Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Reexamination Certificate
1997-12-16
2001-01-23
Lorin, Francis J. (Department: 1775)
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
Reexamination Certificate
active
06176285
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the use of preparations for example rubber latex for the sealing of tires with punctures, and also to an apparatus for the introduction of a sealing preparation into the tires wherein the tire is pumped up to a pressure at which it can be driven, as well as tires with an integrated sealing preparation.
Various sealing preparations for tire punctures are available on the market. They mainly contain colloidal dispersions of polymers in an aqueous medium, known as latexes. Thus, by way of example, polystyrene-butadiene latexes, polyvinylacetate latexes, acrylic copolymer latexes, nitrile latexes and polychloroprene latexes, are used. Sealing preparations are also known which contain not water but rather tetrachloroethylene as the carrier medium.
For the introduction of the sealing preparation into the tire and for the pumping up of the tire to a pressure at which the tire can be driven, use is made of e.g., a spray can, an apparatus comprising a pressure tight container for the sealing preparation which contains a liquefied gas as the pressure source. Generally, a propane/butane mixture and is used as the liquefied gas, in rarer cases hydrochlorofluorocarbons also are used. Contains such as spray cans have at their outlet valve a hose, in which the other end thereof is provided with a screw adapter for the tire valve.
When a tire puncture arises, the sealing preparation is sprayed from the spray can via the tire valve into the interior of the tire and the tire is pumped up by means of a propellant gas to a specific pressure, which is at different levels, depending upon the leak. The tire is then driven for a few kilometers, depending on the nature of the defect, to distribute the sealing preparation in the interior of the tire and to seal off the defect.
In another apparatus the sealing preparation is located in a compressible flask, which is connected via an adapter to the tire valve from which the valve insert was previously removed. The sealing preparation is then injected into the tire by pressing the flask or bottle. After putting the valve insert in place, the tire is inflated again to a specific pressure with the aid of carbon dioxide cartridges.
The above described sealing preparations are not completely satisfactory. They can be relatively easily removed mechanically and are, in part, not adequately water resistant and do not result in a seal when the tire defect lies in the run out of the under-tread rubber, i.e. in the region between the tread and the side surface of the tire.
Difficulties arise with the apparatus for introducing the sealing preparation into the interior of the tire and for the pumping up of the tire. Thus, spray cans which contain propane/butane mixtures as the propellant gas only operate satisfactorily, depending on the mixing ratio, at temperatures down to about 0° or somewhat below.
In the older German patent application 195 45 935.0, sealing preparations for tire punctures and apparatus for the application of the sealing preparation into the tire are described, which do not have the above named disadvantages. The sealing preparations comprise an agent which contains natural rubber latex, optionally together with additional rubber latexes or a rubber latex in combination with a compatible adhesive resin. Latexes of synthetic rubbers, such as stirene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene vinylacetate rubber, chloroprene rubber, vinyl pyridine rubber, butyl rubber and also their mixtures, are named as rubber latexes which can be used together with natural rubber latex. The same synthetic rubber latexes and also natural rubber latex are quoted as rubber latexes which can be used in combination with an adhesive resin. Resins which have been added as a tackifier to elastomers, such as terpene phenolic resins, can be used as the adhesive resin.
The same patent application describes an apparatus for the sealing and pumping up of tires with punctures, in which a pressure-tight container is provided with an outlet valve for the sealing preparation and with a gas inlet. Furthermore, a pressure source is provided, so that gas under pressure can be introduced into the pressure-tight container via the gas inlet in order to introduce the sealing preparation into the interior of the tire and to pump up the tire.
Furthermore, a heat source for the heating up of the sealing preparation can be provided in the pressure-tight container and/or in the pressure source. Pressurised bottles with liquid or compressed gas and also air compressors are named as a pressure source.
SUMMARY OF THE INVENTION
An object of the present invention is to make available further sealing preparations which result in a better seal under wet conditions and also deals with defects in the run out of the under-tread rubber which are also mechanically more difficult to remove. Furthermore, sealing preparations are to be made available in which the year of manufacture can be determined even after it has been applied into the tire. Moreover, further apparatus should be provided for the application of sealing preparations into the tire and for the pumping up of the tire to a pressure at which it can be driven. Finally, tires with an integrated sealing preparation are proposed.
Starting from the initially named sealing preparation, this object is satisfied by a preparation which contains a latex of synthetic isoprene rubbers. Cis 1,4-, trans 1,4-, 1,2- and 3,4-polyisoprenes can be considered as the synthetic isoprene rubbers. The latex of synthetic cis 1,4-isoprene rubber is preferably used.
The latex or synthetic isoprene rubbers can be used on their own as the rubber latex in the sealing preparation or together with latexes of synthetic rubbers, such as acrylate rubber, methacrylate rubber, stirene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-vinylacetate rubber, chloroprene rubber, vinyl pyridine rubber, butyl rubber and others, as well as their mixtures. The content of the latex of synthetic isoprene rubber preferably amounts to at least 40% by weight of the total rubber latex, when it is used together with latexes of synthetic rubbers.
A further embodiment of the invention is a sealing preparation on the basis of natural rubber latex which additionally contains latexes of synthetic isoprene rubber, acrylate rubber and/or methacrylate rubber. The content of natural rubber latex amounts to 10 to 80% by weight, in particular to 40 to 60% by weight of the named rubber latex. Preferably preferred are mixtures of natural rubber latex and synthetic isoprene rubber latex or of natural rubber latex and acrylate rubber latex. The sealing preparations on the basis of natural rubber latex can also contain, in addition to synthetic isoprene rubber latex, acrylate rubber latex and/or methacrylate rubber latex one or more of the above named latexes of synthetic rubbers.
Under acrylate rubbers there are to be understood rubber elastomeric vulcanisable copolymers on the basis of acrylic acid esters, in particular ethyl and butyl acrylates and small quantities of comonomers by which reactive groups which favor rapid vulcanisation can be incorporated into the polyacrylate. In the same way methacrylate rubbers are to be understood as rubber elastomeric, vulcanisable copolymers on the basis of methacrylic acid esters, in particular methyl and ethyl methacrylates, and again small quantities of comonomers with reactive groups.
All the above described sealing preparations can preferably, additionally contain an adhesive resin compatible with the rubber latexes. Compatible signifies that the adhesive resin causes no coagulation of the rubber latex. Adhesive resins are to be understood to be resins which enhance the bonding capability of the rubber latex to the tire. For example, resins can be used which have been added as tackifier to elastomers. The adhesive resins are preferably added to the rubber latex in the form of aqueous dispersions or emulsions. As a rule, they are aqueous dispersions. Preferred are terpene phenoli
Fuchs Hans-Bernd
Gerresheim Manfred
Steinbrecht Ulrich
Birch & Stewart Kolasch & Birch, LLP
Lorin Francis J.
Sumitomo Rubber Industries Ltd.
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