Patent Description:
The tire casing is then typically inspected for injuries, some of which may be skived and filled with a repair gum while others may be severe enough to warrant rejection of the casing. Next, a layer of cement is applied, followed by a layer of cushion gum may be applied to the back, i.e., the inside surface of a new layer of tread, or alternatively, the layer of cushion gum may be applied directly to the tacky surface on the tire casing. Conventionally, the cushion gum is a layer of uncured rubber material. The cushion gum and tread may be applied in combination about the circumference of the tire casing to create a retreaded tire assembly for curing. As an alternative, a length of tire tread may be wrapped around the tire casing with the cushion gum already applied. The cushion gum may form the bond between the tread and the tire casing during curing.

New tread for precured retreading applications is typically molded as a single piece with the tread pattern on one side and cement applied to the other side of the tread. Such treads are sometimes referred to a precured tread. The casing may be trimmed to fit the width of the precured tread. After the new precured tread is applied, a roller pressing process, commonly referred to as stitching, is next performed on the assembly to force air from between the tread strip and casing.

Following assembly of the tire casing, cement, cushion gum, and a precured tire tread strip, the overall retreaded tire assembly may be placed within a flexible rubber envelope. An airtight seal may be created between the envelope and the beads of the tire. The entire envelope tire assembly may be placed within a curing chamber and subjected to a vulcanization process that binds the materials together.

One issue that can frustrate a retread process is that the required amount of capacity of the curing chambers may not be available. In such an instance, it may be difficult or impossible to reach the curing conditions required for vulcanizing rubber, cement, or cushion gum. Curing chambers may also be expensive and present safety concerns, and thus it may be desirable to retread a tire without using a curing chamber.

Relevant prior art is disclosed by documents <CIT> and <CIT>.

According to a first set of embodiments, a method of retreading a tire is provided. The method includes the steps of applying a primer to an inner surface of a circumferential tread and applying the primer to an outer surface of a tire casing; applying an adhesive to the primer disposed on the inner surface and the primer disposed on the outer surface; applying the circumferential tread to the tire casing so the inner surface contacts the outer surface and a bondline edge forms circumferentially about the tire casing proximate to a shoulder of the tire casing; and coupling a moisture reservoir to the circumferential tread proximate to the bondline edge.

According to a second set of embodiments, a method of retreading a tire is provided. The method includes the steps of applying a primer to an inner surface of a circumferential tread and applying the primer to an outer surface of a tire casing; applying an adhesive to the primer disposed on the outer surface; applying the circumferential tread to the tire casing; coupling a moisture reservoir to the circumferential tread; and enclosing the tire casing, the circumferential tread, and the moisture reservoir in an envelope.

According to a third set of embodiments, a method of retreading a tire is provided. The method includes the steps of forming a precured tire tread having a first end and a second end; splicing the first end and the second end to form a circumferential tread having an inner surface and a road-contacting outer surface; applying a primer to the entirety of the inner surface; applying a moisture-curing adhesive to the entirety of the inner surface; applying the circumferential tread to a tire casing so a bondline edge forms circumferentially about the tire casing; enclosing the circumferential tread, the tire casing, and a moisture reservoir within an envelope; positioning the moisture reservoir proximate the bondline edge within the envelope; and vacuuming air out of the envelope to apply a pressure to the circumferential tread in a direction generally toward the tire casing.

Various embodiments discussed herein provide a method of retreading a tire without using a curing chamber or heating oven. The method may include using an adhesive with a curing process facilitated by the presence of moisture, and the method may include positioning a moisture reservoir proximate the adhesive during the curing process.

Following below are more detailed descriptions of various concepts related to, and implementations of, retreading a tire. The various concepts introduced above and discussed in greater detail below may be implemented in any of a number of ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

Tires are used in various applications and under a variety of circumstances. Some tires may be designed to withstand the forces of a landing aircraft. Some tires may be designed to provide extra grip on surfaces covered in snow and ice. Some tires may be manufactured to be more suited to be repairable and retreaded.

Retread tires are used in applications ranging from aircraft landing gear to long-haul tractor-trailers. Retread tires are used all over the world, including remote locations where access to conventional equipment required to retread a tire casing, and more specifically a curing chamber required to vulcanize rubber, may not be readily available. As such, there is a need for a method of retreading a tire without the use of a curing chamber. In such an instance, it may be difficult or impossible to reach the curing conditions (e.g., temperature, pressure, humidity, etc.) required for vulcanizing rubber, cement, or cushion gum.

In some instances, it may be desirable to use an adhesive (e.g., liquid adhesive, etc.) that cures at room temperature to bind (e.g., couple, vulcanize, adhere, etc.) the precured tire tread to the tire casing. The adhesive may be a moisture-curing adhesive that relies on moisture (e.g., water) to cure the adhesive and bind the precured tire tread to the tire casing. For example, the tire casing and the precured tire tread may be primed with a primer that is structured to prepare the binding surfaces for acceptance of the adhesive. The adhesive may then be applied to one or both of the binding surfaces, and then the precured tire tread may be applied to the tire casing, forming a retreaded tire assembly.

When the retreaded tire assembly is placed within a flexible rubber envelope, there may not be enough moisture within the envelope to cure the moisture-curing adhesive and bind the precured tire tread to the tire casing.

To alleviate this deficiency, it may be desirable to place a moisture reservoir within the envelope while the retread tire assembly, and more specifically the adhesive, is curing. The moisture reservoir may include a predetermined amount of moisture required for curing the adhesive. The moisture reservoir may be a towel, cloth, felt, or similar textile able to absorb the predetermined amount of moisture required for curing the adhesive. The towel or cloth may be coupled to the retread tire assembly prior to placing the retread tire assembly in the envelope. The towel or cloth may be coupled to the precured tire tread, such as by using fasteners or an adhesive. In some embodiments, the moisture reservoir may be interposed between the envelope and the retreaded tire assembly after the retreaded tire assembly is placed within the envelope.

Positioning a moisture reservoir proximate to the edges of a bondline formed between the precured tire tread and the tire casing may decrease the amount of time required to cure the adhesive and thus cure the precured tire tread to the tire casing. Further, using an adhesive allows the cold process retreading to be a continuous process instead of a batch process. Because the adhesive can be cured without using a curing chamber - a common bottleneck in the retreading process - tires can be retread continuously, one after another. This also reduces the amount of energy required to retread tires, as curing chambers may require great amount of power to operate. And finally, curing the adhesive using a moisture reservoir enables small-volume retreading operations. For example, it may not be cost-effective to operate a curing chamber to cure a single tire. However, when using a moisture reservoir, a single tire may be retreaded without incurring the losses associated with operating a curing chamber for a single tire.

Curing chambers may be undesirable or ill-equipped for retreading larger tires, such as those used on earth-moving equipment, construction equipment, and farming equipment.

As used herein, the term "precured" refers to a material that is cured. Conversely, "uncured" refers to materials that are in their raw form and have not been cured. For example, curing an uncured material results in a cured or precured material.

As used herein, the term "precured tire tread" refers to a tire tread or BUILD-UP™ (e.g., precured product having no tread pattern thereon; blank; slick) that is separate from (e.g., not cured to) a tire casing. The combination of the precured tread cured to the tire casing forms a tire. The precured tire tread may take the form of a strip, oval, circle, ring, or similar shape. A precured tire tread may include materials and features such as, but not limited to, studs, reinforcing fabrics, Kevlar, nylon, cords, and similar features and materials.

As used herein, the term "retreaded tire assembly" refers to a PCT assembly applied to a tire casing with an uncured adhesive interposed between the mating surfaces. The retreaded tire assembly may be ready to be positioned within an envelope for curing. Once a retreaded tire assembly has been cured, it becomes a tire.

<FIG> depict an example method of retreading a tire <NUM> (e.g., an original tire, a new tire, a previously retread or repaired tire, etc.) without the use of a curing chamber (e.g., curing oven, heating oven, etc.). Referring specifically to <FIG>, the tire <NUM> includes a tire casing <NUM> (e.g., tire carcass, etc.) and a tire tread <NUM>. As shown, the tire <NUM> is a radial tire; however, the retreading process may be completed on other types of tires, such as bias ply tires.

In the illustrated embodiment, the tire <NUM> includes a pair of side walls <NUM> bounded by a generally radial outer wall <NUM> (e.g., crown, etc.) that spans the side walls <NUM>. Each of the side walls <NUM> extend radially inward from outer wall <NUM> and terminates at a bead area <NUM>, the bead area <NUM> structured for mounting on a tire rim (not shown). The bead area <NUM> may be designed in a variety of configurations depending on, for example, tire type, tire size, or rim configuration. In the illustrated embodiment, the bead area <NUM> may also include a bead bundle <NUM>. The bead bundle <NUM> may include, for example, metal strands or wires to improve the strength of the bead area <NUM>.

