FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13) 1. Title of the invention: PUNCTURE SEALANT EXTRUSION
2. Applicant(s)

NAME NATIONALITY ADDRESS
CEAT LIMITED Indian RPG HOUSE, 463, Dr. Annie Besant Road, Worli, Mumbai, Maharashtra 400 030, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD [0001] The present subject matter relates, in general, to puncture sealant and, particularly but not exclusively, to extrusion of the puncture sealant in tire manufacturing process.
BACKGROUND [0002] A puncture sealant is used to repair a tire when the tire undergoes a puncture. The puncture sealant may be externally applied to the tire after the tire is manufactured completely. Alternatively, the puncture sealant may be in-built in the tire, during process of manufacturing the tire. The puncture sealant built in the tire is in form of a sheet and is applied upon inner liner of the tire. The sheet of the puncture sealant may be obtained by process of extrusion, for example, by way of a die.
BRIEF DESCRIPTION OF DRAWINGS [0003] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.
[0004] Fig. 1 illustrates a puncture sealant extrusion assembly, in accordance with an embodiment of the present subject matter.
[0005] Fig. 2(a) illustrates an isometric view of the die holder, in accordance with another embodiment of the present subject matter.
[0006] Fig. 2 (b) illustrates another isometric view of the die holder, in accordance with yet another embodiment of the present subject matter
[0007] Fig. 2(c) illustrates a cross sectional view of the die holder and the cavity of the die holder, in accordance with an implementation of the present subject matter.

[0008] Fig. 2(d) illustrates an outline of the cavity of the die holder in accordance with another implementation of the present subject matter.
[0009] Fig. 3 illustrates a cross sectional view of the die block, in accordance with yet another implementation of the present subject matter.
DETAILED DESCRIPTION [0010] The present subject matter is directed towards to aspects relating to extrusion of puncture sealant sheet.
[0011] Puncture in a tire leads to under inflation. Under inflation in tires amount to increase in tire wear, tire heating, and fuel consumption of vehicle. Further, the under inflation also leads to reduction in resistance of punctures and cuts to tire. The puncture sealant sheet blocks region of the tire affected by puncture and prevent under inflation. Since, the puncture can affect tread part of the tire, it is desirable to have the puncture sealant sheet uniformly spread inside the tire.
[0012] Conventionally known puncture sealant sheets are generally made of rubber material. Known dies used for extrusion of the puncture sealant include multiple circular holes to extrude the material of the puncture sealant in form of parallel noodles. After the extrusion, the parallel noodles swell, coalesce, and bond with each other due to complex nature and flowability of the material. As a result, the extrusion of the puncture sealant in form of sheets of uniform cross section is difficult to achieve, hence, dimensional accuracy of the puncture sealant sheet with respect to the tire cannot be met. Additionally, non-uniform bonding of the noodles amounts to capture of ambient non-desirable components in the puncture sealant sheet. The non-uniform bonding and the capture of the non-desirable components affects uniformity of cross-section of the puncture sealant sheet, mismatch between the puncture sealant sheet and the tire, and in turn affects the strength of the puncture sealant sheet across cross section of the puncture sealant sheet. Thus, puncture sealant sheets extruded from conventionally known dies often have multiple deficiencies associated with non-

uniformity of the cross section of the puncture sealant sheet and strength, as a result, the puncture sealant sheets may not effectively prevent under inflation in case of puncture.
[0013] To this end, a die block for extrusion of puncture sealant sheets is disclosed. Example of the die block for extrusion described herein provides for uniform puncture sealant sheets. The die block for extrusion of puncture sealant sheets and apparatus associated with the die block overcomes the above-described problems associated with strength and performance of the puncture sealant sheet and tire of a vehicle. [0014] In accordance with an embodiment of the present subject matter, the die block may have a rectangular cross-section and a width. Further, an extrusion cavity is formed in the die block, such that an opening of the extrusion cavity is aligned along the width of the die block. Furthermore, the extrusion cavity is defined by a first wall, a second wall and two side walls formed within bulk of the die block. The first wall has a flat surface. The second wall is formed opposite to the first wall, and a surface of the second wall has a plurality of semi-circular curvatures. Additionally, the two side walls are formed between the first wall and the second wall. [0015] The die block as disclosed in the present subject matter is used for extruding uniform puncture sealant sheet. The material gets extruded as the puncture sealant sheet with connected noodles having a flat base uniformly. The flat base of the extruded puncture sealant sheet provides higher dimensional accuracy and uniformity in distribution of the puncture sealant material. Further, the semi-circular shape of the noodles arranged adjacent to each other with the flat base and angular edges eliminates distortion of the puncture sealant sheet at the occurrence of puncture. Thus, the present subject matter provides an effective way of extrusion with an effective utilization of the puncture sealant material. Further, the die block of the present subject matter may be implemented in existing extrusion assemblies as well to provide ease in application and uniform application of the material throughout the circumference of tire without incurring the expense of acquiring or modifying extrusion assemblies.

