight basis.

2. An air bag according to claim 1, wherein the coating weight of the antifriction coating is 1 to 15 g/m.sup.2 on a dry coat weight basis.

3. A process for coating an air bag or air bag fabric in which the bag or fabric is coated with an organopolysiloxane composition to form an organopolysiloxane base coat, wherein the organopolysiloxane base coat is directly top coated with an antifriction coating composition comprising an aqueous dispersion of a siloxane polyether wetting agent, an epoxysilane adhesion promoter, non-ionic surfactant, aluminum trihydrate, and solid lubricant comprising talc and polytetrafluoroethylene, wherein the solid lubricant is dispersed in an urethane polymer binder, wherein the antifriction coating comprises 5 to 30% of the talc on a dry coat weight basis; 20 to 90% of the solid lubricant, including the talc, on a dry coat weight basis; 3 to 50% of the urethane polymer binder on a dry coat weight basis; and 5 to 55% of the aluminum trihydrate on a dry coat weight basis.

4. A process according to claim 3, wherein the siloxane polyether wetting agent has 1-3 alkylpoly(ethyleneoxy)siloxane groups (i) and 1 to 4 alkyl-siloxane groups (ii).

5. A process according to claim 3, wherein the aqueous dispersion contains an aminosilane adhesion promoter.

6. A process according to claim 3, wherein the organopolysiloxane composition which is applied to the bag or fabric as base coat comprises an organopolysiloxane having aliphatically unsaturated hydrocarbon or hydrocarbonoxy substituents, an organosilicon crosslinker having at least 3 silicon-bonded hydrogen atoms, a catalyst able to promote the reaction of the aliphatically unsaturated hydrocarbon or hydrocarbonoxy substituents with SiH groups and a reinforcing filler, and is cured before application of the antifriction coating.

7. A process according to claim 3, wherein the organopolysiloxane base coat is cured before application of the antifriction coating composition.

8. A process according to claim 3, wherein the antifriction coating composition is applied to uncured organopolysiloxane base coat and the combination of the organopolysiloxane base coat composition and the antifriction coating composition is heat cured.

9. An antifriction coating composition comprising a siloxane polyether wetting agent, an epoxysilane adhesion promoter, non-ionic surfactant, aluminum trihydrate, and solid lubricant comprising talc and polytetrafluoroethylene, wherein the solid lubricant is dispersed in an urethane polymer binder, wherein the antifriction coating comprises 5 to 30% of the talc on a dry coat weight basis; 20 to 90% of the solid lubricant, including the talc, on a dry coat weight basis; 3 to 50% of the urethane polymer binder on a dry coat weight basis; and 5 to 55% of the aluminum trihydrate on a dry coat weight basis.

10. An antifriction coating according to claim 9, wherein the siloxane polyether is a 1,1,1,3,5,5,5-heptamethyl-3-polyethoxypropyl-trisiloxane.

Description

(1) The invention is illustrated by the following Examples, in which parts and percentages are by weight unless otherwise stated

EXAMPLE 1

(2) 1,1,1,3,5,5,5-heptamethyl-3-polyethoxypropyl-trisiloxane wetting agent and 3-glycidoxypropyltrimethoxysilane adhesion promoter were added to an aqueous aliphatic polyurethane dispersion stabilized by non-ionic surfactant, and mixed with an aqueous dispersion of PTFE powder stabilized by non-ionic surfactant to form an antifriction coating composition comprising 52% water, 38% PTFE, 3.0% urethane polymer, 3.0% wetting agent, 1.0% epoxysilane adhesion promoter and 3.0% (t-Octylphenoxy)polyethoxyethanol non-ionic surfactant.

(3) The above antifriction coating was applied by gravure roller coating to the coated surface of a woven nylon air bag fabric coated with 55 g/m.sup.2 of a cured liquid silicone rubber. The base coating comprised an organopolysiloxane having aliphatically unsaturated hydrocarbon or hydrocarbonoxy substituents, an organosilicon crosslinker having at least 3 silicon-bonded hydrogen atoms, a platinum complex catalyst and a silica reinforcing filler. The antifriction coating was heat cured at 140 C. In different experiments, the antifriction coating was applied at coat weights of 3 g/m.sup.2 and 6 g/m.sup.2.