The side walls <NUM> may include multiple layers, such as a rubber layer, a radial ply, and an inner liner which cooperate to provide the strong and flexible side walls <NUM>. The side walls <NUM> are joined to the outer wall <NUM> and the tire tread <NUM> through a pair of shoulder areas <NUM>. The shoulder areas <NUM> are contiguous with the side walls <NUM> and the outer wall <NUM>. In some embodiments, the shoulder areas <NUM> are contiguous with the tire tread <NUM>. The outer wall <NUM> may be strengthened by a plurality of belts <NUM> extending circumferentially about the tire casing <NUM> within the outer wall <NUM>.

Speaking generally, after the tire tread <NUM> of the tire <NUM> wears beyond a certain limit, the tire <NUM> must either be discarded, re-grooved, or retreaded before it should be used on a vehicle for which it was designed. In cold process retreading, what remains of the tire tread <NUM> is removed from the tire casing <NUM> by a buffing machine through a buffing operation. During a buffing operation, the tire tread <NUM> is ground away from the tire casing <NUM>, leaving a buffed tread mounting surface <NUM> (e.g., mounting surface, mating surface, bonding surface, curing surface, etc.) on the tire casing <NUM>, as shown, for example, in <FIG>. The mounting surface <NUM> extends circumferentially about the tire casing <NUM> and also extends transversely across the outer wall <NUM> until it terminates at the shoulder areas <NUM>. When a PCT assembly is applied to the mounting surface <NUM>, the interface between the mounting surface <NUM> and the PCT assembly may be referred to as a bondline. The bondline may have a width equal to the width of the mounting surface <NUM>. In some embodiments, the bondline has a width less than the width of the mounting surface <NUM> as the PCT assembly applied to the tire casing <NUM> may have a width less than the width of the mounting surface <NUM> The bondline extends circumferentially about the tire casing <NUM> in between the mounting surface <NUM> and the PCT assembly. Edges of the bondline, shown as edges of the bondline <NUM> (e.g., a bondline edge), may be visible once a PCT assembly has been applied to the tire casing <NUM>. In some embodiments, the edges of the bondline <NUM> are defined between the mounting surface <NUM> and the shoulder areas <NUM>. In some embodiments, the edges of the bondline <NUM> may be visible after a PCT assembly has been cured to the tire casing <NUM>. In some embodiments, the tire <NUM> includes the edges of the bondline <NUM>, still visible once the tire <NUM> is applied to a rim of a vehicle. The edges of the bondline <NUM> may be parallel to each other (e.g., concentric, equidistant, etc.) and may extend circumferentially about the tire casing <NUM>.

The mounting surface <NUM> defines a diameter, shown as a casing diameter DM. As shown in <FIG>, the mounting surface <NUM> exhibits a curvature between the shoulder areas <NUM>. Thus, the casing diameter DM may be greater proximate a center line CM of the mounting surface <NUM> when compared to the casing diameter DM proximate the edges of the bondline <NUM>. In some embodiments, the mounting surface <NUM> is buffed to a slightly rounded (e.g., toroidal) radius extending between the shoulder areas <NUM>. In some embodiments, the mounting surface <NUM> is flat such that the casing diameter DM is generally the same at all points between the edges of the bondline <NUM>.

Referring still to <FIG>, the tire <NUM> is shown after the buffing operation where the tire tread <NUM> has been removed. In some embodiments, a portion of the tire tread <NUM> may be left behind on the tire <NUM>, such as if the user would like to increase a thickness of the outer wall <NUM> before applying a PCT assembly to the tire casing <NUM>. As shown in <FIG>, the tire tread <NUM> has been removed, leaving behind (e.g., exposing, revealing, etc.) the buffed tread mounting surface <NUM>. After the tire tread <NUM> is removed and the mounting surface <NUM> is exposed, a process called skiving and filling may be performed on the tire casing <NUM>. Skiving is the removal of damaged material or undesired material from the tire casing <NUM> prior to making a repair or performing a retread operation. Often, the tire casing <NUM> accumulates holes, nicks, punctures, or tears due to stones or other sharp objects the tire <NUM> comes in contact with during use. The injured or damaged area is first ground smooth by an appropriate grinding tool and then filled with repair gum (e.g., uncured rubber material). It is necessary to fill the injured areas to the level of the mounting surface <NUM> (e.g., such that the tread mounting surface <NUM> remains smooth) to avoid air pockets between the mounting surface <NUM> and a later-applied PCT assembly. Trapped air between the mounting surface <NUM> and the PCT assembly can have negative effects on the longevity of a typical retreaded tire (e.g., the tire <NUM>). Following the skiving and filling operation, a building step occurs in which an adhesive (e.g., cushion gum, polyurethane adhesive, rubber cement, liquid adhesive, etc.) and a PCT assembly are applied to (e.g., wrapped around, placed on, stretched over, disposed about, etc.) the mounting surface <NUM>.

Referring to <FIG>, a PCT assembly <NUM> is shown. The PCT assembly <NUM> may be formed of rubber, natural rubber, synthetic rubber, various polymers, and compounding ingredients, such as such as carbon black, silica, anti-degradants, and zinc oxide, in order to produce the PCT assembly <NUM> having the desired end properties. The PCT assembly <NUM> may be formed in a strip having a tread width DW corresponding to a width of the mounting surface <NUM> between the shoulder areas <NUM>. The PCT assembly <NUM> may define a tread length DL corresponding to the casing diameter DM (e.g., the tread length DT may be equal to a circumference of the mounting surface <NUM>,, the tread length DT may be equal to the circumference of the mounting surface <NUM> proximate the center line CM). In some embodiments, the PCT assembly <NUM> is cut to have a tread length slightly less than (e.g., <NUM>,<NUM> (<NUM> inches) less than) the circumference of the mounting surface <NUM> such that the PCT assembly <NUM> may be stretched over the tire casing <NUM>. The PCT assembly <NUM> may further define a tread thickness, shown as a tread thickness DT. The PCT assembly <NUM> may include a mounting surface <NUM> (e.g., generally planar mounting surface, continuous surface, mating surface, binding surface, etc.) and an opposing surface <NUM> (e.g., generally planar opposing surface, road-contacting surface, tread surface, etc.). The mounting surface <NUM> may be configured such that the PCT assembly <NUM> may be applied to the corresponding mounting surface <NUM> on the tire casing <NUM>. More specifically, the mounting surface <NUM> may be configured to be cured to the mounting surface <NUM> to form the tire <NUM>. While the mounting surface <NUM> is shown as flat in <FIG>, in some embodiments, the PCT assembly <NUM> may include a mounting surface that is curved in order to match the curvature of the mounting surface <NUM>. The opposing surface <NUM> may be configured to interface with a road surface and may include a plurality of grooves <NUM> designed to channel water and provide added traction during certain road and weather conditions.

In some embodiments, the PCT assembly <NUM> may include a reinforcing fabric layer (e.g., a reinforcing belt, a plurality of reinforcing fabric layers, etc.) positioned within the PCT assembly <NUM> between the mounting surface <NUM> and the opposing surface <NUM>. In some embodiments, the PCT assembly <NUM> includes a reinforcing fabric layer coupled to and extending over the mounting surface <NUM>, the reinforcing fabric layer structured to prevent foreign bodies (e.g., nails, sharp objects, glass, etc.) from penetrating the mounting surface <NUM> and damaging the tire casing <NUM>. In some embodiments, the PCT assembly <NUM> includes a plurality of air passages (e.g., air channels) positioned across the mounting surface <NUM>. The plurality of air passages may facilitate the removal of air from between the PCT assembly <NUM> and the tire casing <NUM> during a retreading process of the tire <NUM> (e.g., the tire casing <NUM>). More specifically, the air passages may facilitate the removal of air from between the mounting surface <NUM> and the mounting surface <NUM>.

The PCT assembly <NUM> may include a first PCT end <NUM> and a second PCT end <NUM>. Extending between the first PCT end <NUM> and the second PCT end <NUM>, and positioned on (e.g., profiled along, molded in, cut in, etc.) the opposing surface <NUM>, may be a tread pattern <NUM> (e.g., a tread design, a series of treads, a tread pattern repetition, etc.). The tread pattern <NUM> may include a plurality of lugs, grooves, cuts, sipes, sipe cuts, and similar features. The tread pattern <NUM> may include the grooves <NUM>.

