KR20130009620A - Film for tire inner-liner and preparation method thereof - Google Patents

Abstract

PURPOSE: A film for tire inner liner with enhanced durability and a manufacturing method thereof are provided to express excellent air tightness in thin thickness of the film. CONSTITUTION: A film for tire inner liner comprises a substrate film layer which includes polyamide based resin, a polymer which includes polyamide based segment and poly-ether based segment, and an adhesive layer which is formed on one side of the substrate film layer and includes resorcinol - formalin - latex based adhesive. The content of the polyether based segment of the copolymer is 15-50 weight% based on the total weight of the substrate film layer. [Reference numerals] (AA) Comparative embodiment 2; (BB) Comparative embodiment 4; (CC) Embodiment 3; (DD) Embodiment 2; (EE) Embodiment 1; (FF) Comparative embodiment 3; (GG) Comparative embodiment 1

Description

FILM FOR TIRE INNER-LINER AND PREPARATION METHOD THEREOF}

The present invention relates to a film for tire innerliner and a method of manufacturing the same. More specifically, it is possible to realize excellent airtightness even at a thin thickness, thereby making it possible to reduce the weight of the tire and improve the fuel efficiency of the automobile, and to have a uniform physical property in all directions of the film, and thus have excellent moldability and improved durability. And a method for producing a film for tire innerliner.

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. 2.

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): A 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, tube-less tires in which high pressure air of about 30 to 40 psi is injected without the use of a tube are commonly used. To this end, a highly airtight inner liner is disposed in the carcass inner layer.

Previously, tire inner liners were used, which consist mainly of rubber components such as relatively low air permeability butyl rubber or halo butyl rubber, which had to increase the rubber content or the thickness of the inner liner in order to obtain sufficient airtightness. . As the content and thickness of the rubber component increases, the total tire weight increases and fuel economy of the vehicle decreases, and an air pocket or an inner liner is formed between the inner rubber and the inner liner of the carcass layer during the vulcanization process of the tire or the driving of the vehicle. The phenomena of the shape and physical properties were also changed.

Accordingly, various methods have been proposed to reduce fuel consumption by reducing the thickness and weight of the inner liner, and to reduce the shape and physical properties of the inner liner generated during the vulcanization or driving process of the tire.

However, any previously known method has had a limit in maintaining excellent air permeability and tire formability while sufficiently reducing the thickness and weight of the inner liner, and additional tie gum rubbers for firmly bonding to the carcass layer inside the tire. There was a problem that increases the weight of the tire and lowers the fuel economy of the car. In addition, the inner liner obtained by the previously known method has often failed to have sufficient fatigue resistance such as cracking due to repeated deformation in the manufacturing process or the running process of the tire.

In addition, the previous innerliner film has a large difference in physical properties according to the direction of the discharged from the machine of the manufacturing process and other directions, it is not easy to apply a variety of deformation process or stretching process, tire manufacturing process or There was a problem in that the mechanical properties or durability of the inner liner is deteriorated due to the irregular deformation of the film during the driving process.

The present invention can realize excellent airtightness even in a thin thickness to enable the weight reduction of the tire and the improvement of automobile fuel economy, the film for tire innerliner having excellent moldability and improved durability by having uniform physical properties in all directions of the film and It is for providing the manufacturing method of the film for tire innerliners.

Moreover, this invention is providing the manufacturing method of the film for tire innerliners.

The present invention, polyamide-based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment; and a base film layer comprising at least one surface of the base film layer, the resorcinol-formalin An adhesive layer comprising a latex (RFL) adhesive, wherein the content of the polyether segment of the copolymer is from 15 to 50% by weight relative to the total weight of the base film layer, and an initial 2% elongation of the base film layer The ratio of the tensile modulus in the second direction perpendicular to the first direction to the tensile modulus in the first direction is 0.9 to 1.1.

In addition, the present invention, polyamide-based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment; melting the mixture at 230 to 300 ° C., and melting the melt to a die gap of 0.3 to 1.5 mm. Extruding under a die gap condition to form a base film layer, and forming an adhesive layer including a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film layer. The content of the polyether-based segment included in the copolymer is 15 to 50% by weight relative to the total weight of the base film layer, and to the tensile modulus in the transverse direction (TD) upon initial 2% elongation of the base film layer. Provided is a method for producing a film for tire innerliner, wherein the ratio of tensile modulus in the machine direction (MD) is 0.9 to 1.1.

Hereinafter, a film for a tire innerliner and a method of manufacturing the same according to a specific embodiment of the present invention will be described in detail.

According to one embodiment of the invention, a polyamide-based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment; and a base film layer comprising at least one surface of the base film layer, the resorcinol-formalin An adhesive layer comprising a latex (RFL) adhesive, wherein the content of the polyether segment of the copolymer is from 15 to 50% by weight relative to the total weight of the base film layer, and an initial 2% elongation of the base film layer The ratio of the tensile modulus in the second direction perpendicular to the first direction to the tensile modulus in the first direction may be 0.9 to 1.1, a film for tire innerliner can be provided.

As a result of the researches of the present inventors, by using a base film prepared by mixing a polyamide-based resin and the specific copolymer described above, it is possible to realize excellent airtightness even at a thin thickness to lighten the tire and improve the fuel efficiency of the automobile, It has been confirmed that a film for a tire innerliner that has heat resistance and exhibits excellent moldability and mechanical properties such as high durability and fatigue resistance can be provided.

In particular, the tire inner liner film has excellent moldability which can be easily applied to various deformation processes or stretching processes in all directions of the film, and is irregularly depending on the direction of the film in the tire manufacturing process or the driving process of the automobile. By preventing the phenomenon of deformation can be implemented excellent mechanical properties and improved durability.

Specifically, as shown in the manufacturing method described below, when the polyamide-based resin and the specific copolymer are mixed to a specific content and melted, and the melt is extruded under a specific die gap condition, all of the film A base film having uniform physical properties in the direction may be provided. In addition, by attaching and grounding the melt extruded under the specific die gap condition to a cooling roll installed at a horizontal distance of 10 to 150 mm from the die outlet, it is possible to obtain a base film having substantially no orientation due to stretching.

