KR20130035975A - Film for tire inner-liner and preparation method thereof - Google Patents

Abstract

PURPOSE: A film for tire innerliner is provided to obtain excellent sealability only by a thin thickness film, reduce the weight of a tire, improve the fuel efficiency of a vehicle, and have excellent moldability and mechanical properties. CONSTITUTION: A film for tire innerliner comprises a substrate film layer and an adhesive layer. The substrate film layer includes a polyamide-based resin with a relative viscosity of 3.0-3.5(sulfuric acid 96%); and a copolymer containing a polyamide-based segment and polyether-based segment. The adhesive layer includes a resorcinol-formalin-latex-based adhesive. The content of the polyether-based segment in the copolymer is 15-50wt% based on the total weight of the substrate film layer. The melt viscosity of the copolymer with regard to the melt viscosity of the polyamide-based resin at 260>= and a shearing rate of 1000s^-1 is 0.65-1.2. [Reference numerals] (1) Tread; (2) Shoulder; (3) Sidewall; (4) Cap ply; (5) Belt; (6) Body ply; (7) Innerliner; (8) Apex; (9) Bead;

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 exhibits uniform physical properties in the entire film area, and realizes excellent airtightness even with a thin thickness, thereby making it possible to lighten tires and improve automobile fuel economy, and have mechanical properties such as high durability and fatigue resistance along with excellent formability. A method for producing a film for tire inner liner and a film for tire inner liner.

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

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

Body Ply (or Carcass) (6): 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 innerliners were used, with rubber components such as butyl rubber or halo butyl rubber, which had relatively low air permeability, and had to increase the rubber content or the thickness of the inner liner in order to obtain sufficient airtightness. . However, when the content of the rubber component and the tire thickness increase, there is a problem in that the total tire weight increases and fuel economy of the vehicle decreases.

In addition, the rubber components have relatively low heat resistance, such that air pockets are formed between the inner rubber and the inner liner of the carcass layer or the inner liner of the carcass layer during the vulcanization process of the tire, or the driving of the car, where repeated deformation occurs at high temperature conditions. There was a problem in changing form or physical properties. In addition, in order to couple the rubber components to the tire curker layer, a vulcanizing agent or a vulcanizing process had to be applied, and it was difficult to secure sufficient adhesive force.

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 molding 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 innerliner. In addition, the innerliner obtained by the previously known method may be deteriorated in its physical properties or cracks in the film during the manufacturing process of a tire that is repeatedly formed at a high temperature, or during the driving process of a vehicle in which high heat is generated. This phenomenon appeared.

The present invention exhibits uniform physical properties over the entire area of the film, and realizes excellent airtightness even with a thin thickness, thereby making the tire lighter and improving fuel efficiency, and having excellent moldability and mechanical properties such as high durability and fatigue resistance. It is for providing an inner liner film.

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

The present invention, polyamide resin having a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5; 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, the content of the polyether segment of the copolymer being from 15 to 50% by weight relative to the total weight of the base film layer, a shear rate of 1000s ^-1 and a 260 ° C In the temperature of, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin provides a film for tire innerliner is 0.65 to 1.2.

In addition, the present invention, polyamide resin having a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5; And a copolymer comprising a polyamide-based segment and a polyether-based segment; melting and extruding the mixture at 230 to 300 ° C. to form a base film layer, and the base film Forming an adhesive layer comprising a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the layer, wherein the content of the polyether-based segment of the copolymer is 15 based on the total weight of the base film layer To 50% by weight, and the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin at a shear rate of 1000 s ⁻¹ and a temperature of 260 ° C. is 0.65 to 1.2. to provide.

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

According to one embodiment of the invention, polyamide-based resin having a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5; 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, the content of the polyether segment of the copolymer being from 15 to 50% by weight relative to the total weight of the base film layer, a shear rate of 1000s ^-1 and a 260 ° C At a temperature of, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin may be provided with a film for tire innerliner 0.65 to 1.2.

As a result of the researches of the present inventors, a tire comprising a base film layer formed by using the copolymer comprising a specific content of the polyamide-based resin and a polyether-based segment and the adhesive layer formed on the base layer Inner liner film has excellent airtightness even at a thin thickness to lighten tires and improve fuel efficiency of automobiles, and has excellent heat resistance and excellent moldability and mechanical properties. It has been found that it can be firmly bonded to the tire without the need to increase or significantly increase the thickness of the adhesive layer.

