FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10; rule 13)
TITLE OF THE INVENTION “PROCESS DEVELOPMENT FOR PUNCTURE SEALANT EXTRUSION”
APPLICANT
CEAT LIMITED
of RPG HOUSE, 463, Dr. Annie Besant Road,
Worli, Mumbai 400 030, Maharashtra, India
Nationality: Indian
INVENTORS
AMIT PATIL, DIVYANSH SHUKLA, SUJITH S. NAIR AND BENNY JOSEPH
All of CEAT LIMITED
RPG HOUSE, 463, Dr. Annie Besant Road,
Worli, Mumbai 400 030, Maharashtra, India
Nationality: Indian
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner
in which it is to be performed

FIELD OF THE INVENTION
[0001] The present invention relates to the process development for puncture sealant extrusion. More particularly it discloses a manufacturing a uniform layer of sealant material, which could supply required material to seal the puncture in a tyre and also prevent air loss after tyre is punctured on road/off road during running.
BACKGROUND OF THE INVENTION
[0002] Tires running on road/off road can undergo a puncture by nails, screws or spines etc. which lead to under inflation. Under inflation is very danger situation for tyre performance as well for rider. While riding with punctured tyre rider sometimes not able to identified loss in air/ under inflation and rider continue to drive with under inflation.
[0003] Because of under inflation there is increase in tyre wear, tyre heating and fuel consumptions by vehicle. It also leads to reduction in resistance of punctures and cuts to tyre. Sometimes under inflation leads to fatal accident.
[0004] It becomes critical that to have a sealant material inside the tire in a uniform dimensions so as to ensure a sufficient material, in the puncture prone zone, to seal the puncture.
[0005] Current techniques available are:-
1- Inserting liquid sealant through valve in cured tyre
2- Melt and spray technique in cured tyre
3- Sandwiched between liner and rubber in green tyre
4- Extrusion process
[0006] Brief Explanation of the extrusion process-Figure 1 shows the general steps carried out in performing the extrusion process. Compound (1) will be fed into extruder hopper (2) manually, for initial feeding only. It fills the screw thread grooves (3) of an extruder, with compounds with the help of feed roller thereby making splitting and squeezing of compounds and finally extrusion is carried out through head. The final form of the material, after passing through head, is decided by die holder and die assembly. The die should be replaceable so as to cater different width sizes. Once the material (4) is out of the die, it will be carried towards winding unit (5), on a carrier material

(6) i.e. liner, with the help of a take away conveyor assembly (7). The material is winded up in a shell as per required quantity. Once the windup is done for the required quantity the shell has to be taken out from the windup unit and has to be stored in the trolley.
[0007] Generally, the rubber material extruded from an extruder is in sheet form. But in this process of extrusion, due to the complex nature of the rubber material and its flowability it is practically impossible to extrude it into a sheet form of uniform cross section and as a result the dimensional accuracy cannot be met.
[0008] To process such a highly fluid rubber material into a regular sheet form is very difficult as the extruded product swells in the centre of the die as compared to the edges of the extruded product which is not in the uniform structure. Also, there are issues of non-uniform edges or edge break problem due to varying flow of rubber.
[0009] If a conventional extrusion die design method is used, it could have satisfied the purpose of some regular rubber compound. This compound having a higher swell and higher flow property, is difficult to process cannot be extruded by a rectangular die(conventional method). If a rectangular die is used, the swell at the centre would be enormous (Approx. 300% of the die opening, as observed) than at the edges. If the opening is reduced at the centre as done in regular cases, the flow of the compound gets disturbed and becomes uneven and cannot be corrected even with correction in die.
[0010] For a typical rubber compound, the die designs are simpler in shape mostly rectangular/trapezoidal. If a die design is observed carefully, it is exactly smaller version of the required extrudate shape. The compounds are having a uniform and evenly distributed flow and gives the shapes similar to that designed in a die across the cross section. The regular rubber compound is processed through an extruder and comes out taking the exact shape of die with uniform swell across the cross-section of the die.
[0011] Above mentioned techniques are having some issues like dimensional accuracy of sealant material, inferior quality of ride and handling, inferior fuel efficiency, high drying time, high manufacturing cost, low life cycle of product etc. To overcome mentioned problems, we developed a typical extrusion process.

OBJECT OF THE INVENTION
[0012] The object of the present invention is to provide a Dimensional accuracy throughout the manufacturing of sealant.
[0013] Another object of the present invention is to provide a material which can be used directly without having an additional drying process.
[0014] Yet another object of the present invention is to provide a sealant with low manufacturing cost compared to existing application techniques.
STATEMENT OF INVENTION
[0015] Accordingly the present invention discloses a process development for puncture sealant extrusion comprising a die holder (21) having an input opening (7) provided for fitting of the nozzle of the extruder which opens in the cavity of the die holder (21); at least one die (1) provided for extruding the sealant extrusion in the predetermined form; a die fitting area (5) provided on said die holder (21) for mounting said die (1) on the output side of said die holder (21); plurality of holes (2, 3) of varying diameters provided on said die (1) for extruding the sealant in uniform thickness throughout the width of the extrudate.
[0016] The die holder (21) is configured in a single piece or optionally constructed from two half sections i.e. the top portion and the bottom portion of die holder (21) configured to be mounted on each other by fastening them through the holes (6) provided on said top portion to form a die holder (21). The die holder (21) has the die fitting area (5) having holes (20) on which die (1) is mounted by the fastening means through the die mounting holes (4) provided on said die (1).
[0017] The bottom portion of the die holder is provided with holes (8) for mounting the top portion of the die holder (21). The holes (2) configured at the centre of die (1) are smaller in diameter than the holes (3) towards the edges of the die (1). The diameters of said holes (3) is greater than the diameters of said holes (2) by a range 0.2 to 0.5 mm.
[0018] The die (1) is provided with die mounting holes (4) for mounting said die (1) on the cavity provided on said die holder (21). Each of said holes (2, 3) on the die (1) is separated

