Stock material or miscellaneous articles – All metal or with adjacent metals – Having composition – density – or hardness gradient
Patent
1989-04-14
1990-05-29
Zimmerman, John J.
Stock material or miscellaneous articles
All metal or with adjacent metals
Having composition, density, or hardness gradient
428625, 428677, 428941, B32B 1506
Patent
active
049295128
DESCRIPTION:
BRIEF SUMMARY
FIELD OF TECHNOLOGY
The present invention relates to a metal and a composite material made of the metal and rubber for tires, hoses, conveyor belts, or the like and more specifically a metal and a composite material which exhibit a high adhesion between metal and rubber.
TECHNOLOGICAL BACKGROUND
It is a well-known practice to embed various kinds of reinforcing materials in rubber to improve its strength and durability. A composite material made of rubber and metal is particularly applied to automotive tires, high-pressure rubber hoses, conveyor belts or the like and is expected to meet many quality requirements. Among them, it is a very important requirement to increase the adhesion between the rubber and the metal in a composite material to improve its durability.
This requirement is particularly strong with a steel radial tire in which are used steel cords plated with copper-zinc (brass) binary alloy as a reinforcing metal. With the expansion of highway, such a tire is expected to reveal high durability and high stability while running at high speed. For this purpose, it is very important to improve the adhesion between steel cord and rubber. In particular, a large-sized steel radial tire for trucks and buses is strongly required to maintain good adhesion for a prolonged period of time, since such a tire is used after repairing its tread portion once or even twice.
When the rubber in a composite material is vulcanized, the copper in the plating on the steel cords reacts with the sulfur in the rubber to form a sulfide at the interface between the steel cords and the rubber, thus adhering them together. Various trials have been made to improve the plating on the metal and the rubber in the composite material to increase the adhesion between the metal and the rubber. As a result, the adhesion after vulcanization, that is, the initial adhesion is being improved. But the initial adhesion tends to decrease gradually as the material is exposed to severe conditions during the service life. Thus, the adhesion durability has not yet reached a sufficient level. Therefore, the prior art composite materials have still much to be improved.
If the adhesion between the rubber and the steel cords is insufficient, the adhesion might be broken owing to heat accumulation due to hysteresis loss of rubber while the tire is rotating, causing what is called the separation between the steel cords and the rubber, thus prohibiting the tire from rotating any more.
Further, if the tire gets damaged in its tread or side wall and the damage is so deep as to reach the steel cords, moisture might infiltrate into the tire through the damaged portion, vaporize by heat generated while the tire is rotating, and invade into between the filaments of the steel cords to break the adhesion between the steel cords and the rubber, inducing the aforementioned separation. If the air in the tire contains moisture, it might infiltrate the inner liner to attack the steel cords, thus causing separation in the same manner as described above.
Various methods have been proposed to increase the adhesion between the rubber and the steel cords in a radial tire in order to avoid such a phenomenon.
One of such methods is to modify the composition of the rubber covering the steel cords. It was found out in 1950's that the adhesion between the rubber and the steel cords can be improved by adding a cobalt salt of an organic acid into the rubber. The optimum type and quantity of the cobalt salt have been investigated in various trials since then. Japanese Unexamined Patent Publication No. 60-42440 teaches to optimize the quantities of sulfur and cobalt salt of an organic salt in order to improve the adhesion. Another approach has been to use an HRH series composition containing silica, resorcin and hexamethylenetetramine.
However, if the rubber material contains an excessive amount of cobalt salt of organic acid, the quality of unvulcanized rubber might deteriorate and the adhesion might degrade as a result of long or high-temperature vulcanization or heat agin
REFERENCES:
patent: 2154834 (1939-04-01), De Lamather
patent: 2939207 (1960-06-01), Adler
patent: 3961740 (1976-06-01), Nakamoto et al.
patent: 4218517 (1980-08-01), Van Ooij
patent: 4226918 (1980-10-01), Friend
patent: 4255496 (1981-03-01), Huemers
patent: 4446198 (1984-05-01), Shemenski et al.
patent: 4572263 (1986-02-01), Ogano et al.
patent: 4605590 (1986-08-01), Delseth et al.
patent: 4645718 (1987-02-01), Dambre
patent: 4704337 (1987-11-01), Coppens et al.
Muraoka Kiyoshige
Nakata Hidekazu
Nishimura Yoshifumi
Taguchi Takafumi
Uchida Mamoru
Sumitomo Electric Industries Ltd.
Sumitomo Rubber Industries Ltd.
Zimmerman John J.
LandOfFree
Metal and composite material made of the metal and rubber does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Metal and composite material made of the metal and rubber, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Metal and composite material made of the metal and rubber will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-520221