Abstract:
A method and apparatus are provided for automatic and hands-free threading of an elastomeric mix into a calender set of rolls comprising one or more pairs of rolls that have a nip between them. A stripper roll is positioned next to one of the rolls forming the nip and is rotated so that the outer surface of the stripper roll moves in a direction opposite to the outer surface of the adjacent roll. The stripper roll removes all or a desired portion of the elastomeric mix from the adjacent roll and causes the same to transfer to another roll. Variables such as e.g., the relative surface speed of the stripper roll, diameter of the stripper roll, and distance of the outer surface of the stripper roll from the adjacent roll can be manipulated to control the amount of the elastomeric mix that is stripped by the stripper roll.

Description:
FIELD OF THE INVENTION 
       [0001]    The subject matter of the present disclosure relates generally to a method and apparatus that allow for automatic and hands-free threading of an elastomeric mix into a calender set of rolls comprising one or more pairs of rolls that have a nip between them. 
       BACKGROUND OF THE INVENTION 
       [0002]    Calenders are mechanisms that include a series of pairs of rolls through which a substance that is malleable can be run in order to smooth out the material and form a skim or sheet of uniform thickness. In the tire industry, calenders are used to process an elastomeric or rubber mix that is usually extruded and then sent through the calender to create a sheet of rubber or elastomer mix. Between each pair of rolls is a gap or nip through which the material is run as the rolls are rotated. Depending on a host of processing variables, the sheet will assume some thickness that is proportional to the width of the nip. Often, the material is fed through three sets of rolls and nips in order to create a homogenous and smooth sheet that also has a desired thickness, as is the case for an inverted “L” configured calender as will be described shortly. This sheet is then used to create some portion of the tire, such as the tread or other semi-finished goods used to manufacture and assemble the tire such as belts and carcass plies, etc. 
         [0003]    An illustration of such a typical calendering system  10  is shown in  FIGS. 1 and 2 , which has three pairs of rolls (labeled as rolls  12 ,  14 ,  16 , and  18 ) with a nip between pairs as well as a fifth roll  20 , sometimes referred to as a take-off roll, that takes the sheet as it comes off the fourth roll  18 . The purpose of this roll  20  is to provide tension to remove the sheet  22  as it exits the calender. The calender rolls that are part of a pair rotate in opposite directions or in the same linear direction/surface direction in the nip area  24  so that material that is fed into the entrance  26  of the nip is forced through the nip into the exit area  28  of the nip. For the first pair of rolls, the entrance of the nip is located above the rolls so that material is naturally fed into the nip via gravity upon startup or just before. Usually, a bank  30  of kneaded material (sometimes referred to as a bourelet by the inventor(s)) collects above the nip of the first pair of rolls so that enough material is present to form an uninterrupted sheet of material that can pass through the calendering system. This bank is created by oversupplying slightly the amount of material needed to create the sheet of material from a source of the material such as an extruder. In time, material is forced downward into the nip by the rotation of the rolls. 
         [0004]    After exiting the first nip area  24   a,  the material then winds in a counterclockwise direction around the second roll  14  until it is reaches the third roll  16  where it goes through a second nip area  24   b.  Once it exits, the material then winds in a clockwise direction around the third roll  16  and then encounters the fourth roll  18  where it goes through the third nip area  24   c.  At this point, the sheet then attaches to the fourth roll  18  where it is rotates in a counterclockwise direction once more around the bottom and part of the back of the fourth roll  18  and on top of the fifth roll  20 , which is rotated in the clockwise direction and which is biased upwards to place the sheet in tension before it proceeds to a production center where some tire component is made using the sheet of material. This desired path is shown by the solid outline of material whereas an unintended circulation of material is represented by the dashed arrows as will be described in further detail later. 
