DESC:TECHNICAL FIELD
[001] The embodiments disclosed in this specification generally relate to adhesion or bonding systems, and more particularly to rubber adhesive systems and compositions capable of bonding surfaces.
BACKGROUND
[002] Adhesives are substances capable of bonding two surfaces of an object or different objects in order to achieve low or no permeability to external factors such as air, water, etc. A good adhesive ensures good bonding between the two surfaces. The chemical structure and properties of rubber make it an ideal choice for use as adhesives suitable for industrial application. Rubber adhesives find use in automobile, manufacturing, construction and so on.
[003] The selection of rubber adhesive may depend on the nature of its application. Various types of rubber adhesives are known and used in producing durable and high strength bonding. Rubber bonding systems may be used to bond surfaces such as rubber to metal, rubber to plastic, metal to metal or rubber to rubber.
[004] Generally known rubber bonding systems involve the use of hazardous solvents. These methods may also involve heat and pressurized adhesion. The rubber adhesives that are generally used are in liquid form which is applied by brushing or spraying onto the surface intended for bonding followed by exposure to heat. The application of such liquid adhesives may not always be satisfactory as brushing or spraying fail to provide a layer of uniform thickness which affects the quality of bonding strength.
[005] An establishment of interfacial contact at a molecular level between the activated adhesive and the surfaces would mean a strong adhesion between the object surfaces. A composition capable of establishing strong interfacial bonding by crosslinking at a physical and chemical level would accord as a strong adhesive. In the case of bonding rubber surfaces, in order to achieve bonding by rubber adhesives, the rubber part is exposed to heat after adhesive application and then bonded onto the other surface by vulcanization. However, this method may not always lead to uniformity in adhesion as the heating may not always be uniform throughout the rubber surface. This may lead to unsatisfactory results. Also, the known methods require skilled manpower to achieve bonding efficiently. Further, the process is tedious requiring pre-treatment of the surface once the adhesive is applied. It would be considered convenient if adhesive systems are capable of establishing strong interfacial bonding without such pre-treatment techniques. It would also be convenient if bonding can be achieved by simpler techniques without the need for mechanized or manual interference of skilled personnel. Therefore, there exists a need for an effective and simple rubber bonding system.
OBJECTS
[006] The principal object of the embodiments disclosed herein is to provide a rubber adhesive composition.
[007] A second object of the embodiments disclosed herein is to provide a method of bonding rubber surface(s).
[008] A further object of the embodiments disclosed herein is to provide a method of bonding tube valve to tire tubes conveniently, without the use any hazardous solvent.
[009] Yet another object of the embodiments disclosed herein is to provide a ‘Ready-to-use valve’ capable of bonding with a tire tube without the requirement for additional adhesive application.
[0010] A further object of the embodiments disclosed herein is to provide a method for producing a ‘Ready-to-use valve’.
[0011] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF FIGURES
[0012] The embodiments disclosed herein are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0013] Fig.1 is a representation illustrating a ready-to-use valve, according to the various embodiments disclosed herein;
[0014] Fig. 2 is a pictorial representation of a ready-to-use valve, having a layer of rubber adhesive composition, according to the various embodiments disclosed herein;
[0015] Fig. 3 is a flowchart depicting the process for the preparation of ready-to-use valve, according to the various embodiments disclosed herein.