[0016] These and other advantages of the present subject matter would be described in greater detail in conjunction with the following figures. While aspects of the disclosed puncture sealant extrusion can be implemented in any number of different configurations, the embodiments are described in the context of the following device(s) and method(s).
[0017] Fig. 1 illustrates a puncture sealant extrusion assembly 100, in accordance with an embodiment of the present subject matter.
[0018] In an implementation, the puncture sealant extrusion assembly 100 includes an extruder hopper 102. The extruder hopper 102 is fed with material 104 of a puncture sealant. In an example, the material 104 to the extruder hopper 102 may be fed manually. In another example, the material 104 to the extruder hopper 102 may be fed by an automated mechanism. In yet another example, the material 104 of the puncture sealant may be in form of cream, gel, emulsion, solution, or liquid composition.
[0019] In another implementation, the puncture sealant extrusion assembly 100 may include an extruder screw assembly 106. The extruder screw assembly 106 may be attached to the extruder hopper 102, such that, the extruder hopper 102 transfers the material 104 to the extruder screw assembly 106 to mix the material 104 to form a uniform composition. Further, at one end of the extruder screw assembly 106 a die holder 108 may be mounted in accordance with the present subject matter. In an embodiment, a die block 110 may be detachably mounted on the die block 110. In an example, the die block 110 may receive the material 104 from a nozzle of the extruder screw assembly 106 for extrusion of the material 104 in form of puncture sealant sheets of pre-determined, uniform, and continuous profile.
[0020] The puncture sealant extrusion assembly 100 may further include a conveyor assembly 112 and a winding assembly 114 in accordance with the present subject matter. In an example, the conveyor assembly 112 may constitute a liner 116, a conveyor rollers 118, and motor 120. In an implementation, the liner 116 is

configured to receive the puncture sealant sheets extruded from the die block 110. The liner 116 is a carrier of the puncture sealant sheet and is made up of material compatible with the material 104 of the puncture sealant sheet. Additionally, the liner 116 is placed on the conveyor rollers 118 actuated by way of the motor 120, in an example of the present subject matter.
[0021] In an implementation of the present subject matter, the conveyor assembly 112 transfer the puncture sealant sheet from the die block 110 to the winding assembly 114. In an example, the winding assembly 114 includes a material shell 122 and winding rotor 124. In another example, the winding rotor 124 enables rotation of the material shell 122. In accordance with an embodiment of the present subject matter, the puncture sealant sheet from the liner 116 is fed into the material shell 122. The puncture sealant sheet is winded up in the material shell 122. In an example, a pre¬determined quantity of the puncture sealant sheet is allowed to wind up. In another example, the pre-determined quantity of the puncture sealant sheet to be winded up is based on circumference of tire onto which the puncture sealant sheet has to be applied. Accordingly, the pre-determined quantity of the puncture sealant sheet may vary based on dimension of the tire.
[0022] In an embodiment, after the pre-determined quantity of the puncture sealant sheet is wound up, the material shell 122 is detached from the winding rotor 124 and stored separately.
[0023] In operation, the material 104 of the puncture sealant is fed into the extruder hopper 102 manually. The material 104 flows from the extruder hopper 102 and fills screw thread grooves of the extruder screw assembly 106, by way of a feed roller (not shown). The material 104 is split and squeezed in the extruder screw assembly 106 to form a uniform composition of the material 104. The material 104 with uniform composition is pushed to an inlet of the die block 110 by of the nozzle of the extruder screw assembly 106 through the die holder 108. The material 104 from the die block 110 is extruded as puncture sealant sheet having a continuous profile. Further, the