         [0005]    All the rolls or pairs of rolls can be commonly driven by a single motor using gears, chains, or belts. In such a case, the speed of all the rolls or of the rolls of a pair can be the same or can be different utilizing some sort of transmission system such as a variable speed ratio reducer between the rolls and the motor. Alternatively, all the rolls can be independently driven using a separate motor for each roll. In that case, electronic controls are sometimes furnished that allow tight and independent control of the speed of each roll by way of suitable programming by the operator or some other control algorithm executed by a computer. For example of rolls that are independently driven or that can operate at different adjustable speeds. See, e.g., U.S. Pat. Nos. 2,333,629; 4,444,361; and G.B. Pat. Nos. 856,454; 620,340. 
         [0006]    An example of a production center that can be fed by a calender system is depicted by  FIG. 3 , which is disclosed in U.S. Patent Application Publication No. 20110036485, which is commonly owned by the assignee of the present invention and whose content is incorporated by reference for all purposes in its entirety. Portions of that application are reproduced herein as follows to describe how the process works and how it can be used in conjunction with the present invention. It should be noted that this is given by way of an example of a production center and that the present invention is equally applicable to any manufacture of a tire component that requires a calendering system of any sort including those that only have a single pair of rolls. 
         [0007]    A system  110  for generating a multi-layered tire component in accordance with the methods described in the &#39;485 application is generally shown in  FIG. 3 . System  110  generally operates to form a multi-layered tire component by winding strips  141  about a building surface. Because a tire component is a wound product, it generally forms a complete circle (i.e., a ring). The component is also referred to herein as a band. Also, system  110  generates a sheet  121  from which the strips  141  are formed, and, in particular embodiments, the sheet  121  remains continuous as it travels along a closed-loop path to and from a sheet generator  120 . Accordingly, system  110  automatically returns any unused sheet material for reuse by generator  120 . System  110  generally forms elastomeric tire components, such as, for example, tread, sub-tread, and cushion gum. It can also create a multi-layered band that is a profiled tire tread band. 
         [0008]    In this embodiment, system  110  comprises a sheet generator  120 , a cutting assembly  140 , a strip applicator assembly  160 , a recovery assembly  170 , and a programmable logic control (not shown). System  110  may also include a roll assembly  130  for directing a sheet  121  from generator  120  to cutting assembly  140 . Sheet generator  120  generally transforms input material  112  into a sheet  121 , which is ultimately cut into strips  141  by cutting assembly  140 . 
         [0009]    With continued reference to  FIG. 3 , input material  112  is received through inlet  122 , and may comprise new material  112   a  and/or previously used material  112   b  supplied by recovery assembly  170 . After receiving input material  112 , generator  120  forms the input material by any known means such as by a calendering system shown in  FIGS. 1 and 2  and described above into sheet  121 , where sheet  121  is formed to any desired width and thickness. Sheet  121  is expelled from generator  120  by way of outlet  123 . 
         [0010]    In one embodiment, as shown in  FIG. 3 , generator  120  comprises an extruder. Extruders generally push input material  112  through a die or head, such as by way of a screw. Any extruder known to one of ordinary skill in the art may be used by system  110 . Generator  120  may also comprise a calender in lieu of, or in addition to, an extruder, which may comprise a pair of rolls positioned in close proximity to each other to form a gap or nip, through which input material  112  passes to from a sheet  121  (as described above). The resulting sheet  121  includes a width associated with the width of the calender nip. While an extruder and calender are capable of operating at similarly high speeds, a calender may not be as readily adjustable to changes in speed. This may affect the start-up time of system  110 , as well as the responsiveness of system  110  to restart after a temporary delay. 