DETAILED DESCRIPTION
[0016] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0017] The embodiments herein achieve a bonding system capable of industrial application. Disclosed herein are embodiments of a rubber adhesive composition and method of preparation thereof. The disclosed embodiments of adhesive composition are capable of achieving durable and high strength adhesion conveniently. Also disclosed are embodiments of a method of bonding rubber surfaces. Further, the various embodiments disclosed herein also include a convenient method of bonding tube valve to tire tubes, without the requirement of additional application of adhesives. The embodiments disclosed herein also include a ready-to-use valve and method of manufacture thereof.
Composition
[0018] The embodiments herein disclose a rubber adhesive composition. In an embodiment, the rubber includes an effective amount of a rubber component, at least one activator, at least one filler, at least one plasticizer and at least one curative package.
[0019] In an embodiment, the rubber component shall mean and include natural rubber. In another embodiment, the composition shall mean and include at least one of, but not limited to, the following synthetic rubber: poly isoprene, poly butadiene, halogenated butyl rubber and ethylene propylene rubbers. In yet another embodiment, the rubber component shall mean and include reclaimed rubber. Reclaimed rubber used in the various embodiments herein may be achieved by various methods generally known in the field. In another embodiment, the rubber component shall mean and include a combination of natural and synthetic rubber.
[0020] The disclosed composition includes plasticizers. In an embodiment, the composition includes at least one plasticizer selected from a group consisting of paraffinic plasticizer, rubber processing oils and processing aids. The plasticizer may further include at least one tackifier. In an embodiment, the tackifier is a resin which is compatible with the base polymer used in the composition.
[0021] In an embodiment, the plasticizer includes processing oils, processing aids and resins. In an embodiment, the effective amount of plasticizer is in the range of 1 part to 20 parts by weight per 100 parts by weight of rubber component.
[0022] The disclosed composition includes activators. The activators that may be used in the various embodiments herein may be selected from a list of generally known activators. In an embodiment, the composition includes at least one activator selected from a group consisting of Zinc oxide, metallic oxides and fatty acids. In an embodiment, the activator is a metallic oxide. In another embodiment, the activator is at least one of zinc oxide and fatty acids. In an embodiment, the effective amount of activator is in the range of 1 part to 20 parts by weight per 100 parts by weight of rubber component.
[0023] The composition further includes fillers. In an embodiment, the composition includes at least one filler selected from a group consisting of reinforcing fillers, semi-reinforcing fillers and extenders. In an embodiment, the fillers are silica fillers. In another embodiment, the composition includes carbon black fillers. In an embodiment, the effective amount of filler is in the range of 20 to 90 parts by weight per 100 parts by weight of rubber component.
[0024] The composition includes curative package or curing system. In an embodiment, the composition includes at least one of curative selected from a group consisting of Sulphur Zinc oxide and peroxide curing system. In another embodiment, the curative package includes accelerators and vulcanizing agents. Selection of accelerators is based on the curing system selected. In an embodiment, the effective amount of curative package is in the range of 3 parts to 10 parts by weight per 100 parts by weight of rubber component.
[0025] The rubber adhesive composition disclosed herein may further additionally include other additives, accelerators, activators, fillers, etc that are generally known to be included in such adhesive compositions. It will be apparent to those skilled in the art that many additions or modifications to material and their quantities may be practiced without departing from the scope of the embodiments disclosed herein.
[0026] In an embodiment, the adhesive composition comprises rubber components in an amount of 100 parts by weight, activator in an amount in the range of 1 to 20 parts by weight; filler in an amount in the range of 20 to 90 parts by weight; plasticizer in an amount in the range of 1 to 20 parts by weight and curative package in an amount in the range of 3 to 10 parts by weight of the total composition.
[0027] In another embodiment, the adhesive composition comprises rubber components in an amount of 100 parts by weight, activator in an amount in the range of 2 to 10 parts by weight; filler in an amount in the range of 20 to 60 parts by weight; plasticizer in an amount in the range of 3 to 15 parts by weight and curative package in an amount in the range of 3 to 8 parts by weight of the total composition.
[0028] The rubber adhesive composition disclosed herein may be packaged into containers or as ready-to-use patches. In an embodiment, the composition may be packaged using polythene sheets as ready-to-use peel off patches. In another embodiment, the composition may be packaged in containers that are generally used to package rubber adhesive compositions. Table 1 illustrates an embodiment of rubber adhesive composition.
[0029] Table 1:
No. Ingredients Dosage (phr)
1 Natural /Synthetic Rubber/Reclaim 100
2 Activator 1 to 20
3 Filler comprising of Reinforcing/ Semi-reinforcing/ extenders 20 to 90
4 Plasticizer including tackifier 1 to 20
5 Curative package 3 to 10

