KR20130077480A - Multilayer body for preparing tire, preparation method of the same, preparation method of pneumatic tire using the multilayer body - Google Patents

Abstract

PURPOSE: A laminate for manufacturing a tire, a manufacturing method thereof, and a laminate for manufacturing the tire, and a manufacturing method of the tire using the same are provided to prevent the loss of physical properties of the non-uniform elongation of an innerliner film, thereby being capable of utilizing a tire-manufacturing process to be easy and efficient. CONSTITUTION: A laminate for manufacturing a tire comprises a tire innerliner film; a release film layer which is attached to one side of the tire innerliner film through a first adhesive layer with an adhesive force of 0.5 kgf/5cm or less; and a rubber elastic material layer which is attached to the other side of the tire innerliner film through a second adhesive layer with an adhesive force of 1.5-4.0 kgf/5cm. A manufacturing method of a laminate for manufacturing a tire comprises a step of spreading a resorcinol-formalin-latex-based adhesive on both sides of the tire innerliner film; a step of binding the release film layer onto one side of the tire innerliner film; and a step of binding a rubber elastic material layer onto the other side of the tire innerlner film. [Reference numerals] (AA) Tire cord; (BB) Carcass rubber; (CC) Innerliner film; (DD) Release film

Description

Tire manufacturing laminate, and manufacturing method thereof and pneumatic tire manufacturing method using the tire manufacturing laminate {MULTILAYER BODY FOR PREPARING TIRE, PREPARATION METHOD OF THE SAME, PREPARATION METHOD OF PNEUMATIC TIRE USING THE MULTILAYER BODY}

The present invention relates to a tire manufacturing laminate, a method for manufacturing a tire manufacturing laminate and a pneumatic tire manufacturing method using the laminate. More specifically, a tire manufacturing laminate, which enables a tire manufacturing process to be more easily and efficiently operated, and prevents a phenomenon in which the inner liner film used is unevenly stretched or deteriorated in physical properties, of the tire manufacturing laminate A manufacturing method and a pneumatic tire manufacturing method using the said laminated body.

The tires support the load of the vehicle, alleviate the impact from the road surface, and transmit the driving or braking force of the vehicle to the ground. In general, a tire is a composite of fiber / steel / rubber and generally has a structure as shown in FIG. 1.

Tread (1): This part is to be in contact with the road surface to provide the necessary frictional force for braking and driving, to have good abrasion resistance, to withstand external shocks, and to generate little heat.

Body Ply (or Carcass) (6): The layer of cord inside the tire, which must support loads, withstand impacts, and be resistant to fatigue during rolling.

Belt (5): Located between the body plies, consisting of steel wires in most cases to mitigate external shocks and maintain a wide tread ground to provide excellent driving stability.

Side Wall (3): refers to the rubber layer between the lower part of the shoulder (2) from the bead (9) and serves to protect the body ply (6) inside.

Inner Liner (7): Located on the inside of the tire instead of the tube, it prevents air leakage to enable pneumatic tires.

BEAD (9): A square or hexagonal wire bundle with rubber coating on the wire that rests and secures the tire to the rim.

CAP PLY (4): A special cord paper placed on the belt of some passenger radial tires that minimizes belt movement when driving.

APEX (8): A triangular rubber filler used to minimize the dispersion of beads, to mitigate external impacts, to protect the beads, and to prevent the ingress of air during molding.

Recently, pneumatic tires (or tube-less tires) in which high pressure air is injected into a high pressure air of about 30 to 40 psi are generally used without using a tube. An airtight inner liner is disposed in the carcass inner layer to prevent leakage to the carcass.

Previously, tire innerliners were used, with rubber components such as butyl rubber or halo butyl rubber, which had relatively low air permeability, and had to increase the rubber content or the thickness of the inner liner in order to obtain sufficient airtightness. . However, when the content of the rubber component and the tire thickness increase, there is a problem in that the total tire weight increases and fuel economy of the vehicle decreases. In addition, in order to couple the rubber components to the tire curker layer, a vulcanizing agent or a vulcanizing process had to be applied, and it was difficult to secure sufficient adhesive force.

On the other hand, the manufacturing process of a pneumatic tire previously known is performed by accumulating on the shaping | molding drum in the structural order inside a tire. For example, after the inner liner film, the bead portion, the body fly portion, the cap fly portion, the belt portion, the tread portion, the shoulder portion, and the rubber layers for forming the sidewall portion are sequentially stacked on the forming drum, a constant temperature and pressure condition is applied. When applied, a cylindrical green tire is manufactured, and when the green tire is vulcanized, a pneumatic tire in a final state is manufactured.

On the other hand, the tire innerliner previously known is stored in the state of a final product having a release film attached to one surface, and is applied to a tire manufacturing process by removing the release film immediately before application of a forming drum. However, in the process of removing the release film from the tire inner liner film, the viscosity of the coated film surface may cause stretching of the inner liner film itself, a part of the film may be distorted, or the surface of the film may be damaged. do.

As such, the innerliner film from which the release film has been removed is applied to a tire manufacturing process in which high-temperature repetitive molding is performed, or it is applied to a driving condition of a vehicle in which high heat is generated after repeated deformation after the final product is made into a pneumatic tire. When exposed, the physical properties of the film may be partially uneven or degraded, and a phenomenon such as cracking of the film itself may occur.

Accordingly, with the development of a tire inner liner film having excellent airtightness even at a thin thickness to lighten the tire, improve automobile fuel economy, and having excellent moldability and mechanical properties, the inner liner film is applied to the tire manufacturing process. There is a need to develop a method to prevent stretching or uneven physical properties.

The present invention is to provide a laminate for producing tires, which enables the tire manufacturing process to be operated more simply and efficiently, and prevents the phenomenon that the innerliner film used is unevenly stretched or the physical properties are lowered.

Moreover, this invention is providing the manufacturing method of the said tire manufacturing laminated body.

Moreover, this invention is providing the manufacturing method of a pneumatic tire using the said laminated body for tire manufacture.

The present invention is a tire inner liner film; A release film layer bonded to one surface of the tire inner liner film with an adhesive force of 0.5 kgf / 5 cm or less through a first adhesive layer; And it provides a laminate for producing a tire comprising a rubber elastomer layer bonded to the other side of the tire inner liner film with an adhesive force of 1.5kgf / 5cm to 4.0kgf / 5cm through a second adhesive layer.