Accordingly, the ratio of the tensile modulus in the second direction perpendicular to the first direction to the tensile modulus in the first direction upon initial 2% elongation of the base film layer may be 0.9 to 1.1, preferably 0.92 to 1.08. . The tensile modulus refers to an elastic modulus representing a ratio of stress and strain, and specifically refers to a slope value of a stress-elongation graph (S-S curve) measured at room temperature conditions and an initial 2% elongation point.

On the other hand, the ratio of the yield strength in the second direction perpendicular to the first direction to the yield strength in the first direction of the base film layer may be 0.9 to 1.1, preferably 0.92 to 1.08. The yield strength (Yield strength) refers to the limit stress that the elastic deformation occurs, specifically, the maximum value of the stress appearing in the elongation range of 0 to 50%.

As the difference in yield strength between one direction of the base film and a direction perpendicular thereto is not large, uniform stretching and deformation in both directions are possible in the tire forming process, thereby preventing a poor tire forming, and driving a car. It is possible to prevent the problem that the tire is broken by stress concentration in one direction.

In addition, the flat elongation of the first direction of the base film layer and the flat elongation of the second direction perpendicular to the first direction may be 150% or more, preferably 200% to 400%. . The ratio of flat elongation in the second direction to flat elongation in the first direction of the base film layer may be 0.9 to 1.1, preferably 0.92 to 1.08.

The flat elongation refers to the elongation at which the stress is rapidly increased due to the orientation effect according to the increase in the yield strength tensile strain. Specifically, in the elongation section after the yield point, the elongation at the point where the stress becomes equal to the yield strength development point (or In the stretch section after the yield point, the elongation rate at the point where the slope change of the SS curve is the largest).

Since the flat elongation in the first direction of the base film and the second flat elongation perpendicular to the base film exhibit a value of 150% or more, the difference between them is not large. It is possible to uniformly stretch and deform in both directions during the tire forming process to prevent the failure of the tire molding, and to prevent the problem of tire damage by stress concentration in one direction while driving the vehicle.

Meanwhile, the first direction of the base film described above may be a transverse direction (TD) of the base film, and the second direction perpendicular to the first direction may be a machine direction (MD) of the base film. have.

The machine direction (MD) may be a machine direction (MD) which is a direction in which the base film is formed in the process of manufacturing the tire innerliner film. It means the direction applied to surround or equilibrate the circumferential direction. The transverse direction (TD) means a direction perpendicular to the longitudinal direction, and may be a direction parallel to the axial direction of the tire or the tire building drum.

On the other hand, the base film may exhibit a high reactivity to the above-described adhesive layer due to the characteristic chemical structure, the adhesive layer may also exhibit a high and uniform adhesion to the tire carcass layer. Accordingly, the inner liner film can be firmly bonded to the tire without applying an additional vulcanization process or significantly increasing the thickness of the adhesive layer, and is a tire manufacturing process to which high temperature deformation or stretching step is applied. In this vehicle driving process, the bonding force between the inner liner film and the tire carcass layer may be greatly reduced, or the breakage between the base film and the adhesive layer may be prevented.

In addition, since the tire innerliner film does not require a large amount of additives or rubber components for improving physical properties, the manufacturing process can be simplified and the tire manufacturing cost can be reduced. Accordingly, the tire inner liner film can improve the fuel efficiency of the vehicle by reducing the weight of the tire, and maintain the proper air pressure even after long-term use, to prevent the fallover accident and fuel economy lowered caused by low air pressure, and also when driving Its excellent ability to withstand repeated fatigue ensures durability, and it is possible to manufacture tires with excellent performance even with a simple manufacturing process.

The above-described tire inner liner film is characterized in that a base film layer having an absolute weight average molecular weight is prepared using a copolymer including a polyether-based segment and a polyamide-based segment having a specific content together with the polyamide-based resin. Will follow.

More specifically, the base film layer may have a relatively low modulus with excellent airtightness by using a polyamide-based resin together with a specific copolymer comprising polyether-based segments in a specific content to impart elastomeric properties. have. That is, 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. The modulus is not so high compared to other resins. 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.

Since the polyamide-based resin generally exhibits excellent airtightness, the polyamide-based resin has a role of allowing the base film layer to have low air permeability while having a thin thickness. In addition, since the polyamide-based resin exhibits a modulus that is not relatively higher than that of other resins, an innerliner film that exhibits relatively low modulus characteristics even when applied with a copolymer including the polyether-based segment having a specific content is selected. It can obtain, and can improve the moldability of a tire by this. Also, Since the polyamide-based resin has sufficient heat resistance and chemical stability, the innerliner film may be prevented from being deformed or modified when exposed to chemical substances such as high temperature conditions or additives applied in the tire manufacturing process.

In addition, the polyamide-based resin is used in combination with a copolymer comprising a polyamide-based segment and a polyether-based segment, and thus relatively high relative to an adhesive (for example, a resorcinol-formalin-latex (RFL) -based adhesive). May indicate reactivity. Accordingly, the inner liner film may be easily adhered to the carcass portion, and the inner liner film may be sufficiently prevented by breaking the interface due to heat or repetitive deformation occurring during the tire manufacturing process or the driving process. Allow to have fatigue.

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.

The relative viscosity of the polyamide-based resin refers to the relative viscosity measured using a 96% sulfuric acid solution at room temperature. Specifically, a sample of a certain polyamide-based resin (for example, 0.025 g of specimen) is dissolved in 96% sulfuric acid solution at different concentrations to prepare two or more measurement solutions (for example, a polyamide-based resin specimen). Dissolve in 96% sulfuric acid to make concentrations of 0.25 g / dL, 0.10 g / dL, and 0.05 g / dL, and make three measuring solutions), and the relative viscosity of the measuring solution using a viscosity tube at 25 ° C. , The ratio of the average passage time of the measurement solution to the viscosity tube passage time of 96% sulfuric acid solution can be obtained.

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 be included in the base film layer by preparing a base film using a monomer of the polyamide-based resin or a precursor of the polyamide-based resin as well as a method of using the resin itself.

Meanwhile, as described above, the copolymer including the polyamide-based segment and the polyether-based segment is present in a bonded or dispersed state between the polyamide-based resins. Modulus of the base film layer can be lowered more, the rigidity of the base film layer can be suppressed from rising, and crystallization at high temperature can be prevented. As the specific copolymer is included in the base film layer, the tire innerliner film may realize high elasticity or elastic recovery while securing excellent mechanical properties such as 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 degraded even during a vehicle driving process in which repeated deformation and high heat are continuously generated. have.