         [0011]    As shown in  FIG. 3 , a roll assembly  130  may be located between sheet generator  120  and cutting assembly  140 . Roll assembly  130  generally comprises one or more rolls  132  arranged to form a translation path of sheet  121 . The take up roll described above in  FIGS. 1 and 2  may be considered as such a roll. The particular translation path directs sheet  121  to cutting assembly  140 , and may be used to tense sheet  121  as desired. The location of rolls  132  may be adjusted to impart more or less tension on sheet  121 , which may also provide a means for adjusting the cross-sectional dimensions of sheet  121 . One or more rolls  132  may be driven or powered, such as, for example, by a motor, to assist in the translation of sheet  121 , and/or adjustment of tension in sheet  121 . In addition, biasing means such as springs, pneumatic or hydraulic cylinders, etc. may force the roll against the sheet to provide tension. Sheet  121  may also be tensed by creating a speed differential between drum  125  and/or cutting drum  152 , by increasing or decreasing the rotational speed of either drum. 
         [0012]    Cutting assembly  140  generally forms strips  141  from sheet  121  for subsequent assembly of the tire band. More specifically, cutting assembly  140  utilizes a plurality of cutting members  142  to cut strips  141 , wherein each cutting member  142  includes a cutting edge  143 . Cutting members  142  generally are spaced along a length of sheet  121 , and along a circumference of cutting surface and/or cutting drum  152 . In the embodiment shown in the FIGURES, cutting members  142  are rotating knives. Rotating knives, in the embodiment shown, operate similarly to idler wheels, and freely rotate at the direction of the translating sheet  121 . Still, rotating knives  142  may be driven by a motor or any other known driving means. Also, other means for cutting sheet  121  known to one of ordinary skill in the art may be used in lieu of rotating knives, including other non-rotating knives, blades, or edges. 
         [0013]    With general reference to  FIG. 3 , system  110  also includes an applicator assembly  160  for applying one or more continuous strips  141  to a building surface to form a band. The one or more strips  141  are wound about the building surface to form the multi-layered band. Applicator assembly  160  includes an applicator drum  162  that transfers one or more strips  141  there from to building assembly  180 . To provide adhesion between applicator drum  162  and strips  141 , which promotes the separation of strips  141  from sheet  121 , applicator drum  162  may be heated or cooled. In particular embodiments, applicator drum  162  is maintained at a temperature at least  10  degrees Celsius higher than the temperature of sheet  121  and/or any strips  141 . In other embodiments, applicator drum  162  is maintained at approximately  70  degrees Celsius. The surface of applicator drum  162  may comprise a smooth surface, which may be a chromed or hot chromed surface, so to provide a smooth, capillary-like surface that may promote molecular bonding and/or may operate like a vacuum to facilitate retention of strips  141  thereon. Improved adhesion may also be provided by providing a rough surface, the rough surface providing increased surface area for improved contact area, and therefore, increased adhesion. Applicator drum  162  may also operate as the cutting drum  152 . Further, the temperature controls and conditions, as well as the surface conditions and treatments discussed with regard to applicator drum  162  above may also be applied to cutting drum  152  to improve adhesion between drum  152  and sheet  121 . Using this system, tread features can be built onto a green or uncured tire layer by layer. 
         [0014]    As just described regarding the applicator or cutting drum, the adhesion of rubber strips to a round and rotating surface is apt to occur. Accordingly, when multiple rotating surfaces are present near the exit of the nip of calender rolls, e.g. their respective circumferential surfaces that are rotating away from nip exit, a sheet of elastomeric mix can bond with either of these surfaces, or partially to both at the same time. This can be a problem during the operation of the calender, but especially during the initialization or start-up of the calender as an initial sheet needs to be directed, often by an operator, to follow the proper path until the calender has been successfully “threaded” and is ready to supply a sheet of material to the desired production center. This requires shut-down of the equipment for safety reasons, which can be costly. 