from each other by at least 0.3 mm distance for extruding a series of parallel noodles of the sealant extrudate.
[0019] The extruded series of parallel noodles of the sealant extrudate are configured to swell, coalesce and bonded to the subsequent noodle to form a single extrudate sealant with uniform thickness throughout the width of the extrudate. The process development for puncture sealant extrusion as claimed in preceding claims, wherein said fastening means are nut and bolts, screws, dowel pins, etc.
BRIEF DESCRIPTION OF THE FIGURES
In accordance to this invention the figures are described as follows: [0020] Figure 1 shows a schematic view of an extruder assembly.
[0021] Figure 2 shows a front isometric view of a die holder on which the die is mounted
[0022] Figure 3 shows a rear isometric view of the die holder.
[0023] Figure 4 shows a sectional isometric view of the die holder.
[0024] Figure 5 shows an isometric view of the cavity of the die holder through the extrudate flows.
[0025] Figure 6 shows a front view of the die for sealant extrusion.
DETAILED DESCRIPTION OF THE INVENTION
[0026] For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification are to be understood as being modified in all instances by the term "about". It is noted that, unless otherwise stated, all percentages given in this specification and appended claims refer to percentages by weight of the total composition and the recitation of all numerical ranges by endpoints is meant to include the endpoints of the range, all numbers subsumed within the range and any range within the stated range.

[0027] In describing and claiming the invention, the following terminology will be used in accordance with the definitions set forth below. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any sensing device, methods, system and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred sensing device, methods, system and materials are described herein. As used herein, each of the following terms has the meaning associated with it in this section. Specific and preferred values listed below for individual components, substituents, and ranges are for illustration only; they do not exclude other defined values or other values within defined ranges for the components and substituents.
[0028] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention. As used herein, the terms “comprising,” “including,” “having,” “containing,” “involving,” and the like are to be understood to be open-ended, i.e. to mean including but not limited to.
[0029] Thus, before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified systems or process parameters that may of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to limit the scope of the invention in any manner.
[0030] The following definitions are used in connection with the present application unless the context indicates otherwise. As used herein,
[0031] The term “Extruder” refers to an equipment with screw-barrel assembly and which churns and pushes out material with help of a screw inside it.

[0032] The term “Preformer” refers to a metallic cavity at the end of head which guides the material towards the die and comes out in the required dimensions.
[0033] The term “Holder” refers to a part which holds the die.
[0034] The term “Sealant material” refers to a material which seals the puncture by preventing air loss form the punctured zone.
[0035] The term “Conveyor” refers to an equipment which carries the sealant material & carrier material to desired windup zone.
[0036] The term “Carrier material” refers to a non-sticky liner which has very less adhesion to sealant material and also avoids the contact of sealant material with each other at the windup zone.
[0037] The term “Shell” refers to a part over which wind up of extruded sealant gel material is done.
[0038] Figure 1 shows a schematic setup of an extruder assembly wherein the extruding compound (12) will be fed into extruder hopper (13) manually, for initial feeding only. It fills the screw thread grooves (14) of an extruder, with compounds with the help of feed roller thereby making splitting and squeezing of compounds and finally extrusion is carried out through head. The final form of the material, after passing through head, is decided by die holder and die assembly. The die should be replaceable so as to cater different width sizes. Once the material (15) is out of the die, it will be carried towards winding unit (16), on a carrier material (17) i.e. liner, with the help of a take away conveyor assembly (18). The material is winded up in a shell (19) as per required quantity. Once the windup is done for the required quantity, the shell has to be taken out from the windup unit and has to be stored in the trolley.
[0039] The rubber compound is extruded from the series of holes which are aligned in single line. The varying diameters help in maintaining the dimensional accuracy of the material. The metal piece which consists of the series of hole is called die (1). The material coming out

from the die takes the circular shape due to holes. It looks like a series of noodles coming out of the die that’s why such an extrusion is known as a Noodle extrusion.
[0040] Figure 2 and 3 shows a die holder (21) comprising either in a single piece or can be optionally constructed from two half sections i.e. the top portion and the bottom portion of die holder (21) mounted on each other to form a die holder (21) through holes (6) provided on it. The die holder (21) has the die fitting area (5) having holes (20) on which die (1) is mounted by the fastening means through the die mounting holes (4). The die holder (21) has an input opening (7) provided for fitting of the nozzle of the extruder which opens in the cavity of the die holder (21).
[0041] The bottom portion of the die holder is provided with holes (8) for mounting the top portion of the die holder (21). The flow of the extrudate is shown by arrows (9) in figure 4. The pressure of the extrudate is higher at the center of the cavity than at the sides as the inter molecular friction between the extrudate is much lesser as compared to the frictional force between the extrudate and the walls of the cavity. This is the reason the extrudate will have greater flow towards its core as compared to its flow near to the walls of the cavity of the die holder (21).
[0042] Figure 5 shows the cavity of the die holder wherein the input side (11) is circular in shape and the output side of the cavity (10) is rectangular in shape.
[0043] Figure 6 shows a die (1) according to this invention and its constructional features. A die (1) with varying hole diameters (2) in zone A and holes (3) in zone B, is specifically designed to address the varying swell and non-uniform flow of the rubber extrudate. As shown in the sketch, the diameter of the holes (2) at the centre of die is less than that of the diameter of the holes (3) towards the edges. The diameter of the holes (2) in zone A is lesser than the diameter of the holes (3) in zone B (A