In particular, in the process of manufacturing the base film layer, by selecting and using a copolymer containing a specific content of the polyether-based segment with the polyamide-based resin having a specific relative viscosity, the two components are not phase separated It may be uniformly mixed or combined, and the prepared base film layer may have uniform physical properties over the entire area. In addition, the base film layer prepared as described above has not only high modulus characteristics but also high elasticity or elastic recovery ratio, and thus, exhibits excellent moldability in the tire manufacturing process, and large deformation under high temperature conditions. In a tire manufacturing process or a vehicle driving process that is repeatedly applied, the film itself may be prevented from crystallization or damage such as cracks in the film.

In addition, the copolymer including the polyamide-based resin, the polyamide-based segment and the polyether-based segment may be a high temperature and a specific shear applied in the manufacturing process of the base film layer. Even in the speed range, the proportion of melt viscosity may not vary significantly. Accordingly, the two different components are mixed unevenly in the process of melting and mixing the polyamide-based resin, the copolymer including the polyamide-based segment and the polyether-based segment. It is possible to minimize the phenomenon, and to minimize the parts that can cause a defect during the manufacturing of tires, it is possible to minimize the occurrence of cracks in the base film because the phase separation in the durability test after tire molding.

Specifically, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin may be 0.65 to 1.2 at a shear rate of 1000 s ⁻¹ and a temperature of 260 ° C. The shear rate of 1000 s ⁻¹ and a temperature of 260 ° C. may be a condition that may be applied in the process of mixing the polyamide-based copolymer with the polyamide-based segment and the polyether-based segment. .

Meanwhile, at a shear rate of 100 s ⁻¹ and a temperature of 260 ° C., a ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin may be 1.0 to 2.0. When the melt viscosity of the copolymer becomes very large as compared to the melt viscosity of the polyamide-based resin in a state where the flow rate caused by the shear stress is low, specifically, the shear rate of 100 s ⁻¹ and the temperature at a temperature of 260 ° C. When the copolymer exceeds twice the polyamide-based resin, the mixing of the polyamide-based resin and the copolymer is not easy and the physical properties of the base film to be produced may also be greatly reduced. In addition, even when the melt viscosity of the copolymer becomes very small compared to the melt viscosity of the polyamide-based resin, the mixing of the polyamide-based resin and the copolymer is not easy, and the physical properties of the produced base film It can be greatly reduced.

In addition, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin, may be 0.65 to 1.1 at a shear rate of 2000s ^-1 and a temperature of 260 ℃, a shear rate of 500s ^-1 and 260 ℃ It may be 0.7 to 1.5 at the temperature of.

That is, the polyamide is selected according to the polyamide-based resin and the polyether-based segment together with the polyamide-based resin having the specific relative viscosity, and the content of the polyether-based segment in the copolymer is specified. The resin and the copolymer may have similar melting characteristics with each other in the melting and extruding step, and may be mixed and melted without the phenomenon that each component is aggregated or other components are phase separated.

The melt viscosity refers to the melt viscosity of the product produced in the discharge hole of a specific temperature during the film processing. Since the melt viscosity of the production result is dependent on temperature, shear rate and shear stress, it can be obtained by measuring the stress and shear rate of the polymer in the discharged temperature region and applying it to the following general formula (1).

[Formula 1]

η = σ / γ

Where? Is the melt viscosity,? Is the shear stress, and? Is the shear rate.

On the other hand, 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. When the viscosity of the polyamide-based resin is less than 3.0, sufficient elongation may not be secured due to a decrease in toughness, and thus damage may occur when manufacturing a tire or driving a vehicle. Since the ratio of the melt viscosity of the copolymer to the melt viscosity of the amide resin is very large, the polyamide-based resin and the copolymer may be phase-separated from each other in the manufacturing process of the base film layer, tire manufacturing process or automobile driving, It may be difficult to secure physical properties such as airtightness or moldability that the base film layer should have as a film for tire innerliner. 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.

The tire inner liner film has excellent airtightness and high air pressure holding performance, and has physical properties such as high heat resistance, excellent moldability and high fatigue resistance. The excellent physical properties of such a film for tire innerliner include a base film layer prepared using a copolymer comprising a polyamide-based resin having a specific relative viscosity and a specific content of a polyether-based segment and a polyamide-based segment. Seems to follow.

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

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.