On the other hand, when the content of the polyether segment of the copolymer is 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 base film layer, the tire The innerliner film can exhibit more excellent physical properties and performance. When the content of the polyether-based segment is less than 15% by weight of the entire base film layer, the modulus of the base film layer or the tire inner liner film is increased to reduce the moldability of the tire or to significantly decrease the physical properties due to repeated deformation. May appear. When the content of the polyether segment exceeds 50% by weight of the entire film, the tire innerliner is not good gas tightness (Gas Barrier) property is not good tire performance can be reduced. It may be difficult for the innerliner to easily adhere to the carcass layer because the reactivity to the adhesive may be reduced, and the elasticity of the base film layer may be increased to make it difficult 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.

Such a polyether-based segment can lower the modulus of the film for the tire inner liner, thereby allowing the tire to be easily stretched or deformed to fit the shape of the tire even when a very small force is applied during the tire forming. To be able. In addition, the polyether-based segment can suppress the increase in the rigidity of the film at low temperatures and prevent crystallization at high temperatures, and can prevent damage or tearing of the inner liner film due to repeated deformation, etc. By improving the resilience to the deformation of the liner to suppress the occurrence of wrinkles of the film due to permanent deformation it can improve the durability of the tire or innerliner.

The polyamide-based segment may serve to allow the copolymer to have a certain level or more of mechanical properties but not to significantly increase the modulus properties. In addition, as the polyamide-based segment is applied, the base film layer may have a low air permeability while having a thin thickness, and may secure sufficient heat resistance and chemical stability.

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.

[Formula 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-.

The absolute 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 200,000. If the absolute weight average molecular weight of the copolymer is less than 50,000, the base film layer to be manufactured may not secure sufficient mechanical properties for use in the inner liner film, and the tire inner liner film may have sufficient gas barrier. It can be difficult to secure. In addition, when the absolute weight average molecular weight of the copolymer is more than 300,000, the modulus or crystallinity of the base film layer is excessively increased when heated to a high temperature, it may be difficult to secure the elasticity or elastic recovery to have as an inner liner film.

On the other hand, the copolymer is a polyamide segment and a polyether segment in the range of 15 to 50% by weight based on the total weight of the film, the polyether 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 base film layer or the tire innerliner film may be increased, thereby deteriorating the moldability of the tire or a large decrease in physical properties due to repeated deformation. In addition, if the content of the polyether-based segment is too large, the airtightness of the film for the tire inner liner 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 elasticity of the film layer may be increased and thus it may not be easy to produce a uniform film.

In addition, in the base film layer, the polyamide-based resin and the copolymer described above 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 base film layer may be lowered. In addition, when the content of the polyamide-based resin is too large, the modulus of the base film layer may be excessively high or the moldability of the tire may be lowered, and the polyamide-based resin may be Crystallization may occur and cracks may occur due to repeated deformation.

On the other hand, the base film layer may be an unstretched film. When the base film layer is in the form of an unstretched film, it has a low modulus and a high strain rate and can be suitably 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.

As shown in the method of manufacturing the film for tire innerliner described later, a method of suppressing the orientation of the base film as much as possible, for example, adjusting viscosity by optimizing the melt extrusion temperature, changing the die die specification, and adjusting the installation position of the cooling roller. The base film may be manufactured as an unoriented or unoriented film by adjusting an air knife installation position, adjusting a pinning device (electrostatic imparting device), or adjusting a winding speed.

When the unstretched film is applied to the base film, the inner liner film can be easily produced in a cylindrical or sheet form in a tire manufacturing process. In particular, when the non-stretched sheet-like film is applied to the base film, it is not necessary to construct a film manufacturing facility for each tire size, and it is preferable because the impact and wrinkles applied to the film can be minimized during the transport and storage process. . In addition, when the base film is manufactured in a sheet form, a process of adding an adhesive layer to be described later may be more easily performed, and damage or crushing occurring during the manufacturing process may be prevented due to a difference in specifications with a forming drum.

The base film layer may have a thickness of 30 to 300 ㎛, preferably 40 to 250 ㎛, more preferably 40 to 200 ㎛. Accordingly, the film for tire innerliner of one embodiment of the invention has 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. have.

The base film may further include additives such as heat resistant antioxidants, heat stabilizers, adhesion promoters, or mixtures thereof. Specific examples of the heat resistant antioxidants include N, N'-hexamethylene-bis- (3,5-di- (t-butyl) -4-hydroxy-hydrocinnamamide (N, N'-Hexamethylene-bis- (Commercially available products such as 3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide such as rganox 1098), tetrakis [methylene (3,5-di- (t-butyl) -4-hydroxyhydrocinnanam Mate)] methane (commercially available products such as tetrakis [methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane, such as Irganox 1010) or 4,4'-dicumyldiphenylamine (4,4 ') -di-cumyl-di-phenyl-amine, such as Naugard 445. Specific examples of the heat stabilizer include benzoic acid, triacetonediamine, or N, N'-bis (2). , 2,6,6-tetramethyl-4-piperidyl) -1,3-benzenedicarboxamide (N, N'-Bis (2,2,6,6-tetramethyl-4-piperidyl) -1 , 3-benzenedicarboxamide), etc. However, the additive is not limited to the above examples, and may be used for the film for tire inner liner. It is known can be used without limitation.

On the other hand, the adhesive layer comprising the resorcinol-formalin-latex (RFL) -based adhesive has excellent adhesion and adhesion retention performance to the base film layer and the tire carcass layer, and thus in the manufacturing process or running process of the tire It is possible to prevent breakage of the interface between the inner liner film and the carcass layer generated by the generated heat or repeated deformation so that the inner liner film may have sufficient fatigue resistance.