         [0015]    Looking back at  FIG. 2 , the desired path is denoted by a solid outline of material and an unwanted path by dashed arrows. As can be seen, the first unwanted path can occur when the sheet sticks to the first roll  12  where it rotates clockwise away from the exit  28   a  of the first nip  24   a.  This can lead it back to the top bank  30   a  of kneaded material, creating an undesirable feedback loop where excessive material will spill off the axial ends of the roll and down the sides of the calendering apparatus, potentially causing damage to the apparatus or other equipment by gumming up the equipment and stopping production. A similar situation can occur when the sheet exits the second nip  24   b  as it can continue to run clockwise on the second roll  14  and into the top bank of material  30   a.  After the third nip  24   c,  the material can recycle itself back to the second nip  24   b,  creating unwanted growth of a second bank  30   b  of material. Finally, after the sheet comes back around the bottom of the fourth roll  18 , it can continue to stick to this roll and create a third bank  30   c  of material near the entrance  26   c  of the third nip  24   c.    
         [0016]    Any of these banks of material can become too large and cause the equipment problems. Even after initially threading the calender, all three banks can occur due to some small residue sticking to the rolls and collecting near the entrance to the nips over time, thereby causing some small amount of recycling. Also, there is a desired amount of slight oversupply from each nip to the next that helps to ensure enough material is present for the step reduction in skim thickness at each nip which creates a full width sheet that is smooth, homogenous and that has the correct thickness. So, it is desirable to control the size of the banks of material but not to eliminate them altogether. 
         [0017]    The reason elastomeric mixes are tacky will now be explained. Suitable compositions for making a sheet for use in tire components such as treads include those rubber compositions having a glass transition temperature within a defined range, said rubber compositions being based upon a diene elastomer, a plasticizing system and a cross-linking system. The diene elastomers or rubbers that are useful for such rubber compositions are understood to be those elastomers resulting at least in part, i.e., a homopolymer or a copolymer, from diene monomers, i.e., monomers having two double carbon-carbon bonds, whether conjugated or not. 
         [0018]    In summary, typical diene elastomers include highly unsaturated diene elastomers such as polybutadienes (BR), polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers include butadiene/styrene copolymers (SBR), isoprene/butadiene copolymers (BIR), isoprene/styrene copolymers (SIR) and isoprene/butadiene/styrene copolymers (SBIR). Suitable elastomers may also include any of these elastomers being functionalized elastomers. 
         [0019]    In addition, the elastomeric composition disclosed herein may further include a reinforcing filler. Reinforcing fillers are added to, inter alia, improve the tensile strength and wear resistance of the material. Any suitable reinforcing filler may be suitable for use in compositions disclosed herein including, for example, carbon blacks and/or inorganic reinforcing fillers such as silica, with which a coupling agent is typically associated. Inorganic reinforcing fillers may take many useful forms including, for example, as powder, microbeads, granules, balls and/or any other suitable form as well as mixtures thereof. Examples of suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, such as silica (SiO2), of the aluminous type, such as alumina (AlO3) or combinations thereof. 
         [0020]    For coupling the inorganic reinforcing filler to the diene elastomer, a coupling agent that is at least bifunctional provides a sufficient chemical and/or physical connection between the inorganic reinforcement filler and the diene elastomer. Examples of such coupling agents include bifunctional organosilanes or polyorganosiloxanes. Such coupling agents and their use are well known in the art. The coupling agent may optionally be grafted beforehand onto the diene elastomer or onto the inorganic reinforcing filler as is known. Otherwise it may be mixed into the rubber composition in its free or non-grafted state. 
         [0021]    In addition to the diene elastomer and reinforcing filler, particular embodiments of the rubber composition disclosed herein may further include a plasticizing system. The plasticizing system may provide both an improvement to the processability of the rubber mix and/or a means for adjusting the rubber composition&#39;s glass transition temperature and/or rigidity. Suitable plasticizing systems may include a processing oil, plasticizing resin or combinations thereof. Other plasticizing systems are known. Table I below provides an example of rubber mixes that may be used with the present invention and, more particularly, indicates the percentage of resin and plasticizer that may be present and the type of resin. Other mixes may be used as well. Of resin types, limonene resin is one of the stickiest and was used in tests (discussed below) to demonstrate the efficacy of the invention. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE I 
               