Specifically, 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.

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.

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.

In the manufacturing process of the base film, the polyamide-based resin may be included in the base film by mixing and melting with the copolymer described above, and the monomer or oligomer which is a precursor of the polyamide-based resin together with a reaction initiator or a catalyst It may also be included in the base film by reacting with the copolymer described above.

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 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, the content of the polyether segment of the copolymer may be 15 to 50% by weight, preferably 20 to 45% by weight, more preferably 22 to 40% by weight based on the total weight of the base film layer. 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-based segment exceeds 50% by weight of the entire film, the gas barrier of the tire innerliner film (Gas Barrier) may be lowered, the reactivity to the adhesive is lowered, the inner liner to the carcass layer It may be difficult to easily adhere, and the elasticity of the base film layer may be increased, thereby making it difficult to manufacture a uniform film.

When the content of the polyether segment of the copolymer in the total weight of the base film layer is less than 15% or more than 50% by weight, that is, the content of the polyether segment in the copolymer is too small or too large In the polyamide-based resin, the melt viscosity of the polyamide-based resin and the copolymer may vary greatly. Accordingly, the two different components may be unevenly mixed in the process of mixing and melting the polyamide-based resin and the copolymer. Phase separation or cracking may occur in the base film that is not bonded.

The copolymer including the polyamide-based segment and the polyether-based segment may be a polyamide-based monomer or oligomer and a polyether-based monomer or oligomer It may be a copolymer obtained by reacting, and may be a copolymer obtained by polymerizing or crosslinking a polymer including a polyamide segment and a polymer comprising a polyether segment.

The copolymer including the polyamide-based segment and the polyether-based segment may be a block copolymer in which the segments form a block, and the segments are irregular. It can be a bonded random copolymer. In addition, the copolymer including the polyamide-based segment and the polyether-based segment may include a polymer including the polyamide-based segment and a polyether-based segment. It may be a copolymer including a polymerization reactant between polymers, and may be a crosslinked copolymer including a crosslinking reactant between a polymer including a polyamide-based segment and a polymer including a polyether-based segment.

Meanwhile, in the base film layer, a copolymer including the polyamide-based resin, the polyamide-based segment, and the polyether-based segment is uniformly mixed, or polymerized or crosslinked. Through it may be in a combined state in part or the whole area.

Wherein the copolymer comprising the polyamide segment and the polyether segment is a copolymer of a polymer comprising a polyamide segment and a polymer comprising a polyether segment, Polymeric reactants or crosslinking reactants, the copolymer may comprise a polymer comprising a polyamide-based segment that is not involved in the polymerization or cross-linking reaction, or a polymer comprising a poly-ether-based segment have. Accordingly, the polymer including the polymerization reactant or the crosslinking reactant as well as the polymer including the polyamide-based segment or the polymer including the polyether-based segment may be present in a mixed or combined state with other components. have. Also in this case, the total sum of the content of the polyether segment and the content of the polymer including the polyether segment in the copolymer is in the range of 15 to 50% by weight based on the total weight of the base film layer , The physical properties of the film for the entire inner liner can be optimized.

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.

In addition, 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. Enable molding 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.

The polyamide-based segment may be the polyamide-based repeating unit when a base film layer is produced using a copolymer comprising a polyamide-based repeating unit and a polyether-based repeating unit. In addition, the polyamide-based segment may be derived from a polymer comprising a polyamide segment used in the production of the substrate film, or from a poly-amide-based monomer or oligomer.

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 polyether segment may be the polyether repeating unit when a base film layer is manufactured using a copolymer including a polyamide repeating unit and a polyether repeating unit. In addition, the polyether segment may be derived from a polymer including a polyether segment, or a polyether monomer or oligomer used in the manufacturing process of the base film. .

Meanwhile, 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 110,000 to 250,000. 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 innerliner film, and it may be difficult to have good physical properties capable of gas barrier, and When the absolute weight average molecular weight of the copolymer exceeds 300,000, the modulus or crystallinity of the base film layer may be excessively increased when heated to a high temperature, and thus it may be difficult to secure elasticity or elastic recovery rate to have as an innerliner film.

In the solution containing the polymer material, light scattering occurs due to the chain of the polymer material. Using the light scattering phenomenon, the absolute weight average molecular weight of the polymer material can be measured. In particular, using Wyatt's Multi Angle Light Scattering (MALS) system, the absolute weight average molecular weight of the polymer can be obtained by applying the parameters from the measurement results to the Rayleigh-Gans-Debye equation.