The first PCT end <NUM> may include a first PCT end surface <NUM>. The first PCT end surface <NUM> may be contiguous with both the mounting surface <NUM> and the opposing surface <NUM>. In some embodiments, the first PCT end surface <NUM> may be perpendicular to the mounting surface <NUM>. The second PCT end <NUM> may include a second PCT end surface <NUM>. The second PCT end surface <NUM> may be contiguous with both the mounting surface <NUM> and the opposing surface <NUM>. In some embodiments, the second PCT end surface <NUM> may be perpendicular to the mounting surface <NUM>.

The PCT assembly <NUM> may further include a first PCT side <NUM> and a second PCT side <NUM> opposite the first PCT side <NUM>. The first PCT side <NUM> may be parallel to the second PCT side <NUM>. In some embodiments, the first PCT side <NUM> and the second PCT side <NUM> extend away from the mounting surface <NUM> in a direction generally toward a center line CA of the PCT assembly <NUM>. When the PCT assembly <NUM> is applied to the tire casing <NUM> (e.g., the mounting surface <NUM>), the first PCT side <NUM> and the second PCT side <NUM> may be positioned proximate the edges of the bondline <NUM>. The interface between the mounting surface <NUM> and the mounting surface <NUM> may be referred to as a bondline. In some embodiments, after the mounting surface <NUM> is applied to the mounting surface <NUM>, a portion of the mounting surface <NUM> may still show (e.g., not be covered by the PCT assembly <NUM>) between the edges of the bondline <NUM> and the shoulder areas <NUM>.

The PCT assembly <NUM> may be formed by extrusion. In some embodiments, the PCT assembly <NUM> is formed by molding. The PCT assembly <NUM> may be formed in a mold such that the tread pattern <NUM> proximate the first PCT end <NUM> is continued by the tread pattern <NUM> proximate the second PCT end <NUM> such that when the first PCT end <NUM> and the second PCT end <NUM> are coupled together, the tread pattern <NUM> is not interrupted by a break, but continues infinitely around a perimeter of the opposing surface <NUM>.

Referring now to <FIG>, a precision circumferential tread (e.g., circumferential tread, annular tread, etc.) <NUM> is shown. The precision circumferential tread <NUM> is similar to the PCT assembly <NUM>. A difference between the precision circumferential tread <NUM> and the PCT assembly <NUM> is that the precision circumferential tread <NUM> is formed as a ring (e.g., circle, hoop, cylinder, annular body, etc.). In some embodiments, the precision circumferential tread <NUM> is formed from the PCT assembly <NUM> by coupling (e.g., splicing) the first PCT end <NUM> to the second PCT end <NUM> such that the PCT assembly <NUM> forms a ring. More specifically, the precision circumferential tread <NUM> may be formed by coupling the first PCT end surface <NUM> to the second PCT end surface <NUM>. In some embodiments, the first PCT end <NUM> and the second PCT end <NUM> may be hot spliced together (e.g., vulcanized together using unvulcanized rubber (e.g., a cushion gum), such as HD-<NUM>).

The precision circumferential tread <NUM> defines an inner surface <NUM> and an outer surface <NUM>. The outer surface <NUM> is similar to the opposing surface <NUM>. The outer surface <NUM> may be configured to interface with a road surface (e.g., asphalt, tarmac, cement, road, etc.) when the precision circumferential tread <NUM> is cured to the tire casing <NUM>, and the tire <NUM> is mounted to a vehicle. The outer surface <NUM> may include a tread pattern, such as the tread pattern <NUM>. In some embodiments, the tread pattern <NUM> may infinitely repeat around a circumference of the precision circumferential tread <NUM> (e.g., around the outer surface <NUM>). The precision circumferential tread <NUM> further defines an inner diameter DI and an outer diameter DO.

Another difference between the PCT assembly <NUM> and the precision circumferential tread <NUM> is that the precision circumferential tread <NUM> includes a splice <NUM>. The splice <NUM> is structured to form the inner surface <NUM> such that the inner surface <NUM> is circumferentially contiguous (e.g., is smooth, does not include a bump proximate the splice <NUM>). In some embodiments, the splice <NUM> is structured to form the outer surface <NUM> such that the tread pattern <NUM> is infinitely repeating circumferentially about the circumference of the outer surface <NUM> (e.g., the tread pattern <NUM> is not interrupted, the tread pattern <NUM> has no beginning or end, etc.). In some embodiments, the splice <NUM> is structured to form the outer surface <NUM> such that the tread pattern <NUM> is discontinuous (e.g., non-repeating) at the splice <NUM>. In some embodiments, the splice <NUM> is formed by a hot splicing process between two ends of a PCT assembly. In some embodiments, the splice <NUM> couples together the first PCT end <NUM> and the second PCT end <NUM>. For example, a user may acquire the PCT assembly <NUM> and hot splice the ends together, forming the precision circumferential tread <NUM>. In some embodiments, the splice <NUM> includes a cushion gum (e.g., uncured rubber, rope rubber, etc.) that has been cured using a curing process. For example, the cushion gum forming the splice <NUM> may be HD-<NUM>, a cushion gum having a curing temperature of <NUM> (<NUM>°F degrees Fahrenheit). To hot splice the PCT assembly <NUM> to form the precision circumferential tread <NUM>, the cushion gum may be applied to (e.g., spread on, stuck to, etc.) the first PCT end <NUM>, and then the first PCT end <NUM> may be placed in contact with (e.g., coupled to, stuck to) the second PCT end <NUM>. More specifically, the cushion gum may be applied to the first PCT end surface <NUM> and the second PCT end surface <NUM>, and then the first PCT end surface <NUM> may be placed in contact with the second PCT end surface <NUM>. An inherent tackiness (e.g., stickiness) of the cushion gum may hold the first PCT end <NUM> and the second PCT end <NUM> together prior to curing the cushion gum. The cushion gum may then be cured using a hot splicing machine. In some embodiments, the hot splicing machine includes a mold corresponding to the tread pattern <NUM> and the grooves <NUM> such that as the cushion gum cures, the cushion gum conforms to the mold and the tread pattern <NUM> is uninterrupted across the outer surface <NUM>. In some embodiments, after the cushion gum is cured, the cushion gum is cut (e.g., using tools, knives, razors, skive, etc.) to match the tread pattern <NUM> on the outer surface <NUM> such that the tread pattern <NUM> is not interrupted. In some embodiments, the tread pattern <NUM> is interrupted (e.g., the tread pattern <NUM> is not infinitely continuous around the perimeter of the precision circumferential tread <NUM>, such as by the splice <NUM> between the first PCT end <NUM> and the second PCT end <NUM>.

In some embodiments, the first PCT end <NUM> and the second PCT end <NUM> may be coupled together using an adhesive, such as a liquid adhesive or a moisture-curable adhesive. More specifically, the first PCT end surface <NUM> and the second PCT end surface <NUM> may be bonded using an adhesive to form the precision circumferential tread <NUM>.

The precision circumferential tread <NUM> may be formed of rubber. In some embodiments, the precision circumferential tread <NUM> my exhibit an inherent compliance such that the inner diameter DI may be operable between a relaxed inner diameter (e.g., the inner diameter DI shown in <FIG>) and a stretched inner diameter, where the stretched inner diameter is greater than the relaxed inner diameter DI.

Referring now to <FIG>, a precision circumferential tread <NUM> is shown. The precision circumferential tread <NUM> is similar to the precision circumferential tread <NUM>. A difference between the precision circumferential tread <NUM> and the precision circumferential tread <NUM> is that the precision circumferential tread <NUM> does not include a splice (e.g., the splice <NUM>).

For example, the precision circumferential tread <NUM> may be formed of a single, continuous piece of rubber that was formed in a mold (e.g., cylindrical mold, circular mold, etc.). Forming the precision circumferential tread <NUM> in the mold forms a precured tread assembly without the need for splicing (e.g., hot splicing, coupling together, etc.) the ends of a flat tread (e.g., strip tread, tread strip, PCT assembly <NUM>, etc.). The precision circumferential tread <NUM> includes an inner surface <NUM> defined by the inner diameter DI and an outer surface <NUM> defined by the outer diameter DO. While the precision circumferential tread <NUM> and the precision circumferential tread <NUM> are similar to one another, there are some structural differences between the two. Because the precision circumferential tread <NUM> is formed by coupling the ends of the PCT assembly <NUM> together, the inner surface <NUM>, prior to being bonded to the tire casing <NUM>, may be under a slight compression and the outer surface <NUM> may be under a slight tension. As a person of ordinary skill in the art may appreciate, as the ratio of the tread thickness DT to the inner diameter DI(e.g., DT/DI) decreases, the compressive forces along the inner surface <NUM> will also decrease. The precision circumferential tread <NUM> may not exhibit the same inherent compressive and tensile forces as the precision circumferential tread <NUM> is formed using the circular mold. When the precision circumferential tread <NUM> is positioned around the tire casing <NUM>, the entirety of the precision circumferential tread <NUM> may be under tension.