The main properties of the adhesive layer described above appear to be due to the inclusion of certain resorcinol-formalin-latex (RFL) based adhesives having a specific composition. Previously, adhesives for tire innerliners have been used, such as rubber type tie gums, and thus require additional vulcanization. In contrast, the adhesive layer includes a resorcinol-formalin-latex (RFL) -based adhesive having a specific composition, and has high reactivity and adhesion to the base film, and is compressed under high temperature heating conditions without increasing the thickness. The base film and the tire carcass layer may be firmly bonded. Accordingly, it is possible to reduce the weight of the tire and to improve the fuel efficiency of the automobile, and to prevent the phenomenon of separating the carcass layer and the inner liner layer or the base film and the adhesive layer even during repeated deformation in the tire manufacturing process or the automobile driving process. Can be. In addition, since the adhesive layer may exhibit high fatigue resistance against physical and chemical deformations that may be applied during tire manufacturing or driving, the adhesive force may be applied even during the manufacturing process under high temperature conditions or during the driving of a vehicle in which mechanical deformation is applied for a long time. The degradation of other physical properties can be minimized.

In addition, the resorcinol-formalin-latex (RFL) -based adhesives are capable of crosslinking between latex and rubber, thereby exhibiting adhesive performance, and because they are physically latex polymers, have low curing properties and thus have flexible properties such as rubber. , Chemical bonding between the metirol end of the lesosinol-formalin polymer and the base film is possible. Accordingly, when the resorcinol-formalin-latex (RFL) -based adhesive is applied to the base film, sufficient adhesion performance can be realized.

The resorcinol-formalin-latex (RFL) -based adhesive may be 2 to 32% by weight, preferably 10 to 20% by weight and latex 68 to 98% by weight, preferably 80 to 80%, of a condensate of resorcinol and formaldehyde. 90 weight percent.

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 2% by weight relative to the total amount of the adhesive layer in terms of chemical reaction for excellent adhesion, and may be included in less than 32% by weight in order to secure proper fatigue resistance properties. have.

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. The latex may be included in more than 68% by weight relative to the total amount of the adhesive layer for the flexibility of the material and the effective crosslinking reaction with the rubber, it is included in 98% by weight or less for the chemical reaction with the base film and the rigidity of the adhesive layer.

In addition, the adhesive layer may further include at least one additive such as a surface tension modifier heat-resistant agent, an antifoaming agent, and a filler, together with a condensate and latex of resorcinol and formaldehyde. At this time, the surface tension modifier of the additive is applied for the uniform coating of the adhesive layer, but may cause a problem of the adhesive strength decrease when excessively added, 2 wt% or less or 0.0001 to 2 wt%, preferably based on the total adhesive layer 1.0 wt% or less, or 0.0001 to 0.5 wt%. At this time, the surface tension modifiers sulfonate anionic surfactant, sulfate ester salt anionic surfactant, carboxylate anionic surfactant, phosphate ester salt anionic surfactant, fluorine-based surfactant, silicone-based surfactant and polysiloxane-based surfactant It may be one or more selected from the group consisting of.

The adhesive layer may have a thickness of 0.1 to 20 μm, preferably 0.1 to 10 μm, more preferably 0.2 to 7 μm, even more preferably 0.3 to 5 μm, and one surface of the film for tire innerliner or It can be formed on both surfaces. If the thickness of the adhesive layer is too thin, the adhesive layer itself may be thinner when the tire is inflated, the crosslinking adhesive force between the carcass layer and the base film may be lowered, and stress may be concentrated on a part of the adhesive layer, thereby reducing fatigue characteristics. In addition, when the adhesive layer is too thick, interfacial separation may occur in the adhesive layer, thereby reducing fatigue characteristics. And, in order to adhere the inner liner film to the carcass layer of the tire, it is common to form an adhesive layer on one surface of the base film, but in the case of applying a multilayer inner liner film or the inner liner film wrapping the bead part, etc. And it is preferable to form an adhesive layer on both sides of the base film when rubber and adhesion on both sides according to the structural design.

On the other hand, as the adhesive layer includes a specific resorcinol-formalin-latex (RFL) -based adhesive, it may have excellent modulus characteristics and high elastic recovery. Accordingly, even if the adhesive layer is formed on the base layer, it may have substantially no influence on the elongation or deformation characteristics of the base film. That is, the film for tire innerliner including the base film layer and the adhesive layer may be formed of the above-described stretching property of the above-described base film, for example, the initial modulus of tensile modulus in the first direction when the initial 2% elongation of the film for tire innerliner is stretched. The ratio of the tensile modulus in the second direction perpendicular to the one direction may be 0.9 to 1.1, preferably 0.92 to 1.08, and is perpendicular to the first direction to the yield strength in the first direction of the film for the tire innerliner. The ratio of yield strength in the second direction may be 0.9 to 1.1, preferably 0.92 to 1.08.

Further, the flat elongation in the first direction of the tire inner liner film and the flat elongation in the second direction perpendicular to the first direction are each 150% or more, preferably 200% to 400%. Can be. In addition, the ratio of the flat elongation in the second direction to the flat elongation in the first direction of the film for tire innerliner may be 0.9 to 1.1, preferably 0.92 to 1.08.

On the other hand, according to another embodiment of the invention, polyamide-based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment; melting the mixture at 230 to 300 ° C., and melting the melt to a die gap of 0.3 to 1.5 mm. Extruding under a die gap condition to form a base film layer, and forming an adhesive layer including a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film layer. The content of the polyether-based segment included in the copolymer is 15 to 50% by weight relative to the total weight of the base film layer, and to the tensile modulus in the transverse direction (TD) upon initial 2% elongation of the base film layer. A method for producing a film for tire innerliner can be provided, wherein the ratio of tensile modulus in the machine direction (MD) is 0.9 to 1.1.

The film for tire innerliner obtained according to the above manufacturing method can not only realize excellent airtightness and high air pressure holding performance even with a thin thickness, but can also have uniform physical properties in all directions of the film, in particular in the longitudinal and transverse directions. In this case, it has excellent moldability that can be easily applied to various deformation processes or stretching processes, and can prevent the phenomenon of irregular deformation in accordance with the direction of the film during the tire manufacturing process or driving of the automobile, and the base film is It exhibits high reactivity with certain adhesives so that even a thin, lightweight adhesive layer can be firmly and uniformly bonded inside the tire.

