Base fabric for air bags and method for the preparation thereof

An air bag for an automobile which is a foldable and inflatable bag formed by sewing together pieces of a base fabric which comprises:

• (A) a woven fabric web of a synthetic fiber;
• and
• (B) a coating layer formed on at least one surface of the woven fabric web as the component (A) which is a layer cured from an organopolysiloxane composition in the form of an aqueous emulsion comprising:
• (a) 100 parts by weight of an organopolysiloxane, as an anionic emulsion polymerization product, represented by the general formula
• X--›--SiR.sup.1.sub.2 --O--!.sub.m --›SiZ.sub.2 --O--!.sub.n --SiR.sup.1.sub.2 --X,
• in which R.sup.1 is, independently from the others, a monovalent hydrocarbon group having 1 to 20 carbon atoms optionally substituted by halogen atoms or epoxy, carboxyl, amino or methacryl groups, each Z is, independently from the other, R.sup.1, OR.sup.2 or --(--O--SiR.sup.1.sub.2).sub.k -- OR.sup.2, R.sup.2 being a hydrogen atom or R.sup.1 and the subscript k being a positive integer not exceeding 1,000, each X is, independently from the other, R.sup.1 or OR.sup.2, the subscript m is a positive integer of 100 to 10,000 and the subscript n is 0 or a positive integer not exceeding 1,000 and which contains at least two groups denoted by OR.sup.2 in a molecule;
• (b) from 0.5 to 50 parts by weight of an organohydrogen polysiloxane, as an aqueous emulsion product, having, in a molecule, at least three hydrogen atoms directly bonded to the silicon atoms,
• (c) from 0.5 to 100 parts by weight of a finely divided silica filler, as a colloidal silica aqueous dispersion;
• (d) from 0.1 to 20 parts by weight of an alkoxy silane compound having, in a molecule, at least one amido group and at least one carboxyl group or a partial hydrolysis-condensation product thereof;
• (e) from 0.1 to 20 parts by weight of an alkoxy silane compound having, in a molecule, at least one epoxy group or at least one amino group or a partial hydrolysis-condensation product thereof;
• (f) from 0.01 to 10 parts by weight of a curing catalyst for the composition, which is a metal salt of an organic acid or an amine compound;
• and
• (g) a water-soluble polymer thickening agent;
• the aqueous emulsion having a viscosity in the range from 2,000 to 100,000 centipoise at 25.degree. C. and the amount of the coating layer being in the range from 10 to 100 g/m.sup.2 as dried.