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

• US 4,052,524 A
• Filed: 08/15/1975
• Issued: 10/04/1977
• Est. Priority Date: 08/15/1975
• Status: Expired due to Term

• Current Assignee: Solutia Incorporated (Eastman Chemical Company)
• Original Assignee: Monsanto Company (Bayer AG)
• Inventors: Tierney, Paul A., Fulton, Kent H., Bender, Malcolm F., Harakas, Nicholas K.
• Primary Examiner(s): Kendall, Ralph S.
• Application Number:
  US05/605,086
• Time in Patent Office: 781 Days
• Field of Search: 428/391, 428/450, 428/382, 428/383, 428/295, 428/110, 428/112, 428/460, 156/110 R, 156/110 A, 156/110 C, 156/124, 156/329, 427/327, 427/409, 427/387, 427/388 B, 152/356, 152/359
• US Class Current: 428/383
• CPC Class Codes: C08J 2321/00 Characterised by the use of unspecified rubbers
• CPC Class Codes: C08J 5/06 using pretreated fibrous materials
• CPC Class Codes: D07B 1/0666 the wires being characterised by an anti-corrosive or adhesion promoting coating
• CPC Class Codes: D07B 2205/20 Organic high polymers
• CPC Class Codes: D07B 2401/2025 avoiding corrosion
• CPC Class Codes: D07B 2401/2095 Improving filler wetting respectively or filler adhesion
• CPC Class Codes: D07B 2501/2046 Tire cords
• CPC Class Codes: D07B 2501/2076 Power transmissions
• CPC Class Codes: D07B 2801/18 Coating
• CPC Class Codes: Y10S 156/91 Bonding tire cord and elastomer: improved adhesive system
• CPC Class Codes: Y10T 152/10846 Bead characterized by the chemical composition and or physical properties of elastomers or the like
• CPC Class Codes: Y10T 428/249933 Fiber embedded in or on the surface of a natural or synthetic rubber matrix
• CPC Class Codes: Y10T 428/2947 Synthetic resin or polymer in plural coatings, each of different type
• CPC Class Codes: Y10T 428/2962 Silane, silicone or siloxane in coating
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A method is disclosed for improving the hydrolytic stability of the adhesive bond between an RFL type organic adhesive and a steel reinforcing element in steel-rubber composite articles. This is achieved by a pre-treatment of the steel surface before it is coated with the organic adhesive. The pre-treatment includes first immersing the steel element in an aqueous bath containing an acid, or base followed by a water rinse. A primer coating is then applied onto the surface of the steel element which consists of an organo-silane compound of the following formula:

X -- R.sup.1 -- Si -- (OR.sup.2).sub.3

where X is an amino, glycidoxy or an aminoethyl radical; and wherein R¹ is an alkylene radical of from 2 to 4 carbon atoms when X is amino or glycidoxy and --HN--R³ --, where R³ is an alkylene radical of from 2 to 3 carbon atoms when X is aminoethyl; and wherein R² is an alkyl of from 1 to 2 carbon atoms.

Claims

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

a. immersing a steel or alloy steel reinforcing element in an aqueous bath which contains an inorganic acid having a pH in the range of from about 1 to 2.5 at make-up or a strong base having a pH in the range of 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°

C. to 95°

C.;

b. subjecting said element to a water rinse;

c. coating the surface of the steel element with an organosilane compound of the formula

space="preserve" listing-type="equation">X -- R.sup.1 -- Si -- (OR.sup.2).sub.3

where X is an amino, glycidoxy or an aminoethyl radical; and

wherein R¹ is an alkylene radical of from 2 to 4 carbon atoms when X is amino or glycidoxy and --HN--R³ --, where R³ is an alkylene radical of from 2 to 3 carbon atoms when X is aminoethyl; and

wherein R² is an alkyl of from 1 to 2 carbon atoms;

d. dipping said element in an RFL organic adhesive; and

e. curing said dipped element.

2. The method of claim 1, wherein said organosilane compound is selected from the group consisting of gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and N-beta-aminoethyl gamma-aminopropyltrimethoxysilane.

3. A steel or alloy steel reinforcing element for rubber products which has been treated in accordance with the method of claim 1.

4. A pneumatic tire containing steel or alloy steel reinforcing elements which have been treated in accordance with the method of claim 1.

5. A steel or alloy steel reinforcing element having a ribbon configuration which has been treated in accordance with the method of claim 1.

6. A pneumatic tire containing steel or alloy steel reinforcing elements having a ribbon configuration which have been treated in accordance with the method of claim 1.

7. 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°

C. to 95°

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°

C. to 95°

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;

space="preserve" listing-type="equation">X -- R.sup.1 -- Si (OR.sup.2).sub.3

where X is an amino, glycidoxy or an aminoethyl radical; and

wherein R¹ is an alkylene radical of from 2 to 4 carbon atoms when X is amino or glycidoxy and --HN--R³ --, where R³ is an alkylene radical of from 2 to 3 carbon atoms when X is aminoethyl; and

wherein R² 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.

8. A steel or alloy steel reinforcing element having a ribbon configuration which has been treated in accordance with the method of claim 7.

9. A pneumatic tire containing steel or alloy steel reinforcing elements having a ribbon configuration which have been treated in accordance with the method of claim 7.