               
                   
               
               
                   
                   
                 % Total Plasticizer 
                   
               
               
                 Mix 
                 % Resin 
                 (include oil and resin) 
                 Resin Type 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 8.7 
                 21.8 
                 Limonene 
               
               
                 2 
                 15.6 
                 20.4 
                 Limonene 
               
               
                 3 
                 7.0 
                 7.0 
                 Formophenolic 
               
               
                   
                   
                   
                 (i.e. tackifier resin) 
               
               
                   
               
             
          
         
       
     
         [0022]    Also, the rubber compositions disclosed herein may have, or be cured with, any suitable curing system including a peroxide curing system or a sulfur curing system, many of which are known in the art. Other additives can be added to the rubber compositions disclosed herein as known in the art. Such additives may include, for example, some or all of the following: antidegradants, antioxidants, fatty acids, pigments, waxes, stearic acid and zinc oxide. 
         [0023]    These constituents, notably the polymers used in the elastomeric mix, make the sheet sticky or have tack. Increasing the amount or type of certain ingredients such as pigments, fillers, additives, and plasticizers can increase tack. Also, some polymers have inherently more tack than others. Consequently, different mixes have more tack than others and can therefore be more prone to the problems just described. 
         [0024]    As can be imagined, a number of methods have been devised to control or eliminate unwanted sticking of the sheet of material to calender rolls. Some methods have been already described above and include providing a temperature or surface finish differential between the two rolls that define a nip so that the sheet of material is prone to stick to one versus the other. Also, surface treatments that decrease adhesion to the roll to which adherence is undesirable after the sheet exits the nip can be applied to that roll. Such treatments include TEFLON, alkanolamines, alkylene glycols, and polyalkylene glycols (see U.S. Pat. No. 3,841,899). In Japanese Patent Application Publication No. JP9201838A, there is disclosed a method of continually applying a release agent on a roll using a soft roll onto which the agent is sprayed that rubs against the roll for solving sticking problems associated with that roll. Finally, the use of scraper blades is often used to prevent the unwanted recycling of material that can contribute to bank growth over time (See Jap. Pat. Application Publication No. 08-197558 A and U.S. Pat. No. 4,221,022 for examples). Also, the use of scraper blades to prevent the improper threading of a sheet processed by a calender processing elastomeric mixes, preventing it from recycling to the entrance of the nip thereby aiding in the start-up of a calendering process is also known (see col. 3, lines 5-10 of U.S. Pat. No. 4,871,409). 
         [0025]    However, all these methods have drawbacks. Concerning maintaining the temperature of the rolls, it is necessary to maintain consistency the entire time the calendering apparatus is running, which could be difficult depending on ambient conditions. Also, this method could delay start-up until the rolls reach the desired temperature. Surface treatments that are applied to rolls such as disclosed in U.S. Pat. No. 3,841,800 can wear off over time which adds cost to reapply the treatment and possibly some downtime for the equipment. Continuously applying a release agent can be both expensive and messy, and may cause the agent to seep into the material causing a degradation of the properties of the sheet of material. Finally, scraper blades do not allow for the automatic, hands-free threading of a calender processing an elastomeric mix as admitted by the prior art (see comments regarding U.S. Pat. No. 4,871,409 above). 
         [0026]    Accordingly, a method and apparatus for solving the sticking issue upon start-up in a more reliable and cost-effective way without degrading the material properties of the sheet produced by the calender would be beneficial. Such a method and apparatus that can allow for the automatic and hands-free threading of the apparatus would be particularly beneficial. Additionally, such a method and apparatus that can help maintain uninterrupted and continuous production of the calendering system after startup would also be useful. 
       SUMMARY OF THE INVENTION 
       [0027]    The present invention relates to a method and apparatus for automatic and hands-free threading of an elastomeric mix into a calender set of rolls comprising one or more pairs of rolls that have a nip between them. More specifically, a stripper roll is positioned next to one of the rolls forming the nip and is rotated so that the outer surface of the stripper roll moves in a direction opposite to the outer surface of the adjacent roll. The stripper roll removes all or a desired portion of the elastomeric mix from the adjacent roll and causes the same to transfer to another roll. Variables such as e.g., the relative surface speed of the stripper roll, diameter of the stripper roll, and distance of the outer surface of the stripper roll from the adjacent roll can be manipulated to control the amount of the elastomeric mix that is stripped by the stripper roll. Additional objects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
         [0028]    In one exemplary aspect, the present invention provides a method for operating a calendering system that processes elastomeric mixes at a desired calendering rate, the calendering system comprising a first roll and a second roll that form a nip therebetween. The method includes the steps of providing a stripper roll having an outside surface; positioning the stripper roll proximate to, and downstream of, the nip with the outer surface of the stripper roll within a predetermined distance of the outer surface of the first roll; rotating the first roll in a first roll surface direction at a first roll surface speed; rotating the stripper roll in a stripper roll surface direction at a stripper roll surface speed, wherein the stripper roll surface direction is opposite to the first roll surface direction; stripping an elastomeric mix from the outer surface of the first roll; and transferring the elastomeric mix to the outer surface of the second roll. 