In addition, the present invention comprises the steps of applying a resorcinol-formalin-latex (RFL) -based adhesive on both surfaces of the tire inner liner film; Bonding a release film layer to one surface of the tire innerliner film; And it provides a method for producing a laminate for producing a tire comprising the step of bonding a rubber elastic layer to the other surface of the tire inner liner film.

In addition, the present invention provides a pneumatic tire manufacturing method comprising the step of removing the release film from the tire manufacturing laminate, and placing it on a tire forming drum.

Hereinafter, a tire manufacturing laminate according to a specific embodiment of the present invention, a manufacturing method of a tire manufacturing laminate, and a pneumatic tire manufacturing method using the laminate will be described in detail.

According to one embodiment of the invention, a tire inner liner film; A release film layer bonded to one surface of the tire inner liner film with an adhesive force of 0.5 kgf / 5 cm or less through a first adhesive layer; And a rubber elastic layer bonded to the other surface of the tire inner liner film by an adhesive force of 1.5 kgf / 5 cm to 4.0 kgf / 5 cm through a second adhesive layer.

In the laminate for producing tires, each of the rubber elastomer layer and the release film layer is bonded to both sides of the inner liner film with a specific adhesive force, so that the rubber elastic layer having a higher adhesive force in the process of removing the release film supports the inner liner film. Or it may serve to fix, thereby preventing the phenomenon such as stretching or distortion of the inner liner film due to the removal of the release film.

In addition, as the rubber elastic layer corresponding to the body ply of the inner liner film and the tire is applied to the tire manufacturing process in a state of being bonded with high adhesive force, a problem that may appear in the process of bonding the body ply and the inner liner film, for example For example, it is possible to prevent distortion or tearing caused by the difference in the modulus of the inner liner film and the body ply, which may occur due to expansion in a turn-up process or the like on the forming drum. In addition, by using the tire manufacturing laminate, the inner liner layer and the body fly layer can be arranged in a single step, replacing the previous manufacturing process of separately placing the inner liner layer and the body fly layer in the forming process. In addition, the innerliner layer and the body ply layer can be cut at the same time, thereby simplifying the tire manufacturing process and designing the manufacturing process more efficiently.

That is, by using the tire manufacturing laminate, it is possible to operate the tire manufacturing process more simply and efficiently, and to prevent the phenomenon that the inner liner film used is unevenly stretched or the physical properties are lowered.

The first adhesive layer bonding one surface of the tire inner liner film and the release film layer may have an adhesive force of 0.5 kgf / 5 cm or less, preferably 0.3 kgf / 5 cm or less with the release film layer.

In addition, the second adhesive layer that combines the other surface of the tire inner liner film and the rubber elastomer layer is 1.5kgf / 5cm to 4.0kgf / 5cm, preferably 2.5kgf / 5cm to 4.0 with an unvulcanized body ply rubber layer. It may have an adhesive force of kgf / 5 cm.

As described above, as the first adhesive layer and the second adhesive layer each have the aforementioned adhesive force, the rubber elastic layer serves to support or fix the inner liner film when the release film is removed. It may not be stretched or twisted.

Each of the first adhesive layer and the second adhesive layer may include a resorcinol-formalin-latex (RFL) adhesive. Due to the chemical composition of the resorcinol-formalin-latex (RFL) -based adhesive, each of the first adhesive layer and the second adhesive layer may exhibit the aforementioned adhesive characteristics.

The composition of the resorcinol-formalin-latex (RFL) adhesive included in each of the first adhesive layer and the second adhesive layer may be the same or different, but the resorcinol-formalin-latex (RFL) adhesive is Since the adhesive force is different with respect to the release film layer and the rubber elastic layer, each of the first adhesive layer and the second adhesive layer may have the specific adhesive force described above.

As shown in the manufacturing method described below, each of the first adhesive layer and the second adhesive layer may be formed by applying a resorcinol-formalin-latex (RFL) -based adhesive in a solution to the tire innerliner, and such a solution. After the adhesive is applied in a state, the above-described adhesive properties may appear while undergoing a process such as drying. The total solid content of the resorcinol-formalin-latex (RFL) -based adhesive in this solution may be 15% to 40%.

Specifically, the resorcinol-formalin-latex (RFL) -based adhesive included in each of the first adhesive layer and the second adhesive layer is 5 to 50% by weight of condensate of resorcinol and formaldehyde and 50 to 95% by weight of latex. %, Preferably 10 to 30% by weight of the condensate of resorcinol and formaldehyde and 70 to 90% by weight of the latex.

The condensate of resorcinol and formaldehyde may be obtained by mixing the resorcinol and formaldehyde in a molar ratio of 1: 0.3 to 1: 3.0, preferably 1: 0.5 to 1: 2.5, and then condensation reaction. In addition, the condensate of resorcinol and formaldehyde may be included in more than 5% by weight of the resorcinol-formalin-latex (RFL) -based adhesive to secure an appropriate adhesive layer, to ensure the proper fatigue resistance properties It may be included in less than 50% by weight.

When the latex is included in less than 50% by weight based on the total amount of the adhesive included in each of the first adhesive layer and the second adhesive layer, it may be difficult to sufficiently secure the flexibility and adhesion of the material of the adhesive layer. In addition, when the latex is included in more than 95% by weight relative to the total amount of the adhesive, the viscosity of the adhesive layer may be contaminated due to the increased viscosity of the tire manufacturing layer or manufacturing equipment, tearing the inner liner film during the tire manufacturing process May appear.

The latex may be one or a mixture of two or more selected from the group consisting of natural rubber latex, styrene / butadiene rubber latex, acrylonitrile / butadiene rubber latex, chloroprene rubber latex, and styrene / butadiene / vinylpyridine rubber latex.

Preferably, the latex included in the resorcinol-formalin-latex (RFL) -based adhesive is 20 to 70% by weight of natural rubber latex; And other rubber latex 30 to 80% by weight. If the content of the natural rubber latex in the latex is less than 20% by weight, the adhesive force between the inner liner film and the release film layer or the rubber elastomer layer may not be sufficiently expressed, and the content of the natural rubber latex in the latex exceeds 70% by weight. In this case, the viscosity of the resorcinol-formalin-latex (RFL) -based adhesive may be greatly increased or contaminate the laminate or manufacturing device for manufacturing the tire.

