KR101995476B1 - Film for tire inner-liner and preparation method thereof - Google Patents

Abstract

The present invention relates to a base film layer comprising a polyamide-based resin, a copolymer containing a poly-amide-based segment and a poly-ether-based segment, and a resorcinol-formalin-latex (RFL) A film for a tire inner liner comprising an adhesive layer containing an adhesive and hardly causing a difference in physical properties between the longitudinal direction and the transverse direction, and a method for producing a film for a tire innerliner wherein the polyamide based resin and the copolymer are melted at 230 to 300 DEG C and extruded And forming an adhesive layer comprising a resorcinol-formalin-latex (RFL) -based adhesive on the base film. The present invention also relates to a method for producing a film for a tire innerliner.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a film for a tire innerliner,

The present invention relates to a film for a tire inner liner and a method of manufacturing the same. More specifically, the present invention relates to a tire inner liner film having excellent airtightness even with a thin thickness, which makes it possible to reduce the weight of a tire and improve automobile fuel economy, and has uniform physical properties in all directions of the film, And a method for producing a film for a tire inner liner.

The tire supports the load of the vehicle, mitigates the impact from the road surface, and transmits the driving force or braking force of the vehicle to the ground. Generally, a tire is a composite of fiber / steel / rubber, and generally has a structure as shown in Fig.

Tread (1): It is a part that comes into contact with the road surface, it should provide friction force necessary for braking and driving, good abrasion resistance, able to withstand external impact, and low heat generation.

Body Ply (or Carcass) (6): It is a coil layer inside the tire. It should support the load and resist the impact.

Belt (5): It is located between the body fly, and it is made of steel wire in most cases, it alleviates the external impact and keeps the ground surface of the tread wide to improve the running stability.

Side Wall (3): A rubber layer between the lower portion of the shoulder (2) and the bead (9), and protects the inner body ply (6).

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

BEAD (9): A square or hexagonal wire bundle with rubber coated wire to seat and fix the tire on the rim.

CAP PLY (4): It is a special cloth paper placed on the belt of the radial tires for some passenger cars, minimizing the movement of the belt when driving.

APEX (8): It is a triangular rubber filling material used to minimize the dispersion of beads, protect the beads by mitigating external impact, and prevent the inflow of air during molding.

In recent years, tube-less tires having high-pressure air of about 30 to 40 psi have been generally used without using a tube. In order to prevent the inner air from leaking to the outside during the operation of the vehicle An inner liner having high airtightness is disposed on the inner layer of the carcass.

Previously, a tire inner liner having rubber components such as butyl rubber or halobutyl rubber, which is relatively low in air permeability, was used. In this inner liner, the rubber content or the thickness of the inner liner had to be increased in order to obtain sufficient airtightness . As the content and the thickness of the rubber component increase, the total weight of the tire increases and the fuel consumption of the automobile decreases. Also, air pockets are formed between the inner rubber of the carcass layer and the inner liner in the process of vulcanizing the tire or running the vehicle, And the shape and physical properties of the material are changed.

Accordingly, various methods have been proposed to reduce the thickness and weight of the inner liner to reduce the fuel consumption, and to reduce changes in the shape and physical properties of the inner liner that occur in the vulcanization or running process of the tire.

However, any of the previously known methods have had limitations in maintaining excellent air permeability and moldability of the tire while sufficiently reducing the thickness and weight of the inner liner, The weight of the tire is increased and the fuel consumption of the automobile is lowered. In addition, the inner liner obtained by a previously known method often fails to have sufficient fatigue resistance, such as cracking due to repeated deformation during the manufacturing process or running process of the tire.

In addition, since the former inner liner film is largely different in physical properties depending on the direction of the release from the machine in the manufacturing process and in the other direction, it is not easy to apply various deformation processes or stretching processes, There is a problem that the mechanical properties or durability of the inner liner is deteriorated due to irregular deformations depending on the direction of the film during the running of the vehicle.

The present invention relates to a film for a tire inner liner having an excellent moldability and an improved durability because it can realize excellent airtightness even with a thin thickness, To provide a method for manufacturing a film for a tire inner liner.

The present invention also provides a method for producing a film for a tire innerliner.

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

Further, the present invention provides a polyamide resin composition comprising: a polyamide-based resin; And a copolymer comprising a poly-amide-based segment and a poly-ether-based segment; melting the mixture at 230 to 300 캜; and heating the melt to a die gap of 0.3 to 1.5 mm Die Gap) to form a base film layer; and forming an adhesive layer on the at least one surface of the base film layer, the adhesive layer including a resorcinol-formalin-latex (RFL) Wherein the content of the polyether segment in the copolymer is 15 to 50% by weight based on the total weight of the base film layer and the tensile modulus in the transverse direction (TD) And a ratio of a tensile modulus in the machine direction (MD) is 0.9 to 1.1. The present invention also provides a method for producing a film for a tire innerliner.

BEST MODE FOR CARRYING OUT THE INVENTION The film for a tire inner liner according to a specific embodiment of the present invention and a method for producing the same will be described in detail below.

According to one embodiment of the invention, a polyamide-based resin; And a copolymer comprising a poly-amide-based segment and a poly-ether-based segment, and a copolymer formed on at least one side of the base film layer, wherein the resorcinol-formalin - an adhesive layer comprising a latex (RFL) based adhesive, wherein the content of the polyether segment in the copolymer is from 15 to 50% by weight based on the total weight of the substrate film layer, and the initial 2% elongation Wherein the ratio of the tensile modulus in the first direction to the tensile modulus in the second direction perpendicular to the first direction is 0.9 to 1.1.

As a result of research conducted by the inventors of the present invention, it has been found that the use of a base film produced by mixing a polyamide based resin with the above-mentioned specific copolymer realizes excellent airtightness even with a thin thickness to lighten the tire, It has been confirmed that a film for a tire inner liner can be provided which exhibits excellent moldability while having heat resistance characteristics and exhibits mechanical properties such as high durability and fatigue resistance.

Particularly, the film for a tire innerliner has excellent moldability which can be easily applied to various deformation processes or stretching processes in all directions of the film, and it can be applied in a tire manufacturing process or an automobile in a non- It is possible to prevent deformation and realize excellent mechanical properties and improved durability.

