FIELD OF THE INVENTION

The present invention generally relates to sealant compositions and more particularly to a sealant composition for self-repairing and puncture resistant tires with enhanced sealing effectiveness.

BACKGROUND OF THE INVENTION

There are many transportation methods today that incorporate inflatable pneumatic tires. A flat tire is always a risk and its repair is time consuming and inconvenient. Some of the repair solutions require the user to disassemble and reassemble the tire valve. In most cases, there is a need to disassemble and reassemble the entire tire. These procedures require a great amount of technical skill.

One simple option to repair a puncture is the use of various puncture sealants. These sealant compositions are convenient and tires can often be treated easily even at a remote location.

Conventional tire sealant compositions include a solid component dispersed in a liquid carrier. The solid component intends to seal the tire before a puncture, tear or rupture causing loss in inflation. There are problems associated with the conventional composition such that the compositions have been known to accumulate on the inside of the tire. This affects the balance and ultimately the ride and rotation of the tire is hindered. In addition, the solid component does not properly disperse in the liquid carrier. This results in escaping of the liquid carrier and solid component from the tire through the puncture of the tire without any sealing. Therefore there remains a need for using such tire sealant composition which evenly coats the inner side of the tire instead of pooling therein. Some of the known compositions include water-based latexes, which are effective for only a short time, because they dry by evaporation and coagulation, leaving a rubbery mass. Another known type of tire sealant employs a solution of sodium silicate or similar materials which dry to form a sealing plug. Solutions of dextrin and similar organic gums have also been used. All of these compositions have the shortcoming such as they dry after a relatively short period of time and therefore cannot be used for permanent or long-term protection from punctures.

There have been a number of sealant compositions provided for tire puncture repair and few of them have been discussed below.

CN103640235B discloses an automatic automobile inflation tire- mending liquid and a preparation method thereof. The liquid comprises of nitrile rubber powder, ethylene glycol, distilled water, stabilizer, thickening agent, tackifier, emulsifying agent, preservative and propellant. US5772747A discloses a sealant composition comprising a viscous fluid such as propylene glycol or polypropylene glycol, one or more fibrous materials such as cellulose, wool, nylon, rayon, hair, wollastonite, rock-wool, glass wool fibers, polyester, polypropylene, or other material of like nature; and flat plate-like particles, such as mica. US5364463A discloses a sealant composition containing a hydratable salt and clay such as barium sulfate and sodium bentonite and a substantial portion of a plate like mineral such as mica. It relates to a composition and method for preventing inflation loss due to puncture of vehicle tires and increases tire weight providing ballast.

US9126375B2 reported two sealant embodiments. In one embodiment, the composition was too viscous to be readily passed through a pneumatic tire valve stem, so the viscous product is installed into the tire while the tire is dismounted from the wheel. In another embodiment, the composition was made of two parts, each of which is sufficiently low in viscosity to pass readily through the valve stem, but which react on mixing inside the tire to form a liquid of higher viscosity. This invention used propylene glycol in place of ethylene glycol to eliminate toxicity.

The aforesaid documents and similar disclosures which talk about varied tire sealant compositions comprise of number of shortcomings and drawbacks such as, but not limited to, continuous leakage of the composition through the repair plug formed by the fibers, thus allowing the liquid to eventually leak from the tire. When this happens, the sealant is no longer effective in case of series of punctures.

Accordingly, there remains a need in the prior art to have an improved tire sealant composition which overcomes the aforesaid problems and shortcomings.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a sealant composition.

Another object of the present invention is to provide the sealant composition for self-repairing and puncture resistant tires with enhanced sealing effectiveness.

Yet another object of the present invention is to provide the sealant composition which is helpful for stopping air loss through accidental punctures in pneumatic rubber vehicle tires. Yet another object of the present invention is to provide the sealant composition which is capable of lining and sealing the punctured tire while vehicle is in motion.

Yet another object of the present invention is to provide the tire sealant composition which saves cost substantially and possesses high flexural strength.

Yet another object of the present invention is to provide the tire sealant composition which helps in increasing the life of tire by ensuring puncture prevention support. Yet another object of the present invention is to provide the tire sealant composition that possesses anti-sagging property.

Yet another object of the present invention is to provide the tire sealant composition with uniform viscosity even at varying temperatures.