0.3 to 1.5 mm, preferably a result obtained by melting a mixture of the polyamide-based segment and the copolymer comprising the polyether-based segment and the polyamide-based resin at 230 to 300 ° C Is extruded under a die gap condition of 0.5 to 1.2 mm to produce a base film, so that physical properties in all directions of the base film, for example, the longitudinal direction and the transverse direction, may be uniform. Accordingly, the tire inner liner film has excellent moldability that can be easily applied to various deformation processes or stretching processes, and prevents uneven deformation of the tire inner liner film according to the direction of the film during the tire manufacturing process or driving of the automobile. Therefore, excellent mechanical properties and improved durability can be realized.

In the step of forming the base film, if the die gap (Die Gap) is too small, the die shear pressure of the melt extrusion process is too high and the shear stress is so high that it is difficult to form a uniform shape of the extruded film and the productivity is lowered If the die gap is too large, the stretching of the melt-extruded film may be too high, the orientation may occur, the difference in physical properties between the longitudinal and transverse direction of the substrate film to be produced may be increased.

The temperature for melting the mixture may be 230 to 300 ℃, preferably 240 to 280 ℃. The melting temperature should be higher than the melting point of the polyamide-based compound, but if it is too high, carbonization or decomposition may occur and the physical properties of the film may be hindered. Unstretched may occur due to bonding between the polyether-based resins or orientation in the fiber array direction. It may be disadvantageous for producing a film.

The extrusion die may be used without any limitation as long as it is known that it can be used for extrusion of the polymer resin, but in order to make the thickness of the base film more uniform or to prevent the orientation of the base film from using a T-type die It is preferable.

On the other hand, by adhering and grounding the melt extruded under the above specific die gap conditions to a cooling section provided at a horizontal distance of 10 to 150 mm from the die outlet, it is possible to obtain a base film having substantially no orientation due to stretching.

 When the resultant obtained by melting and extruding is stretched before cooling and solidifying, orientation occurs in the base film to be produced. Accordingly, it is necessary to solidify the molten resin by bringing the molten resin into the film as quickly as possible to minimize the stretching orientation. That is, as described above, the melt extruded under the specific die gap condition may be attached or grounded to a cooling unit installed at a horizontal distance of 10 to 150 mm, preferably 20 to 120 mm, from the die outlet, thereby preventing stretching and orientation. . The horizontal distance from the die outlet to the cooler may be the distance between the die outlet and the point where the discharged melt grounds to the cooler. If the linear distance between the exit of the die and the point of attachment of the cooling portion of the molten film is too small, it may interfere with the uniform flow of the molten extruded resin and cause film cooling unevenness, and if the distance is too large, suppression of the stretching effect of the film may be achieved. Can't.

Specifically, the method for producing a film for tire innerliner further comprises the step of solidifying the base film layer formed by melting and extruding in a cooling unit maintained at a temperature of 5 to 40 ℃, preferably 10 to 30 ℃. can do. The base film layer formed by melting and extruding may be provided on a film having a more uniform thickness by being solidified in a cooling unit maintained at a temperature of 5 to 40 ° C. The substrate film layer obtained by melting and extruding may be grounded or adhered to the cooling unit maintained at the appropriate temperature so that the stretching may not occur substantially, and the substrate film layer may be provided as an unstretched film.

In addition, by adjusting the horizontal distance between the die outlet and the cooling unit properly, the extrudate discharged from the die is further added using an air knife, an air nozzle, an electrostatic pinning device or a combination thereof. By being able to adhere to the cooling unit quickly and solidify, it is possible to prevent the orientation due to the stretching of the base film to occur substantially. Specifically, the method for producing a film for tire innerliner is the extrudate using at least one device selected from the group consisting of an air knife, an air nozzle and an electrostatic device, located at a horizontal distance of 10 to 300 mm from the die outlet. It may further comprise the step of uniformly in close contact with the cooling unit.

In the step of forming the base film, except for the specific steps and conditions described above, extrusion processing conditions of the film commonly used in the production of the polymer film, for example, screw diameter, screw rotational speed, or line speed, etc. Can be selected and used appropriately.

On the other hand, as described above, the ratio of the tensile modulus in the second direction perpendicular to the first direction to the tensile modulus in the first direction at the time of initial 2% elongation of the base film layer obtained by the method is 0.9 to 1.1, preferably Preferably 0.92 to 1.08. In addition, the ratio of the yield strength in the second direction perpendicular to the first direction to the yield strength in the first direction of the prepared base film layer may be 0.9 to 1.1, preferably 0.92 to 1.08. In addition, the flat elongation of the first direction of the base film layer and the flat elongation of the second direction perpendicular to the first direction may be 150% or more, preferably 200% to 400%, respectively. The ratio of the flat elongation in the second direction to the flat elongation in the first direction may be 0.9 to 1.1, preferably 0.92 to 1.08.

Details of the copolymer including the polyamide-based resin, the polyamide-based segment, and the polyether-based segment are as described above.

On the other hand, in the step of forming the base film layer, in order to extrude a film having a more uniform thickness, the copolymer and the polyamide-based resin may be adjusted to have a uniform size. As such, as the size of the copolymer and the polyamide-based resin are adjusted, the copolymer and the polyamide-based resin may be mixed in the step of mixing them, staying at a raw material supply unit maintained at a constant temperature, or melting and extruding. The resin may be more uniformly mixed, and the copolymer and the polyamide-based resin may be prevented from increasing in size by being aggregated with each other or with each other, whereby a base film layer having a more uniform thickness may be formed. .

When the copolymer and the polyamide-based resin have a similar size, it is possible to minimize the phenomenon that the raw material chips agglomerate or appear uneven shape or region in the subsequent mixing, melting or extrusion step, and thus the film A base film layer having a uniform thickness can be formed over the entire area. The size of the copolymer and the polyamide-based resin that can be used in the production method is not particularly limited.

On the other hand, in the step of manufacturing the base film, the winding speed of the film is preferably maintained at an appropriate speed in order to prevent problems of poor cooling and increase in the degree of orientation, for example, preferably 100 m / min or less to suppress the winding speed as much as possible It is possible to apply a speed of 50m / min or less.

On the other hand, in the step of forming the base film, by adjusting the thickness of the molten resin sheet discharged by combining the extruder discharge amount, the width or gap of the die, the winding speed of the cooling roll, or the like, the air knife and air nozzle, electrostatic edge pinnig The thickness of the base film can be adjusted to 30 to 300 ㎛ by cooling uniformly in contact with the apparatus.