Specifically, as shown in the production method described below, when the polyamide based resin and the specific copolymer are mixed and melted in a specific amount, and the melt is extruded under a specific die gap condition, all of the film A substrate film having uniform physical properties can be provided. In addition, a substrate film having substantially no orientation due to stretching can be obtained by attaching the melt extruded under the specific die gap condition to a cooling roll installed at a distance of 10 to 150 mm horizontally from the die outlet.

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 means an elastic modulus representing the ratio of stress to strain, and specifically refers to a slope of a stress-strain curve (S-S curve) measured at room temperature and at an initial 2% elongation point.

On the other hand, the ratio of the yield strength in the first direction and the yield strength in the second direction perpendicular to the first direction of the base film layer may be 0.9 to 1.1, preferably 0.92 to 1.08. The yield strength refers to a critical stress at which elastic deformation occurs, and specifically refers to a maximum value of a stress occurring in an elongation period of 0 to 50%.

Since the difference in yield strength between one direction of the base film and the perpendicular direction thereof is not large, it is possible to uniformly stretch and deform in both directions during the tire molding process, thereby preventing defective tire molding, It is possible to prevent the problem that the stress is concentrated in one direction and the tire is broken.

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

The flat elongation refers to the elongation at the point of time when the stress is rapidly increased due to the orientation effect due to the increase in yield stress tensile strain. Specifically, in the elongation period after the yield point, the elongation at the point where the stress becomes equal to the yield strength point The elongation at the point where the change in the slope of the SS curve is largest in the elongation period after the yield point).

The flat elongation of the base film in the first direction and the elongation in the second direction perpendicular to the first elongation are both at least 150% and the difference therebetween is not large. Therefore, when the film for a tire innerliner is applied It is possible to uniformly elongate and deform in both directions during the tire forming process, thereby preventing defective tire forming and preventing the tire from being damaged due to stress concentration in one direction during running of the vehicle.

The first direction of the base film 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) have.

The machine direction (MD) may be a machine direction (MD) in which the base film is formed in the process of manufacturing the tire innerliner film. In the actual manufacturing of the tire, Means a direction in which the circumferential direction is surrounded or equally applied. 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 can exhibit high reactivity to the above-described adhesive layer due to its characteristic chemical structure, and the adhesive layer can also exhibit a high and uniform adhesive force with respect to the tire carcass layer. Accordingly, the film for inner liner is a tire manufacturing process which can be firmly bonded to a tire without applying an additional vulcanization process or greatly increasing the thickness of the adhesive layer, and is subjected to a high temperature deformation or stretching step. It is possible to prevent the bonding force between the inner liner film and the tire carcass layer from remarkably lowering during the running of the vehicle, or to prevent the base film from being broken between the base film and the adhesive layer.

Further, since the film for a tire innerliner does not need any additional additives or rubber components for improving the physical properties, the manufacturing process can be simplified and the manufacturing cost of the tire can be reduced. Accordingly, the tire innerliner film can improve the fuel consumption of the automobile by reducing the weight of the tire, and it is possible to maintain the proper air pressure even after long-time use and to prevent the rollover accident caused by the low air pressure and the fuel consumption deterioration, Excellent durability is ensured due to excellent ability to withstand repeated fatigue, and excellent performance tires can be manufactured even in a simple manufacturing process.

The feature of the film for a tire inner liner described above is that a copolymer containing a specific amount of a polyether-based segment and a polyamide-based segment together with the polyamide-based resin is used to produce a base film layer having an absolute weight average molecular weight .

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 containing a specific amount of a polyether-based segment imparting elastomeric properties have. That is, the polyamide resin contained in the base film layer exhibits excellent airtightness due to its inherent molecular chain characteristics, for example, about 10 to 20 times as much as butyl rubber commonly used in a tire at the same thickness, It exhibits modulus not so high compared to other resins. The polyether segments contained in the copolymer are present in a state of being bonded or dispersed among polyamide-based segments or polyamide-based resins, so that the modulus of the base film layer can be further lowered, It is possible to inhibit the increase of the rigidity and to prevent crystallization at a high temperature.

Since the polyamide based resin generally exhibits excellent airtightness, the base film layer has a thin thickness and low air permeability. In addition, since such a polyamide-based resin exhibits a relatively high modulus as compared with other resins, the film for inner liner exhibiting a relatively low modulus characteristic even when applied together with the copolymer containing the specific amount of the polyether-based segment And thus the moldability of the tire can be improved. Also, Since the polyamide resin has sufficient heat resistance and chemical stability, it is possible to prevent deformation or denaturation of the inner liner film upon exposure to chemicals such as high temperature conditions or additives applied in the tire manufacturing process.

The polyamide-based resin may be used together with a copolymer containing a polyamide segment and a polyether segment so as to have a relatively high (e.g., high) relative to an adhesive (for example, a resorcinol-formalin-latex (RFL) It may show reactivity. As a result, the innerliner film can be easily adhered to the carcass portion, and breakage of the interface due to heat or repetitive deformation occurring in the manufacturing process or running process of the tire can be prevented, Fatigue.

The polyamide based resin may have a relative viscosity (96% sulfuric acid solution) of 3.0 to 3.5, preferably 3.2 to 3.4. If the viscosity of the polyamide resin is less than 3.0, a sufficient elongation can not be secured due to a reduction in toughness, which may cause breakage during tire manufacturing or automobile operation, and the airtightness or airtightness of the base film layer It may be difficult to ensure physical properties such as moldability. When the viscosity of the polyamide resin exceeds 3.5, the modulus or viscosity of the base film layer to be produced may become unnecessarily high, and the innerliner of the tire may not have adequate moldability or elasticity.

The relative viscosity of the polyamide resin refers to the relative viscosity measured using a 96% solution of sulfuric acid at room temperature. Specifically, after dissolving a sample of a certain polyamide resin (for example, 0.025 g of a test piece) in 96% sulfuric acid solution at different concentrations to prepare two or more measuring solutions (for example, a polyamide based resin sample The solution was dissolved in 96% sulfuric acid so as to have a concentration of 0.25 g / dL, 0.10 g / dL and 0.05 g / dL to prepare three measurement solutions), and the relative viscosity of the solution for measurement , The ratio of the average passage time of the measuring solution to the viscosity tube passing time of the 96% solution of sulfuric acid).