The other rubber latex means rubber latex other than the natural rubber latex, and specific examples thereof are not limited thereto, and may include commonly known rubber latex, and for example, styrene / butadiene rubber latex and acrylonitrile / Butadiene rubber latex, chloroprene rubber latex, styrene / butadiene / vinylpyridine rubber latex or mixtures thereof.

Each of the first adhesive layer or the second adhesive layer may have a thickness of 0.1 to 20 μm, preferably 1 to 6 μm. If the thickness of the adhesive layer is too thin, it may be difficult to sufficiently express the above-described adhesive force, the second adhesive layer is further thinned during the expansion or deformation of the tire manufacturing process, the bonding between the tire inner liner film and the rubber elastomer layer It may be weakened, and the adhesive force expressed by the second adhesive layer may not be sufficient by a heat compression process or a vulcanization process. If the thickness of the adhesive layer is too thick, the thickness or weight of the tire manufacturing laminate may be unnecessarily increased, and the aforementioned adhesive force may not be sufficiently expressed.

The 'adhesion' is a physical or chemical property of the second adhesive layer is changed by the above-described hot pressing process or vulcanization process, so that the tire inner liner film and the rubber elastic layer are chemical or physical force or both It means that it is integrated by, and can be distinguished from the above-mentioned 'sticky' due to this feature.

On the other hand, the tire inner liner film is a polyamide-based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment, wherein the content of the polyether-based segment in the copolymer is the entire tire innerliner film. It may be 15 to 50% by weight based on the weight.

The tire innerliner film may have a relatively low modulus with excellent airtightness by using a copolymer including a specific content of a polyether-based segment that imparts elastomeric properties to the polyamide-based resin. The polyamide-based resin included in the base film layer exhibits excellent airtightness due to inherent molecular chain properties, for example, about 10 to 20 times higher than that of butyl rubber generally used in tires at the same thickness, and other resins. The modulus is not so high compared to. In addition, the polyether-based segment of the copolymer may be present in a bonded or dispersed state between polyamide-based segments or polyamide-based resins, thereby lowering the modulus of the base film layer, and the base film layer The increase in the rigidity of can be suppressed and the crystallization at high temperature can be prevented.

Examples of the polyamide-based resin that can be used for the base film layer include polyamide-based resins such as nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, and nylon 6/66. Nylon 6/66/610 copolymer, nylon MXD6, nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer and nylon 66 / PPS copolymer; Or their N-alkoxyalkylates, for example methoxymethylate of 6-nylon, methoxymethylate of 6-610-nylon or methoxymethylate of 612-nylon, nylon 6, nylon 66, nylon Preference is given to using 46, nylon 11, nylon 12, nylon 610 or nylon 612.

The polyamide-based resin may have a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5, preferably 3.2 to 3.4. If the viscosity of the polyamide-based resin is less than 3.0, sufficient elongation may not be secured due to toughness deterioration, and thus damage may occur during tire manufacturing or driving of a vehicle, and the airtightness that the base film layer should have as a film for tire innerliner or It may be difficult to secure physical properties such as moldability. In addition, when the viscosity of the polyamide-based resin is more than 3.5, the modulus or viscosity of the base film layer to be produced may be unnecessarily high, and it may be difficult for the tire innerliner to have proper moldability or elasticity.

Meanwhile, a copolymer including a polyamide-based segment and a polyether-based segment is present in a bonded or dispersed state between the polyamide-based resins, thereby forming the tire innerliner film. Modulus can be lowered more, the rigidity of the tire innerliner film can be suppressed from rising, and crystallization can be prevented at high temperatures. The tire inner liner film including such a copolymer may realize high elasticity or elastic recovery rate while securing mechanical properties such as excellent durability, heat resistance, and fatigue resistance. Accordingly, the inner liner film may exhibit excellent moldability, and the tire to which the inner liner film is applied may not be physically damaged or its physical properties or performance may be deteriorated even during a vehicle driving process in which repeated deformation and high heat are continuously generated. .

On the other hand, the content of the polyether segment of the copolymer may be 15 to 50% by weight, preferably 20 to 45% by weight, more preferably 22 to 40% by weight based on the total weight of the tire innerliner film. When the content of the polyether-based segment is less than 15% by weight of the entire tire inner liner film, the modulus of the tire inner liner film may be increased, thereby degrading the formability of the tire or significantly reducing the physical properties due to repeated deformation. When the content of the polyether-based segment exceeds 50% by weight of the entire film, the airtightness of the tire innerliner film may be lowered, and the reactivity to the adhesive is lowered, making it difficult for the innerliner to easily adhere to the carcass layer. The elasticity of the base film layer may be increased, and thus it may not be easy to prepare a uniform film.

The polyether-based segment may be present in the state of being bonded to the polyamide-based segment or dispersed between the polyamide-based resins. It is possible to suppress or prevent the base film layer from being easily broken.

The polyamide-based segment of the copolymer may include a repeating unit of Formula 1 or Formula 2.

[Formula 1]

In Formula 1, R ₁ is a linear or branched alkylene group having 1 to 20 carbon atoms or a linear or branched arylalkylene group having 7 to 20 carbon atoms.

(2)

In Formula 2, R ₂ is a linear or branched alkylene group having 1 to 20 carbon atoms, R ₃ is a straight or branched alkylene group having 1 to 20 carbon atoms or a straight or branched arylalkyl having 7 to 20 carbon atoms. It's Rengi.

In addition, the polyether segment of the copolymer may include a repeating unit represented by the following Formula 3.

(3)

In Formula 3, R ₅ is a linear or branched alkylene group having 1 to 10 carbon atoms, n is an integer of 1 to 100, R ₆ and R ₇ may be the same or different from each other, and are a direct bond, -O- , -NH-, -COO- or -CONH-.

Meanwhile, the weight average molecular weight of the copolymer including the polyamide-based segment and the polyether-based segment may be 50,000 to 300,000, preferably 70,000 to 150,000. The weight average molecular weight of the copolymer is less than 50,000, it is not possible to secure sufficient mechanical properties for use in the inner liner film, it is difficult to have gas barrier properties due to low air permeability, the weight average molecular weight of the copolymer exceeds 300,000 If the back surface is heated to a high temperature, the modulus or crystallinity of the inner liner film may be excessively increased, and thus it may be difficult to secure sufficient elasticity or elastic recovery rate.

