Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1996-07-09
2002-09-24
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C152S503000, C523S166000
Reexamination Certificate
active
06454892
ABSTRACT:
This invention relates to a preparation for sealing punctures in tires and also to an apparatus for the application of the sealing preparation to the tire and for pumping it up to a pressure at which it can be used.
BACKGROUND OF THE INVENTION
Various puncture sealing preparations are available on the market. They mainly contain colloidal dispersions of polymers in an aqueous medium, known in the following as lattices. Thus, for example polystyrene butadiene lattices, poly (vinyl acetate) lattices, acrylic copolymer lattices, nitrile lattices and polychloroprene lattices are used. Sealing preparations are also known which do not contain water but rather tetrachloroethylene as the carrier medium.
The prior art uses, for the introduction of such sealing preparations into a tire and for pumping up the tire to a pressure at which it can be used, an apparatus comprising a pressure-tight container for the sealing preparation which contains a liquefied gas as a pressure source. This is referred to as a spray can in the following. A propane/butane mixture is mainly used as the liquefied gas. In rare cases, fluorochlorohydrocarbons are also used. These spray cans have a hose at their outlet valve, the other end of the hose being provided with a screw adapter for the tire valve.
When a tire puncture occurs, the sealing preparation is sprayed from the spray can into the interior of the tire through the tire valve and the tire is reinflated by means of the propellant gas to a specific pressure which is of different levels depending on the leak. The tire is then driven a few Kilometer, dependent 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 with the valve insert having been previously removed. The sealing preparation is then sprayed into the tire by pressing the flask. After the insertion of the valve insert, the tire is then pumped up again to a specific pressure with the aid of carbon dioxide cartridges. The previously used sealing preparations are not completely satisfactory. They can be mechanically removed relatively easily, some of them are not adequately effective in wet conditions and do not result in a seal when the tire defect is present at the edge of the breaker, i.e. at the edges of the tire treads.
Difficulties also arise with the prior art apparatus for introducing the sealing preparation into the interior of the tire and for pumping up the tire. Thus, with spray cans which contain propane/butane mixtures as the propellant gas, one can, depending on the mixture ratio, only satisfactorily operate to temperatures down to about 0° C. Furthermore, propane/butane mixtures are combustible and explosive. Fluorochlorohydrocarbons are a burden for the environment. Finally all known propellants are only available in a limited quantity when a puncture occurs.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a sealing preparation which results in an effective seal even in the wet and also for punctures at the edge of the breaker strips and which is mechanically more difficult to remove. Furthermore, devices are provided for the successful 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 used and which do not have at least one of the above-named disadvantages.
According to one aspect of the present invention, a preparation for sealing a tire with a puncture comprises natural rubber latex. Preferably, the sealing preparation of the invention contains, apart from the natural rubber latex, an adhesive resin compatible with the rubber latex.
Such sealing preparations result in substantially better sealing than the prior art commercially available sealing preparations. The sealing preparations of the invention are more difficult to mechanically remove from the tire, seal better under wet conditions and result in a good seal, even for punctures at the edge of the breaker strip.
For the adhesive resin, “compatible” signifies that the adhesive resin does not cause any coagulation of the rubber latex. As adhesive resins, there are to be understood resins which improve the ability of the rubber latex to bond to the tire. By way of example, resins can be used which are added to elastomers as tackifiers. The adhesives resins are preferably added in the form of aqueous dispersions or emulsions of rubber latex. As a rule, these are aqueous dispersions. Particularly preferred are terpene-phenol-resins.
Latex which has been concentrated by centrifuging or vaporization can also be used as natural rubber latex.
In the embodiment without the addition of adhesive resin, a part of the natural rubber latex can be replaced by lattices of synthetic rubbers, such as for example styrene butadiene rubber, acryl nitrile butadiene rubber, ethylenevinylacetate rubber, chloroprene rubber, vinylpyridene rubber, butyl rubber and others as well as their mixtures. The content of natural rubber latex then amounts to 10 to 80R by weight, in particular to 40 to 60% by weight of the rubber latex. The sealing preparation preferably contains only natural rubber latex as the rubber latex.
In the embodiment in which an adhesive resin is contained in the sealing preparation, lattices of natural rubber and of synthetic rubbers, such as, for example, styrene butadiene rubber, acryl nitrile butadiene rubber, ethylenevinylacetate rubber, chloroprene rubber, vinylpyridene rubber, butyl rubber and others can be used as well as their mixtures. Preferred are mixtures of natural rubber with the said lattices of synthetic rubbers and it is particularly preferred if only natural rubber latex is contained as rubber latex in the sealing preparation.
The sealing preparations of the invention can be used for the sealing of pneumatic tires of all types, including bicycles, motorcycles, motorcars, commercial vehicles, industrial vehicles, wheelchairs, caravans, agricultural and garden vehicles, wheelbarrows, and so on.
In the sealing preparations of the invention, which contain an adhesive resin, the ratio by weight of rubber to adhesive resins preferably lies in the range from about 10:1 to 1:10, more preferably from 5:1 to 1:3 and particularly preferably from 4:1 to
A frost protection agent is preferably added to the sealing preparations of the invention. Customary frost protection agents can be used, such as high boiling point, water soluble, difficult to ignite organic liquids, such as glycols, preferably ethylene glycol. Polyethylene glycols with molecular masses up to 300 to 400 g/mol can also be used. Through this addition, one obtains a good sealing at low temperatures, even when these are associated with the effects of wetness.
For the thinning of the sealing preparations, a dispersion agent can be used, as a rule, water. Furthermore, the sealing preparations of the invention can contain customary dispersants, emulsifying agents, foam stabilizers and/or pH-regulators, such as ammonia or sodium hydroxide. Moreover, it can be of advantage for rapid sealing and for the sealing of larger holes to use one or more fillers. Suitable fillers are, for example, silicic acid, chalk, carbon black, fibrous materials, such as natural fibers, chemical fibers of natural polymers or synthetic fibers, glass fiber reinforced plastics, polystyrene particles, rubber dust which is produced by comminution of vulcanized products such as tires, saw dust, moss rubber particles, particles of rigid foam for cut flowers and the like. Particularly preferred are fibrous materials, small rubber particles in combination with silicic acids and glass fiber reinforced plastics.
The fillers can be directly added to the sealing preparation. However, insofar as the fillers have a size which would make it difficult or impossible to introduce the sealing preparation via the valve without a change in the valve size, these fillers are generally to be introduced into the
Ditzel Eduard
Fuchs Hans-Bernd
Gerresheim Manfred
Steinbrecht Ulrich
Stransky Norbert
Birch & Stewart Kolasch & Birch, LLP
Knable Geoffrey L.
Sumitomo Rubber Industries Ltd.
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