SUMMARY OF THE INVENTION Embodiments of the present invention aim to provide a sealant composition for self-repairing and puncture resistant tires with enhanced sealing effectiveness. The disclosed sealant composition ensures 75% - 100% air retaining capacity for a hole created by a puncturing object having diameter upto 9.5 mm. Hence, provides efficient sealing of the punctured tire. Further, the sealant composition possesses an anti-sagging property that helps in achieving a proper puncture sealing and the sealant composition continues to line the inner surface of the tire. Also, the sealant composition is potential cost saver and easy to prepare.

According to an embodiment of the present invention, a sealant composition, comprises an adhesive material present in a range of, but not limited to, 27-33% by weight, an anti-freezing agent present in a range of, but not limited to, 27-33% by weight, a plurality of thickening agents present in an amount upto, but not limited to, 2% by weight, water present in a range of, but not limited to, 28-32% by weight, a plurality of solid additives and a plurality of fibrous materials.

According to an embodiment of the present invention, the adhesive material is an, but not limited to, Ethylene-Vinyl Acetate (EVA) based Polyvinyl Acetate Emulsion (PAE).

According to an embodiment of the present invention, the anti-freezing agents are selected from a group consisting of, but not limited to, ethylene glycol, propylene glycol, polyethylene glycol and polypropylene glycol.

According to an embodiment of the present invention, the plurality of solid additives is selected from a group consisting of, but not limited to, sodium chloride (NaCI), rubber crumb, mica and a plurality of anti-sagging agents.

According to an embodiment of the present invention, the plurality of anti-sagging agents are present in a range of, but not limited to, 2-6% by weight. Further, the plurality of anti-sagging agents are selected from a group consisting of, but not limited to, ceramic microspheres. According to an embodiment of the present invention, the rubber crumb is having size in a range of, but not limited to, 800-1400 microns.

According to an embodiment of the present invention, the mica is having a particle size upto, but not limited to, 60 microns.

According to an embodiment of the present invention, the mica is present in an amount upto, but not limited to, 2% by weight. According to an embodiment of the present invention, the sodium chloride (NaCI) is present in a range of, but not limited to, 0.4-5% by weight.

According to an embodiment of the present invention, the plurality of fibrous materials are selected from a group consisting of, but not limited to, cellulose, wool, nylon, rayon, hair, wollastonite, rock-wool, glass wool fibers, polyester, carbon fibers and polypropylene.

According to an embodiment of the present invention, the carbon fibers having a predetermined length is present in a range of, but not limited to, 2- 5% by weight. Further, the length of the carbon fibers is in a range of, but not limited to, 3-6 mm.

According to an embodiment of the present invention, the plurality of thickening agents is select from a group consisting of, but not limited to, xanthum gum (XG) and cross-linked carboxymethyl cellulose (CMC).

According to an embodiment of the present invention, the sealant composition, further comprises a plurality of rest of the additives present in an amount <1% by weight.

According to an embodiment of the present invention, the plurality of rest of the additives is selected from a group consisting of, but not limited to, potash alum, a plurality of antioxidants, anti-fungal agent, colorant, fragrant and other miscellaneous additives.

According to an embodiment of the present invention, the plurality of antioxidants are selected from a group consisting of, but not limited to, phosphoric acid and triethanol amine. According to an embodiment of the present invention, the sealant composition blocks the hole created by a puncturing object having diameter upto 9.5 mm.

According to an embodiment of the present invention, the sealant composition has a viscosity in a range of, but not limited to, 2200-3300 cP at room temperature of 25°C and at 20 rpm.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular to the description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, the invention may admit to other equally effective embodiments. These and other features, benefits and advantages of the present invention will become apparent by reference to the following text figure, with like reference numbers referring to like structures across the views, wherein:

Fig 1 is a graph showing the variation of a composition viscosity as a function of temperature using an Anton-Paar rheometer in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described, and are not intended to represent the scale of the various components. It should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claim. As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one" and the word "plurality" means "one or more" unless otherwise mentioned. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes.

In this disclosure, whenever a composition or an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element or group of elements with transitional phrases "consisting of, "consisting", "selected from the group of consisting of, "including", or "is" preceding the recitation of the composition, element or group of elements and vice versa.

The present invention is described hereinafter by various embodiments with reference to the accompanying drawing, wherein reference numerals used in the accompanying drawing correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the following detailed description, numeric values and ranges are provided for various aspects of the implementations described. These values and ranges are to be treated as examples only, and are not intended to limit the scope of the claims. In addition, a number of materials are identified as suitable for various facets of the implementations. These materials are to be treated as exemplary, and are not intended to limit the scope of the invention. According to an embodiment of the present invention, a sealant composition comprises an adhesive material, an anti-freezing agent, a, a plurality of thickening agents, water, plurality of solid additives and a plurality of fibrous materials.