Examples of the polyamide resin that can be used for the base film layer include a polyamide resin such as a copolymer of nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 , Nylon 6/66/610 copolymers, nylon MXD6, nylon 6T, nylon 6 / 6T copolymers, nylon 66 / PP copolymers and nylon 66 / PPS copolymers; Or N-alkoxyalkylates thereof, such as methoxymethylated 6-nylon, methoxymethylated 6,610-nylon or methoxymethylated 612-nylon, and nylon 6, nylon 66, nylon 66, 46, nylon 11, nylon 12, nylon 610 or nylon 612 is preferably used.

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

On the other hand, as described above, the copolymer comprising a poly-amide-based segment and a poly-ether-based segment is present in a state bonded or dispersed among the polyamide-based resins, The modulus of the base film layer can be further lowered, the increase in the rigidity of the base film layer can be suppressed, and crystallization at a high temperature can be prevented. As such a specific copolymer is contained in the base film layer, the tire innerliner film can realize high elasticity or elastic recovery rate while securing mechanical properties such as excellent durability, heat resistance and fatigue resistance. Accordingly, the innerliner film can exhibit excellent moldability, and the tire to which the innerliner film is applied can be physically damaged or deteriorated in its physical properties or performance even in the course of running of the vehicle 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 innerliner film can exhibit better physical properties and performance. If the content of the polyether segment is less than 15% by weight based on the total amount of the base film layer, the modulus of the base film layer or the film for innerliner of the tire becomes high and the moldability of the tire is deteriorated. . If the content of the polyether segment exceeds 50% by weight of the entire film, the gas barrier property required for the tire inner liner is poor, and the tire performance may be deteriorated. The reactivity to the adhesive is lowered so that it is difficult for the inner liner to easily adhere to the carcass layer, and the elasticity of the base film layer increases, so that it may not be easy to produce a uniform film.

The polyether-based segments may be bonded to the polyamide-based segments or may be dispersed among the polyamide-based resins so that large crystals grow in the base film layer during tire manufacturing or automobile operation Or the base film layer can be prevented from being broken easily.

Such a polyether-based segment can lower the modulus of the film for a tire innerliner, thereby enabling the tire to be easily stretched or deformed in conformity with the shape of the tire even when a relatively small force is applied thereto I will. The polyether segment can prevent the rigidity of the film from rising at a low temperature and can prevent crystallization at a high temperature and can prevent damage or tear of the inner liner film due to repeated deformation or the like, The durability of the tire or inner liner can be improved by suppressing the occurrence of wrinkles of the film due to the permanent deformation by improving the resilience against deformation of the liner.

The polyamide segment may serve to prevent the modulus of the copolymer from significantly increasing while allowing the copolymer to have mechanical properties above a certain level. In addition, as the polyamide-based segment is applied, the base film layer can have a thin thickness and low air permeability, and sufficient heat resistance and chemical stability can be ensured.

The polyamide-based segment of the copolymer may comprise repeating units of the following formula (1) or (2).

[Chemical Formula 1]

In the above formula (1), R ₁ is a linear or branched alkylene group having 1 to 20 carbon atoms or a linear or branched alkylene group having 7 to 20 carbon atoms.

(2)

R ₂ is a linear or branched alkylene group having 1 to 20 carbon atoms and R ₃ is a linear or branched alkylene group having 1 to 20 carbon atoms or a linear or branched alkylaryl group having 7 to 20 carbon atoms It is a stove.

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

(3)

Wherein R ₅ is a straight 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 and are each a direct bond, -O- , -NH-, -COO- or -CONH-.

The absolute weight average molecular weight of the copolymer comprising 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 produced may not have sufficient mechanical properties for use in the inner liner film, and the tire inner liner film may have sufficient gas barrier properties It may be difficult to secure. If the absolute weight average molecular weight of the copolymer exceeds 300,000, the modulus or degree of crystallization of the base film layer may excessively increase during heating at a high temperature, so that it may be difficult to ensure the elasticity or elastic recovery rate to be provided as the film for inner liner.

On the other hand, in the copolymer, the polyether segment and the polyether segment are dispersed in the range of 15 to 50 wt% based on the total weight of the film in a ratio of 6: 4 to 3: 7, preferably from 5: 5 to 4: 6.

As described above, if the content of the polyether segment is too small, the modulus of the base film layer or the innerliner film for a tire becomes high, so that the moldability of the tire may be deteriorated or the physical properties may deteriorate due to repeated deformation. If the content of the polyether segment is too large, the airtightness of the tire innerliner film may be deteriorated, the reactivity to the adhesive may be lowered, and the inner liner may be difficult to adhere to the carcass layer easily, The elasticity of the film layer may increase and it may not be easy to produce a uniform film.

In the base film layer, the polyamide resin and the above-mentioned copolymer may be contained in a weight ratio of 6: 4 to 3: 7, preferably 5: 5 to 4: 6. If the content of the polyamide resin is too small, the density or airtightness of the base film layer may be lowered. If the content of the polyamide resin is too large, the modulus of the base film layer may become excessively high or the moldability of the tire may be deteriorated. In a high temperature environment occurring during a tire manufacturing process or an automobile running process, It can be crystallized, and a crack can be generated by 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 can be suitably applied to a tire forming process in which high expansion occurs due to low modulus and high strain. Further, since the crystallization phenomenon 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 deviation in orientation and physical properties in a specific direction, an inner liner having uniform physical properties can be obtained.

As shown in the method for producing a film for a tire innerliner to be described later, a method of suppressing the orientation of the base film as much as possible, for example, a method of adjusting the viscosity through optimization of the melt extrusion temperature, , The adjustment of the installation position of the air knife (air knife), the adjustment of the installation position of the pinning device (electrostatic application device), or the adjustment of the winding speed.

