DE2831356A1 - Puncture-proof tires - Google Patents

Description

DR.-ING. WALTER ABITZ

DR. DIETER F. MORF '3'

DIPL.-PHYS. M. GRITSCHNEDER

Patent attorneys

Munich.

I978

Postal address PO Box 86O1O9, 8OOO Müm

Fienzenauerstrasse 28

Telephone 983222

Telegrams: Chemindus Munich

Telex: CO) 523992

356

GT-1240

THE GENERAL TIRE & RUBBER COMPANY Akron, Ohio, V.St.A.

Puncture-proof tire

9088U / 0636

ORIGINAL INSPECTED

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The invention relates to a puncture-proof (puncture-sealing) Tires with band wire belt layers and one between the air chamber and the belt layers, sticky puncture sealant.

In the past, great efforts have been made to increase the operational safety of motor vehicle tires. The reliability has been up to a point improved, in which the automobile manufacturers are considering switching to the replacement tire for cost saving to renounce. However, the operational reliability of the tires still leaves a lot to be desired.

The use of ribbon wire in tires to solve various problems is taught in U.S. Patents 4,011,899 and 3,667,529 and US Pat by B.K. Daniels, "Steel Ribbon Belt Reinforcement Mechanics," Tire Science and Technology, TSTCA, Vol. 5, No. 1 (February 1977).

The use of puncture sealants or puncture protection compounds for tires is described, for example, in U.S. Patents 3,903,947 and 3,935. According to the first patent specification, a partial cured rubber made from ethylene, propylene and a non-conjugated diene in combination with other components used as a sealant.

From the aforementioned article by Daniels (op. Cit.) It emerges that wire band tires presumably hold back nails more firmly and therefore allow longer driving without loss of air.

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According to US Pat. No. 3,935,893, a mixture of one becomes a high one Molecular weight, curable isobutene / isoprene copolymers, a low molecular weight, curable poly (isobutene / isoprene) rubber, liquid butene as a tackifier, a partially hydrogenated block copolymer made of styrene and styrene / isoprene, carbon black, a crosslinking agent and an initiator used. While these puncture sealants are effective to a certain extent on stiff, thick-walled four-ply diagonal tires, this is the case with the flexible two-ply radial tires are not the case to the same extent.

The terms "four layers" and "two layers" refer to the body layers. As for the attempt to prevent the As regards tire air loss due to puncture, the prior art lacks any reference to it the functional relationship that exists between ribbon wire and a puncture sealant in solving the problem the breakdown-related loss of air and the removal of the object causing the puncture.

The invention relates to a tire having belts consisting of at least one ribbon wire belt ply, and one contains puncture sealant disposed between the air chamber and the belt plies. It turned out that there is a functional connection between the ribbon wire layers in the belt and the puncture sealant, which greatly reduces leaks due to nail punctures in the tire. The ribbon wire preferably has a Thickness of 0.1 to 0.5 mm, in particular 0.2 to 0.4 mm, and a width of 0.2 to 6 mm, in particular 0.5 to 2 mm, on. ■

The ribbon wire can be made into ribbon shape either by flat rolling steel wire or by cutting sheet steel are made and is preferably brass-plated. In the tire, the ribbon wire is arranged in the belts in such a way that

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it is perpendicular to the tire radius. The ribbon wire layers of the tire preferably have an angle of 15 to the circumferential center line of the tire and an angle of 30 to 60 ° to one another. In other words, the band wire layers are laid at a diagonal angle corresponding to the steel cords of conventional tires. Further, the steel strip wire preferably covers 50 to 98 % (particularly 80 to 90 %) of the entire tread area (assuming that the tread area has no depth). The tire is preferably a one- or two-ply radial tire with curved sidewalls and a thick, rigid tread with a wide groove width.

A typical formulation for a preferred sealing compound according to the invention comprises 100 parts by weight of an EPDM rubber and, in each case based on 100 parts of rubber, 100 to 180 parts by weight (preferably 120 to 140 parts by weight) of a paraffinic oil, 10 to 50 parts by weight (preferably 15 to 30 parts by weight) of coarse-grained carbon black, 2 to 8 parts by weight (preferably about 5 parts by weight) of a heat stabilizer (such as zinc oxide) and 1 to 3 parts by weight (preferably about 2 parts by weight) of an antioxidant, such as the commercial high-temperature condensation product of acetone and diphenylamine.