In accordance with an embodiment of the present invention, the adhesive material is capable of providing adequate cohesion of the sealant components with the tire lining. Further, the adhesive material is present in a range of, but not limited to, 27-33% by weight. Further, the adhesive material used is, but not limited to, an Ethylene-Vinyl Acetate (EVA) based Polyvinyl Acetate Emulsion (PAE). In accordance with an embodiment of the present invention, the anti- freezing agent is present in a range of, but not limited to, 27-33% by weight. Further, the anti-freezing agents is selected from a group consisting of, but not limited to, ethylene glycol, propylene glycol, polyethylene glycol and polypropylene glycol.

In accordance with an embodiment of the present invention, the plurality of solid additives are selected from a group consisting of, but not limited to, sodium chloride (NaCI), rubber crumb, mica and a plurality of anti- sagging agents.

In accordance with another embodiment of the present invention, the plurality of anti-sagging agents are present in an amount ranging from, but not limited to, 2-6% by weight. Further, the plurality of anti-sagging agents are selected from a group consisting of, but not limited to, ceramic microspheres. The anti- sagging property helps the sealant composition to line and coat the tire even after the vehicle is stopped. The typical size of such ceramic microspheres used is upto, but not limited to, 200 microns and helps to fill the spaces in the network provided by the carbon fibers. The shape, size and chemical nature of the ceramic microspheres also help to reinforce the network so created by the carbon fibers more effectively. Further, mica having a particle size upto, but not limited to, 60 microns is used in an amount upto, but not limited to, 2% by weight. Further, the rubber crumb is used within a range of, but not limited to, 0.5-1.5 % by weight having size in a range of, but not limited to, 800-1400 microns. Further, sodium chloride (NaCI) is present in a range of, but not limited to, 0.4-5% by weight.

In accordance with an embodiment of the present invention, the fibrous materials such as carbon fibers provide a high flexural strength to the composition and reduces air exit from the tire during puncture. Further, the plurality of fibrous materials is selected from a group consisting of, but not limited to, cellulose, wool, nylon, rayon, hair, wollastonite, rock-wool, glass wool fibers, polyester, carbon fibers and polypropylene. Further, the carbon fibers used possess a length in a range of, but not limited to, 3-6 mm and is present in an amount ranging from, but not limited to, 2-5% by weight.

In accordance with another embodiment of the present invention, the plurality of thickening agents provide a uniform viscosity to the sealant composition for its flow within the tire during normal running of vehicle and specifically during the time of puncture of the tire. Further, the plurality of thickening agents is present in an amount upto, but not limited to, 2% by weight. Further, the plurality of thickening agents used is selected from a group consisting of, but not limited to xanthum gum and cross-linked carboxymethyl cellulose CMC.

In accordance with another embodiment of the present invention, the sealant composition further comprising water present in a range of, but not limited to, 28-32% by weight. In accordance with another embodiment of the present invention, the sealant composition comprising a plurality of rest of the additives provides viscosity to the sealant composition. Further, the plurality of rest of the additives are preferably present in an amount <1% by weight. Further, the plurality of rest of the additives is selected from a group consisting of, but not limited to, potash alum, a plurality of antioxidants, anti-fungal agent, colorant, fragrant and other miscellaneous additives

In accordance with another embodiment of the present invention, the plurality of antioxidants are selected from a group consisting of, but not limited to phosphoric acid and triethanol amine. Further, the antioxidants is used in an amount upto, but not limited to, 1% by weight.

According to another embodiment of the present invention the tire sealant composition has the capability to completely block a hole, created by a puncturing object having diameter upto 9.5 mm and retaining 75% -100% air in the tire. The puncturing object is selected from a group consisting of, but not limited to, a nail, a screw, a thorn, a pin, a railroad spike and a glass piece. Further, the sealant composition has a viscosity in a range of, but not limited, to 2200-3300 cP at room temperature of 25°C and at 20 rpm. The viscosity of the sealant composition remains uniform with a minimal standard deviation of 3.5% as shown in figure 1. Hereinafter, examples of the present invention will be provided for more detailed explanation.

