Silane compositions and methods for bonding rubber to metals

• US 8,029,906 B2
• Filed: 07/27/2010
• Issued: 10/04/2011
• Est. Priority Date: 10/08/2003
• Status: Expired due to Fees

• Current Assignee: Ecosil Technologies, LLC, University of Cincinnati
• Original Assignee: Ecosil Technologies, LLC, University of Cincinnati
• Inventors: Stacy, Matthew B., Sorenson, Max, van Ooij, William J.
• Primary Examiner(s): Feely; Michael J
• Application Number:
  US12/844,543
• Publication Number:
  US 20100291382A1
• Time in Patent Office: 434 Days
• Field of Search: None
• US Class Current: 428/450
• CPC Class Codes: B60C 2009/0021 Coating rubbers for steel cords
• CPC Class Codes: B60C 9/0007 Reinforcements made of metallic elements, e.g. cords, yarns, filaments or fibres made from metal
• CPC Class Codes: C08G 77/26 nitrogen-containing groups
• CPC Class Codes: C08G 77/28 sulfur-containing groups
• CPC Class Codes: C08L 2666/44 Silicon-containing compounds
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C09D 183/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen, and oxygen
• CPC Class Codes: C09D 183/10 Block or graft copolymers containing polysiloxane sequences obtained by polymerising a compound having a carbon-to-carbon double bond on to a polysiloxane C09D151/08, C09D153/00
• CPC Class Codes: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• CPC Class Codes: C09J 183/08 containing silicon bound to organic groups containing atoms other than carbon, hydrogen, and oxygen
• CPC Class Codes: C09J 183/10 Block or graft copolymers containing polysiloxane sequences obtained by polymerising a compound having a carbon-to-carbon double bond on to a polysiloxane C09J151/08, C09J153/00
• CPC Class Codes: C09J 4/00 Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
• CPC Class Codes: D07B 1/0666 the wires being characterised by an anti-corrosive or adhesion promoting coating
• CPC Class Codes: D07B 2201/2012 comprising polymers
• CPC Class Codes: D07B 2205/3017 Silicon carbides
• 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 2801/18 Coating
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/2924 Composite
• CPC Class Codes: Y10T 428/31663 : As siloxane, silicone or silane

Abstract

Compositions and methods for treating metal substrates and/or bonding metal substrates to polymeric materials, such as rubber, are provided. The compositions include at least one substantially hydrolyzed amino silane and at least one substantially hydrolyzed sulfur-containing silane Optionally, the compositions include a nano-size particulate material. The compositions provide coatings on metal substrates for protecting the metal from corrosion and for adhering rubber-like polymeric compositions to the metal with polymer-to-metal vulcanization conditions less dependent on the coating thickness, and with use of less coating materials.

Claims

1. A method of bonding rubber to a metal substrate, the method comprising:

mixing a bis amino-silane with a first aqueous-based medium containing a nanosize particulate material to substantially hydrolyze the bis amino-silane;

mixing a bis sulfur-containing silane with a second aqueous-based medium containing a nanosize particulate material to substantially hydrolyze the bis sulfur-containing silane;

mixing the substantially hydrolyzed bis amino-silane with the substantially hydrolyzed sulfur-containing silane to form a silane solution comprising the substantially hydrolyzed bis amino-silane, the substantially hydrolyzed bis sulfur-containing silane, and the nanosize particulate materials of the first and second aqueous-based media, wherein the silane solution comprises a ratio of the hydrolyzed bis amino-silane to the hydrolyzed bis sulfur-containing silane of about 1;

1 by volume;

applying the silane solution to at least a portion of a surface of the metal substrate;

drying the silane solution on the metal substrate to form a coating having a thickness in the range from about 0.1 μ

m to about 1 μ

m thereon; and

applying an uncured, sulfur curable rubber onto the surface of the metal substrate having the coating thereon and sulfur curing the rubber to bond the rubber to the coated metal substrate;

wherein the bis amino-silane is a compound of the general formula I;

(R¹O)₃—

Si—

R²—

X—

R²—

Si—

(OR¹)₃ 

 

(formula I)

wherein;

each R¹, independently, is selected from the group consisting of a C₁-C₂₀ alkyl and C₂-C₂₀ acyl;

each R², independently, is selected from the group consisting of a substituted or unsubstituted aliphatic and aromatic group; and

X is selected from —

N(R³)—

, wherein R³ is selected from the group consisting of hydrogen, substituted or unsubstituted, straight, branched or cyclic C₁-C₂₀ alkyl, alkenyl, and alkynyl groups and substituted or unsubstituted C₃-C₂₀ aryl and alkylaryl groups;

wherein the bis sulfur-containing silane is a compound of the general formula II;

2. The method of claim 1 wherein the aqueous-based medium comprises water and alcohol.

3. The method of claim 1 wherein the bis amino-silane is bis(trimethoxysilylpropyl) amine.

4. The method of claim 1 wherein the bis sulfur-containing silane is bis(triethoxysilylpropyl) tetrasulfide.

5. The method of claim 1 wherein applying the solution to the metal substrate comprises dipping the metal substrate in the solution.

6. The method of claim 1 wherein the nanosize particulate material has an average particle size of about 0.1 μ

m or less.

7. The method of claim 1 wherein the nanosize particulate material is in a concentration range from about 10 ppm to about 1% by weight of the solution.