         [0029]    In another exemplary embodiment, the present invention provides a calendering system for processing an elastomeric mix at a desired calendering rate. The system includes a first roll having an outer surface and rotatable along a first roll surface direction, and a second roll having an outer surface and rotatable along a second roll surface direction that is the same as the first roll surface direction. The second roll is positioned next to the first roll so as form a nip therebetween for the elastomeric mix. A stripper roll is positioned near the nip and at a predetermined distance from the first roll. The stripper roll is configured to rotate with a stripper surface direction that is opposite to the first roll surface direction. 
         [0030]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
           [0032]      FIG. 1  illustrates a perspective view of an exemplary calendering operation. 
           [0033]      FIG. 2  is a side view of the rolls of the calendering apparatus shown in  FIG. 1  with certain features removed to further reveal the position and operation of the rolls. 
           [0034]      FIG. 3  illustrates an exemplary production center that uses a calendered sheet for making strips that are applied to a green tire to create the tread of the tire. 
           [0035]      FIG. 4  is a side view of an exemplary embodiment of the present invention. 
           [0036]      FIG. 5  is a side view of another exemplary embodiment of the present invention. 
           [0037]      FIGS. 6 and 7  are plots of certain data as will be further described below. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    For purposes of describing the invention, reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0039]      FIG. 4  provides a side view of an exemplary embodiment of the present invention in which a roll  32 , referred to herein as a stripper roll, is provided proximate to a nip formed by the pair of rolls  16  and  18  (which will also be referred to as first roll  16  and second roll  18  for purposes of describing the operation of stripper roll  32 ). Rolls  16  and  18  are chosen by way of example, a stripper roll could be placed at any one or more of the nips provided by calendering system  10 . In terms of the flow of the elastomeric mix, stripper roll  32  is positioned downstream of the nip between first roll  16  and second roll  18  and in its exit area  28   c.  Furthermore, and referring now to  FIGS. 4 and 5 , stripper roll  32  is positioned so that its outer surface  38  is within a predetermined distance S of the outer surface  36  of first roll  16  (S is measured along a line connecting the axis of rotation of stripper roll  32  and first roll  16 ). For this exemplary embodiment, predetermined distance S is in the range of about 2 mm or less. In another exemplary embodiment of the present invention, predetermined distance S is in the range of about 0.5 mm or less. Other values for predetermined distance S may be used as well. For example, during start up or operation, the predetermined distance S may be adjusted so as to control the amount of elastomeric mix that is transferred to second roll  18 . 
         [0040]    The direction of rotation of stripper roll  32  and first roll  16  is the same. By way of example, from the view point of  FIG. 5 , stripper roll  32  and first roll  16  each rotate in a clockwise direction as indicated by arrows R 32 and R   16 , respectively. For purposes of describing this exemplary embodiment of the invention, it can be understood that the outer surface  38  of stripper roll  32  moves in a direction referred to herein as the “stripper roll surface direction” while the outer surface  36  of the first roll  16  moves in a direction referred to as the “first roll surface direction.” As shown in  FIG. 5 , these directions are opposite to each other—i.e. the movement of a point on surface  36  and a point on surface  38  in the vicinity of the nip created by rolls  16  and  18  are in opposite directions. 
         [0041]    Accordingly, as previously described, first roll  16  rotates as shown to carry material into the nip between rolls  16  and  18 . Material then leaves the nip in exit area  28   c.  Particularly during startup, the material may attempt to stick or adhere to the surface  36  of first roll  16  as previously explained and attempt to continue on first roll  16  (see arrow  37  in  FIG. 4 ). However, in this exemplary embodiment of the invention, the material comes into contact with roll  32 , the outer surface  38  of which is moving in a direction opposite to outer surface  36  and, therefore, opposite to the direction of movement of the material. This causes all or some portion of the material to be stripped or removed from outer surface  36  and redirected to second roll  18 . The material is now transferred to the surface  40  of second roll  18 —where it is carried by second roll  18  in the direction shown for take-off and tensioning by roll  30  in the form of sheet  22  as previously described. 
         [0042]    Thus, stripper roll  32  can be used during start-up of calendering system  10  to ensure that the material is properly routed around second roll  18  upon exiting the nip between first roll  16  and second roll  18 . In addition, a stripper roll can be similarly positioned downstream and of each the nips created by the rolls  12 ,  14 ,  16 ,  18 , and  20  (or any combination thereof) to ensure that the elastomeric material is properly routed after exiting each nip. For example, a stripper roll could be configured with a first roll  12  and second roll  14  and/or a first roll  14  and second roll  16 , and so on. Also, the stripper roll can be left in position after start-up and during the calendering process. Alternatively, the stripper roll may be placed on a mechanism for selectively moving the stripper roll towards or away from the first roll so that e.g., the stripper roll may be withdrawn after start-up (i.e. proper threading of the elastomeric mix in calender  10 ) is completed. 
         [0043]    The inventor has determined that several variables affect the efficacy with which the stripper roll can strip material from a first roll and cause the same to transfer to a second roll. Importantly, the speed of the stripper roll relative to the first roll determines whether material will be properly stripped during operation of a calendering system. Table II below provides experimental results using elastomeric mixes  1 ,  2 , and  3  from Table I and where the speed of the stripper roll was varied relative to the first roll. 
         [0000]    
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE II 
               