On the other hand, the copolymer is a polyamide-based segment and a polyether-based segment in a range of 10 to 50% by weight based on the total weight of the film, the polyether-based segment 6: 4 to 3: 7, preferably 5: 5 to 4: 6.

As described above, when the content of the polyether-based segment is too small, the modulus of the tire innerliner film may be increased, thereby reducing the moldability of the tire, or the physical property decrease due to repeated deformation. In addition, if the content of the polyether-based segment is too large, the airtightness of the tire inner liner film may be lowered, the reactivity to the adhesive is lowered, it is difficult for the inner liner to easily adhere to the carcass layer, the inner liner The elasticity of the film may increase and may not be easy to produce a uniform film.

In addition, in the inner liner film, the polyamide-based resin and the copolymer may be included in a weight ratio of 6: 4 to 3: 7, preferably 5: 5 to 4: 6. If the content of the polyamide-based resin is too small, the density or airtightness of the inner liner film may be lowered. In addition, if the content of the polyamide-based resin is too large, the modulus of the inner liner film may be excessively high or the moldability of the tire may be reduced, the polyamide-based resin in a high temperature environment appearing in the tire manufacturing process or automobile driving process Crystallization may occur and cracks may occur due to repeated deformation.

Meanwhile, the tire inner liner film may include only a copolymer of the polyamide-based segment and the polyether-based segment as a substrate of the film. Accordingly, the inner liner film can be distinguished from the film for the tire inner liner, which has a rubber component or a thermoplastic resin component as a main component of the substrate, and does not require an additional vulcanizer. Can have Substrate of the film means a substrate of a resin or rubber component that retains the shape of the film, except for an additional dispersing component such as an additive in the tire innerliner film. Often contained various rubber components or resin components. By the way, the tire inner liner film may include a polyamide-based resin or the like together with the copolymer as a base material, but may also include only the copolymer, in which case it may be substantially free of other resins or rubber components. .

Even when the tire inner liner film includes only a copolymer of a polyamide-based segment and a polyether-based segment as a substrate of the film, the content of the polyether-based segment is 15 to 50% by weight based on the total weight of the tire inner liner film. , Preferably 20 to 45% by weight, more preferably 22 to 40% by weight.

The polyamide-based segment refers to a repeating unit including an amide group (-CONH-), and may be formed from a polyamide-based resin or a precursor thereof that participates in a polymerization reaction. The polyamide-based segment may include the repeating unit of Formula 1 or Formula 2 described above.

The polyether segment refers to a repeating unit including an alkyl oxide ('-Akyl-O-' group, and may be formed from a polyether resin or a precursor thereof that participates in a polymerization reaction. The system segment may include the repeating unit of Formula 5 described above.

The tire innerliner film may have a thickness of 30 to 300 ㎛, preferably 40 to 250 ㎛, more preferably 40 to 200 ㎛. Such tire innerliner films may have a thinner thickness than previously known, but may have a low air permeability, for example, an oxygen permeability of 200 cc / (m 2 · 24hr · atm) or less.

The aforementioned tire innerliner film may have high reactivity with the resorcinol-formalin-latex (RFL) -based adhesive having the specific composition due to the characteristic chemical structure. Accordingly, the second adhesive layer may exhibit the above-described adhesive properties at room temperature, but after the high temperature compression or vulcanization process, the tire inner liner film and the rubber elastomer layer (body ply) may be bonded with a high and uniform adhesive force. Since the tire manufacturing process is subjected to a high temperature deformation or stretching step, it is possible to prevent a phenomenon in which adhesive force is lowered or a breakage between tire inner layers even in a vehicle driving process in which repeated physical deformation is applied for a long time.

Meanwhile, the tire inner liner film may be an unstretched film. When the tire inner liner film is in the form of an unstretched film, the tire inner liner film may have a low modulus and a high strain rate and may be appropriately applied to a tire forming process in which high expansion occurs. In addition, since crystallization hardly occurs in the unstretched film, damage such as cracks can be prevented even by repeated deformation. In addition, since the unoriented film does not have a large variation in the orientation and physical properties in a specific direction, an inner liner having uniform physical properties can be obtained. The inner liner film in the form of such an unstretched film can be produced by a method of suppressing orientation as much as possible, for example, by adjusting the melt extrusion temperature through optimization, changing a die die specification, or adjusting a winding speed.

In particular, as described above, in the laminate for producing tires, each of the rubber elastic layer and the release film layer are bonded to both sides of the inner liner film with a specific adhesive force, so that the rubber elastic layer is the inner liner film in the process of removing the release film. It may serve to support or fix the, and accordingly, the inner liner film of the unstretched film state may be applied to a tire manufacturing process while maintaining its properties, physical properties or orientation. That is, when the unstretched tire inner liner is used in a state in which the tire manufacturing liner is included in the tire manufacturing line, it is possible to prevent a phenomenon in which the physical properties are deteriorated or damaged during the tire manufacturing process or the automobile driving process, and to exhibit uniform physical properties throughout the film. Can be.

On the other hand, the rubber elastomer layer may include at least 30% by weight of one or more rubber components selected from the group consisting of synthetic rubber and natural rubber. The rubber elastic layer may be a portion corresponding to the body ply of the tire. The rubber component used in the rubber elastomer layer may be included without any limitation as long as it is a conventionally known material, and may include, for example, 30% by weight or more of synthetic rubber or natural rubber, and various other additives. have. Specifically, the rubber elastomer layer may include at least 50% by weight of butyl rubber, halogenated butyl rubber or a mixture thereof.

The rubber elastic layer corresponds to the body ply of the tire after the tire is manufactured, which has a structure in which a tire cord is included in a predetermined rubber component as a skeleton of the tire supporting the load of the vehicle body. That is, the rubber elastic layer may further include one or more tire cords. As the tire cord included in the rubber elastomer layer, various natural fibers or rayon, nylon, polyester, kevlar, or the like may be used, and a steel cord braided with a thin wire may also be used.

The thickness of the rubber elastomer layer may vary depending on the type or structure of the tire to be manufactured and the fineness of the reinforcing material or tire cord used.

On the other hand, the release film layer may include one or more selected from the group consisting of polyester resins and polyolefin resins. Specific examples of the polymer resin included in such a release film include polyethylene resins, polypropylene resins, polyethylene terephthalate resins, mixtures thereof or copolymers thereof. The release film layer may have a thickness of 5 ㎛ to 50 ㎛. In addition, the release film layer is a stretched product having a high initial modulus of 500 Mpa or more, so that deformation due to external force is reduced.