On the other hand, the tire innerliner film production method may further comprise the step of mixing the polyamide-based resin and the copolymer in a weight ratio of 6: 4 to 3: 7. If the content of the polyamide-based resin is too small, the density or airtightness of the base film layer may be lowered. In addition, when the content of the polyamide-based resin is too large, the modulus of the base film layer may be excessively high or the moldability of the tire may be lowered, and the polyamide-based resin may be Crystallization may occur and cracks may occur due to repeated deformation. In this mixing step, any device or method known to be used for mixing the polymer resin can be used without particular limitation.

The polyamide-based resin and the copolymer may be injected into a raw material feeder after being mixed, or may be mixed by being injected sequentially or simultaneously with the raw material feeder.

As described above, the copolymer may include a polyamide-based segment and a polyether-based segment in a weight ratio of 6: 4 to 3: 7.

On the other hand, the method for manufacturing a film for tire innerliner may include forming an adhesive layer including a resorcinol-formalin-latex (RFL) adhesive on at least one surface of the base film layer.

The adhesive layer including the resorcinol-formalin-latex (RFL) -based adhesive may be formed by coating a resorcinol-formalin-latex (RFL) -based adhesive on one surface of the base film layer, and the resorcinol- It can also be formed by laminating an adhesive film comprising a formalin-latex (RFL) -based adhesive on one surface of the base film layer.

Preferably, the forming of the adhesive layer may be performed by coating a resorcinol-formalin-latex (RFL) -based adhesive on one or both surfaces of the formed base film and then drying. The formed adhesive layer may have a thickness of 0.1 to 20 ㎛, preferably 0.1 to 10 ㎛. The resorcinol-formalin-latex (RFL) -based adhesive may comprise 2 to 32% by weight of condensate of resorcinol and formaldehyde and 68 to 98% by weight of latex, preferably 80 to 90% by weight.

More specific information regarding the resorcinol-formalin-latex (RFL) adhesive of the specific composition is as described above.

The coating or coating method or apparatus conventionally used for the application of the adhesive may be used without any limitation, but may be a knife coating method, a bar coating method, a gravure coating method or a spray method, or a dipping method. 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 the adhesive layer is formed on one or both surfaces of the base film, the drying and the adhesive reaction may be simultaneously performed, but may be divided into the heat treatment reaction step after the drying step in consideration of the reactivity of the adhesive, In order to apply the thickness of the adhesive layer or the adhesive of the multi-stage, the adhesive layer forming, drying and reaction steps may be applied several times. In addition, after the adhesive is applied to the base film, the heat treatment may be performed by solidifying and reacting under heat treatment conditions at about 30 seconds to 3 minutes at 100 to 150 ° C.

As described above, even if the above-described adhesive layer is formed on the base film layer, since the stretch property of the base film does not change significantly, the film for tire innerliner may have the same stretch property as the base film described above. For example, the ratio of the tensile modulus in the second direction perpendicular to the first direction to the tensile modulus in the first direction when the initial 2% elongation of the tire innerliner film is 0.9 to 1.1, preferably 0.92 to 1.08 days The ratio of the yield strength in the second direction perpendicular to the first direction to the yield strength of the tire inner liner film may be 0.9 to 1.1, preferably 0.92 to 1.08.

Further, the flat elongation in the first direction of the tire inner liner film and the flat elongation in the second direction perpendicular to the first direction are each 150% or more, preferably 200% to 400%. Can be. In addition, the ratio of the flat elongation in the second direction to the flat elongation in the first direction of the film for tire innerliner may be 0.9 to 1.1, preferably 0.92 to 1.08.

In forming the copolymer or mixture, or melting and extruding the copolymer, additives such as a heat resistant antioxidant or a heat stabilizer may be further added. Details of the additives are as described above.

According to the present invention, it is possible to implement excellent airtightness even at a thin thickness to enable the weight reduction of the tire and the improvement of automobile fuel economy, and for tire innerliner having excellent formability and improved durability by having uniform physical properties in all directions of the film. A method for producing a film and a film for tire innerliner can be provided.

1 shows a longitudinal stress-strain graph of a film according to Examples and Comparative Examples.
2 schematically shows the structure of a tire.

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: Production of Film for Tire Inner Liner

Example 1

(1) Production of base film

40% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.4 and a copolymer resin having an absolute weight average molecular weight of 100,000 (including 50% by weight of each polyamide repeating unit and polyether repeating unit) 60% by weight were mixed and the melt was extruded into a T-die under a diegap 0.6 mm condition at 260 ° C. The molten film obtained at this time is fixed, cooled, and solidified on a cooling roll (maintained at 15 ° C., rotational speed: 15 m / min) within 30 mm of the horizontal distance from the die outlet, and the discharge amount of the extruder is adjusted to G / P to obtain a thickness of 70 μm. The unstretched base film which had was obtained. The thickness of the base film was measured using a gauge tester.

In the step of grounding the molten film on the cooling roll, the edge pinning is installed inside 5mm of both ends of the ground line of the sheet to be grounded by placing the air knife at a horizontal distance of 30mm from the grounding position to closely adhere the molten film to the cooling roll by air pressure and static electricity. I was.

(2) application of adhesive

Resorcinol and formaldehyde were mixed in a molar ratio of 1: 2, and then condensation reaction was carried out to obtain a condensate of resorcinol and formaldehyde. 12% by weight of the condensate of resorcinol and formaldehyde and 88% by weight of styrene / butadiene-1,3 / vinylpyridine latex were mixed to obtain a resorcinol-formalin-latex (RFL) adhesive having a concentration of 20%.

In addition, the resorcinol-formalin-latex (RFL) -based adhesive was coated on the base film to a thickness of 1 um using a gravure coater, dried and reacted at 150 ° C. for 1 minute to form an adhesive layer.

Example 2

Tire inners were manufactured in the same manner as in Example 1, except that an unstretched film having a thickness of 100 μm was manufactured using a cooling roll rotating at 10 m / min with an extrusion temperature of 270 ° C. and a die gap of 0.8 mm. A liner film was prepared.

