Method for improving adhesive bonding in steel/rubber composites and article

A method for improving the hydrolytic stability of the adhesive bond between an RFL organic adhesive and a steel or alloy steel reinforcing element for rubber products, said method comprising the following steps in sequence:

• a. immersing a steel or alloy steel reinforcing element in an aqueous bath which contains a strong base having a pH ranging from about 9 to 10.5 at make-up for a period of from 3 to 25 seconds with the bath being maintained at a temperature in the range of from 20.degree. C. to 95.degree. C.;
• b. rinsing the steel or steel alloy element with water;
• c. introducing said element into an aqueous bath containing an inorganic acid having a pH ranging from about 1 to 2.5 at make-up for a period of from 3 to 25 seconds with the bath being maintained at a temperature in the range of from 20.degree. C. to 95.degree. C.;
• d. subjecting said element to a second water rinse;
• e. coating the surface of the steel or alloy steel element with an organosilane compound of the formula:
• X -- R.sup.1 -- Si (OR.sup.2).sub.3
• where X is an amino, glycidoxy or an aminoethyl radical;
• and wherein R.sup.1 is an alkylene radical of from 2 to 4 carbon atoms when X is amino or glycidoxy and --HN--R.sup.3 --, where R.sup.3 is an alkylene radical of from 2 to 3 carbon atoms when X is aminoethyl;
• and wherein R.sup.2 is an alkyl of from 1 to 2 carbon atoms;
• f. dipping said element in an RFL organic adhesive;
• and
• g. curing said dipped element.