On the other hand, according to another embodiment of the invention, the tire innerliner film is a step of applying a resorcinol-formalin-latex (RFL) -based adhesive on both surfaces; Bonding a release film layer to one surface of the tire innerliner film; And bonding a rubber elastic layer to the other surface of the tire inner liner film.

As described above, according to the manufacturing method, there may be provided a laminate for manufacturing tires according to one embodiment of the invention described above, wherein the laminate for producing tires has a rubber adhesive layer and a release film layer each having a specific adhesive force on both sides of the inner liner film. In the process of removing the release film, the rubber elastomer layer having a higher adhesive force may serve to support or fix the inner liner film, thereby stretching or twisting the inner liner film due to the removal of the release film. This phenomenon can be prevented.

Specifically, the resorcinol-formalin-latex (RFL) adhesive applied to one surface of the tire inner liner film may form a first adhesive layer bonding the release film layer, and the other of the tire inner liner film. The resorcinol-formalin-latex (RFL) -based adhesive applied to one surface may form a second adhesive layer bonding the rubber elastomer layer.

In addition, the first adhesive layer bonding one surface of the tire inner liner film and the release film layer may have an adhesive force of 0.5 kgf / 5 cm or less, preferably 0.3 kgf / 5 cm or less with the release film layer. In addition, the second adhesive layer for bonding the other surface of the tire inner liner film and the rubber elastomer layer may be 1.5 kgf / 5 cm to 4.0 kgf / 5 cm, preferably 2.5 kgf / 5 cm to 4.0, with an unvulcanized body ply rubber layer. It may have an adhesive force of kgf / 5 cm.

That is, when the resorcinol-formalin-latex (RFL) adhesive is applied to both sides of the tire inner liner film, the chemical composition of the resorcinol-formalin-latex (RFL) adhesive and the resorcinol-formalin Due to the property that the latex (RFL) adhesive has different adhesion to the release film layer and the rubber elastic layer, a first adhesive layer and a second adhesive layer having different adhesive strengths as described above may be formed.

The total solid content of the resorcinol-formalin-latex (RFL) -based adhesive used in the tire manufacturing method of manufacturing a laminate may be 15% to 40%. Since the resorcinol-formalin-latex (RFL) -based adhesive includes the solids in the above-described content, the adhesive having an appropriate adhesive force on the tire innerliner film through the application process of the adhesive or the drying process of the applied adhesive Layers can be formed.

In addition, the solid content of the resorcinol-formalin-latex (RFL) -based adhesive may include 5 to 50% by weight of condensate of resorcinol and formaldehyde and 50 to 95% by weight of latex, and preferably 10 to 30% by weight of condensates of knol and formaldehyde and 70 to 90% by weight of latex.

The condensate of resorcinol and formaldehyde may be obtained by mixing the resorcinol and formaldehyde in a molar ratio of 1: 0.3 to 1: 3.0, preferably 1: 0.5 to 1: 2.5, and then condensation reaction. In addition, the condensate of the resorcinol and formaldehyde may be included in more than 5% by weight of the resorcinol-formalin-latex (RFL) -based adhesive to secure the proper adhesive strength, 50 to secure the proper fatigue resistance properties It may be included in the wt% or less.

When the latex is included in less than 50% by weight relative to the total amount of solids of the entire adhesive, it may be difficult to sufficiently secure the flexibility and adhesion of the material of the adhesive layer to be formed. In addition, when the latex is included in more than 95% by weight relative to the total amount of solids of the entire adhesive, the viscosity of the adhesive layer may be contaminated due to the increased viscosity of the tire manufacturing laminate or manufacturing equipment, the inner liner film torn during the tire manufacturing process Losing symptoms may occur.

The latex may be one or a mixture of two or more selected from the group consisting of natural rubber latex, styrene / butadiene rubber latex, acrylonitrile / butadiene rubber latex, chloroprene rubber latex, and styrene / butadiene / vinylpyridine rubber latex.

Preferably, the latex included in the resorcinol-formalin-latex (RFL) -based adhesive is 20 to 70% by weight of natural rubber latex; And other rubber latex 30 to 80% by weight. If the content of the natural rubber latex in the latex is less than 20% by weight, the adhesive force between the inner liner film and the release film layer or the rubber elastomer layer may not be sufficiently expressed, and the content of the natural rubber latex in the latex exceeds 70% by weight. In this case, the viscosity of the resorcinol-formalin-latex (RFL) -based adhesive may be greatly increased or contaminate the laminate or manufacturing device for manufacturing the tire.

The other rubber latex means rubber latex other than the natural rubber latex, and specific examples thereof are not limited thereto, and may include commonly known rubber latex, and for example, styrene / butadiene rubber latex and acrylonitrile / Butadiene rubber latex, chloroprene rubber latex, styrene / butadiene / vinylpyridine rubber latex or mixtures thereof.

In addition, more specific details regarding the tire inner liner film, the release film layer, and the rubber elastic layer are also described above.

Meanwhile, in the step of applying the resorcinol-formalin-latex (RFL) adhesive on both surfaces of the tire inner liner film, one surface of the tire inner liner film is sequentially or on both surfaces simultaneously. Formalin-latex (RFL) based adhesives may be applied. The coating or coating method or apparatus conventionally used may be used for the application of the adhesive without any limitation, but the knife coating method, the bar coating method, the gravure coating method or the spray method, or the dipping method may be used. Can be used. However, it is preferable to use a knife coating method, a gravure coating method, or a bar coating method in terms of uniform application and coating of the adhesive.

After applying the resorcinol-formalin-latex (RFL) -based adhesive, the applied adhesive may be dried, and the specific method or conditions of the drying step are not limited, for example. It may be made for 5 seconds to 30 minutes in the temperature range of 80 ℃ to 200 ℃.

Meanwhile, the bonding of the release film layer to one surface of the tire inner liner film may include laminating the release film when the tire inner liner film is coated with a resorcinol-formalin-latex (RFL) adhesive. can do. That is, after applying and drying the resorcinol-formalin-latex (RFL) -based adhesive on the tire inner liner film, the above-described release on one surface of the inner liner film using a release film supply device in the process of winding the film. The film can be bonded.

