Estimation of the adhesion strength of rubber-metal bonds

Abstract

53Rubber-metal products are widely used in different branches of industry. The work efficiency and durability of such items depend on the strength of the bond at a rubber-metal boundary. If a chemical interaction takes place between metal and rubber, the strength of bonding is high and does not reduce even upon heating to 100°C. When the bonding strength is determined only by the intermolecular interaction forces, the strength between rubber and metal significantly reduces with temperature increase. Rubbers are usually attached to ferrous metals and stainless, heat resistant, and acidproof steels, as well as to some nonferrous metals and alloys thereof (titanium, magnesium, copper, bronze, brass, duralu minum, and so on) [1].To join rubber and metal, the methods of hot bond ing via vulcanization and cold bonding are used. Upon cold bonding, vulcanized rubber, which is glued to the metal surface, is used. To bond butadiene, butadienestyrene, and natural rubbers to steel and duralumi num, an 88NP adhesive or Khemosil X6025 adhesive is used in combination with a Khemosil 211 primer. Hot bonding of rubber to metal via vulcanization is carried out through an intermediate layer of ebonite, brass, or rubber adhesive. Independently of the bond ing technique, the metal surface must be preliminary purified from the oxide layer and oil and grease traces. Hot BondingThis method of joining of resin to metal is the sim plest and cheapest, providing the sufficient thermal stability and resistance to dynamic loads. At the begin ning of vulcanization, the unvulcanized rubber mix ture stays in a viscous flow state, which allows good contact with metal. Hot bonding can be performed without the application of special adhesives. However, the greatest strength of the bond is observed upon glu ing of rubbers to brass plated metal surfaces. Bonding Using BrassingThe bonding of rubber to metal via brassing finds application mainly in production of automobile tires. This method provides high strength and the highest thermal stability of the bonding of natural or isoprene rubbers to metals, as well as good resistance of the resulting products to shock and vibrations. The strength of rubber bonding to metal prepared by this method depends to a great extent on the composition of brass and rubber mixture [1].It is though [7] that, to form a strong adhesion bond, the thickness of the brass coating needs to vary within 0.20 µm and the optimal content of copper in the coating should compose 69%. Such brasses ensure better retention of the adhesion properties during aging.The greatest strength of rubber bonding to a brass coated metal surface is reached upon vulcanization in presses under a pressure of no less than 2-3 MPa. It increases up to the attainment of a vulcanization opti mum and changes further only insignificantly.The strength of rubber bonding to metal also depends on the composition of the rubber mixture (no plasticizers migrating to the surface are permitted) and dynamics of the vulcanization process. If the rubber mixture stays for...

On characterizing microscopically the adhesion interphase for the adhesion between metal and rubber compound part I. Effect of hexamethoxymethylmelamine in rubber compound

“…Recently reported by Hotaka et al [2], the addition of HMMM into rubber compound played the role of scavenger of amine generated during cure. The amine produced during cure made corrosion of adhesion interphase during hostile aging conditions.…”

“…Brass-plated steel cords inserted in the belt and carcass of tires have long been used as a reinforcing material to provide sufficient mechanical strength and stability to endure cars themselves and their loads [1]. Brass plating on the surface of steel cords reacts with sulfur in the rubber compound during the curing process of tire manufacturing, forming an adhesion interphase between the rubber compound and the steel cord [1][2][3][4][5][6][7][8][9]. Copper and zinc also react with oxygen and water in the rubber, forming oxides and hydroxides of copper and zinc.…”

A Multifunctional Interlocked Binder with Synergistic In Situ Covalent and Hydrogen Bonding for High‐Performance Si Anode in Li‐ion Batteries

“…Due to the rubber–metal binding mechanism, thiourea moieties of the TUPN binder can be interlocked to the Cu current collector as Cu x S with a dendrite form. [ 45 , 46 ] Cu current collector and sulfur can form the Cu x S interaction by reacting with Cu during in situ polymerization and can increase the binding force with the Cu current collector. [ 29 , 31 , 32 ] In addition, because the isocyanurate moiety comprising triurea moieties favors the adsorption to Cu and CuO, it can increase the adhesion force via physical bonding.…”

Improving the Electrochemical Property of Silicon Anodes through Hydrogen-Bonding Cross-Linked Thiourea-Based Polymeric Binders

“…In the tire industry, steel cords within the tire need to be brass-plated on their surface to enhance the tire durability because the rubber would peel off from the steel cord without brass coating and cause the tire to burst. , Besides, the valve of the inner tube of the tire also mainly consists of brass, to strengthen the binding at the rubber–metal boundary. Pioneering studies have reported that the high strength of rubber binding to brass is derived from the formation of a nonstoichiometric copper sulfide (Cu x S) intermediate layer at the rubber–metal contact boundary upon vulcanization. , Nonstoichiometric Cu x S grows as dendrites into the viscous rubber during the initial stage. When the Cu x S growth levels off, the cross-linking of the viscoelastic rubber entrapped in the dendrites would result in tight interlocking of the rubber in the Cu x S dendrites .…”

“…When the Cu x S growth levels off, the cross-linking of the viscoelastic rubber entrapped in the dendrites would result in tight interlocking of the rubber in the Cu x S dendrites . The tight and physical interlocking forces between the Cu x S layer and the vulcanized rubber are the main factor for the high binding strength. , The chemical cross-linking via Cu–S–rubber is also proposed, but its contribution toward the rubber–brass adhesion is considered minor. ,, In the battery industry, copper (Cu) foils and organic polymers are used as current collectors and binders, respectively. Therefore, the concept of the binding mechanism at the rubber–metal boundary can be extensively applied in lithium-ion batteries to strength the binding force between sulfur-containing polymer binders and Cu current collectors.…”