When an unoriented film is applied to the base film, the inner liner film can be easily formed into a cylindrical shape or a sheet shape in a tire manufacturing process. In particular, when an unstretched sheet-like film is applied to the base film, it is not necessary to separately construct a film manufacturing facility for each tire size, and it is possible to minimize shocks and creases that are applied to the film during transportation and storage . In addition, when the base film is formed into a sheet shape, the step of adding an adhesive layer described below can be performed more easily, and damage or dents or the like occurring during the manufacturing process can be prevented due to the difference in specification from the forming drum.

The base film layer may have a thickness of 30 to 300 占 퐉, preferably 40 to 250 占 퐉, more preferably 40 to 200 占 퐉. Accordingly, the film for a tire inner liner of an embodiment of the present invention has a low thickness and a low air permeability, for example, an oxygen permeability of 200 cc / (m < 2 > have.

The base film may further include additives such as a heat-resistant antioxidant, a heat stabilizer, an adhesion promoter, or a mixture thereof. Specific examples of the heat-resistant antioxidant include N, N'-hexamethylene-bis- (3,5-di- (t-butyl) -4-hydroxy-hydrocinnamamide (3,5-di-tert-butyl-4-hydroxy-hydrocinnamamide, for example, Methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)] methane such as Irganox 1010) or 4,4'-dicumyldiphenylamine (4,4 ' Specific examples of the heat stabilizer include benzoic acid, triacetonediamine, N, N'-bis (2-phenyl-amine) , 2,6,6-tetramethyl-4-piperidyl) -1, 3-benzenedicarboxamide (N, N'- , 3-benzenedicarboxamide), etc. However, the additive is not limited to the above-mentioned examples, and the additives can be used for a tire innerliner film It is known can be used without limitation.

On the other hand, the adhesive layer containing the resorcinol-formalin-latex (RFL) -based adhesive has excellent adhesion and adhesive holding performance to the base film layer and the tire carcass layer, and accordingly, It is possible to prevent breakage of the interface between the inner liner film and the carcass layer caused by the generated heat or repetitive deformation, so that the inner liner film has sufficient fatigue resistance.

The main characteristic of the adhesive layer described above appears to be due to the inclusion of certain resorcinol-formalin-latex (RFL) based adhesives having a particular composition. Previously, as the adhesive for the inner liner of a tire, a rubber type tie gum or the like was used, and accordingly, an additional vulcanization process was required. On the contrary, the adhesive layer contains a resorcinol-formalin-latex (RFL) -based adhesive having a specific composition and has high reactivity and adhesion to the base film, and is also pressed under high temperature heating conditions without increasing the thickness The base film and the tire carcass layer can be firmly bonded. This makes it possible to reduce the weight of the tire and to improve the fuel consumption of the automobile and to prevent the separation of the carcass layer and the inner liner layer or the base film and the adhesive layer even in the tire manufacturing process or the repeated deformation in the automobile running process . Also, since the adhesive layer can exhibit high endothelial characteristics against physical / chemical deformation that can be applied in the tire manufacturing process or automobile operation process, the adhesive layer can exhibit high endothelial property even during the manufacturing process of the high temperature condition or the long- And deterioration of other physical properties can be minimized.

In addition, the above-mentioned resorcinol-formalin-latex (RFL) -based adhesive is capable of crosslinking between latex and rubber to exhibit adhesive performance, and since it is a latex polymeric material physically, , Chemical bonding between the methylol end group of the resorcinol-formalin polymer and the substrate film is possible. Accordingly, when the above-mentioned 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 comprises 2 to 32% by weight, preferably 10 to 20% by weight of a condensate of resorcinol and formaldehyde, and 68 to 98% by weight, 90% by weight.

The condensate of resorcinol and formaldehyde may be obtained by mixing resorcinol and formaldehyde in a molar ratio of 1: 0.3 to 1: 3.0, preferably 1: 0.5 to 1: 2.5, followed by condensation. In addition, the condensate of resorcinol and formaldehyde may be contained in an amount of 2% by weight or more based on the total amount of the adhesive layer in terms of chemical reaction for excellent adhesion, and may be contained in an amount of 32% by weight or less have.

The latex may be one or a mixture of two or more selected from natural rubber latex, styrene / butadiene rubber latex, acrylonitrile / butadiene rubber latex, chloroprene rubber latex and styrene / butadiene / vinylpyridine rubber latex. The latex may be contained in an amount of not less than 68% by weight based on the total amount of the adhesive layer for the flexibility of the material and an effective crosslinking reaction with the rubber, and not more than 98% by weight for the chemical reaction with the base film and the rigidity of the adhesive layer.

The adhesive layer may further comprise at least one additive such as a surface tension modifier, a heat-resistant agent, a defoamer, and a filler together with a condensate of resorcinol and formaldehyde and a latex. At this time, the surface tension modifier of the additive is applied for uniform application of the adhesive layer, but it may cause a problem of decrease in the adhesive strength when an excessive amount of the additive is added. Therefore, the amount of the surface tension modifier is preferably 2% by weight or 0.0001 to 2% by weight, 1.0% by weight or less, or 0.0001% by weight to 0.5% by weight. At this time, the surface tension regulator may be at least one selected from the group consisting of a sulfonate anionic surfactant, a sulfuric acid ester salt anionic surfactant, a carboxylate anionic surfactant, a phosphate ester anionic surfactant, a fluorine surfactant, a silicone surfactant, and a polysiloxane surfactant And at least one selected from the group consisting of

The adhesive layer may have a thickness of 0.1 to 20 占 퐉, preferably 0.1 to 10 占 퐉, more preferably 0.2 to 7 占 퐉, still more preferably 0.3 to 5 占 퐉, and may be formed on one surface of the film for a tire innerliner Can be formed on both surfaces. If the thickness of the adhesive layer is too thin, the adhesive layer itself may become thinner when the tire is inflated, the crosslinking adhesive force between the carcass layer and the base film may be lowered, and the stress may concentrate on a part of the adhesive layer. In addition, if the adhesive layer is too thick, the interface separation in the adhesive layer may occur and the fatigue characteristics may be deteriorated. In order to adhere the inner liner film to the carcass layer of the tire, an adhesive layer is generally formed on one surface of the base film. However, in the case of applying the inner liner film of a multilayer or the tire laminating method It is preferable to form an adhesive layer on both sides of the base film when adhesion with rubber is required on both sides in accordance with the structural design.