Example 3

The tire inner was made in the same manner as in Example 1 except that an unstretched film having a thickness of 120 um was manufactured using a cooling roll rotating at 8 m / min with an extrusion temperature of 280 ° C. and a die gap of 1.0 mm. A liner film was prepared.

Comparative Example: Production of Film for Tire Inner Liner

Comparative Example 1

The release agent and the processing agent were added to the butyl rubber, mixed and refined to obtain a tire inner liner film having a thickness of 70 μm, and an adhesive rubber (tie gum) having a thickness of 1 μm was formed on the inner liner film.

Comparative Example 2

(1) Production of base film

90% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.3 and a copolymer resin (50% by weight of polyamide repeating unit and 50% by weight of polyether repeating unit) with an absolute weight average molecular weight of 100,000 It was prepared in the same manner as in Example 1 except that 10% by weight of the base film was prepared.

(2) application of adhesive

A resorcinol-formalin-latex (RFL) -based adhesive was prepared in the same manner as in Example 1, and was then coated and dried on the base film to form an adhesive layer having a thickness of 1 μm.

Comparative Example 3

(1) Production of base film

20% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.3 and a copolymer resin (20% by weight of polyamide repeating unit and 80% by weight of polyether repeating unit) with an absolute weight average molecular weight of 100,000 It was prepared in the same manner as in Example 1 except that 80% by weight of the base film was prepared.

(2) application of adhesive

A resorcinol-formalin-latex (RFL) -based adhesive was prepared in the same manner as in Example 1, and was then coated and dried on the base film to form an adhesive layer having a thickness of 1 μm.

Comparative Example 4

 (1) Production of base film

40% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.4 and a copolymer resin having an absolute weight average molecular weight of 100,000 (including 50% by weight of each polyamide repeating unit and polyether repeating unit) A molten film obtained by mixing 60% by weight and melt extruding the mixture to a T-die under a diegap 2.0 mm condition at a temperature of 260 ° C was cooled to a roll (maintained at 15 ° C at a temperature of 30 ° C) within a horizontal distance of 30 mm from the die outlet. 15 m / min), and cooled and solidified to obtain an unstretched base film having a thickness of 70 μm. The thickness of the base film was measured using a gauge tester.

In the step of grounding the molten film on the cooling roll, the edge pinning is installed inside 5mm of both ends of the ground line of the sheet to be grounded by placing the air knife at a horizontal distance of 30mm from the grounding position to closely adhere the molten film to the cooling roll by air pressure and static electricity. I was.

(2) application of adhesive

An adhesive layer was formed in the same manner as in Example 1 except that the obtained base film was used.

Experimental Example: Measurement of Physical Properties of Tire Inner Liner Film

Experimental Example 1 Measurement of Modulus, Yield Strength and Flat Elongation of Base Film

Modulus, yield strength and flat elongation were measured based on the longitudinal and transverse directions (MD, Machine Direction) directions of the films for innerliners obtained in the above Examples and Comparative Examples. The specific measuring method is as follows.

(1) Measuring instrument: Universal Testing Machine (Model 4204, Instron)

(2) Measuring conditions: 1) Head Speed 300mm / min, 2) Grip Distance 100mm, 3) Sample Width 10mm, 4) 25 ℃ and 60RH% atmosphere

(3) It measured 5 times each and calculated | required the average value.

In the stress-strain curve obtained from the above measured data, 1) the 'slope value of the stress-elongation graph' was modulus at the initial elongation of 2%, and 2) the yield strength was 0 to 50 of the stress-elongation graph. 3) The elongation at flat is the elongation at the point where the stress becomes the same as the yield strength (or at the yield point above the yield point). , The elongation at the point where the slope change of the SS curve is the largest).

Experimental Example 2: Oxygen Permeability Experiment

Oxygen permeability of the tire innerliner film obtained in the above Examples and Comparative Examples was measured. The specific measuring method is as follows.

(1) Oxygen permeability: The method of ASTM D 3895 was measured in the atmosphere of 25 degree | times 60RH% using the Oxygen Permeation Analyzer (Model 8000, the product of Illinois Instruments).

Experimental Example 3: Measurement of Air Pressure Holding Performance

Tires were manufactured by applying tire inner liner films of Examples and Comparative Examples to 205R / 65R16. In addition, the manufactured tires 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 1 to 3 are shown in Table 1 below. And, the graph of the stress that appears when the substrate film obtained in Examples and Comparative Examples in the longitudinal direction is shown in Figure 1.

Results of Experimental Examples 1 to 3 Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Modulus
Vertical / lateral (MPa) 408 /
398 418 /
405 467 /
432 73 /
71 1620 /
1450 168 /
151 721 /
615 Modulus
Relative ratio (length / width) 1.02 1.03 1.08 1.02 1.11 1.11 1.17 Yield strength
Vertical / lateral (MPa) 14 /
13 15 /
14.5 17 /
16.5 3.1 /
3.0 46 /
38 8/
7 21 /
17 Yield strength
Relative ratio (length / width) 1.08 1.03 1.03 1.03
1.21 1.14 1.23 Flat Shinto
Vertical / lateral (%) 215 /
225 210 /
220 200 /
215 - -
250 /
270 125 /
130 Flat Shinto
Relative ratio (length / width) 0.95 0.95 0.93 - 0.91 0.92 0.96 Oxygen permeability
(cc / m ² day atm) 65 50 42 650 30 230 63 Air pressure retention rate
(%) 96 97 98 75 - 85 - Air pressure retention rate / formability observation Good Good Good Pneumatic failure Molding
Bad Pneumatic failure Molding
Bad

As shown in Table 1, the film for the tire innerliner of the embodiment exhibits air permeability of 200 cc / m 2 * 24hr * atm or less, so that excellent airtightness can be realized even at a thin thickness, and the force is not so great during the tire manufacturing process. It can be easily stretched or deformed even if it is added, and it is confirmed that the moldability of the green tire or the final tire is excellent.

In addition, it was confirmed that the base film obtained in the above example had uniform physical properties in all directions of the film, and in particular, there was almost no difference in physical properties between the longitudinal direction and the transverse direction of the film. Specifically, the ratio of the longitudinal tensile modulus and the transverse tensile modulus, the ratio of the longitudinal yield strength and the transverse yield strength, and the ratio of the longitudinal flat elongation and the transverse flat elongation at the time of elongation of the base film. All were found to be in the range of 0.9 to 1.1. In addition, it was confirmed that the longitudinal flat elongation and the transverse flat elongation of the tire inner liner film were each 150% or more.