Referring now to <FIG>, the tire casing <NUM> is shown in a retreading process that includes the PCT assembly <NUM>. The tire casing <NUM> is shown as having the mounting surface <NUM>, smoothed, buffed, and prepared to accept a tread assembly (e.g., the PCT assembly <NUM>, the precision circumferential tread <NUM>, the precision circumferential tread <NUM>). As shown in <FIG>, the mounting surface <NUM> has the inner diameter DI. In some embodiments, the casing diameter DC is equal to the tread length DL.

After the tire casing <NUM> and the PCT assembly <NUM> have been buffed, the mounting surface <NUM>, the mounting surface <NUM>, the first PCT end surface <NUM>, and the second PCT end surface <NUM> are subjected to a priming treatment. The term "priming treatment" as used herein means any treatment which optimizes the surface (e.g., the mounting surface <NUM>, the mounting surface <NUM>, the first PCT end surface <NUM>, the second PCT end surface <NUM>) of the substrate (e.g., tire casing <NUM>, PCT assembly <NUM>) for reception of the adhesive and subsequent curing of the adhesive to bond the tire casing <NUM> and the PCT assembly <NUM> together. Thus, it will be appreciated that various different types of priming treatments may be employed, and the method is not limited to any particular priming treatment. Examples of suitable priming treatments are discussed below.

In some embodiments, where the adhesive is hydrophilic, the primer behaves as a compatibilization agent to improve the adhesion between the mounting surface <NUM> and the mounting surface <NUM>. The mounting surface <NUM> and the mounting surface <NUM> may both be inherently hydrophobic such that application of the adhesive alone to either of the surfaces causes the adhesive to 'bead up,' resulting in gaps of no adhesive existing between the PCT assembly <NUM> and the tire casing <NUM>. The primer effectively transforms the otherwise hydrophobic surfaces into hydrophilic surfaces such that the adhesive is better able to spread across the mounting surface <NUM> and the mounting surface <NUM>. Because the primer acts as a compatibilization agent, the adhesive is able to penetrate into each crevice, buff, cut, pit, and discontinuity within the buffed surface of both the mounting surface <NUM> and the mounting surface <NUM>. When the adhesive cures, the adhesive may form a physical bond, a chemical bond, or a combination of physical and chemical bonds, between the PCT assembly <NUM> and the tire casing <NUM>.

In some embodiments, the primer modifies (e.g., chemically modifies) the mounting surface <NUM> and the mounting surface <NUM> such that the adhesive is able to couple together (e.g., adhere to, cross-link with, etc.) the now-reactive polymer chains of the PCT assembly <NUM> and the tire casing <NUM>.

According to one possible approach, the surfaces of the substrates may be treated with a halogen-containing priming agent.

The priming agent is applied to the tire casing <NUM> as a solution in a solvent, for example a volatile organic solvent. Caution should be exercised when combining primer and solvents; in certain combinations, explosive reactions are possible. Examples of typically suitable organic solvents are dichloromethane, ethyl acetate, and acetone. The concentration of the priming agent solution may be about <NUM>-<NUM>% by weight, inclusive. In some embodiments, the concentration of the priming agent is <NUM>-<NUM>% by weight, inclusive, based on the total weight of the solvent and the priming agent. The priming agent may be a <NUM> weight percent solution of <NUM>,<NUM>-dichloro-<NUM>,<NUM>-dimethylhydantoin in dichloromethane. The priming agent rate of application may be <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (<NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive). In some embodiments, the priming agent is applied at a rate of about <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (e.g., <NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive).

The priming agent may be applied to the tire casing <NUM> and the PCT assembly <NUM> using any conventional mode of application, for example brushing or spraying. One coat of the priming agent is generally sufficient, but it is important to ensure that all of the mounting surface <NUM>, the mounting surface <NUM>, the first PCT end surface <NUM>, and the second PCT end surface <NUM> have been wetted with the priming agent. The priming agent rate of application may be <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (<NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive). In some embodiments, the priming agent is applied at a rate of about <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (e.g., <NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive). The priming agent solution generally dries within a matter of minutes, to leave the primed surfaces ready for application of the adhesive composition.

The above-described priming treatment is not the only priming technique which can be employed. In some embodiments, the tire casing <NUM> and the PCT assembly <NUM> are primed by oxidation methods using oxidative reactants which may introduce functional groups upon application to the rubber surface, the type and number depending on reaction conditions and subsequently occurring chemical reactions. In a strict sense, the mechanism may not be an "oxidation", but the introduction of polar groups may be facilitated. In the case of some reactants (particularly the mineral acids), other functional groups may be introduced which will enhance the interaction with unreacted urethane (e.g., urethane precursors). Some of the groups introduced may be derived from epoxide, dioxetane (a <NUM>-membered ring with <NUM> carbons and <NUM> oxygens), aldehyde, ketone, organic carboxylic acid, and alcohol. Reactants used may be strong mineral acids such as nitric or sulphuric acid; bases such as sodium hydroxide or potassium hydroxide; peroxides such as hydrogen peroxide or t-butyl hydroperoxide; inorganic oxidants such as potassium permanganate and potassium dichromate; organic acids, such as formic and trifluoroacetic; and peracids such as peroxyacetic and peroxybenzoic acid. Other reactants may be singlet oxygen sensitizers such as Rose Bengal and methylene blue; reactants such as aqueous ozone; reactants which cause addition of halogen such as HBr, HCl, Cl<NUM> and Br<NUM>; reactants which cause addition to carbon-carbon unsaturation using R-substituted <NUM>,<NUM>,<NUM>-triazoline <NUM>,<NUM> diones, where R is methyl, phenyl, butyl or naphthyl; or bis-(p-<NUM>,<NUM>-dioxo-<NUM>,<NUM>,<NUM>-triazoline-<NUM>-yl-phenyl) methane. Priming can also be effected using high energy radiation, including microwave discharge, corona discharge, and plasma treatment. The resulting surface modification may depend on the surface chemistry, the gases present, and the energy level employed.

Once the mounting surface <NUM>, the mounting surface <NUM>, the first PCT end surface <NUM>, and the second PCT end surface <NUM> have been primed (e.g., prepared), an adhesive is applied to the mounting surface <NUM>, the mounting surface <NUM>, the first PCT end surface <NUM>, and the second PCT end surface <NUM>. In some embodiments, the mounting surface <NUM> has a width greater than the width of the mounting surface <NUM>. Thus, it may be desirable, in some embodiments, to apply the adhesive to the mounting surface <NUM> only where the mounting surface <NUM> will contact. In other words, the adhesive may be applied to the mounting surface <NUM> between the edges of the bondline <NUM>. In some embodiments, between the edges of the bondline <NUM> is the entire mounting surface <NUM>. In some embodiments, between the edges of the mounting surface <NUM> is a portion of the mounting surface <NUM>, referred to as a contact area (e.g., bondline).

In some embodiments, the adhesive may be a low-temperature curing adhesive (e.g., an adhesive structured to cure at a temperature near room temperature). In some embodiments, the adhesive is structured to cure between <NUM>,<NUM>-<NUM>,<NUM> (<NUM>-<NUM>°F), inclusive. In some embodiments, the adhesive is structured to cure between <NUM>,<NUM>-<NUM>,<NUM> (<NUM>-<NUM>°F), inclusive. In some embodiments, the adhesive is configured to cure between <NUM>,<NUM>-<NUM>,<NUM> (<NUM>-<NUM>°F), inclusive. In some embodiments, the adhesive is configured to cure at approximately <NUM>,<NUM> <NUM>°F (e.g., <NUM>,<NUM>-<NUM> (<NUM>-<NUM>°F), inclusive). In some embodiments, the adhesive is configured to cure when exposed to moisture (e.g., water, mist, etc.).

The adhesive may be a polyurethane adhesive. Polyurethane adhesive compositions may be one-part systems, and comprise an isocyanate-terminated prepolymer and a polyhydroxide curing agent. The isocyanate-terminated prepolymer is generally in liquid form and is formed by reacting a polyether polyol or polyester polyol with a molar excess of an isocyanate (e.g., polyisocyanate, di-isocyanate, etc.). The prepolymer may be formed by reacting the polyisocyanate with a polyester polyol. In order to reduce reactivity of the polyhydroxide curing agent and to prevent substantial gelling or hardening of the adhesive composition during storage, the polyhydroxide compound may be present as an insoluble phase in the isocyanate-terminated liquid prepolymer phase.