The separating and top layers or padding sheets (squeegee sheets) fulfill two main functions. The first function is mechanical and is that these layers prevent the uncured or slightly cured sealant from being damaged during vulcanization of the green tire used crown hose to adhere. The second function is to prevent migration Plasticizer oils from the sealant layer. According to the invention, it is preferred to use in the upholstered panels Nitrile rubbers with medium to high acrylonitrile contents

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(at least 20 wt -.%, more preferably at least 30 wt -.% acrylonitrile). Typical suitable nitrile rubbers generally contain from about 30 to 35 wt -.% Of acrylonitrile units, and have Mooney viscosities (ML _{1 +} ^ at 100 ⁰ C or 212 ° F) of about 30 to about 60. Nitrile rubbers are known to have an extremely high resistance to paraffin oil. Therefore, when nitrile rubber is used in the separating and top layers, the paraffin oil used in the synthetic rubber sealing compound is effectively prevented from migrating therefrom. The nitrile rubber preferably makes up at least half of the total rubber content of the release and cover layers. The nitrile rubber can be wholly or partially replaced by a rubber-like, vulcanizable copolymer of propylene oxide and allyl glycidyl ether with an allyl glycidyl ether unit content of about 0.5 to 10% by weight or a similar propylene oxide rubber.

Since the separating and top layer compounds are vulcanized, they must inevitably have components to bring about the Vulcanization as well as a number of other additives to achieve the desired properties. The total amount these substances can range from 50 to 150 parts by weight per 100 parts by weight of total rubber in the composition. Examples of the components mentioned and others Additives are carbon black, zinc oxide, stearic acid, accelerators, Antioxidants and fillers. A typical cushion sheet formulation according to the invention comprises 70 to 100 parts by weight of a hydrocarbon rubber with a medium to high nitrile content, 0 to 30 parts by weight natural rubber, 20 to 100 phr (Parts per 100) (preferably 50 to 70 phr) carbon black and other fillers, 0 to 20 phr tackifier, 0.8 to 1.6 phr Sulfur and 1 to 10 phr stabilizers, accelerators, antioxidants and other additives. The types of rubber and others Ingredients are combined using conventional rubber mixing methods. After the laminate production, the

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Cover layers vulcanized during the curing or vulcanization cycle of the tire.

A brief explanation of the accompanying drawings follows.

Fig. 1 shows a cross section through a tire with ribbon wire belt layers and a puncture sealant 1 enclosed between the air chamber and the belt plies;

Fig. 2 shows a partial cross-section through the tread of the tire and illustrates the diagonal arrangement the ribbon wire layers in the belt; and

Fig. 3 is a cross-section through a ribbon wire layer which shows a ribbon wire (calendered wire) embedded in rubber material.

FIG. 1 shows a radial tire with curved, flexible side walls 17 and a tread 13. The tread 13 preferably consists of a relatively stiff, a ■ curvature resistant rubber compound and has wide grooves 2. The side walls 17 are curved and flexible, so that the tire can drive smoothly. The stiff tread 1 3 t the wide grooves 2 and the strong tread ribs are intended to prevent the movement of a nail after it has penetrated the tire and thus the extent of the widening of the hole decrease. The side walls contain two layers 19 and 20 which extend radially from bead 15 to bead 15 of the tire and the beads 15 thus overlap. There are two belt layers under the running surface 13 9 and 11. The belt layers are produced from ribbon wire strands 23, as FIG. 2 shows. The ribbon wire is a commercial product from Baekert (Belgium). The number of the wire is V4554 ribbon wire. The wire is brass-plated, has one

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0.25mm thick and 1mm wide. He owns has a tensile strength of 556 Newtons and is used in an end number of 15 per 2.54 cm (in.). For the production A belt ply, the rubber wire is calendered with rubber to a thickness of about 1.39 mm.

The angle of the ribbon wire cord to the circumferential center line of the tire after curing or vulcanization is about 22 °. The puncture sealing compound 1 is arranged under the ribbon wire and the two cord layers. This contains 60 parts of a rubber made of ethylene, propylene and a non-conjugated diene (Nordel 1070 'from DuPont), 40 parts of ethylene / propylene / ethylidine norbornene (Epsyn 70 from Copolymer Rubber and Chemicals Co., Baton Rouge, La .; hardenable rubber based on zinc oxide / phenolic resin), 120 parts of a highly viscous paraffin oil (Sunpar 20-80 from Sun Oil Company), 15 parts Austin Black, a fine bituminous coal from Slab Fork Coal Co. and / or Columbia Carbon, 2 parts BLE -25-amine as an antioxidant (diphenylamine / acetone reaction product from Uniroyal Chemical, Naugatuck, Conn.) And 12 parts of brominated phenolic resin SP1055 (a bromomethylalkylphenylformaldehyde resin from Schenectady Chemicals).

For partial hardening or vulcanization of the puncture sealing compound the tire containing the mass is subjected to the curing process described below. the The combination of zinc oxide and the brominated phenolic resin only leads to crosslinking of the EPDM rubber Epsyn 7OA. Further details regarding the production and embedding of the sealing compound can be found in US Pat. No. 3,903,947.