Although the order of forming the release film layer and the rubber elastic layer is not particularly limited, it is preferable to form a release film on the tire inner liner film and form a rubber elastic layer.

Specifically, coupling the rubber elastic layer to the other surface of the tire inner liner film may include calendering the tire inner liner film and the rubber elastic layer bonded to the release film layer. have. In this calendaring step, a known device and method can be used without any significant limitation. For example, a rubber inner calendar film of the tire innerliner film to which the release film layer is bonded may be used by using a calendar calendering device (Calendaring M / C). The second adhesive layer and the rubber elastic layer may be bonded.

On the other hand, according to another embodiment of the invention, there can be provided a pneumatic tire manufacturing method comprising the step of removing the release film from the above-mentioned tire manufacturing laminate, and placing it on a tire forming drum.

As described above, when the tire laminate is used, each of the rubber elastic layer and the release film layer is bonded to both sides of the inner liner film with a specific adhesive force, so that the rubber elastic layer is the inner liner film in the process of removing the release film. It can serve to support or fix the, it is possible to prevent the phenomenon such as stretching or distortion due to the removal of the release film.

Specifically, as the rubber elastic layer corresponding to the inner ply of the inner liner film and the tire is applied to the tire manufacturing process in a state of being bonded with high adhesive force, a problem that may appear during the bonding process of the body ply and the inner liner film, eg For example, it is possible to prevent distortion or tearing caused by the difference in the modulus of the inner liner film and the body ply, which may occur due to expansion in a turn-up process on the forming drum.

In addition, in the pneumatic tire manufacturing method, the inner liner layer and the body ply layer can be arranged in a single step, replacing the previous manufacturing step of separately placing the inner liner layer and the body fly layer. The cutting process of the layer and the body ply layer can be performed simultaneously, thereby simplifying the tire manufacturing process and designing the manufacturing process more efficiently. That is, by using the tire manufacturing laminate, it is possible to operate the tire manufacturing process more simply and efficiently, and to prevent the phenomenon that the inner liner film used is unevenly stretched or the physical properties are lowered.

The pneumatic tire manufacturing method may use any method, condition, and apparatus used in a normal pneumatic tire manufacturing process without any limitation, except that the release film is removed from the above-described tire manufacturing laminate.

Specifically, the pneumatic tire manufacturing method, the step of attaching a bead wire to the end of the forming drum width direction of the laminate; Forming a belt portion on the tire building drum-laminated stack; Forming a cap fly portion on the belt portion; And forming a rubber layer for forming a tread portion, a shoulder portion, and a sidewall portion on the formed belt portion.

Accordingly, the pneumatic tire manufactured according to the pneumatic tire manufacturing method, a pair of bead portion; A pair of sidewall portions continuous to each of the bead portions; A tread portion continuous between the pair of interwall portions; A belt part disposed on the inner side of the tread part; A cap fly portion formed between the tread portion and the belt portion; And a laminate for manufacturing a tire, in which the release film is removed, coupled to the belt unit.

According to the present invention, it is possible to operate the tire manufacturing process more simply and efficiently, the laminated body for tire production which can prevent the phenomenon that the inner liner film used is unevenly stretched or the physical property falls, and the said tire manufacturing laminated body There can be provided a method for producing a pneumatic tire using.

1 schematically shows the structure of a pneumatic tire.
Figure 2 shows a schematic cross-sectional view of a laminate for producing a tire according to an embodiment of the present invention.

The invention is explained in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

 [ Example  And Comparative example : Tire manufacturing The laminate  And Pneumatic  Manufacture of tires]

< Example 1 >

(1) Manufacture of tire inner liner film

50 wt% of the nylon 6 resin of 3.3 (relative viscosity 96% solution) and 50 wt% of the copolymer resin (including 50 wt% of the polyamide segment and 50 wt% of the polyether segment) were mixed. . At this time, the mixture was adjusted to prevent agglomeration between chips and dried, and then the temperature of the raw material supply part was adjusted to 50 to 100 ° C. so that the mixture was fused in the extruder screw, and fed to the extrusion die while preventing feeding failure. .

Then, the supplied mixture is extruded while maintaining a uniform melt flow through a T-type die (die gap [1.0 mm) at a temperature of 260 ° C., and an air knife is placed on a surface of a cooling roll controlled at 25 ° C. The molten resin was cooled and solidified into a film of uniform thickness. Then, an undrawn tire inner liner having a thickness of 100 μm was obtained without passing through the stretching and heat treatment sections at a speed of 15 m / min.

(2) Adhesive treatment of tire inner liner film and bonding with release film

On one surface of the prepared unstretched tire innerliner, resorcinol-formalin-latex (RFL) -based adhesive (solid content in total weight: 20wt%, latex content in solids: 85wt%, natural rubber content in latex 40wt%) Was applied using a gravure coating method, and the applied adhesive was dried for 30 seconds in an oven at 150 ° C. Then, in the same manner, the unstretched tire innerliner prepared above was coated and dried with a resorcinol-formalin-latex (RFL) adhesive having the same composition.

At this time, in order to prevent fusion between the coated surfaces when the second surface is applied, a stretched PET film having a thickness of 10 μm and an initial modulus of 1300 Mpa is supplied through a release film supply device, and the inner liner film is wound on the inner liner film winding unit. The release film was allowed to be bonded while being wound at the same time. The winding tension at this time was maintained at 0.5-2 kgf / 100cm.

(3) Bonding of tire inner liner film and rubber elastomer layer

The body ply and the tire innerliner film on which the release film was formed were combined by pressure through a rotating roller before the final winding step after rolling the body ply including the 1300De '/ 2p PET HMLS tire cord. Through this, a laminate for producing tires, in which a release film layer and a rubber elastomer layer were formed on both surfaces of a tire inner liner film, was prepared.

And, when applied to the body fly cutting process, the release film was removed and prepared by cutting the tire manufacturing laminate to the specifications required for tire molding. At this time, the inner liner film was attached to the carcass rubber layer with high adhesive strength, and it was confirmed that there was no deformation or stretching while the release film was removed.

< Example 2 >

The use of resorcinol-formalin-latex (RFL) adhesive (20 wt% of total weight, latex content of solids: 85 wt% of solids, and 50 wt% of natural rubber in latex) of a composition different from that of Example 1 Except for producing a laminate for producing tires in the same manner as in Example 1.