The adhesive is applied to the primer disposed on the mounting surface <NUM>. In other words, the adhesive is applied to the now-primed mounting surface <NUM> in small patches. The adhesive is then spread evenly on the mounting surface <NUM> using a trowel to a thickness of about <NUM> (<NUM> thousandths of an inch). Any excess adhesive is removed.

The adhesive is also applied to the primer disposed on the mounting surface <NUM>. In other words, the adhesive is spread evenly on the now-primed mounting surface <NUM>, in some embodiments to a thickness of about <NUM> (<NUM> thousandths of an inch). This is accomplished by applying the adhesive in small amounts via the trowel while the tire casing <NUM> is slowly rotated. As the tire casing <NUM> is rotated, moderate pressure on the mounting surface <NUM> by the trowel will remove undesired adhesive by doctoring action.

In some embodiments, after applying the adhesive and before applying the PCT assembly <NUM> to the tire casing <NUM>, a user may mist the adhesive with water. In some embodiments, misting the adhesive on the mounting surface <NUM> only, misting the adhesive on the mounting surface <NUM> only, or misting both the adhesive on the mounting surface <NUM> and the mounting surface <NUM>.

In some embodiments, the adhesive is a two-part adhesive, such as an epoxy, having a first part and a second part. The first part may be applied to the mounting surface <NUM> and the second part may be applied to the mounting surface <NUM> such that the first part and the second part mix when the PCT assembly <NUM> is applied to the tire casing <NUM>.

After the adhesive has been applied to the mounting surface <NUM> and the mounting surface <NUM>, the PCT assembly <NUM> may be placed on the tire casing <NUM> and the two adhesive-coated surfaces mated. Specifically, the mounting surface <NUM> and the mounting surface <NUM> may be mated. After the PCT assembly <NUM> is applied to the tire casing <NUM>, the first PCT end <NUM> and the second PCT end <NUM> may be mated together. For example, the first PCT end <NUM> and the second PCT end <NUM> may be stapled together with setting staples every <NUM> (<NUM>/<NUM> inch) such that the first PCT end surface <NUM> interfaces with the second PCT end surface <NUM>. In some embodiments, the adhesive is applied to the first PCT end surface <NUM> and the second PCT end surface <NUM> prior to the PCT assembly <NUM> being placed on the tire casing <NUM>. In some embodiments, the adhesive is applied to the first PCT end surface <NUM> and the second PCT end surface <NUM> after the PCT assembly <NUM> is placed on the tire casing <NUM> and before the first PCT end <NUM> and the second PCT end <NUM> are stapled together. In some embodiments, the adhesive is interposed (e.g., squeezed in, etc.) between the first PCT end surface <NUM> and the second PCT end surface <NUM> after the first PCT end <NUM> and the second PCT end <NUM> are stapled together.

After the PCT assembly <NUM> is disposed on the tire casing <NUM>, a roller pressing process, commonly referred to as stitching, may be performed on the retreaded tire assembly to produce a bondline of more uniform thickness. In some embodiments, stitching is used to force air out and away from the bondline (e.g., from between the tire casing <NUM> and the PCT assembly <NUM>). Specifically, to force air out and away from between the mounting surface <NUM> and the mounting surface <NUM>.

After stitching, a film <NUM> may be coupled to the opposing surface <NUM> about the circumference of the opposing surface <NUM>. In some embodiments, the film <NUM> is a perforated polymer film, for example polyethylene film, in some embodiments triple folded (three thicknesses, <NUM>,<NUM> (<NUM> inches) wide), and centered onto the opposing surface <NUM> and stapled to the PCT assembly <NUM> after the stitching process. The retreaded tire assembly is then rotated on a tire building device (e.g., a tire building system, a rim assembly, a tire assembly machine, etc.) and the polymer film wrapped around the opposing surface <NUM> as the retreaded tire assembly rotates. The free end of the film is then stapled onto the opposing surface <NUM>, through the area containing the setting staples. Specifically, the free end of the film is stapled to the PCT assembly <NUM> proximate the first PCT end <NUM> and the second PCT end <NUM>.

The film <NUM> may be coupled to the PCT assembly <NUM> using glue, fasteners, staples, or similar fasteners. The film <NUM> may have a film width greater than the tread width DW such that the film <NUM> extends over the shoulder areas <NUM> and covers the edges of the bondline <NUM> (e.g., covers the first PCT side <NUM> and the second PCT side <NUM>). During the retreading and stitching processes, some of the adhesive may be disposed near or proximate the edges of the bondline <NUM>. The film <NUM> is configured to protect the edges of the bondline <NUM> from coming into contact with foreign bodies (e.g., dust, towels, clothing, curing envelope, etc.) and getting stuck to or cured to the tire <NUM>. The film <NUM> may be profiled with perforations such that air can escape from within the grooves <NUM> when the tire <NUM> is placed in an envelope for curing. In some embodiments, the film <NUM> also helps to maintain the positioning of the PCT assembly <NUM> on the tire casing <NUM>, the film <NUM> applying a force radially inward on the PCT assembly <NUM>.

Referring now to <FIG>, the tire casing <NUM> is shown in a retreading process that includes the precision circumferential tread <NUM>. However, it should be noted that, in some embodiments, the precision circumferential tread <NUM> may be interchanged with the precision circumferential tread <NUM>. The tire casing <NUM> is shown as having the mounting surface <NUM>, smoothed, buffed, and prepared to accept a tread assembly (e.g., the PCT assembly <NUM>, the precision circumferential tread <NUM>, the precision circumferential tread <NUM>). As shown in <FIG>, the mounting surface <NUM> has the inner diameter DI. The precision circumferential tread <NUM> is shown in its stretched inner diameter configuration where the inner surface <NUM> defines a diameter greater than the inner diameter DI.

After the tire casing <NUM> and the precision circumferential tread <NUM> have been buffed, the mounting surface <NUM> and the inner surface <NUM> are subjected to a priming treatment. The term "priming treatment" as used herein means any treatment which optimizes the surface (e.g., the mounting surface <NUM>, the inner surface <NUM>) of the substrate (e.g., tire casing <NUM>, precision circumferential tread <NUM>, precision circumferential tread <NUM>) for reception of the adhesive and subsequent curing of the adhesive to bond the tire casing <NUM> and the precision circumferential tread <NUM> together. Thus, it will be appreciated that various different types of priming treatments may be employed, and the method is not limited to any particular priming treatment. Examples of suitable priming treatments are discussed below.

In some embodiments, where the adhesive is hydrophilic, the primer behaves as a compatibilization agent to improve the adhesion between the mounting surface <NUM> and the inner surface <NUM>. The mounting surface <NUM> and the inner surface <NUM> may both be inherently hydrophobic such that application of the adhesive alone to either of the surfaces causes the adhesive to 'bead up,' resulting in gaps of no adhesive existing between the precision circumferential tread <NUM> and the tire casing <NUM>. The primer effectively transforms the otherwise hydrophobic surfaces into hydrophilic surfaces such that the adhesive is better able to spread across the mounting surface <NUM> and the inner surface <NUM>. Because the primer acts as a compatibilization agent, the adhesive is able to penetrate into each crevice, buff, cut, pit, and discontinuity within the buffed surface of both the mounting surface <NUM> and the inner surface <NUM>. When the adhesive cures, the adhesive may form a physical bond, a chemical bond, or a combination of physical and chemical bonds between the precision circumferential tread <NUM> and the tire casing <NUM>.

In some embodiments, the primer modifies (e.g., chemically modifies) the mounting surface <NUM> and the inner surface <NUM> such that the adhesive is able to couple together (e.g., adhere to, cross-link, etc.) the now reactive polymer chains of the precision circumferential tread <NUM> and the tire casing <NUM>.

The priming agent is applied to the tire casing <NUM> and the precision circumferential tread <NUM> as a solution in a solvent, for example a volatile organic solvent. Caution should be exercised when combining primer and solvents; in certain combinations, explosive reactions are possible. Examples of suitable organic solvents may be dichloromethane, ethyl acetate and acetone. The concentration of the priming agent solution may be <NUM>-<NUM>% by weight. In some embodiments, the concentration of the priming agent solution is <NUM>-<NUM>% by weight, inclusive, based on the total weight of the solvent and the priming agent. The priming agent may be a <NUM> weight percent solution of <NUM>,<NUM>-dichloro-<NUM>,<NUM>-dimethylhydantoin in dichloromethane. The priming agent rate of application may be <NUM>-<NUM> kPa (<NUM><NUM>-<NUM> ounces per square inch), inclusive (<NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive). In some embodiments, the priming agent is applied at a rate of about <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (e.g., <NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive).