Examples

Example 1

1. Preparation of a sealant composition. The components used in the formulation included double distilled water. Xanthum gum (XG) was taken as a thickening agent in an amount of 1% by weight, Ethylene-Vinyl Acetate (EVA) based Polyvinyl Acetate Emulsion (PAE) was taken as an adhesive material, Ethylene Glycol was taken as an anti-freezing agent in an amount of 29.5% by weight, 3mm length carbon fibers were taken in an amount of 2-3% by weight, about 1100 micron or 24 mesh sized rubber crumb was taken as fibrous material, mica was taken with average particle size in a range of 25-50 microns., ceramic microspheres or ceramic glass microspheres or ceramic glass beads were taken as anti- sagging agents from 3M (~25 micron size) and sodium chloride (NaCI) was taken in an amount of 0.5% by weight. Apart from this, rest of the solid additives were taken in an amount of <0.5% by weight. The rest of the solid additives were namely potash alum taken in an amount of 1% by weight, followed by antioxidants. The antioxidants taken were phosphoric acid and triethanol amine in a ratio of 1 :5 of about 0.5 % by weight. The ceramics content was limited to 2-6% range. The extent of stirring of formulation and defibrillation of carbon fibers was limited such that composition viscosity remained in the range 2300 to 3000 cP as estimated using Anton-Paar Rheometer at room temperature of 25°C and at 20 rpm.

EXAMPLE 2

The sealant composition as proposed in example 1 was tested in an assembly in lab where a 155/80 R 13 tire was filled with about 350 gms of the sealant composition. The 155/80 R 13 tire was filled with air to maintain a pressure of 35 psi and then punctured with a 9.5 mm nail. The 155/80 R 13 tire was then rotated for 5 mins at a speed of 60 km/hr to uniformly wet the inner surface of the 155/80 R 13 tire. Further, the nail was removed and the 155/80 R 13 tire was subsequently quickly rotated from rest to 60 km/hr. After rotating the 155/80 R 13 tire for a period of 1 min, the 155/80 R 13 tire was stopped and the tire sealing was then qualitatively observed through a visual inspection. Further, the pressure of air remaining in the 155/80 R 13 tire was captured using a pressure measuring device. An average of residual air pressure of 5 such tests is then noted.

EXAMPLE 3

The composition as mentioned in example 1 was checked for its anti-sagging property. To demonstrate this, a 155/80 R 13 tire was opened and filled with 350 gm of the composition. The 155/80 R 13 tire was then rotated such that the 155/80 R 13 tire was wetted uniformly with the composition. Further, after 70-80 hrs the 155/80 R 13 tire was kept stationary and the coated composition was observed after a period of every 12 hours.

RESULTS

Characterization for its Shear Viscosity. Figure 1 is a graph showing the constant viscosity of the sealant composition with an average of 2,331 cP with a very minimal standard deviation of 3.5% across tested range of the temperature (in °C).

Referring to Figure 1 , which is a graph showing the viscosity of the sealant composition in cP as mentioned in Example 1 , as a function of temperature in °C, illustrates the characterization of the sealant composition for its shear viscosity using an Anton-Paar Rheometer. The sample was sheared at 20rpm for a temperature ranging from room temperature (RT) (~24.5°C) to 95°C. The change of viscosity as a function of temperature has been recorded and presented as shown in figure 1.

As per the composition testing, the residual sealant pressures for five such test cases for a hole created by a puncturing object having diameter upto 9.5 mm were recorded as 31 , 26, 28, 24 and 21 psi. Further, the average residual pressure calculated was 26.0 psi. The result was extrapolated to ensure an air retaining capacity of 75% air in the 155/80 R 13 tire or a 25% air loss from the 155/80 R 13 tire.

As per the composition testing for anti-sagging property, it was observed that the formulation visually qualitatively continued to wet and adhere to the 155/80 R 13 tire surface for a period of upto 60 hours which is general vehicle requirement. Further, the test clearly demonstrated the anti- sagging property and its usefulness.

CONCLUSION

A sealant composition for self-repairing and puncture resistant tires with enhanced sealing effectiveness has been successfully prepared. The sealant composition described above offers a number of advantages. Further, the sealant composition possesses anti-sagging property. Hence, the sealant composition achieves a proper puncture sealing when the vehicle has started after halt. Also, the sealant composition ensures an air retaining capacity of 75-100% air in the tire. Further, the sealant composition shows constant viscosity even at high temperature. Also, the sealant composition saves cost substantially and is easy to prepare.

Various modifications to these embodiments are apparent to those skilled in the art from the description and the accompanying drawings. The principles associated with the various embodiments described herein may be applied to other embodiments. Therefore, the description is not intended to be limited to the embodiments shown along with the accompanying drawings but is to be provided broadest scope consistent with the principles and the novel and inventive features disclosed or suggested herein. Accordingly, the invention is anticipated to hold on to all other such alternatives, modifications, and variations that fall within the scope of the present invention and appended claims.