Formula 2: Rayleigh-Gans-Debye equation

In Formula 2, M is the molar mass, and in the case of a polydisperse sample, Mw is the absolute weight average molecular weight, R (θ) is the excess Rayleigh ratio, and K = 4πn ₀ ² ( dn / dc ) ² λ ₀ ^-4 N _A ^-1 , C is the polymer concentration in solution (g / ml), and A ₂ is the second virial coefficient. And, in the K, n ₀ is the refractive index of the solvent, N _A is Avogadro's number, λ ₀ is the wavelength of the light source under vacuum, P (θ) = R (θ) / R ₀ , R ₀ is incident light.

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 copolymer may be included in a weight ratio of 6: 4 to 3: 7, preferably 5: 5 to 4: 6. If the content of the polyamide-based resin is too small, the density or airtightness of the 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.

As such, the tire innerliner film may exhibit improved adhesion to the adhesive or the adhesive layer due to the characteristics of the above-described base film, and the thinner and lighter adhesive layer may be applied to the carcass layer without the need for laminating additional adhesive layers or rubber layers. It can be fixed firmly and evenly.

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 for manufacturing the tire innerliner film described below, a method of suppressing the orientation of the base film layer as much as possible, for example, adjusting viscosity by optimizing melt extrusion temperature, changing a die die specification, or adjusting a winding speed, etc. Through the method of the base film can be prepared in an unoriented or unoriented film.

When the unstretched film is applied to the base film layer, the inner liner film can be easily manufactured 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 layer, it is not necessary to construct a film manufacturing facility for each tire size, and the impact and wrinkles applied to the film during the transport and storage process can be minimized. Do. 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.

On the other hand, 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 adhesive is capable of crosslinking between latex and rubber, thereby exhibiting adhesive performance. 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.

In addition, the tire inner liner film can maintain a proper air pressure even after long-term use, for example, the tire inner liner film at 21 ℃ and 101.3 kPa in accordance with the method of ASTM F 1112-06 standards When the internal pressure retention (IPR) was measured for 90 days on the applied tire, the pneumatic retention rate as shown in the following general formula 2 may be 95% or more, that is, the pneumatic pressure reduction rate may be 5% or less. Accordingly, by using the tire inner liner film, it is possible to prevent a rollover accident and fuel consumption reduction caused by low air pressure.

 [Formula 2]

On the other hand, according to another embodiment of the invention, polyamide-based resin having a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5; And a copolymer comprising a polyamide-based segment and a polyether-based segment; melting and extruding the mixture at 230 to 300 ° C. to form a base film layer, and the base film Forming an adhesive layer comprising a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the layer, wherein the content of the polyether-based segment of the copolymer is 15 based on the total weight of the base film layer To 50% by weight, and the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin at a shear rate of 1000 s ⁻¹ and a temperature of 260 ° C. is 0.65 to 1.2. Can be provided.

As described above, at least one of the base film layer formed using the specific polyamide-based resin and the specific copolymer (including 15 to 50 wt% of the polyether-based segment based on the total weight of the base film layer) The tire innerliner film produced by forming an adhesive layer containing a resorcinol-formalin-latex (RFL) -based adhesive on the surface can realize excellent airtightness even at a thin thickness, thereby making the tire lighter and improving fuel efficiency of the automobile. It may have high heat resistance and yet have excellent moldability and mechanical properties, and may be firmly bonded to the tire without applying an additional vulcanization process or significantly increasing the thickness of the adhesive layer.

In particular, in the step of forming the base film layer, by specifying the relative viscosity of the polyamide-based resin and the content of the polyether-based segment in the copolymer, the polyamide-based resin and the copolymer is not phase separated It can be mixed or combined uniformly without, and the prepared base film layer may have uniform physical properties over the entire area. In addition, the base film layer prepared as described above has not only high modulus characteristics but also high elasticity or elastic recovery ratio, and thus, exhibits excellent moldability in the tire manufacturing process, and large deformation under high temperature conditions. In a tire manufacturing process or a vehicle driving process that is repeatedly applied, the film itself may be prevented from crystallization or damage such as cracks in the film.