The priming agent may be applied to the tire casing <NUM> and the precision circumferential tread <NUM> using any conventional mode of application, for example brushing or spraying. One coat of the priming agent is generally sufficient, but it is important to ensure that all of the mounting surface <NUM> and the inner surface <NUM> have been wetted with the priming agent. The priming agent rate of application may be <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (<NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive). In some embodiments, the priming agent is applied at a rate of about <NUM>-<NUM> kPa (<NUM>-<NUM> ounces per square inch), inclusive (e.g., <NUM>-<NUM> kPa (<NUM>-<NUM> grams per square inch), inclusive). The priming agent solution generally dries within a matter of minutes, to leave the primed surfaces ready for application of the adhesive composition.

The above-described priming treatment is not the only priming technique which can be employed. In some embodiments, the tire casing <NUM> and the precision circumferential tread <NUM> are primed by oxidation methods using oxidative reactants which may introduce functional groups upon application to the rubber surface, the type and number depending on reaction conditions and subsequently occurring chemical reactions. In a strict sense, the mechanism may not be an "oxidation", but the introduction of polar groups may be facilitated. In the case of some reactants (particularly the mineral acids), other functional groups may be introduced which will enhance the interaction with unreacted urethane (e.g., urethane precursors). Some of the groups introduced may be derived from epoxide, dioxetane (a <NUM>-membered ring with <NUM> carbons and <NUM> oxygens), aldehyde, ketone, organic carboxylic acid, and alcohol. Reactants used may be strong mineral acids such as nitric or sulphuric acid; bases such as sodium hydroxide or potassium hydroxide; peroxides such as hydrogen peroxide or t-butyl hydroperoxide; inorganic oxidants such as potassium permanganate and potassium dichromate; organic acids, such as formic and trifluoroacetic; and peracids such as peroxyacetic and peroxybenzoic acid. Other reactants may be singlet oxygen sensitizers such as Rose Bengal and methylene blue; reactants such as aqueous ozone; reactants which cause addition of halogen such as HBr, HCl, Cl<NUM> and Br<NUM>; reactants which cause addition to carbon-carbon unsaturation using R-substituted <NUM>,<NUM>,<NUM>-triazoline <NUM>,<NUM> diones, where R is methyl, phenyl, butyl or naphthyl; or bis-(p-<NUM>,<NUM>-dioxo-<NUM>,<NUM>,<NUM>-triazoline-<NUM>-yl-phenyl) methane. Priming can also be effected using high energy radiation, including microwave discharge, corona discharge, and plasma treatment. The resulting surface modification may depend on the surface chemistry, the gases present, and the energy level employed.

Once both the mounting surface <NUM> and the inner surface <NUM> have been primed (e.g., prepared), an adhesive is applied to both the mounting surface <NUM> and the inner surface <NUM>.

In some embodiments, the adhesive may be a low-temperature curing adhesive (e.g., an adhesive structured to cure at a temperature near room temperature). In some embodiments, the adhesive is structured to cure between <NUM>-<NUM> (<NUM>-<NUM>°F), inclusive. In some embodiments, the adhesive is structured to cure between <NUM>-<NUM> (<NUM>-<NUM>°F), inclusive. In some embodiments, the adhesive is configured to cure between <NUM>-<NUM> (<NUM>-<NUM>°F), inclusive. In some embodiments, the adhesive is configured to cure at approximately <NUM> (<NUM>°F) (e.g., <NUM>-<NUM> (<NUM>-<NUM>°F), inclusive). In some embodiments, the adhesive is configured to cure when exposed to moisture.

The adhesive is applied to the primer disposed on the inner surface <NUM>. In other words, the adhesive is applied to the now-primed inner surface <NUM> in small patches. The adhesive is then spread evenly on the inner surface <NUM> using a trowel to a thickness of about <NUM> (<NUM> thousandths of an inch). Any excess adhesive is removed.

The adhesive is also spread evenly on the primer disposed on the mounting surface <NUM>. In other words, the adhesive is applied to the now-primed mounting surface <NUM>, in some embodiments to a thickness of about <NUM> (<NUM> thousandths of an inch). This is accomplished by applying the adhesive in small amounts via the trowel while the tire casing <NUM> is slowly rotated. As the tire casing <NUM> is rotated, moderate pressure on the mounting surface <NUM> by the trowel will remove undesired adhesive by doctoring action.

After the adhesive has been applied to the mounting surface <NUM>, the precision circumferential tread <NUM> may be stretched over the tire casing <NUM> and the inner surface <NUM> may be placed in contact with the mounting surface <NUM> such that the adhesive is interposed between the tire casing <NUM> and the precision circumferential tread <NUM>. After the precision circumferential tread <NUM> is disposed on the tire casing <NUM>, a roller pressing process, commonly referred to as stitching, may be performed on the precision circumferential tread <NUM> to produce a bondline of more uniform thickness. In some embodiments, stitching is used to force air out and away from the bondline (e.g., from between the tire casing <NUM> and the precision circumferential tread <NUM>).

After stitching the precision circumferential tread <NUM> to the tire casing <NUM>, the film <NUM> may be coupled to the outer surface <NUM> about a circumference of the outer surface <NUM>. In some embodiments, the film <NUM> is a perforated polymer film, for example polyethylene film, in some embodiments triple folded (three thicknesses, <NUM> (<NUM> inches) wide), and centered onto the outer surface <NUM> and stapled to the precision circumferential tread <NUM> after the stitching process. The retreaded tire assembly is then rotated on the tire building device and the film <NUM> wrapped around the outer surface <NUM> as the retreaded tire assembly rotates. The free end of the film is then stapled onto the outer surface <NUM>.

The film <NUM> may be coupled to the precision circumferential tread <NUM> using glue, fasteners, staples, or similar fasteners. The film <NUM> may have a film width greater than the tread width DW such that the film <NUM> extends over the shoulder areas <NUM> and covers the edges of the bondline <NUM> (e.g., covers the first PCT side <NUM> and the second PCT side <NUM>). In some embodiments, the film <NUM> covers the entirety of the edges of the bondline <NUM>. During the retreading and stitching processes, some of the adhesive may be disposed near or proximate the edges of the bondline <NUM>. The film <NUM> is configured to protect the edges of the bondline <NUM> from coming into contact with foreign bodies and getting stuck to or cured to the tire <NUM>. The film <NUM> may be profiled with perforations such that air can escape from within the grooves <NUM> when the tire <NUM> is placed in an envelope for curing.

Referring now to <FIG>, the retreaded tire assembly is shown. The retreaded tire assembly may include the tire casing <NUM> and any one of the PCT assembly <NUM>, the precision circumferential tread <NUM>, or the precision circumferential tread <NUM>. A method of curing the adhesive is substantially the same for the PCT assembly <NUM>, the precision circumferential tread <NUM>, and the precision circumferential tread <NUM>. Herein, the method will be described with respect to the PCT assembly <NUM>.

As shown in <FIG>, a moisture reservoir may be positioned on the retreaded tire assembly. The moisture reservoir may be positioned on the retreaded tire assembly such that the moisture reservoir is positioned proximate to the edges of the bondline <NUM>. The moisture reservoir is configured to present moisture proximate to the edges of the bondline <NUM> such that moisture may permeate the bondline and facilitate curing of the adhesive. Positioning a moisture reservoir proximate to the edges of the bondline <NUM> may decrease the amount of time required to cure the adhesive (e.g., facilitate faster curing of the adhesive). The adhesive may be a moisture-curable adhesive, requiring the presence of moisture to cure. In some embodiments, the adhesive may be configured to cure without a moisture reservoir, but the curing time and the bond strength may be improved by the presence of a moisture reservoir during a transition of the adhesive from uncured to cured.

The film <NUM> may be interposed between the moisture reservoir and the PCT assembly <NUM>. In some embodiments, the moisture reservoir is coupled directly to the PCT assembly <NUM>. The moisture reservoir may be positioned such that the moisture reservoir covers the entirety of the edges of the bondline <NUM>.

Moisture may include water, distilled water, adhesive reactants, isocyanate reactants, or similar liquids and moistures.

The moisture reservoir is configured to introduce moisture to the adhesive interposed between the tire casing <NUM> and the PCT assembly <NUM> via the edges of the bondline <NUM>. In some embodiments, the moisture reservoir is configured to produce steam, such as through increasing the temperature of (e.g., boiling) water. In some embodiments, the moisture reservoir releases water vapor (e.g., evaporated water) proximate to the edges of the bondline <NUM>. The release of either steam or water vapor may be controlled such that the predetermined amount of moisture is presented to the edges of the bondline <NUM> (e.g., not too much and not too little). In some embodiments, the moisture reservoir passively holds moisture such that the moisture may evaporate from the moisture reservoir and permeate the edges of the bondline <NUM> to facilitate curing of the adhesive proximate to the bondline.