Valve
[0030] The embodiments disclosed herein provide a ready-to-use valve having the adhesive composition layer disclosed in the various embodiments herein. In an embodiment, the ready-to-use valve comprises a valve stem, a rubber base having first end and second end, at least one layer of adhesive composition and a removable protective covering. In an embodiment, the tube valve is secured at the first end of the rubber base while the layer of adhesive composition is secured at the second end of the rubber base which is intended for bonding. In an embodiment, the adhesive composition includes the adhesive composition disclosed in the various embodiments herein. In an embodiment, the layer of adhesive composition is of uniform thickness which enables good rubber to rubber bonding.
[0031] The removable protective covering is secured at the open end of the adhesive layer such that the adhesive layer is protected from the atmosphere. In an embodiment, the protective covering is such that it protects the adhesive layer from contamination, exposure to air, dust, etc. In an embodiment, the removable protective covering includes a polythene sheet. In an embodiment, the removable protective covering includes an embossed polythene sheet. Fig. 1 illustrates a ready-to-use valve [100]. The ready-to-use valve [100] of Fig.1 includes a valve stem [101], a rubber base [102], a layer of rubber adhesive composition [103] and a removable protective covering [not shown]. The layer of rubber adhesive composition [103] is secured on to the rubber base [102] by applying pressure. Fig. 2 is a pictorial representation of a ready-to-use valve, according to the various embodiments disclosed herein.
Method
[0032] The embodiments disclosed herein provide a method of bonding rubber surfaces. According to the various embodiments herein, the disclosed adhesive composition after application may be directly vulcanized onto a rubber surface during adhesion. In an embodiment, the method includes applying an embodiment of the adhesive layer onto an object surface; and contacting the object surfaces intended for adhesion.
[0033] The application of the adhesive composition on the object surface may be instantaneous or a pre-application. In an embodiment, a layer of the adhesive composition may be stuck to object surface(s) instantly during the time of adhesion, followed by contacting the object surface(s) intended for adhesion. In another embodiment, the adhesive composition layer may be a pre-application, wherein one end of the adhesive layer has been secured on the object surface intended for adhesion, and is at the other end, the adhesive layer is protected from exposure to atmosphere. The pre-applied adhesive layer may be protected by a protective peel off covering. In an embodiment, the adhesive layer is protected with polythene sheet. In an embodiment, the adhesive layer is protected with embossed polyethene sheet.
[0034] Accordingly, in an embodiment, the method includes removing the protective covering to expose the pre-applied adhesive layer and contacting the object surfaces intended for adhesion.
[0035] The object surfaces according to the various embodiments herein include any object surface intended for adhesion such as rubber, metal, plastic, etc. In an embodiment, the object surfaces intended for adhesion are rubber surfaces.
[0036] The embodiments disclosed herein provide a method of bonding rubber surfaces. In an embodiment, the method of bonding comprises bonding of tube valve base and tube of a tire. In an embodiment, the method includes applying an embodiment of the adhesive layer onto a tube valve; and contacting the adhesive layer of the tube valve and tube of a tire.
[0037] In an embodiment, applying the disclosed adhesive composition layer onto a valve is instantaneous to adhesion. In alternate embodiment, the adhesive may be stuck on to the valve as a pre-application. In an embodiment, the method of pre-application of the adhesive layer includes sheeting out the adhesive to a desired thickness; cutting of the sheeted out adhesive to a desired shape; securing the valve base with the adhesive layer; and covering the adhesive layer end intended for adhesion with a protective sheet to avoid contamination. In an embodiment, the protective sheet is a polythene sheet. In another embodiment, securing the valve base with the adhesive layer includes sticking the adhesive layer onto the valve base. In an embodiment, contacting the adhesive layer of the tube valve and a tire tube further includes vulcanizing the valve onto the tube. Vulcanization may be performed by methods generally known in the field.
[0038] The embodiments disclosed herein further provide a method of preparation of a ready-to-use valve. In an embodiment, the method includes:
preparing adhesive composition by mixing of ingredients;
aging the adhesive by natural aging;
rolling of the adhesive to obtain sheets;
milling to obtain cuttings of desired shape and size;
fixing on to the valve; and
fixing of the protective covering to obtain ready-to-use valve.
[0039] Adhesive composition mentioned in the embodiments of the method is the rubber adhesive composition disclosed in the various embodiments herein. In an embodiment, the method comprises preparing adhesive composition by mixing of the following ingredients: a rubber component, at least one activator, at least one filler, at least one plasticizer and at least one curative package to obtain the adhesive composition.
[0040] In an embodiment, the fixing of the adhesive to valve is performed by applying pressure. In another embodiment, the protective covering is plain or embossed polyethene sheet.
[0041] Fig. 3 depicts the process for the preparation of an embodiment of a ready-to-use valve, according to the various embodiments disclosed herein. As depicted in Fig. 3, the ingredients are mixed to obtain rubber based adhesive composition (also referred to as gum compound). Mixing is performed to obtain a homogenous composition by methods generally known in the field. The adhesive is then allowed to age by natural aging. In one embodiment the duration for aging may range from 15 to 40 hours. In a preferred embodiment the duration for natural aging is at least 16 hours. Further, the adhesive is rolled into sheets of desired thickness. In an embodiment the desired thickness of the sheet ranges from 0.1 to 0.8 mm. The sheet of adhesive is now cut into desired shape and size as per requirement. In an embodiment, the adhesive sheets are cut out to fit the rubber base of a tire tube valve. The cut outs are now fixed onto the valve by applying pressure. Once fixed, the adhesive is covered with a protective covering such as polyethene sheet to obtain a ready-to-use valve.
Use
[0042] The embodiments disclosed herein provide use of disclosed adhesive compositions in bonding rubber surfaces. The disclosed bonding system is eco-friendly, convenient, and minimizes the need for mechanized and skilled techniques in bonding rubber surfaces. The disclosed composition is such that it may be implemented without the use of any hazardous solvents that are generally used in rubber bonding systems. The embodiments of the adhesive composition disclosed herein may be useful in bonding or adhesion of rubber to rubber surfaces, rubber to metal surfaces, rubber to plastic surfaces and rubber to glass surfaces. In an embodiment, the adhesive composition disclosed herein is used in adhesion of rubber to rubber surfaces. The embodiments of the adhesive disclosed herein may be used in adhesion of object surfaces in automobiles, manufacturing, construction, etc. In an embodiment, the rubber adhesive disclosed in the various embodiments herein is useful in adhesion of tube valves and tube of tires. In another embodiment, the rubber adhesive disclosed in the various embodiments herein is useful in adhesion of rubber base of a tube valve and a tire tube of an automobile. In an embodiment, the rubber adhesive composition disclosed in the various embodiments herein is useful in adhesion of a valve and a tube of a pneumatic tire.
[0043] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
,CLAIMS:We claim:

1. A rubber adhesive composition comprising an effective amount of a rubber component comprising reclaimed rubber; at least one activator; at least one filler; at least one plasticizer; and at least one curative package.

2. The rubber adhesive composition as claimed in claim 1, wherein the amount of said activator is in the range of 1 part to 20 parts by weight per 100 parts of rubber component.

3. The rubber adhesive composition as claimed in claim 1 and 2, wherein the amount of said activator is in the range of 2 parts to 10 parts by weight per 100 parts of rubber component.

4. The rubber adhesive composition as claimed in claim 1, wherein the amount of said filler is in the range of 20 parts to 90 parts by weight per 100 parts of rubber component.

5. The rubber adhesive composition as claimed in claim 1 and 4, wherein the amount of said filler is in the range of 20 parts to 60 parts by weight per 100 parts of rubber component.

6. The rubber adhesive composition as claimed in claim 1, wherein the amount of said plasticizer is in the range of 1 part to 20 parts by weight per 100 parts of rubber component.

7. The rubber adhesive composition as claimed in claim 1 and 6, wherein the amount of said plasticizer is in the range of 3 parts to 15 parts by weight per 100 parts of rubber component.

8. The rubber adhesive composition as claimed in claim 1, wherein the amount of said curative package is in the range of 3 parts to 10 parts by weight per 100 parts of rubber component.

9. The rubber adhesive composition as claimed in claim 1 and 8, wherein the amount of said curative package is in the range of 3 parts to 8 parts by weight per 100 parts of rubber component.

10. The rubber adhesive composition as claimed in claim 1, wherein said rubber component is 100 parts by weight of the total composition.

11. The rubber adhesive composition as claimed in claim 1, wherein said rubber component comprises at least one rubber selected from a group consisting of natural rubber, poly isoprene, poly butadiene, halogenated butyl rubber and ethylene propylene rubbers.

12. The rubber adhesive composition as claimed in claim 1, wherein said plasticizer is selected from a group consisting of processing oils, processing aids and resins.

13. The rubber adhesive composition as claimed in claim 1, wherein said activator is selected from a group consisting of Zinc oxide, metallic oxides and fatty acids.

14. The rubber adhesive composition as claimed in claim 1, wherein said filler is selected from a group consisting of white fillers and carbon black.

15. The rubber adhesive composition as claimed in claim 1, wherein said curative package is selected from a group consisting of Sulphur, Zinc oxide and peroxide curing system.
16. The rubber adhesive composition as claimed in claim 1, wherein said curative package further comprises at least one accelerator and at least one vulcanizing agent.

17. The rubber adhesive composition as claimed in claim 1, wherein said composition is secured on a tube valve comprising a valve stem and a rubber base configured for adhesion to a tire tube.

18. A tube valve [100] comprising:
a valve stem [101];
a rubber base [102] comprising a first end and a second end, wherein said first end is connected to said valve stem [101];
at least one layer of adhesive composition [103] secured to said second end of said rubber base [102]; and
a removable protective covering [not shown] secured on the layer of adhesive composition [103].

19. The tube valve as claimed in claim 18, wherein said adhesive composition comprises a rubber component comprising reclaimed rubber; at least one activator; at least one filler; at least one plasticizer; and at least one curative package.

20. The tube valve as claimed in claim 18, wherein said protective covering is polyethene sheet.

21. A method for bonding a tire tube and a tube valve claimed in claim 18, comprising removing said protective covering to expose adhesive composition; contacting said tube valve to a tire tube; and applying pressure.

22. A method for producing ready-to-use tube valve, comprising:
preparing adhesive composition by mixing a rubber component comprising reclaimed rubber; at least one activator; at least one filler; at least one plasticizer; and at least one curative package;
aging said adhesive composition by natural aging;
rolling said adhesive composition into sheets;
milling said sheets to obtain cuttings of desired shape and size;
fixing said cuttings on to rubber base of a tube valve by applying pressure; and
fixing of a protective covering to obtain a ready-to-use tube valve.