On the other hand, as the adhesive layer includes a specific resorcinol-formalin-latex (RFL) -based adhesive, it can have excellent modulus characteristics and high elastic restoring force. Accordingly, even if the adhesive layer is formed on the base layer, the stretching or deformation characteristics of the base film may be substantially not affected. That is, the film for a tire innerliner including the base film layer and the adhesive layer has the above-described elongation properties of the base film, for example, the tensile modulus in the first direction at the initial 2% elongation of the tire innerliner film, The ratio of the tensile modulus in the first direction perpendicular to the first direction and the tensile modulus in the second direction perpendicular to the first direction may be 0.9 to 1.1, preferably 0.92 to 1.08, The ratio of the yield strength in the second direction may be 0.9 to 1.1, preferably 0.92 to 1.08.

The flat elongation in the first direction and the flat elongation in the second direction perpendicular to the first direction of the tire innerliner film are respectively 150% or more, preferably 200% to 400% . The ratio of the flat elongation in the second direction to the flat elongation of the tire innerliner film in the first direction may be 0.9 to 1.1, preferably 0.92 to 1.08.

According to another embodiment of the present invention, there is provided a polyamide-based resin; And a copolymer comprising a poly-amide-based segment and a poly-ether-based segment; melting the mixture at 230 to 300 캜; and heating the melt to a die gap of 0.3 to 1.5 mm Die Gap) to form a base film layer; and forming an adhesive layer on the at least one surface of the base film layer, the adhesive layer including a resorcinol-formalin-latex (RFL) Wherein the content of the polyether segment in the copolymer is 15 to 50% by weight based on the total weight of the base film layer and the tensile modulus in the transverse direction (TD) And a ratio of a tensile modulus in the machine direction (MD) of 0.9 to 1.1 can be provided.

The film for a tire innerliner obtained by the above production method not only can realize excellent airtightness and high air pressure holding performance even with a thin thickness, but also can have uniform physical properties in all directions of the film, particularly in the longitudinal direction and the transverse direction And has excellent moldability that can be easily applied to various deformation processes or elongation processes and can prevent irregular deformation of the film during the manufacturing process of the tire or the running of the vehicle, And exhibits high reactivity with respect to a certain adhesive, so that even a thin and lightweight adhesive layer can be firmly and uniformly bonded to the inside of the tire.

A resultant product obtained by melting a mixture of a polyamide-based segment and a polyamide-based copolymer and a polyamide-based resin at 230 to 300 ° C is 0.3 to 1.5 mm, Can be uniformized in all directions, for example, longitudinal and transverse directions, of the base film by extruding the base film under die gap conditions of 0.5 to 1.2 mm. Accordingly, the innerliner film of the tire has excellent moldability that can be easily applied to various deformation processes or stretching processes, and prevents the tire from being deformed irregularly according to the direction of the film during a tire manufacturing process or an automobile running process Thereby realizing excellent mechanical properties and improved durability.

In the step of forming the base film, if the die gap is too small, the die shear pressure of the melt extrusion process becomes too high and the shear stress becomes high, so that it is difficult to form a uniform film of the extruded film, If the die gap is too large, stretching of the melt-extruded film becomes too high and orientation may occur, and the difference between the longitudinal and transverse properties of the base film to be produced may become large.

The temperature at which the mixture is melted may be 230 to 300 占 폚, preferably 240 to 280 占 폚. The melting temperature should be higher than the melting point of the polyamide-based compound. However, when the melting point is too high, carbonization or decomposition may occur to deteriorate the physical properties of the film, and bonding between the polyether- Which may be disadvantageous for producing a film.

The extrusion die may be used without any limitations as long as it is known to be usable for extrusion of the polymer resin. However, in order to make the thickness of the base film more uniform or prevent orientation from occurring in the base film, a T- .

On the other hand, a substrate film having substantially no orientation due to stretching can be obtained by attaching the melt extruded under the specific die gap condition to a cooling section provided at a distance of 10 to 150 mm horizontally from the die exit.

 When the resultant obtained by melting and extruding is stretched before being cooled and solidified, orientation is generated in the base film to be produced. Accordingly, it is necessary to firmly adhere the molten resin to the cooling roll as soon as possible on the film so that the stretching orientation is minimized. That is, as described above, the melt extruded under the specific die gap condition can be attached to or grounded from a cooling portion provided at a horizontal distance of 10 to 150 mm, preferably 20 to 120 mm, from the die outlet to eliminate elongation and orientation . The horizontal distance from the die outlet to the cooling portion may be the distance between the die outlet and the point where the discharged melt is grounded to the cooling portion. If the linear distance between the outlet of the die and the point of attachment of the cooling part of the molten film is too small, it may interfere with the uniform flow of the melt extruded resin and cause film cooling unevenness, and if the distance is too large, I can not.

Specifically, the method for manufacturing a film for a tire innerliner further includes solidifying the base film layer formed by the melt and extrusion in a cooling part maintained at a temperature of 5 to 40 캜, preferably 10 to 30 캜 can do. The base film layer formed by the melt and extrusion is solidified in the cooling part maintained at the temperature of 5 to 40 캜 and can be provided as a film having a more uniform thickness. The base film layer obtained by melting and extruding can be grounded or brought into close contact with the cooling section maintained at the above-mentioned appropriate temperature, so that the stretching can be substantially prevented. The base film layer can be provided as an unstretched film.

Further, it is also possible to appropriately adjust the horizontal distance to the die outlet and the cooling section, and further use an air knife, an air nozzle, an electrostatic application device (pinning device) or a combination thereof, It is possible to promptly adhere to the cooling portion to be solidified, so that orientation due to stretching of the base film can be substantially prevented. Specifically, the method for producing a film for a tire innerliner includes using at least one device selected from the group consisting of an air knife, an air nozzle, and an electrostatic application device, the horizontal distance being 10 to 300 mm from the die outlet, To the cooling unit uniformly.