               
                   
               
               
                   
                   
                 Stripper 
                 Ratio of 
                 First 
                   
                   
                   
               
               
                   
                   
                 Roll 
                 Roll 
                 Roll 
                 Predetermined 
               
               
                   
                   
                 Surface 
                 Surface 
                 Surface 
                 Distance S 
                 Skim Thickness 
               
               
                 Mix 
                 Trial # 
                 Speed 
                 Speeds 
                 Speed 
                 (mm) 
                 (mm) 
                 OK/NOK 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 1 
                 5 
                 160% 
                 8 
                 0.5 
                 1 
                 NOK 
               
               
                   
                 2 
                 5 
                 200% 
                 10 
                 0.5 
                 1 
                 NOK 
               
               
                   
                 3 
                 5 
                 300% 
                 15 
                 0.5 
                 1 
                 OK 
               
               
                   
                 4 
                 5 
                 300% 
                 15 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 5 
                 5 
                 300% 
                 15 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 6 
                 5 
                 300% 
                 15 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 7 
                 3 
                 300% 
                 9 
                 0.5 
                 1 
                 OK 
               
               
                   
                 8 
                 1 
                 300% 
                 3 
                 0.5 
                 1 
                 OK 
               
               
                   
                 9 
                 5 
                 500% 
                 25 
                 0.5 
                 1 
                 OK 
               