The puncture sealant or puncture protection compound is in a nitrile rubber shell 3, 5 embedded. The nitrile rubber cover is incompatible with the puncture sealant and does not bond with it during curing. the

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Nitrile rubber envelope 3.5 contains 100 parts by weight of a nitrile hydrocarbon rubber or rubber, 35 parts of HAF carbon black (highly abrasion-resistant carbon black), 20 parts of Austin Black, 2 parts of n-cyclohexyl-2-benzothiazole sulfenamide and 1.2 parts Sulfur. The rubber and the other ingredients are compounded by conventional rubber compounding rivets. When the tire is vulcanized, the cover sheets are hardened and the puncture sealant is partially hardened. The curing or vulcanization of the tire is carried out by 20 min. Long application of 1379 kilopascals (kPa) at a steam temperature of 196 ⁰ C, followed by 9.5 min. Long hot water treatment at 1724 kPa and 1 66 ° C and subsequent 8 min. long treatment with circulating water at 38 ° C and an applied pressure of 1724 kPa. Care should be taken that there is no pressure drop inside the tire during the curing or vulcanization stages. See U.S. Patent No. 3,903,947 for further details regarding the nitrile rubber shell.

The puncture sealant is extruded onto a strip or a layer of uncured nitrile rubber, after which a second strip or a second layer of nitrile rubber as a cover layer over the sealant gives. The top layer can be used to prevent it from being removed divide it into a number of sections or fields. The tires can be made in a conventional manner using somewhat longer curing or vulcanization cycles. When using a conventional puncture sealant of the spray type, the tire is cured in the usual manner. During the tire production, the inner lining 7 placed on the tire building drum, then the sealant pack 1,3,5 is applied centrally to the tire building drum and then a fiber-filled cushion plate or rubber insert 24,. Ply beads and other conventional Components built into the tire in the usual way. The fiber-filled pad or rubber insert

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prevents cords from getting through the sealant pack be pulled through. The for the production of the invention The sealant packs used in tires were relatively old and affected by age and other factors the flow properties of the sealing compound.

After the tire has cured, the sealing compound has a somewhat higher flowability than expected. To compare the invention with the prior art, several tires are built using the combination of the ribbon wire in the belt plies and the sealant pack between the inner liner and the body plies. The tire size is GR78-15. The body layers are two radial layers made of polyester. The tires are under normal inflation pressure. You drive nails into the tires and then remove them again to see if there is a leak or not. Half of the nails are made up of 6d nails (about 5.1 cm long) and half are made up of 16d nails (about 8.9 cm long). In 96% of cases, no air escapes after removing the nails. The same test was previously performed using tires made from the same potted caulking compound and having cable wire in the belt plies. Only 39 % of the tires retained their air pressure after the nails were removed. An examination of the nails removed from the ribbon wire belted tires shows that not only sealing compound but also metal was scraped off their surface.

It can be assumed that a sealing compound, like the commercially available Rocket Research sealant that is equal to or superior to that used above. It It is anticipated that the nitrile rubber liner of the sealant pack used above tended to lose from the sealant to be stripped off before the nail penetrated the opening in the tread.

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In this application, all parts and data relate to weight, unless otherwise stated.

Ribbon wire can also be used to make the body layers.

The invention is not based on a concept of manufacture of a tire or belt plies using ribbon wire or the caulking compound. These materials have been known per se for a long time and are therefore not described in more detail. Presumably are suitable for the invention any type of tire reinforcing tape wire and any type of tire puncture sealant. The invention is based on the synergistic combination of the ribbon wire and the puncture sealant.

End of description

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Claims (1)

PATENT CLAIMS Pneumatic tires with an air chamber, beads, a carcass reinforced with at least one carcass ply, a tread surrounding the crown region of the carcass and at least one circumferentially around the crown region the carcass between this and the tread arranged belt ply to reinforce the tread, characterized in that at least one belt reinforcement layer (9, 11) with flat steel wires (23) is present, which is twice as wide than are thick, with the broad faces of the wires perpendicular to the radius of the tire, and that in combination therewith a puncture sealing compound (1) between the air chamber (4) and the belt reinforcement layer (s) (n). (9, 11) is arranged. Tire according to claim 1, characterized in that it a belt or radial tire and that the reinforcing belt plies (9, 11) are two adjacent plies of Comprise flat wires (23), the wires each. Belt- _ 1 ..
9098U / 0636 ORfGfNAl INSPECTED was at an angle to the circumferential center line of the Tires from 15 to 30 ° and at an angle to each other are arranged from 30 to 60 °. - 2 9098U / 0636