In the step of forming the base film, the extrusion processing conditions of a film commonly used in the production of a polymer film, for example, a screw diameter, a screw rotation speed, or a line speed Can be appropriately selected and used.

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 upon initial 2% elongation of the base film layer obtained according to the above method is 0.9 to 1.1 Lt; / RTI > may be 0.92 to 1.08. The ratio of the yield strength in the first direction of the base film layer to the yield strength in the second direction perpendicular to the first direction may be 0.9 to 1.1, preferably 0.92 to 1.08. The flat elongation of the base film layer in the first direction and the flat elongation in the second direction perpendicular to the first direction may be 150% or more, and 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.

The specific contents of the polyamide based resin and the copolymer including the poly-amide based segment and the poly-ether based segment are as described above.

On the other hand, in the step of forming the base film layer, the copolymer and the polyamide resin can be adjusted to have a uniform size in order to extrude a film having a more uniform thickness. As described above, by adjusting the size of the copolymer and the polyamide resin, mixing them, staying in a raw material supply portion maintained at a constant temperature, melting or extruding, and the like, It is possible to more uniformly mix the resin and prevent the phenomenon that the copolymer and the polyamide resin are aggregated with each other or increase in size so that a base film layer having a more uniform thickness can be formed .

If the copolymer and the polyamide-based resin have similar sizes, it is possible to minimize the phenomenon of aggregation of raw material chips or appearance of uneven shapes or regions in a subsequent mixing, melting or extruding step, A base film layer having a uniform thickness over the entire area can be formed. The size of the copolymer and the polyamide resin usable in the above production method is not limited to a great extent.

On the other hand, in the step of producing the base film, it is preferable that the winding speed of the film is maintained at a proper speed in order to prevent the problem of poor cooling and increase in orientation. For example, A speed of 50 m / min or less can be applied.

Meanwhile, in the step of forming the base film, the thickness of the molten resin sheet to be discharged may be adjusted by combining the extruder discharge amount, the width or gap of the die, and the winding speed of the cooling roll, or by adjusting the thickness of the air knife, air nozzle, The thickness of the base film can be adjusted to 30 to 300 mu m by cooling the film uniformly by using the apparatus.

The method for manufacturing a film for a tire innerliner may further include mixing the polyamide resin and the copolymer at a weight ratio of 6: 4 to 3: 7. If the content of the polyamide resin is too small, the density or airtightness of the base film layer may be lowered. If the content of the polyamide resin is too large, the modulus of the base film layer may become excessively high or the moldability of the tire may be deteriorated. In a high temperature environment occurring during a tire manufacturing process or an automobile running process, It can be crystallized, and a crack can be generated by repeated deformation. In this mixing step, devices or methods known to be usable for mixing polymer resins can be used without any limitations.

The polyamide based resin and the copolymer may be mixed into a feeder after they are mixed and may be injected sequentially or simultaneously to the raw material feeder and mixed.

As described above, the copolymer may include a poly-amide-based segment and a poly-ether-based segment at a weight ratio of 6: 4 to 3: 7.

Meanwhile, the method for producing a film for a tire innerliner may include forming an adhesive layer containing a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film layer.

The adhesive layer containing the resorcinol-formalin-latex (RFL) -based adhesive may be formed by applying a resorcinol-formalin-latex (RFL) -based adhesive to one surface of the base film layer, and the resorcinol- And then laminating an adhesive film containing a formalin-latex (RFL) -based adhesive on one side of the base film layer.

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

More specific details regarding the resorcinol-formalin-latex (RFL) -based adhesive of the above specific composition are as described above.

The application of the adhesive may be carried out by any conventional coating or coating method or apparatus without limitation, but it may be applied by a knife coating method, a bar coating method, a gravure coating method, a spraying 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 surface or both surfaces of the base film, the drying and the adhesive reaction may be simultaneously performed. However, the reaction may be divided into a drying step and a heat treatment reaction step in consideration of the reactivity of the adhesive, In order to apply the thickness of the adhesive layer or the multi-stage adhesive, the adhesive layer formation, the drying and the reaction step may be applied several times. Further, the heat treatment reaction may be performed by applying an adhesive to the base film, and then solidifying and reacting at 100 to 150 ° C for about 30 seconds to 3 minutes under heat treatment conditions.

As described above, even when the above-mentioned adhesive layer is formed on the base film layer, the stretching property of the base film described above does not greatly change, so that the film for a tire inner liner can have elongation properties similar to those of the base film described above. For example, the ratio of the tensile modulus in the first direction and the tensile modulus in the second direction perpendicular to the first direction with respect to the tensile modulus in the first direction upon initial 2% elongation of the film for a tire innerliner is 0.9 to 1.1, preferably 0.92 to 1.08 And the ratio of the yield strength in the first direction to the yield strength in the second direction perpendicular to the first direction of the film for a tire innerliner may be 0.9 to 1.1, preferably 0.92 to 1.08.

The flat elongation in the first direction and the flat elongation in the second direction perpendicular to the first direction of the tire innerliner film are respectively 150% or more, preferably 200% to 400% . The ratio of the flat elongation in the second direction to the flat elongation of the tire innerliner film in the first direction may be 0.9 to 1.1, preferably 0.92 to 1.08.

In the step of forming the copolymer or the mixture, or the step of melting and extruding the copolymer, an additive such as a heat-resistant antioxidant or a heat stabilizer may be further added. The specific contents of the additive are as described above.

According to the present invention, it is possible to realize excellent airtightness even with a thin thickness, thereby making it possible to reduce the weight of the tire and improve the automobile fuel economy, and to have uniform physical properties in all directions of the film, A method for producing a film for a film and a 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 will be described 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 a polyamide based resin (nylon 6) having a relative viscosity of 96% (sulfuric acid solution) 3.4 and a copolymer resin having an absolute weight average molecular weight of 100,000 (each containing 50% by weight of polyamide based repeating units and polyether based repeating units) 60% by weight, The mixture was melt-extruded at a temperature in a T-die under a die gap of 0.6 mm. The obtained molten film was fixed at a horizontal distance of 30 mm from the exit of the die to a cooling roll (maintained at 15 rpm, rotation speed: 15 m / min), cooled and solidified to adjust the discharge amount of the extruder to G / Was obtained. The thickness of the base film was measured using a gauge tester.