And, as shown in Figure 1, the tire innerliner film of Examples 1 to 3 has a flat elongation level of 150% or more in the strain-stress graph and the initial inclination of the graph is relatively small, so that low modulus characteristics and excellent molding characteristics It was confirmed that it can represent.

On the other hand, the film for tire innerliner of Comparative Example 4 has a flat shingeul less than 150%, the initial slope of the graph is high, and the yield point is relatively high, so that the tire formability or other physical properties are applied to the actual tire. Turned out to be not enough. Moreover, it was confirmed that the film for tire innerliner of the comparative example 2 was too high in yield point, it did not have a flat new tool, and it was not easy to shape | mold in a general tire manufacturing process. In addition, in the case of the films for tire innerliners of Comparative Examples 1 and 3, the modulus and flat elongation were good, but the air barrier property was insufficient, and it was confirmed that they were not suitable for application to actual tires.

Claims (22)

Polyamide-based resins; And a copolymer comprising a polyamide-based segment and a polyether-based segment.
An adhesive layer formed on at least one surface of the base film layer and comprising a resorcinol-formalin-latex (RFL) adhesive;
The content of the polyether segment of the copolymer is 15 to 50% by weight based on the total weight of the base film layer,
And a ratio of the tensile modulus in the second direction perpendicular to the first direction to the tensile modulus in the first direction upon initial 2% elongation of the base film layer is 0.9 to 1.1.
The method of claim 1,
The film for tire innerliner whose ratio of the yield strength of a 2nd direction perpendicular | vertical to the said 1st direction with respect to the yield strength of the said base film layer is 0.9-1.1.
The method of claim 1,
The flat elongation of the first direction of the base film layer and the flat elongation of the second direction perpendicular to the first direction are each 150% or more,
The film for tire innerliners whose ratio of the flat elongation of a 2nd direction to the flat elongation of a 1st direction is 0.9-1.1.
The method of claim 1,
A film for tire innerliners, wherein the first direction is the same as the transverse direction (TD; transverse direction) of the base film and the second direction is the same as the machine direction (MD) of the base film.
The method of claim 1,
The film for tire innerliners whose relative viscosity (96% solution of sulfuric acid) of the said polyamide resin is 3.0-3.5.
The method of claim 1,
A film for tire innerliner having an absolute weight average molecular weight of 50,000 to 300,000 of the copolymer including the polyamide-based segment and the polyether-based segment.
The method of claim 1,
Polyamide-based segment of the copolymer is a tire innerliner film comprising a repeating unit of the following formula (1) or (2):
[Chemical Formula 1]

In Formula 1, R ₁ is a linear or branched alkylene group having 1 to 20 carbon atoms or a straight 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.
The method of claim 1,
Polyether-based segment of the copolymer is a tire innerliner film comprising a repeating unit of the following formula (3):
[Formula 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-, respectively.
The method of claim 1,
The copolymer is a tire inner liner film comprising a polyamide-based segment and a polyether-based segment in a weight ratio of 6: 4 to 3: 7.
The method of claim 1,
In the base film layer, the polyamide-based resin and copolymer is a tire inner liner film is included in a weight ratio of 6: 4 to 3: 7.
The method of claim 1,
The thickness of the base film layer is 30 to 300 ㎛,
The film for tire innerliner whose thickness of the said contact bonding layer is 0.1-20 micrometers.
The method of claim 1,
The film for tire innerliner whose said base film layer is an unstretched film.
The method of claim 1,
The resorcinol-formalin-latex (RFL) -based adhesive may include 2 to 30% by weight of a condensate of resorcinol and formaldehyde; And 68 to 98% by weight of latex.
Polyamide-based resins; And a copolymer comprising a polyamide-based segment and a polyether-based segment; melting the mixture at 230 to 300 ° C.,
Extruding the melt under a die gap condition of 0.3 to 1.5 mm to form a base film layer;
Forming an adhesive layer including a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film layer,
The content of the polyether segment contained in the copolymer is 15 to 50% by weight based on the total weight of the base film layer,
Method of producing a film for tire innerliner, wherein the ratio of tensile modulus in the machine direction (MD) to the tensile modulus in the transverse direction (TD) at initial 2% elongation of the base film layer is 0.9 to 1.1. .
15. The method of claim 14,
Forming the base film layer,
And the extrudate is attached to a cooling unit located at a horizontal distance of 10 to 150 mm from the die outlet.
16. The method of claim 15,
Using at least one device selected from the group consisting of an air knife, an air nozzle and an electrostatic device, located at a horizontal distance of 10 to 300 mm from the die exit,
The method of producing a film for tire innerliner further comprising the step of uniformly in close contact with the extrudate.
15. The method of claim 14,
And solidifying the base film layer formed by melting and extruding in a cooling unit maintained at 5 to 40 ° C.
15. The method of claim 14,
Copolymer copolymer comprising the polyamide-based resin, the polyamide-based segment and the polyether-based segment is mixed in a weight ratio of 6: 4 to 3: 7, tire inner liner Method for producing a film for use.
15. The method of claim 14,
The copolymer includes a polyamide-based segment and a polyether-based segment in a weight ratio of 6: 4 to 3: 7.
15. The method of claim 14,
Forming the adhesive layer, 2 to 30% by weight of a condensate of resorcinol and formaldehyde; And applying an adhesive comprising latex 68 to 98% by weight on at least one surface of the base film layer to a thickness of 0.1 to 20 μm.
15. The method of claim 14,
The manufacturing method of the film for tire innerliners whose ratio of the yield strength of the transverse direction (TD; transverse direction) and the yield strength of a machine direction (MD) of the said base film layer manufactured is 0.9-1.1.
15. The method of claim 14,
Flat elongation in the transverse direction (TD; transverse direction) and flat elongation in the machine direction (MD) of the substrate film layer to be produced are each 150% or more,
The ratio of the flat elongation of the machine direction (MD) to the flat elongation of the said transverse direction (TD;) is 0.9-1.1, The manufacturing method of the film for tire innerliners.

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