puncture sealant sheet extruded from the die block 110 is passed onto the liner 116 on the conveyor. The conveyor actuates by the motor 120 and delivers the liner 116 with the puncture sealant sheet to the winding assembly 114. Next, the material shell 122 of the winding assembly 114 receives the puncture sealant sheet from the liner 116 and winds up the puncture sealant sheet in the pre-determined quantity. [0024] Thus, the puncture sealant sheet of continuous and uniform profile extruded from the die block 110 is transferred to unit for manufacturing of the tire without deformation to the profile, as a result, dimensional accuracy needed for efficient functioning of the puncture sealant sheet is obtained. Further, the material shell 122 allows variation in quantity of the puncture sealant sheet based on size of tire, hence, the puncture sealant extrusion assembly 100 can be used for different tires, adding to acceptability, cost efficiency, and adaptability of the puncture sealant extrusion assembly 100.
[0025] Figs. 2(a) and 2(b) illustrate isometric views of the die holder 108, in accordance with embodiments of the present subject matter. In an example, the die holder 108 may be formed as a single piece. In another example, the die holder 108 may be formed of two half sections. The two half sections of the die holder 108 may be a top portion and a bottom portion. In an example, the top portion and the bottom portion of the die holder 108 may be mounted on each other to form the die holder 108 through holes provided thereon. In another example, the bottom portion of the die holder 108 is provided with holes for mounting the top portion of the die holder 108. [0026] In accordance with the present subject matter, the die holder 108 has a die fitting area 200. The die fitting area 200 has connectors enabling mounting of the die block 110 onto the die holder 108. In an example, the connectors may be holes on which the die block 110 is mounted by fastening means.
[0027] In an implementation, the die holder 108 has an input opening 202 provided for fitting of the nozzle of the extruder screw assembly 106. The nozzle of the extruder screw assembly 106 opens in cavity 204 of the die holder 108.

[0028] Fig. 2(c) illustrates cross sectional views of the die holder 108 and the cavity 204 of the die holder 108, in accordance with an embodiment of the present subject matter. Further, Fig. 2(d) illustrates outline of the cavity 204 of the die holder 108 in accordance with another embodiment of the present subject matter. For sake of clarity, Fig. 2(c) and Fig. 2(d) will be explained together.
[0029] In an implementation of the present subject matter, the cavity 204 of the die holder 108 may be in form of a trapezoid. Further, the input opening 202 of the cavity 204 of the die holder 108 circular in shape and output opening of the cavity 204 is rectangular.
[0030] Arrows in Fig. 2(c) show flow of the material 104 in the cavity 204. In an example, pressure of the material 104 flowing through the die holder 108 cavity 204 is higher at center of the cavity 204 than at sides as, inter molecular friction in the material 104 is much lesser as compared to frictional force between the material 104 and walls of the cavity 204. Thus, the material 104 will have greater flow towards core of the cavity 204 as compared to flow near to the walls of the cavity 204 of the die holder 108.
[0031] Fig. 3 illustrates a cross sectional view of the die block 110, in accordance with an embodiment of the present subject matter. The die block 110 in accordance with an implementation of the present subject matter, has a rectangular cross-section and has a width W. In another implementation, an opening of an extrusion cavity 302 is aligned along the width W of the die block 110. The die block 110 further may have die mounting holes for mounting the die block 110 on respective cavity 204 of the die holder 108.
[0032] In an embodiment the extrusion cavity 302 is defined by a first wall 304, a second wall 306, and two side walls 308, 310 with bulk of the die block 110. In an example, the first wall 304 has a flat surface. Further, the second wall 306 is formed opposite to the first wall 304. In an embodiment, surface of the second wall 306 has multiple semi-circular curvatures. In an example, the two side walls 308, 310 are

formed between the first wall 304 and the second wall 306. In an embodiment, the two side walls 308, 310 are perpendicular to the first wall 304 and the second wall 306. According to the present subject matter, the extrusion cavity 302 of the die block 110 has flat base and curved top surface.
[0033] In an implementation of the present subject matter, the extrusion cavity 302 has the inlet for ingress of the material 104 to be extruded. Additionally, the extrusion cavity 302 has an outlet for egress of extruded material, in form of a sheet of a continuous profile. In example, the outlet may egress the puncture sealant sheet of a continuous profile.
[0034] In an embodiment, the multiple semi-circular curvatures of the die block 110 are linked to each other. In an example, a minimal of 0.3 mm distance may be maintained between each semi-circular curvature from amongst the multiple semi-circular curvatures.
[0035] In another embodiment, the multiple semi-circular curvatures have curvatures of varying diameter. In an example, diameter of the multiple semi-circular curvatures in region one B and region three B is larger than diameter of the multiple semi-circular curvatures in region two A. The region one B and the region three B are regions around left and right peripheral ends of the second wall 306. Further, the region two A is region around center of the second wall 306. Accordingly, the semi-circular curvatures at the center of the second wall 306 of the die block 110 have lesser diameter than that of the diameter of the semi-circular curvatures towards the peripheral walls or edges.
[0036] In an exemplary embodiment, the diameter of the semi-circular curvatures in region two A is lesser than the diameter of the semi-circular curvatures in region one B and region three B, that is, A