< Example 3 >

The use of resorcinol-formalin-latex (RFL) -based adhesives (solid content: 20 wt% in total weight, latex content in solids: 85 wt%, natural rubber content in latex 40wt%) of the composition different from Example 1 Except for producing a laminate for producing tires in the same manner as in Example 1.

< Example 4 >

A laminate for producing a tire was manufactured in the same manner as in Example 1, except that a PE stretched film having a thickness of 30 μm and an initial modulus of 1100 Mpa was used as the release film.

< Example 5 : Pneumatic  Manufacturing of Tires>

The release film was removed while inserting the roll of the tire manufacturing laminate obtained in Examples 1 to 4 into a cutting machine, and the body ply size that fits the tire standard was cut. Thereafter, the cut laminate was laminated on the tire drum, and then the green tire was manufactured by laminating bead wires, side inserts, belts, and cap fly belts. After confirming that the appearance and shape of the green tire manufactured as described above was good, it was put in a vulcanization mold and vulcanized for 160 degrees to prepare a tire.

< Comparative Example 1 : Pneumatic  Manufacturing of Tires>

1. Tire Innerliner  Manufacture of film

50 wt% of the nylon 6 resin of 3.3 (relative viscosity 96% solution) and 50 wt% of the copolymer resin (including 50 wt% of the polyamide segment and 50 wt% of the polyether segment) were mixed. . At this time, the mixture was adjusted to prevent agglomeration between chips and dried, and then the temperature of the raw material supply part was adjusted to 50 to 100 ° C. so that the mixture was fused in the extruder screw, and fed to the extrusion die while preventing feeding failure. .

Then, the supplied mixture is extruded while maintaining a uniform melt flow through a T-type die (die gap [1.0 mm) at a temperature of 260 ° C., and an air knife is placed on a surface of a cooling roll controlled at 25 ° C. The molten resin was cooled and solidified into a film of uniform thickness. Then, an undrawn tire inner liner having a thickness of 100 μm was obtained without passing through the stretching and heat treatment sections at a speed of 15 m / min.

(2) Adhesive treatment of tire inner liner film and bonding with release film

On one surface of the prepared unstretched tire innerliner, resorcinol-formalin-latex (RFL) -based adhesive (solid content in total weight: 20wt%, latex content in solids: 85wt%, natural rubber content in latex 40wt%) Was applied using a gravure coating method, and the applied adhesive was dried for 30 seconds in an oven at 150 ° C.

In addition, when winding the inner liner film having the adhesive layer formed thereon, a stretched PET film having a thickness of 20 μm and an initial modulus of 1300 Mpa is supplied through a release film supply device, and the inner liner film and the release film are formed at an inner liner film winding portion. At the same time it can be wound and combined. The winding tension at this time was maintained at 0.5-2 kgf / 100cm.

(3) manufacture of tires

After the release film was removed from the obtained tire innerliner film and placed on the tire forming drum, a body fly layer including 1300 De '/ 2p PET HMLS tire cord was laminated. And green tire was manufactured by laminating | stacking bead wire, a side insert, a belt, and a cap fly belt in order. After confirming that the appearance and shape of the green tire manufactured as described above was good, it was put in a vulcanization mold and vulcanized for 160 degrees to prepare a tire.

< Comparative Example 2 : Manufacturing of Tires>

Using a resorcinol-formalin-latex (RFL) adhesive (composition of 20 wt% in total weight, latex content in solids: 85 wt% in solids and 10 wt% natural rubber in latex) of a composition different from Comparative Example 1 Except that, a tire was manufactured in the same manner as in Comparative Example 1.

< Comparative Example 3 : Manufacturing of Tires>

A tire was manufactured in the same manner as in Comparative Example 1, except that an unstretched PET film having a thickness of 20 μm and an initial modulus of 300 Mpa was used as a release film.

 [ Experimental Example ]

< Experimental Example 1 : Adhesive force measurement>

1. Tire Innerliner  Film and Carcass Micheal With rubber layer  Adhesive force measurement

The uncured rubber (1 mm thick) used for the carcass layer was cut into 10 cm * 20 cm (width * length), and a 2 cm * 12 cm (width * length) PET film was attached to the top of the cut rubber.

And, both sides used in the Examples and Comparative Examples cut the tire inner liner film treated with resorcinol-formalin-latex (RFL) -based adhesive to 10cm * 20cm (width * length) and the vulcanizate attached to the PET film Laminated onto rubber. Then, the tire innerliner was pushed three times using a 5 kgf metal cylindrical weight to be pressed onto the unvulcanized rubber.

After cutting the unvulcanized rubber and tire inner liner composite bonded through the adhesive layer to have a width of 5 cm, using the 5 kg metal cylindrical weight, the tire inner liner is pushed three times with a force of 5 kgf and pressed again to the unvulcanized rubber. I was.

Then, the scotch tape is attached twice to the outer surfaces of the inner liner film and the unvulcanized rubber to prevent stretching, and then Instron Clamp (Grip): CAT. The adhesion between the innerliner film and the Curcus uncured rubber layer was measured by the PEEL test method using NO 2712-041. At this time, Cross Head Speed was applied to 300mm / min.

2. Tire Innerliner  Film and release Between films  Adhesive force measurement

The adhesive force between the inner liner film and the release film was measured using the same method except that the release film was used instead of the 1 mm thick unvulcanized rubber layer used to measure the adhesion between the tire inner liner film and the carcass uncured rubber layer.

Adhesive force measurement result division Adhesive Latex NR Specific Gravity (%) Release film used early
Modulus Adhesion with Release Film (kgf / 5cm) Adhesion with uncured carcass rubber layer (kgf / 5cm) Example 1 40 1300 0.3 3.0 Example 2 50 1300 0.4 3.7 Example 3 30 1300 0.3 2.0 Example 4 40 1100 0.2 3.0 Comparative Example 1 40 1300 0.3 3.0 Comparative Example 2 10 1300 0.2 1.1 Comparative Example 3 40 500 0.3 3.0

< Experimental Example 2 : Measuring Ease of Molding>

In the above examples and comparative examples, the ease of manufacture and appearance were evaluated after the manufacture of the green tires, and then the final appearance of the tires after vulcanization was examined.