As such, by using a polyamide-based resin having a specific relative density and a copolymer including a specific content of a polyether-based segment and a polyamide-based segment, the melt viscosity of the polyamide-based resin used in the manufacturing method The melt viscosity ratio of the copolymer may be 0.65 to 1.2 at a shear rate of 1000 s ⁻¹ and a temperature of 260 ° C.

In addition, at a shear rate of 100 s ⁻¹ and a temperature of 260 ° C., a ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin may be 1.0 to 2.0. When the melt viscosity of the copolymer is equal to or less than twice the melt viscosity of the polyamide-based resin in a state where the flow rate caused by the shear stress is low, the polyamide-based resin and the copolymer are melted and extruded. In the step may have similar melting properties to each other, and may be mixed and melted without the phenomenon that each of the components are agglomerated or the other components are phase separated.

In addition, the polyamide ratio of the melt viscosity of the copolymer to the melt viscosity of the resin may be in the shear rate and a temperature of 260 ℃ of 2000s ^-1 0.65 to 1.1, a shear rate of 500s ^-1 and 260 ℃ It may be 0.7 to 1.5 at the temperature.

As described above, 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. And, the content of the polyether segment of the copolymer may be 15 to 50% by weight, preferably 20 to 45% by weight, more preferably 22 to 40% by weight based on the total weight of the base film layer.

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

The polyamide-based resin may be included in the base film by mixing or compounding with the above-mentioned copolymer, and then the monomer or oligomer, which is a precursor of the polyamide-based resin, may be mixed with the reaction initiator, And may be incorporated into the base film by mixing and reacting with a combination.

In addition, the copolymer including the polyamide-based segment and the polyether-based segment is a base film by melting the copolymer itself after mixing or compounding with the polyamide-based resin. Can be included.

In addition, after mixing or compounding a polymer including a polyamide-based segment and a polymer including a polyether-based segment and performing a polymerization reaction or a crosslinking reaction, the product of the polymerization reaction or the crosslinking reaction is The base film layer may be formed by mixing and melting the polyamide-based resin. In addition, by mixing or compounding a polymer comprising a polyamide-based segment and a polymer comprising a polyether-based segment, and mixing and melting such a mixture or compound with a polyamide-based resin, The polymer of may cause a polymerization reaction or a crosslinking reaction, and the base film layer may be formed through this process.

In the base film layer, a copolymer including the polyamide-based resin, the polyamide-based segment, and the polyether-based segment is uniformly mixed or polymerized or crosslinked. It may be coupled in some or all areas.

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.

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.

The mixture of the polyamide-based resin and the copolymer may be supplied to the extrusion die through a raw material supply unit maintained at a temperature of 50 to 100 ℃. As the raw material supply unit is maintained at a temperature of 50 to 100 ℃, the mixture of the polyamide-based resin and the copolymer has a physical property such as an appropriate viscosity can be easily moved to another part of the extrusion die or extruder, It is possible to prevent the poor feeding of the raw material (feeding) phenomenon that occurs due to agglomeration of the mixture, it is possible to form a more uniform base film in the subsequent melting and extrusion process. The raw material supplier is a part that serves to supply the raw material injected from the extruder to the extrusion die or other parts, the configuration is not limited to a large, and is a conventional raw material feeder (feeder) included in the extruder for producing a polymer resin, etc. Can be.

On the other hand, by melting and extruding the mixture supplied to the extrusion die through the raw material supply unit at 230 to 300 ℃, it is possible to form a base film layer. 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, the step of forming the base film layer, the mixture of the copolymer comprising the polyamide-based resin, polyamide-based segments and polyether-based segments of 30 to 300 ㎛ And extruding into a film of thickness. The adjustment of the thickness of the film to be produced can be made by adjusting the extrusion conditions, for example, the extruder discharge amount or the gap of the extrusion die, or by changing the winding speed of the cooling process or recovery process of the extrudate.

In order to more uniformly control the thickness of the base film layer in the range of 30 to 300 μm, the die gap of the extrusion die may be adjusted to 0.3 to 1.5 mm. 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.

In addition, in the method for producing a film for tire innerliner, a portion of an extrusion die corresponding to a position at which a non-uniform thickness appears by continuously measuring the thickness of the base film manufactured by the above-described steps, and feeding back a measurement result. For example, the film having a more uniform thickness can be obtained by reducing the deviation of the base film manufactured by adjusting the lip gap adjusting bolt of T-Die. In addition, the adjustment of the thickness measurement-feedback-extrusion die of such films can be configured by using an automated system such as an Auto Die system or the like.