The moisture reservoir may be an absorbent textile, such as a textile <NUM>. The textile <NUM> may be formed of a flexible material, such as cotton, nylon, polyester, synthetic fibers, and similar materials known to be absorbent. In some embodiments, the moisture reservoir is formed of felt or foam. In some embodiments, the textile <NUM> may be formed of an elastic material, structured to expand and increase a surface area upon the application of force. For example, the textile <NUM> may be formed of Spandex or Lycra. In some embodiments the textile <NUM> may be formed of a combination of flexible materials and elastic materials such that the textile <NUM> exhibits a desirable amount of absorption, flexibility, and stretchability. In some embodiments, the textile <NUM> is a towel, such as a cotton towel, a microfiber towel, or a similar towel. The textile <NUM> may be absorbent such that the textile <NUM> can absorb and retain the predetermined amount of moisture.

The textile <NUM> may define a generally rectangular shape having the same size as the film <NUM>. In some embodiments, the textile <NUM> may be a thin strip (e.g., <NUM>(<NUM> inch) wide) that covers one of the edges of the bondline <NUM>. In some embodiments, two thin strips of the textile <NUM> may be positioned proximate to and covering both of the edges of the bondline <NUM>. The textile <NUM> may come on a spool that is applied to the PCT assembly <NUM> after the film <NUM> is applied to the PCT assembly <NUM>. The textile <NUM> may be disposable after the curing process is complete. In some embodiments, the textile <NUM> is able to be reused for more than one curing process of the adhesive.

The textile <NUM> may be coupled to the PCT assembly <NUM> proximate to the opposing surface <NUM> such that the textile <NUM> interfaces with the film <NUM>. In some embodiments, the film <NUM> is entirely interposed between the textile <NUM> and the opposing surface <NUM>, preventing contact between the textile and the opposing surface <NUM>. In some embodiments, the textile <NUM> and the film <NUM> are integrally formed into a single body to facilitate easier application of the textile <NUM>. For example, the textile <NUM> may be STRIP WICK™. In some embodiments, the textile <NUM> is a disposable cloth (e.g., paper cloth, paper towels, Handi-Wipes, etc.). In some embodiments, the sides of the film <NUM> may extend toward the side walls <NUM> of the tire casing <NUM>, the film <NUM> covering (e.g., positioned above, contacting, etc.) the first PCT side <NUM>, the second PCT side <NUM>, and the edges of the bondline <NUM>. The film <NUM> may be interposed between the textile <NUM> and the PCT assembly <NUM> such that the textile <NUM> does not interface with the opposing surface <NUM>, the first PCT side <NUM>, the second PCT side <NUM>, and the edges of the bondline <NUM>.

The textile <NUM> may be coupled to the PCT assembly <NUM> using staples, tacks, pins, nails, or similar fasteners. In some embodiments, the textile <NUM> may be sized such that the textile <NUM> may cover the entire opposing surface <NUM>. In some embodiments, the textile <NUM> may cover the entire PCT assembly <NUM> (e.g., extend toward the rotational axis of the tire casing <NUM> and cover a portion of the tire casing <NUM> such that the PCT assembly <NUM> and the edges of the bondline <NUM> are hidden from view). The textile <NUM> may be approximately the same size (e.g., have the same length and width) as the film <NUM>. In some embodiments, the textile <NUM> may not, alone, cover the entirely of the opposing surface <NUM>, but multiple textiles may be required, shown as a second textile <NUM>, a third textile <NUM>, and a fourth textile <NUM> to cover the entirely of the opposing surface <NUM>.

Referring to <FIG>, the textile <NUM> may be fastened to the opposing surface <NUM> in an overlapping pattern such that a portion of the textile <NUM> overlaps with a portion of the second textile <NUM>, and a portion of the second textile <NUM> overlaps with a portion of the third textile <NUM>.

After the textile <NUM> is fastened to the opposing surface <NUM>, the textile <NUM> may be wetted (e.g., moistened, soaked, drenched, sprayed, submerged, etc.) with moisture. For example, as the tire casing <NUM> is rotated, a sprayer may mist the textile <NUM> with the predetermined amount of moisture such that the textile <NUM> absorbs the predetermined amount of moisture. In some embodiments, the textile <NUM> may be wetted prior to being coupled to the PCT assembly <NUM>. For example, the textile <NUM> may be stored in a humidor such that the textile <NUM> is kept at an optimal temperature and optimally saturated (e.g., saturated with the predetermined amount of moisture).

Referring to <FIG>, the PCT assembly <NUM> is shown as being covered by the textiles (e.g., the textile <NUM>, the second textile <NUM>, the third textile <NUM>, and the fourth textile <NUM>). To retain the textiles to the retreaded tire assembly (e.g., the PCT assembly <NUM>, the opposing surface <NUM>), a belt <NUM> may be positioned circumferentially around the opposing surface <NUM> and the textiles, the belt <NUM> configured to apply a circumferentially inward force on the textiles in a direction generally toward the tire casing <NUM>. In some embodiments, the textile <NUM> is not fastened to the PCT assembly <NUM> using fasteners, but is instead only secured to the PCT assembly <NUM> using the belt <NUM>.

Referring to <FIG>, the retreaded tire assembly and the textiles are inserted into an envelope <NUM> using an envelope spreader <NUM> (e.g., spreader, envelope stretcher, etc.). In some embodiments, the textiles are positioned on the opposing surface <NUM> such that no portion of the envelope <NUM> comes into contact with the opposing surface <NUM> during the curing process. In some embodiments, the textiles are (e.g., the textile <NUM> is) positioned on the PCT assembly <NUM> such that no portion of the envelope <NUM> interfaces with the PCT assembly <NUM> or the film <NUM> during the curing process.

Speaking generally, the textile <NUM> is positioned within the envelope <NUM> along with the retreaded tire assembly such that the predetermined amount of moisture may be present within the envelope <NUM> proximate to the edges of the bondline <NUM> to facilitate curing of the adhesive. In some embodiments, the predetermined amount of moisture required to cure the adhesive is able to be absorbed into a single textile, such as the textile <NUM>. In such an embodiment, the textile <NUM> may be fastened to the opposing surface <NUM> and not cover and entirety of the opposing surface <NUM>, allowing the envelope <NUM> to come into contact with the film <NUM> during curing. In some embodiments, one-half of the opposing surface <NUM> (e.g., not necessarily a contiguous half, net half, etc.) may be covered by textiles configured to absorb and maintain the predetermined amount of moisture required to cure the adhesive.

Turning now to <FIG>, the textile <NUM>, the precision circumferential tread <NUM>, and the tire casing <NUM> are shown positioned within the envelope <NUM>. The envelope <NUM> may include an envelope rim <NUM> (e.g., the BANDAG™ ARC RING SYSTEM™, etc.) inserted into the bead area <NUM> and expanded, forming an air tight seal between the retreaded tire assembly and the envelope <NUM>. Thus, air and moisture may only circulate within a volume <NUM> defined between the envelope <NUM> and the retreaded tire assembly.

The envelope <NUM> further includes a conduit <NUM> fluidly coupled to the volume <NUM>. Air is removed from the volume <NUM> through the conduit <NUM> by way of a pump or other suitable vacuum system. The air is removed such that the envelope <NUM> and the retreaded tire assembly move toward one another. At some points, such as proximate to the side walls <NUM>, the envelope <NUM> may contact the tire casing <NUM>. As a result of the vacuum (e.g., low vacuum, medium vacuum, high vacuum, etc.) within the envelope <NUM>, a pressure is applied to the PCT assembly <NUM> in a direction generally toward the mounting surface <NUM> of the tire casing <NUM>. The vacuum alone may apply approximately <NUM>,<NUM> kPa (<NUM> pound per square inch PSI) of pressure to the opposing surface <NUM>. The pressure facilitates proper binding between the mounting surface <NUM> and the mounting surface <NUM> as the adhesive cures.