8. The method of claim 1 wherein the nanosize particulate material is in a concentration range from about 50 ppm to about 1000 ppm of the solution.

9. The method of claim 1 wherein drying comprises heating the silane solution on the metal substrate to a temperature of at least about 60°

C.

10. The method of claim 1 wherein the coating formed has a thickness in the range from about 0.2 μ

m to about 0.6 μ

m.

11. The method of claim 1 wherein curing comprises applying heat and pressure to the rubber and coated metal substrate to form a bond therebetween.

12. The method of claim 1 wherein the sulfur curable rubber is selected from the group consisting of natural rubber, synthetic rubber, and combinations thereof.

13. The method of claim 1 wherein the bis amino-silane is bis(trimethoxysilylpropyl) amine and the bis sulfur-containing silane is bis(triethoxysilylpropyl) tetrasulfide.

14. A bonded tire cord prepared by the method of claim 1.

15. A method of bonding rubber to a metal substrate, the method comprising:

mixing a bis amino-silane with a first aqueous-based medium containing a nanosize particulate material to substantially hydrolyze the bis amino-silane;

mixing a bis sulfur-containing silane with a second aqueous based-medium containing a nanosize particulate material to substantially hydrolyze the bis sulfur-containing silane;

mixing the substantially hydrolyzed bis amino-silane with the substantially hydrolyzed sulfur-containing silane to form a silane solution comprising the substantially hydrolyzed bis amino-silane, the substantially hydrolyzed bis sulfur-containing silane, and the nanosize particulate materials of the first and second aqueous-based media, wherein the silane solution comprises a ratio of the hydrolyzed bis amino-silane to the hydrolyzed bis sulfur-containing silane of about 1;

1 by volume;

applying the silane solution to at least a portion of a surface of the metal substrate;

drying the silane solution on the metal substrate to form a coating having a thickness in the range from about 0.1 μ

m to about 1 μ

m thereon; and

applying an uncured, sulfur curable rubber onto the surface of the metal substrate having the coating thereon and sulfur curing the rubber with heat and pressure to bond the rubber to the coated metal substrate;

wherein the bis amino-silane is a compound of the general formula I;

(R¹O)₃—

Si—

R²—

X—

R²—

Si—

(OR¹)₃ 

 

(formula I)

wherein;

each R¹, independently, is selected from the group consisting of a C₁-C₂₀ alkyl and C₂-C₂₀ acyl;

each R², independently, is selected from the group consisting of a substituted or unsubstituted aliphatic and aromatic group; and

X is selected from —

N(R³)—

, wherein R³ is selected from the group consisting of hydrogen, substituted or unsubstituted, straight, branched or cyclic C₁-C₂₀ alkyl, alkenyl, and alkynyl groups and substituted or unsubstituted C₃-C₂₀ aryl and alkylaryl groups;

wherein the bis sulfur-containing silane is a compound of the general formula II;

16. A tire cord comprising:

sulfur curable rubber, a metal substrate, and an adhesive film therebetween bonding the rubber to the metal substrate;

wherein the adhesive film has a thickness in the range from about 0.1 μ

m to about 1 μ

m and is formed from a dried silane solution comprising a substantially hydrolyzed bis amino-silane, a substantially hydrolyzed bis sulfur-containing silane, and a nanosize particulate material;

wherein the solution prior to drying is formed by;

mixing a bis amino-silane with a first aqueous-based medium containing a nanosize particulate material to substantially hydrolyze the bis amino-silane;

mixing a bis sulfur-containing silane with a second aqueous-based medium containing a nanosize particulate material to substantially hydrolyze the bis sulfur-containing silane; and

mixing the substantially hydrolyzed bis amino-silane with the substantially hydrolyzed sulfur-containing silane to form a silane solution comprising the substantially hydrolyzed bis amino-silane, the substantially hydrolyzed bis sulfur-containing silane, and the nanosize particulate materials of the first and second aqueous-based media, wherein the silane solution comprises a ratio of the hydrolyzed bis amino-silane to the hydrolyzed bis sulfur-containing silane of about 1;

1 by volume;

wherein the bis amino-silane is a compound of the general formula I;

(R¹O)₃—

Si—

R²—

X—

R²—

Si—

(OR¹)₃ 

 

(formula I)

wherein;

each R1, independently, is selected from the group consisting of a C₁-C₂₀ alkyl and C₂-C₂₀ acyl;

each R², independently, is selected from the group consisting of a substituted or unsubstituted aliphatic and aromatic group; and

X is selected from —

N(R³)—

, wherein R³ is selected from the group consisting of hydrogen, substituted or unsubstituted, straight, branched or cyclic C₁-C₂₀ alkyl, alkenyl, and alkynyl groups and substituted or unsubstituted C₃-C₂₀ aryl and alkylaryl groups;

wherein the bis sulfur-containing silane is a compound of the general formula II;

17. The tire cord of claim 16 wherein the rubber is selected from the group consisting of natural rubber, sulfur-cured rubber, peroxide-cured rubber, EPDM, NBR, SBR, and combinations thereof.

18. The tire cord of claim 16 wherein the substrate comprises a metal selected from the group consisting of zinc, steel, stainless steel, titanium, nickel, brass, copper, tin, aluminum, cobalt, alloys thereof, and combinations thereof.