On the other hand, the method for producing a film for tire innerliner may further comprise 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 be.

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 detail, the solidifying step may be performed by using an air knife, an air nozzle, an electrostatic charge device (Pinning device), or a combination thereof, on a cooling roll having the base film layer formed by melting and extruding at a temperature of 5 to 40 ° C. It may include the step of uniformly contact.

In the solidifying step, the base film layer formed by melting and extruding by using an air knife, an air nozzle, an electrostatic pinning device or a combination thereof is brought into close contact with a cooling roll. It is possible to prevent phenomena such as blowing in the air or cooling partially unevenly, so that a film having a more uniform thickness can be formed, and some areas of the film that are relatively thick or thin as compared to the surrounding part are substantially It may not be formed as.

Meanwhile, the melt extruded under the specific die gap condition may be attached or grounded to a cooling roll installed at a horizontal distance of 10 to 150 mm, preferably 20 to 120 mm, at a horizontal distance from the die outlet, thereby eliminating stretching and orientation. The horizontal distance from the die outlet to the chill roll may be the distance between the die outlet and the point where the discharged melt grounds to the chill roll. If the straight line distance between the exit of the die and the cold roll attachment point of the molten film is too small, the uniform flow of the molten extruded resin may be disturbed and the film may be unevenly cooled, and if the distance is too large, the stretching effect of the film may be achieved. Can not.

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, 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 forming of the adhesive layer may be performed by coating a resorcinol-formalin-latex (RFL) adhesive on one or both surfaces of the formed base film, and then drying the adhesive layer. May have a thickness of preferably 0.1 to 10 μm. 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. That is, the forming of the adhesive layer may include 2 to 30 wt% of a condensate of resorcinol and formaldehyde on at least one surface of the base film layer; And applying (coating) an adhesive including latex 68 to 98 wt% to a thickness of 0.1 to 20 μm.

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.

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 reduce the weight and improve the fuel economy of the tire by implementing excellent airtightness even at a thin thickness, and for the film for the tire inner liner and the tire inner liner having high heat resistance characteristics and excellent moldability and mechanical properties Methods of making films can be provided.

1 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 : tire For inner liner  Preparation of film]

< Example 1 >

(1) Production of base film

50% by weight of a polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.3 and a copolymer resin having an absolute weight average molecular weight of 145,000 (45% by weight of the polyethylene glycol at the end of the amine group and 55% by weight of the nylon 6 resin) 50 wt%) was mixed. At this time, by controlling the temperature of the raw material supply unit to 50 to 100 ℃ was fed to the extrusion die, while preventing the mixture from fusion in the extruder screw occurs feeding.

In addition, the cost feed mixture T die at 260 ℃ temperature for the cold-rolling surface which keeps a uniform melt flow extrusion, and adjusted to 25 ℃ through the Air Knife (die gap [Die Gap] 1.0 mm) The molten resin was cooled and solidified into a film of uniform thickness. Then, an unstretched base film having a thickness of 100 μm was obtained without passing through the stretching and heat treatment sections at a speed of 15 m / min.

(2) 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 >

(1) Production of base film

35% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.3 and a copolymer resin having an absolute weight average molecular weight of 150,000 (60% by weight of the polyethylene glycol at the end of the amine group and 40% by weight of the nylon 6 resin) Synthesis using) 65% by weight was mixed, and a base film was prepared in the same manner as in Example 1.

(2) application of adhesive

On the substrate film prepared above, an adhesive layer was formed in the same manner as in Example 1.

[ Comparative example : tire For inner liner  Preparation of film]

< Comparative Example 1 >

(1) Production of base film

A base film was prepared in the same manner as in Example 1, except that nylon 6 resin having a relative viscosity (96% sulfuric acid solution) 2.54 was used.

(2) application of adhesive

On the substrate film prepared above, an adhesive layer was formed in the same manner as in Example 1.

< Comparative Example 2 >

(1) Production of base film

A base film was prepared in the same manner as in Example 2, except that a nylon 6 resin of 2.54 relative viscosity (96% sulfuric acid solution) was used.

(2) application of adhesive

On the substrate film prepared above, an adhesive layer was formed in the same manner as in Example 1.