               
                 2 
                 10 
                 5 
                 300% 
                 15 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 11 
                 5 
                 150% 
                 8 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 12 
                 5 
                 200% 
                 10 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 13 
                 5 
                 300% 
                 15 
                 0.5 
                 1.4 
                 OK 
               
               
                   
                 14 
                 5 
                 300% 
                 15 
                 0.5 
                 1 
                 OK 
               
               
                   
                 15 
                 5 
                 200% 
                 10 
                 0.5 
                 1 
                 OK 
               
               
                   
                 16 
                 5 
                 500% 
                 25 
                 0.5 
                 1 
                 OK 
               
               
                 3 
                 17 
                 5 
                 200% 
                 10 
                 0.5 
                 1 
                 OK 
               
               
                   
                 18 
                 5 
                 300% 
                 15 
                 0.5 
                 1 
                 OK 
               
               
                   
                 19 
                 5 
                 150% 
                 8 
                 0.5 
                 1 
                 NOK 
               
               
                   
                 20 
                 5 
                 110% 
                 6 
                 0.5 
                 1 
                 NOK 
               
               
                   
                 21 
                 5 
                 80% 
                 4 
                 0.5 
                 1 
                 NOK 
               
               
                   
                 22 
                 5 
                 500% 
                 25 
                 0.5 
                 1 
                 OK 
               
               
                   
               
             
          
         
       
     
         [0044]    In Table II, the skim thickness refers to the thickness of the elastomeric mix travelling on the rolls. Three different mixes were tested over at least  22  trials as shown. “OK” indicates that all or an acceptable portion of the material transferred from the first roll to the second roll after stripping by the stripper roll while NOK indicates an no transfer or an unacceptable amount of transfer. For the tests, a stripper roll having a diameter of about 150 mm was used with a first roll having a diameter of about 250 mm. 
         [0045]    The results from Table II are plotted in  FIG. 6  with plot line  600  indicating the ratio of stripper roll surface speed to first roll surface speed. The shaded portions indicate unacceptable or “NOK” trials. The bars show the relative speeds of the rolls. For trials  1 - 22 ,  FIG. 7  provides a plot of the material thickness (plot line  700 ) and the distance between the stripper roll and the first roll (plot line  702 ). Again, the shaded portions indicate unacceptable or “NOK” trials. 
         [0046]    As demonstrated in Table II and  FIG. 6 , for the mixes tested, a stripper roll surface speed that was at least about 200 percent of the first roll surface speed was required in order to obtain proper stripping and transfer of the elastomeric mix of material. Higher speed ratios may be used, but lower speed ratios were not acceptable. For example, the stripper roll may be configured to operate with a surface speed in the range of about 200 to about 300 percent of the surface speed of the first roll. During start-up or operation, the stripper roll surface speed, the first roll surface speed, or both may be adjusted so as to ensure the stripping and transfer of the material as well as the amount of material transferred. 
         [0047]    The surface of the stripper roll can also be important. For example, in certain embodiments of the invention, the stripper roll is provided with a polished or mirror like finish. Such smoothing of the surface of the stripper roll can improves its ability to strip and transfer material. In addition or as an alternative thereto, the surface of the stripper roll may be provided with one or more coatings. For example, a plasma with silicone surface treatment can be used. 
         [0048]    Other variables include the diameter of the stripper roll and/or the relative diameter of the stripper roll relative the first roll. As stated, for the trials in Table II, a stripper roll having a diameter of about 150 mm was used with a first roll having a diameter of about 250 mm. In other embodiments, a stripper roll having a diameter in in the range of about 50 mm to about 200 mm may be used. In still another embodiment, a stripper roll having a diameter of about 50 mm may be used. Additionally, the stripper roll may also be heated. For example, the stripper roll may operate more effectively to strip and transfer material from the first roll if the stripper roll is maintained at about the same temperature as the first roll. 
         [0049]    While the present subject matter has been described in detail with respect to specific exemplary embodiments and methods thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art using the teachings disclosed herein.