(4) The coefficient of friction (COF) of the overcoated surfaces was measured according to ASTM D-1894 by the TMI Monitor/Slip and Friction Tester from Testing Machine Inc. of Ronkonkoma, N.Y., using a 200 g sled. The COF of the fabric coated with 3 g/m.sup.2 antifriction coating was 0.9 and the COF of the fabric coated with 6 g/m.sup.2 antifriction coating was 0.8. By comparison, the COF of fabric coated with a cured liquid silicone rubber base coat is in the range 1.2 to 1.9.

(5) The fabric coated with 6 g/m.sup.2 antifriction coating was made up into a curtain air bag. The air bag was tested in a dynamic pressure retention test in which a 10 liter tank is pressurized to 140 kPa and is evacuated within 0.2 seconds into the bag. The pressure in the bag is tracked over a period of 10 seconds after pressure release. The time taken to reach 50 kPa was 6 seconds. By comparison, when an air bag made from the fabric coated with the cured liquid silicone rubber base coat only was tested, the time taken to reach 50 kPa was 3 seconds.

EXAMPLE 2

(6) Example 1 was repeated except that talc of average particle size 4 m sold under the trade name Imifabi HTP3 was mixed into the dispersion of PTFE and polyurethane binder. The formulation of the antifriction coating was 50% water, 32% PTFE, 8.3% talc, 2.7% polyurethane, 3.0% wetting agent, 1.0% adhesion promoter and 3.0% non-ionic surfactant.

(7) The COF of the fabric coated with 3 g/m.sup.2 antifriction coating of Example 2 was 0.5 and the COF of the fabric coated with 6 g/m.sup.2 antifriction coating was 0.3. It can be seen that the use of talc in conjunction with PTFE in the antifriction coating further reduced the COF of the coated air bag surfaces.

EXAMPLE 3

(8) Aliphatic polyurethane and a 2,5-furandione 1-butene copolymer were dispersed in water stabilized by anionic surfactant containing cosolvents. A PTFE dispersion was mixed with the resulting dispersion to form an antifriction coating comprising 45.0% water, 26.0% PTFE, 9.3% polyurethane, 8.3% furandione butene copolymer, 5.0% sodium dodecylbenzene sulfonate anionic surfactant, 3.0% isopropanol, 2.6% N-methylpyrrolidone and 0.87% dipropylene glycol monomethyl ether.

(9) The antifriction coating of Example 3 was applied by gravure roller coating to the coated surface of air bag fabric coated with a cured liquid silicone rubber coating and heat cured as described in Example 1. Reduced friction properties were achieved with greater process stability in the gravure coating process.

EXAMPLE 4

(10) An antifriction coating was prepared by the procedure of Example 2 with addition of aluminum trihydrate with the talc. The resulting coating composition comprised 52 parts water, 38 parts PTFE, 10 parts talc, 20 parts aluminum trihydrate, 3.0 parts urethane polymer, 2.0 parts wetting agent, 1.0 part epoxysilane adhesion promoter and 3.0 parts (t-Octylphenoxy)polyethoxyethanol non-ionic surfactant.

(11) The antifriction coating was applied by gravure roller coating at 8 g/m.sup.2 to the coated surface of a 1.7 m.sup.3 woven nylon air bag fabric coated with 52 g/m.sup.2 of a cured liquid silicone rubber. The base coating comprised an organopolysiloxane having aliphatically unsaturated hydrocarbon or hydrocarbonoxy substituents, an organosilicon crosslinker having at least 3 silicon-bonded hydrogen atoms, a platinum complex catalyst and a silica reinforcing filler. The antifriction coating was heat cured at 140 C. The COF of the fabric coated with 6 g/m.sup.2 antifriction coating was 0.3.

(12) The air bag thus coated was subjected to a pressure retention test in which the air bag was pressurized to 80 kPa. The air valves were closed and the pressure inside the air bag was electronically monitored over 10 seconds. After 10 seconds, the pressure was 58 kPa.

(13) In a comparative experiment, the air bag was coated with 60 g/m.sup.2 of the silicone base coating. After 10 seconds in the pressure retention test the pressure was 48 kPa. The top coat thus improved the pressure retention of the air bag coated with silicone rubber alone, even at the same total coating weight on the air bag.