< Comparative Example 3 >

(1) Production of base film

50% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 3.3 and a copolymer resin having an absolute weight average molecular weight of 150,000 (80% by weight of the polyethylene glycol at the end of the amine group and 20% by weight of the nylon 6 resin) Synthesis using) A base film was prepared in the same manner as in Example 1, except that 50% by weight was mixed.

(2) application of adhesive

On the substrate film prepared above, an adhesive layer was formed in the same manner as in Example 1.

< Comparative Example 4 >

(1) Production of base film

50% by weight of polyamide-based resin (nylon 6) having a relative viscosity (96% solution of sulfuric acid) 2.54 and a copolymer resin having an absolute weight average molecular weight of 150,000 (80% by weight of the polyethylene glycol at the end of the amine group and 20% by weight of the nylon 6 resin) Synthesis using) A base film was prepared in the same manner as in Example 1, except that 50% by weight was mixed.

(2) application of adhesive

On the substrate film prepared above, an adhesive layer was formed in the same manner as in Example 1.

< Experimental Example : tire For inner liner  Measurement of Film Properties>

Experimental Example 1 : Measurement of melt viscosity

The melt viscosity of each of the nylon 6 and the copolymer resin used in each of the examples and the comparative examples was measured using a GOTTFERT Rheo-tester 2000 device, and the melt viscosity at the temperature of 260 ° C. and the shear rate shown in Table 1 below was measured. It was measured at 1mm * length 20mm.

From the measured melt viscosity, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin was determined. The results are shown in Table 1 below.

Results of Experiment 1 Ratio of melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin (260 ° C.) Shear rate 100 s ^-1 500 s ^-1 1000 s ^-1 2000 s ^-1 Example 1 1.127 0.745 0.678 0.668 Example 2 1.684 1.035 0.920 0.859 Comparative Example 1 3.285 1.710 1.373 1.196 Comparative Example 2 4.910 2.374 1.863 1.539 Comparative Example 3 0.923 0.686 0.639 0.628 Comparative Example 4 2.692 1.574 1.294 1.125

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 : Air pressure holding performance measurement

Tires were manufactured by applying tire inner liner films of Examples and Comparative Examples to 205R / 65R16. In addition, the produced tires were evaluated by measuring the IPR Internal Pressure Retention for 90 days according to the following Formula 2 at 101.3 kPa pressure at 21 ° C. using the ASTM F1112-06 method.

 [Formula 2]

The results of Experimental Example 2 and Experimental Example 3 are shown in Table 2 below.

Results of Experimental Examples 2 and 3 Oxygen permeability Air pressure holding performance unit cc / (㎡, 24hr, atm) % Example 1 60 1.3 Example 2 100 1.8 Comparative Example 1 70 1.4 Comparative Example 2 109 1.9 Comparative Example 3 40 1.2 Comparative Example 4 50 1.1

Experimental Example 4 : Easy measurement of molding

Tires were manufactured by applying tire inner liner films of Examples and Comparative Examples to 205R / 65R16. During the tire manufacturing process, the manufacturing ease and appearance were evaluated after the production of green tires, and the final appearance of the tires after vulcanization was examined.

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

Experimental Example 5 Durability Measurement Experiment

The tire durability measurement method was used to evaluate the tire durability by increasing the load. This durability measurement is performed by two methods, Endurance Test which increases the load by using the Step Load method and High Speed Test which increases the speed, and checks whether there is a crack inside the tire. '

The results of Experimental Examples 4 and 5 are shown in Table 3 below.

Results of Experimental Examples 4 and 5 Green Tire Manufacturing Status
Of
Final tire condition Durability measurement
Endurance Test Durability measurement
High Speed Test Example 1 Good / good Good Good Example 2 Good / good Good Good Comparative Example 1 Good / poor shape crack crack Comparative Example 2 Good / poor shape crack crack Comparative Example 3 Bad shape / bad shape - - Comparative Example 4 Bad shape / bad shape - -

As shown in Table 1, the polyamide-based resin having a relative viscosity (96% solution of sulfuric acid) of 3.3 and the specific copolymer resin (the content of the polyether-based segment were 22.5% by weight and 39% by weight in the base film, respectively). The tire innerliner films of Examples 1 and 2 obtained by using the N ^- Mn ^-A- C-C-C-C-P ^- C-C are the ratio of the melt viscosity (at 260 ° C) of the copolymer to the melt viscosity of the polyamide-based resin, at a shear rate of 1.0 to ^{1 at} a shear rate of ¹⁰⁰ s ⁻¹ . in the range of 2.0, in the range of 500s ^-1 shear rate of from 0.7 to 1.5, the shear rate of 1000s ^-1 in the range of 0.65 to 1.2, the shear rate of 2000s ^-1 was confirmed that the range of 0.65 to 1.1.