In the step of grounding the molten film to the cooling roll, an edge pinning is installed inside the 5 mm of both ends of the ground wire of the sheet grounded with an air knife at a horizontal distance of 30 mm from the grounding position so that the molten film is closely contacted with the cooling roll by air pressure and static electricity .

(2) Application of adhesive

Resorcinol and formaldehyde were mixed at a molar ratio of 1: 2, followed by condensation reaction to obtain a condensate of resorcinol and formaldehyde. 12% by weight of a 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%.

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

Example 2

Except that a 100 mm thick unoriented film was produced by using a cooling roll having a resin extrusion temperature of 270 ° and a die gap of 0.8 mm and rotating at a speed of 10 m / min. In the same manner as in Example 1, To prepare a film for a liner.

Example 3

Except that the extruding temperature of the resin was set at 280 °, the die gap was set at 1.0 mm, and a cooling roll rotating at 8 m / min was used to produce an unoriented film having a thickness of 120 μm. To prepare a film for a liner.

≪ Comparative Example: Production of film for innerliner of tire &

Comparative Example 1

A releasing agent and a processing agent were added to the butyl rubber, and the mixture was refined to obtain a tire inner liner film having a thickness of 70 占 퐉, and adhesive rubber (tie gum) having a thickness of 1 占 퐉 was formed on the inner liner film.

Comparative Example 2

(1) Production of base film

90% by weight of a polyamide based resin (nylon 6) having a relative viscosity of 96% (sulfuric acid solution) 3.3 and a copolymer resin having an absolute weight average molecular weight of 100,000 (50% by weight of polyamide- Except that 10% by weight of a polyvinyl chloride resin was mixed.

(2) Application of adhesive

Resorcinol-formalin-latex (RFL) adhesive was prepared in the same manner as in Example 1, applied to the base film, and dried to form a 1-μm-thick adhesive layer.

Comparative Example 3

(1) Production of base film

20% by weight of a polyamide based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) of 3.3 and a copolymer resin having an absolute weight average molecular weight of 100,000 (20% by weight of polyamide- Except that 80% by weight of a polyvinyl chloride resin was mixed.

(2) Application of adhesive

Resorcinol-formalin-latex (RFL) adhesive was prepared in the same manner as in Example 1, applied to the base film, and dried to form a 1-μm-thick adhesive layer.

Comparative Example 4

 (1) Production of base film

40% by weight of a polyamide based resin (nylon 6) having a relative viscosity of 96% (sulfuric acid solution) 3.4 and a copolymer resin having an absolute weight average molecular weight of 100,000 (each containing 50% by weight of polyamide based repeating units and polyether based repeating units) 60% by weight, The melt obtained by melt extrusion of the mixture at a temperature of 2.0 mm under a die gap of T-die was fixed at a horizontal distance of 30 mm from the exit of the die to a cooling roll (maintained at 15 DEG C, rotation speed: 15 m / min) And solidified to obtain an unstretched base film having a thickness of 70 mu m. The thickness of the base film was measured using a gauge tester.

In the step of grounding the molten film to the cooling roll, an edge pinning is installed inside the 5 mm of both ends of the ground wire of the sheet grounded with an air knife at a horizontal distance of 30 mm from the grounding position so that the molten film is closely contacted with the cooling roll by air pressure and static electricity .

(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 Film for Inner Liner of Tire>

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 MD and Machine Direction of the inner liner film obtained in the above Examples and Comparative Examples. The specific measurement method is as follows.

(1) Measuring instrument: universal material testing machine (Model 4204, Instron)

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

(3) 5 times each, and the average value was obtained.

In the stress-strain curves obtained from the data measured above, 1) the slope value of the stress-strain curve at the initial elongation of 2% was taken as the modulus, 2) the yield strength was 0 to 50 (3) Flat elongation is defined as the elongation at the point where the stress is equal to the yield strength point in the elongation section of the stress / elongation graph (or the elongation at yield point above the yield point) , And the elongation at the point where the change in the slope of the SS curve is largest).

Experimental Example 2: Oxygen permeability experiment

The oxygen permeability of the tire inner liner film obtained in the above Examples and Comparative Examples was measured. The specific measurement method is as follows.

(1) Oxygen Permeability: The Oxygen Permeation Analyzer (Model 8000, manufactured by Illinois Instruments) was measured in a manner of ASTM D 3895 at 25 degrees and 60 RH% atmosphere.

Experimental Example 3: Measurement of air pressure maintenance performance

A tire was manufactured by applying the tire inner liner film of the above Examples and Comparative Examples to the 205R / 65R16 standard. Then, the produced tire was subjected to comparative evaluation by measuring the IPR internal pressure retention (IPR internal pressure retention) at a pressure of 101.3 kPa at 21 ° C for 90 days using the ASTM F1112-06 method.

The results of Experimental Examples 1 to 3 are shown in Table 1 below. FIG. 1 shows a graph of stress occurring when the base film obtained in Examples and Comparative Examples was strained in the longitudinal direction.

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
Longitudinal / lateral (MPa) 408 /
398 418 /
405 467 /
432 73 /
71 1620 /
1450 168 /
151 721 /
615 Modulus
Contrast (longitudinal / transverse) 1.02 1.03 1.08 1.02 1.11 1.11 1.17 Yield strength
Longitudinal / lateral (MPa) 14 /
13 15 /
14.5 17 /
16.5 3.1 /
3.0 46 /
38 8/
7 21 /
17 Yield strength
Contrast (longitudinal / transverse) 1.08 1.03 1.03 1.03
1.21 1.14 1.23 Flat stretch
Longitudinal / lateral (%) 215 /
225 210 /
220 200 /
215 - -
250 /
270 125 /
130 Flat stretch
Contrast (longitudinal / transverse) 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 maintenance rate
(%) 96 97 98 75 - 85 - Air pressure retention rate / Moldability observation Good Good Good Poor air pressure Molding
Bad Poor air pressure Molding
Bad

As shown in Table 1, the film for a tire innerliner of the embodiment shows air permeability of 200 cc / m &lt; 2 &gt; * 24 hr * atm or less so that excellent airtightness can be realized even with a thin thickness. It can be easily stretched or deformed, and thus it has been confirmed that the moldability of the green tire or the final tire is excellent.