In some embodiments, the retreaded tire assembly and the envelope <NUM> may be placed into a pressure chamber where pressures above atmospheric pressures may be achieved. Once the envelope <NUM> and the retreaded tire assembly are placed in the pressure chamber, the conduit <NUM> may extend out of the pressure chamber to allow air to escape from the envelope <NUM> via the conduit <NUM>. The pressure chamber door is shut and the chamber pressurized. In some embodiments, it may be desirable to seal the edges of the bondline <NUM> such that air may not enter the bondline <NUM>. When the pressure in the chamber reaches <NUM> kPa (<NUM> PSI), the pressure in the envelope <NUM> may be increased. When the chamber reaches <NUM> kPa (<NUM> PSI), air may be injected into the envelope <NUM> to a pressure of <NUM> kPa (<NUM> PSI). In this way, the pressure in the chamber is higher than the pressure in the envelope <NUM>, and reduces any tendency for the grooves <NUM> or spaces in the PCT assembly <NUM> to be closed due to lateral pressure imparted on the opposing surface <NUM> by the envelope <NUM>. In some embodiments, the adhesive is cured at <NUM>°F for <NUM> days (e.g., one week). In some embodiments, the adhesive is cured at <NUM> kPa (<NUM> PSI) for <NUM> days.

The pressure applied to the PCT assembly <NUM> within the pressure chamber may be between <NUM>-<NUM> kPa (<NUM>-<NUM> PSI), inclusive. In some embodiments, the pressure applied to the PCT assembly <NUM> is between <NUM>-<NUM> kPa (<NUM>-<NUM> PSI), inclusive. In some embodiments, the pressure applied is approximately <NUM> kPa (<NUM> PSI) (between <NUM>-<NUM> kPa (<NUM>-<NUM> PSI), inclusive). In some embodiments, the pressure applied to the PCT assembly <NUM> may be lower. The pressure applied to the PCT assembly <NUM> may be between <NUM>-<NUM> kPa (<NUM>-<NUM> PSI), inclusive. In some embodiments, the pressure applied to the PCT assembly <NUM> is between <NUM>-<NUM> kPa (<NUM>-<NUM> PSI), inclusive. In some embodiments, the pressure applied is approximately <NUM> kPa (<NUM> PSI) (between <NUM>-<NUM> kPa (<NUM>-<NUM> PSI), inclusive). While the PCT assembly <NUM> is under pressure, the predetermined amount of moisture absorbed within the textile <NUM> may circulate within the volume <NUM> and interact with the adhesive proximate to the edges of the bondline <NUM>, facilitating the curing of the adhesive.

In some embodiments, such as those where a curing chamber is not readily accessible, air is removed from the volume <NUM> via the conduit <NUM> to form a vacuum (e.g., a substantial vacuum) within the envelope <NUM>. As air is removed from the envelope <NUM>, the envelope <NUM> exerts pressure generally toward the tire casing <NUM>. The envelope <NUM> may begin to conform to the shape of the tire casing <NUM>, the PCT assembly <NUM>, and the textile <NUM>. As shown in <FIG>, the envelope <NUM> may bias the film <NUM> and the textile <NUM> toward the edges of the bondline <NUM>, the film <NUM> interposed between the textile <NUM> and the edges of the bondline <NUM> such that the textile <NUM> does not interface with the edges of the bondline <NUM>. The perforations in the film <NUM> may facilitate the transfer of moisture from the textile <NUM> to the bondline via the edges of the bondline <NUM>, the perforations allowing the moisture to pass through the film <NUM>. The vacuum may cause the moisture absorbed within the textile <NUM> to vaporize, increasing the amount of moisture available proximate to the edges of the bondline <NUM>. In some embodiments, removing the air within the volume <NUM> through the conduit <NUM> may also remove some moisture from the textile <NUM>, and thus it may be desirable, in some embodiments, to moisten the textile <NUM> with more moisture (e.g., slightly more moisture) than what is required of the adhesive to cure, to ensure that enough moisture interacts with (e.g., reacts with) the adhesive.

In some embodiments, where portions of the film <NUM> contact portions of the envelope <NUM> proximate to the opposing surface <NUM>, the envelope <NUM> may extend into the grooves <NUM> of the tread pattern <NUM>, reaching (e.g., nearly reaching) the bottom of the grooves <NUM>. This may be desirable in some embodiments, as the elasticity of the envelope <NUM> helps to ensure that the PCT assembly <NUM>, even the portions of the PCT assembly <NUM> positioned at the bottom of the grooves <NUM>, are pressed toward the mounting surface <NUM> and properly cured. In some embodiments, such as when a curing chamber is used to cure the PCT assembly <NUM>, air pressure is re-applied within the envelope to apply pressure to the bottom of the grooves <NUM>. In some embodiments, the film <NUM> is interposed between the PCT assembly <NUM> (e.g., the opposing surface <NUM>) and the envelope <NUM> such that as the envelope <NUM> extends into the grooves <NUM> and the film <NUM> is biased into the grooves <NUM>, where the perforations of the film <NUM> prevent air from becoming trapped within the grooves <NUM>.

In some embodiments, where the textile <NUM> is positioned between the envelope <NUM> and the film <NUM> proximate to the opposing surface <NUM>, the envelope <NUM> may push portions of the textile <NUM> into the grooves <NUM>. In some embodiments, the textile <NUM> is made of a strong, flexible, and resilient material able to be flush against each surface of the tread pattern <NUM> and the grooves <NUM> when the volume <NUM> is under a vacuum. In some embodiments, the textile <NUM> may include perforations (e.g., holes, mesh, etc.) that allow air to pass through the textile <NUM>, preventing air from being trapped within the grooves <NUM> by the textile <NUM>. The perforations may improve the conformity of the textile <NUM> to the tread pattern <NUM> and grooves <NUM> when the volume <NUM> is under vacuum.

In some embodiments, the textile <NUM> may be positioned in confronting relation to the edges of the bondline <NUM>, the film <NUM> disposed between the textile <NUM> and the edges of the bondline <NUM> such that the textile <NUM> does not cure to the tire <NUM>. This may be desirable, in some embodiments, where air circulation, and thus moisture circulation, within the volume <NUM> is minimal or zero. In some embodiments, the film <NUM> may extend over the first PCT side <NUM> and the second PCT side <NUM>, but not the edges of the bondline <NUM>, allowing the textile <NUM> to come into contact with the edges of the bondline <NUM> when the envelope <NUM> is under the vacuum.

In some examples, the PCT assembly <NUM> was positioned about the mounting surface <NUM>, the adhesive interposed between, and the retreaded tire assembly placed within the envelope without a moisture reservoir (e.g., the textile <NUM>) positioned proximate to the edges of the bondline <NUM> within the envelope. After the designated curing time had elapsed, the retreaded tire assembly was removed from the envelope <NUM> and it was determined that the adhesive had not adequately cured, causing the tire <NUM> to fail testing.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing embodiments (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate embodiments and does not pose a limitation on the scope of the invention unless otherwise claimed.

It should be noted that the term "example" as used herein to describe some embodiments is intended to indicate that some embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that some embodiments are necessarily extraordinary or superlative examples).

The terms "coupled," "connected," and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.

Some embodiments are described herein. Variations of those embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the embodiments to be practiced otherwise than as specifically described herein. Accordingly, embodiments include all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the embodiments unless otherwise indicated herein or otherwise clearly contradicted by context.

It is important to note that the construction and arrangement of the various embodiments are illustrative only. Although some embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein.

Claim 1:
A method of retreading a tire (<NUM>), the method comprising:
interposing a moisture-curing adhesive between an inner surface (<NUM>, <NUM>) of a circumferential tread (<NUM>, <NUM>) and an outer surface of a tire casing (<NUM>);
applying the circumferential tread (<NUM>, <NUM>) to the tire casing (<NUM>) so the inner surface (<NUM>, <NUM>) contacts the outer surface and a bondline (<NUM>) edge forms circumferentially about the tire casing (<NUM>) proximate to a shoulder (<NUM>) of the tire casing (<NUM>);
coupling a moisture reservoir (<NUM>) to the circumferential tread (<NUM>, <NUM>) proximate to the bondline (<NUM>) edge;
wetting the moisture reservoir (<NUM>) such that, responsive to the wetting, moisture is released from the moisture reservoir (<NUM>) and permeates the bondline (<NUM>) edge;
enclosing the circumferential tread (<NUM>, <NUM>), the tire casing (<NUM>), and the moisture reservoir (<NUM>) within an envelope (<NUM>), the envelope (<NUM>) being positioned so as to extend within grooves (<NUM>) of a tread pattern (<NUM>) on an outer surface (<NUM>, <NUM>) of the circumferential tread (<NUM>, <NUM>); and
removing air from the envelope (<NUM>) to apply a pressure to the circumferential tread (<NUM>, <NUM>) in a direction generally toward the tire casing (<NUM>), wherein the envelope (<NUM>) is positioned within the grooves (<NUM>) to reduce moisture circulation between the envelope (<NUM>) and the circumferential tread (<NUM>, <NUM>).