At this time, if the tire after the green tire or vulcanization is not crushed, the standard deviation of the diameter is within 5% was evaluated as 'good'. In addition, if the tire is not properly manufactured due to crushing on the tire after the green tire or the vulcanization, or the inner liner inside the tire is melted or torn, the tire is damaged or the standard deviation of the diameter exceeds 5%. .

< Experimental Example 3 : Innerliner  Film Stretching  Occurrence>

After the tire production in the Examples and Comparative Examples, it was checked whether the inner liner film is stretched or not through the number and wrinkles generated by the stretching of the film inside the inner liner.

< Experimental Example 4 Durability measurement

Tire durability was measured using FMVSS139, an American tire durability evaluation method. Specifically, while the pneumatic tires obtained in the above Examples and Comparative Examples were rotated using a running drum at a speed of 120 km / hour under a pneumatic pressure of 180 kpa, a load of 464 kg was added for the first 4 hours, followed by a load of 491 kg for 6 hours. After 24 hours was compared to the point of failure while imposing a load of 545kg.

And the durability measurement result was compared with the tire of the following reference example.

[ Reference Example ]

After a 1.2 mm thick innerliner obtained using halobutyl rubber 100 PHR was placed on a tire forming drum, a body ply layer containing 1300 De '/ 2p PET HMLS tire cord was laminated. And green tire was manufactured by laminating | stacking bead wire, a side insert, a belt, and a cap fly belt in order. After confirming that the appearance and shape of the green tire manufactured as described above was good, it was put in a vulcanization mold and vulcanized for 160 degrees to prepare a tire.

< Experimental Example 5 : Air Pressure Maintenance Performance Measurement>

The tires prepared in Examples and Comparative Examples were compared and evaluated by measuring the IPR Internal Pressure Retention for 90 days under a pressure of 101.3 kPa at 21 ° C. using ASTM F1112-06.

The results of Experimental Examples 2 to 4 are shown in Table 2 below.

Results of Experimental Examples 2 to 4 division Tire formability evaluation Film wrinkles in tire Reference example Durability compared to tires (%) 90 day air pressure retention rate (%) Example 1 Good 0 102 98.2 Example 2 Good 0 105 98.3 Example 3 Good 0 100 98.1 Example 4 Good 0 102 98.2 Comparative Example 1 Bad shape 5 80 97.0 Comparative Example 2 Good 0 65 98.0 Comparative Example 3 Somewhat poor 2 92 97.5

Claims (19)

Tire innerliner film;
A release film layer bonded to one surface of the tire inner liner film with an adhesive force of 0.5 kgf / 5 cm or less through a first adhesive layer; And
A tire manufacturing laminate comprising a rubber elastomer layer bonded to the other side of the tire innerliner film with an adhesive force of 1.5 kgf / 5 cm to 4.0 kgf / 5 cm through a second adhesive layer.
The method of claim 1,
A laminate for manufacturing tires, wherein each of the first adhesive layer and the second adhesive layer has a thickness of 0.1 μm to 20 μm.
The method of claim 1,
A laminate for manufacturing a tire, wherein each of the first adhesive layer and the second adhesive layer includes a resorcinol-formalin-latex (RFL) adhesive.
The method of claim 3,
The resorcinol-formalin-latex (RFL) -based adhesive is a laminate for producing a tire comprising 5 to 50% by weight of condensate of resorcinol and formaldehyde and 50 to 95% by weight of latex.
5. The method of claim 4,
The latex is 20 to 70% by weight of natural rubber latex; And
A laminate for producing a tire, comprising 30 to 80% by weight of other rubber latex.
The method of claim 1,
The tire inner liner film is a polyamide resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment.
A laminate for producing tires, wherein the content of the polyether segment of the copolymer is 15 to 50% by weight based on the total weight of the tire innerliner film.
The method of claim 1,
The tire innerliner film contains only a copolymer of a polyamide-based segment and a polyether-based segment as a substrate of the film,
A laminate for producing tires, wherein the content of the polyether segment of the copolymer is 15 to 50% by weight based on the total weight of the tire innerliner film.
The method of claim 1,
The tire inner liner film is a laminate for producing a tire having a thickness of 30 to 300 ㎛.
The method of claim 1,
The tire inner liner film is a laminate for producing tires, which is an unstretched film.
The method of claim 1,
The rubber elastic layer is a tire manufacturing laminate comprising at least 30% by weight of one or more rubber components selected from the group consisting of synthetic rubber and natural rubber.
The method of claim 1,
The release film layer is a tire manufacturing laminate comprising at least one polymer resin selected from the group consisting of a polyester resin and a polyolefin resin.
The method of claim 1,
The release film layer is a laminate for producing tires having a thickness of 5 μm to 50 μm and an initial modulus of 500 Mpa or more.
Applying a tire innerliner film to both surfaces of a resorcinol-formalin-latex (RFL) -based adhesive;
Bonding a release film layer to one surface of the tire innerliner film; And
Bonding a rubber elastic layer to the other side of the tire inner liner film manufacturing method of a laminate for producing a tire.
The method of claim 13,
The total solid content of the resorcinol-formalin-latex (RFL) adhesive is 15% to 40%,
The solid content of the resorcinol-formalin-latex (RFL) adhesive comprises a condensate of 5 to 50% by weight of condensate of resorcinol and formaldehyde and 50 to 95% by weight of latex.
15. The method of claim 14,
The latex is 20 to 70% by weight of natural rubber latex; And other rubber latex 30 to 80% by weight.
The method of claim 13,
Bonding the release film layer to one surface of the tire inner liner film,
A method for producing a laminate for producing a tire, comprising the step of laminating a release film upon winding of a tire innerliner film coated with a resorcinol-formalin-latex (RFL) -based adhesive.
The method of claim 13,
Bonding a rubber elastic layer to the other side of the tire inner liner film,
Calendering the tire inner liner film and the rubber elastic layer bonded to the release film layer on one surface (calendering) manufacturing method of a laminate for producing a tire.
Removing the release film from the laminate of claim 1, the method of manufacturing a pneumatic tire comprising the step of placing on the tire forming drum.
19. The method of claim 18,
Attaching a bead wire to an end in the forming drum width direction of the laminate;
Forming a belt portion on the tire building drum-laminated stack;
Forming a cap fly portion on the belt portion; And
And forming a rubber layer for forming a tread portion, a shoulder portion, and a sidewall portion on the formed belt portion.

Images