It was also 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 to the transverse tensile modulus, the ratio of the longitudinal yield strength to the lateral yield strength, and the ratio of the longitudinal flat elongation to the lateral elongation All within the range of 0.9 to 1.1. Further, it was confirmed that the longitudinal flat elongation and the lateral elongation of the tire inner liner film were 150% or more, respectively.

As shown in Fig. 1, in the films for tire innerliners of Examples 1 to 3, the flat elongation was 150% or more in the strain-stress graph and the initial slope of the graph was relatively small, Can be expressed.

On the other hand, the tire innerliner film of Comparative Example 4 had a flat elongation period of less than 150%, an initial slope of the graph was high, and a yield point was relatively high, so that tire formability or other properties were applied to actual tires Was not enough. In addition, the tire innerliner film of Comparative Example 2 was found to have an excessively high yield point and a flat elongation period, making it difficult to mold in a general tire manufacturing process. In the case of the tire innerliner films of Comparative Examples 1 and 3, it was confirmed that the modulus and the flat elongation were good but the air barrier properties were insufficient, and thus they were not suitable for actual tire application.

Claims (22)

Polyamide based resin; And a copolymer comprising a poly-amide-based segment and a poly-ether-based segment,
An adhesive layer formed on at least one side of the base film layer and including a resorcinol-formalin-latex (RFL) -based adhesive,
The copolymer comprises a poly-amide-based segment and a poly-ether-based segment in a weight ratio of 6: 4 to 3: 7,
In the base film layer, the polyamide resin and the copolymer are contained in a weight ratio of 6: 4 to 3: 7,
The content of the polyether segment of the copolymer is from 15 to 50% by weight based on the total weight of the base film layer,
Wherein the ratio of the tensile modulus in the first direction and the tensile modulus in the second direction perpendicular to the first direction with respect 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 according to claim 1,
Wherein the ratio of the yield strength of the base film layer in the first direction to the yield strength in the second direction perpendicular to the first direction is 0.9 to 1.1.
The method according to claim 1,
Wherein a flat elongation of the base film layer in the first direction and a flat elongation in the second direction perpendicular to the first direction are 150% or more,
Wherein a ratio of a flat elongation in a second direction to a flat elongation in the first direction is 0.9 to 1.1.
The method according to claim 1,
Wherein the first direction is the same as the transverse direction (TD) of the base film, and the second direction is the same as the machine direction (MD) of the base film.
The method according to claim 1,
And the relative viscosity (96% solution of sulfuric acid) of the polyamide resin is 3.0 to 3.5.
The method according to claim 1,
Wherein the copolymer comprising the polyamide-based segment and the polyether-based segment has an absolute weight average molecular weight of 50,000 to 300,000.
The method according to claim 1,
Wherein the polyamide segment of the copolymer comprises a repeating unit of the following formula (1) or (2):
[Chemical Formula 1]

Wherein R ₁ is a linear or branched alkylene group having 1 to 20 carbon atoms or a linear or branched alkylene group having 7 to 20 carbon atoms,
(2)

R ₂ is a linear or branched alkylene group having 1 to 20 carbon atoms and R ₃ is a linear or branched alkylene group having 1 to 20 carbon atoms or a linear or branched alkylaryl group having 7 to 20 carbon atoms It is a stove.
The method according to claim 1,
Wherein the polyether segment of the copolymer comprises a repeating unit represented by the following formula (3):
(3)

In Formula 3,
R ₅ is a straight 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 and are each a direct bond, -O-, -NH-, -COO- or -CONH-.
delete delete The method according to claim 1,
Wherein the base film layer has a thickness of 30 to 300 占 퐉,
Wherein the adhesive layer has a thickness of 0.1 to 20 占 퐉.
The method according to claim 1,
Wherein the base film layer is an unstretched film.
The method according to claim 1,
Wherein the resorcinol-formalin-latex (RFL) based adhesive comprises 2 to 30% by weight of a condensate of resorcinol and formaldehyde; And 68 to 98 wt% of a latex.
Polyamide based resin; And a copolymer comprising a poly-amide-based segment and a poly-ether-based segment, 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 containing a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film layer,
The copolymer comprises a poly-amide-based segment and a poly-ether-based segment in a weight ratio of 6: 4 to 3: 7,
In the base film layer, the polyamide resin and the copolymer are contained in a weight ratio of 6: 4 to 3: 7,
The content of the polyether-based segment contained in the copolymer is 15 to 50% by weight based on the total weight of the base film layer,
Wherein the ratio of the tensile modulus in the machine direction (MD) to the tensile modulus in the transverse direction (TD) in the initial 2% elongation of the base film layer is 0.9 to 1.1. .
15. The method of claim 14,
Wherein forming the base film layer comprises:
Further comprising the step of attaching the extrudate to a cooling portion located at a horizontal distance of 10 to 150 mm from the outlet of the die.
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 application device, which is located at a horizontal distance of 10 to 300 mm from the die outlet,
Further comprising the step of uniformly adhering the extrudate to the cooling section uniformly.
15. The method of claim 14,
Further comprising the step of solidifying the base film layer formed by melting and extrusion in a cooling portion maintained at 5 to 40 캜.
delete delete 15. The method of claim 14,
The step of forming the adhesive layer comprises: 2 to 30% by weight of a condensate of resorcinol and formaldehyde; And 68 to 98 wt% of a latex on at least one surface of the base film layer to a thickness of 0.1 to 20 mu m.
15. The method of claim 14,
Wherein a ratio of a yield strength in a transverse direction (TD) to a yield strength in a machine direction (MD) of the base film layer is 0.9 to 1.1.
15. The method of claim 14,
The flat elongation in the transverse direction (TD) and the flat elongation in the machine direction (MD) of the base film layer are 150% or more, respectively,
Wherein a ratio of a flat elongation in the machine direction (MD) to a flat elongation in a transverse direction (TD) is 0.9 to 1.1.

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