In Examples 1 and 2, the polyamide-based resin and the copolymer may be uniformly kneaded and melted with each other to form a base film layer having uniform physical properties in the entire region of the film. As can be seen from the results, the film for tire innerliner of the embodiment using the base film layer not only has excellent moldability, but also has high airtightness and air pressure holding performance.

In contrast, in Comparative Examples 1,2 and 4, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin exceeded 2.5 at a shear rate of 100 s ⁻¹ and a temperature of 260 ° C., and 500 s ⁻ the shear rate and a temperature of 260 ℃ ¹ in that it exceeds 1.5, and the shear rate and a temperature of 260 ℃ of 1000s ^-1 exceeds 1.2, and the shear rate and a temperature of 260 ℃ of 2000s ^-1 exceeds 1.1 check It became.

That is, in the case of forming the base film layer by kneading the polyamide-based resin and the copolymer used in Comparative Examples 1,2 and 4, the melt density is greatly different, so that the mixing is not easy and phase separation between the two components is performed. Symptoms may occur. As confirmed in Experimental Examples 2 and 3, the film for tire innerliner obtained in Comparative Examples 1,2 and 4 not only greatly reduced moldability even when actual tires were produced and tested. There was a problem that cracks occurred even when the durability test was performed.

In Comparative Example 3, the ratio of the melt viscosity of the copolymer to the melt viscosity of the polyamide-based resin was less than 1.0 at a shear rate of 100 s ⁻¹ and a temperature of 260 ° C., and a shear rate of 500 s ⁻¹ and 260. It was confirmed that it was less than 0.7 at the temperature of ° C, and less than 0.65 at the shear rate of 1000 s ^-1 and the temperature of 260 ° C. That is, in the case of kneading the polyamide-based resin and the copolymer used in Comparative Example 3 to form the base film layer, the melting density is greatly different, so that mixing is not easy and phase separation between the two components may occur. In addition, as in the other comparative examples, in the case of Comparative Example 3, not only the moldability is greatly reduced when the actual tire is formed. It was confirmed in Experimental Examples 2 and 3 that the airtightness and pneumatic holding performance were not secured to the extent that actual tires could be applied.

Claims (22)

Polyamide-based resin having a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5; 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,
A film for tire innerliner having a ratio of melt viscosity of the copolymer to melt viscosity of the polyamide-based resin at a shear rate of 1000 s ⁻¹ and a temperature of 260 ° C., from 0.65 to 1.2.
The method of claim 1,
A film for tire innerliner having a ratio of melt viscosity of the copolymer to melt viscosity of the polyamide-based resin at a shear rate of 100 s ⁻¹ and a temperature of 260 ° C. of 1.0 to 2.0.
The method of claim 1,
A film for tire innerliner having a ratio of melt viscosity of the copolymer to melt viscosity of the polyamide-based resin at a shear rate of 2000 s ⁻¹ and a temperature of 260 ° C., from 0.65 to 1.1.
The method of claim 1,
A tire innerliner film having a ratio of melt viscosity of the copolymer to melt viscosity of the polyamide-based resin at a shear rate of 500 s ⁻¹ and a temperature of 260 ° C., from 0.7 to 1.5.
The method of claim 1,
The film for tire innerliners whose relative viscosity (96% solution of sulfuric acid) of the said polyamide resin is 3.2-3.4.
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 resin having a relative viscosity (96% solution of sulfuric acid) of 3.0 to 3.5; And a copolymer comprising a polyamide-based segment and a polyether-based segment; melting and extruding the mixture at 230 to 300 ° C. 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 of the copolymer is 15 to 50% by weight based on the total weight of the base film layer,
The manufacturing method of the film for tire innerliners whose ratio of the melt viscosity of the said copolymer with respect to the melt viscosity of the said polyamide resin is 0.65-1.2 at the shear rate of 1000s <^-1> and 260 degreeC.
15. The method of claim 14,
The manufacturing method of the film for tire innerliners whose ratio of the melt viscosity of the said copolymer with respect to the melt viscosity of the said polyamide resin is 1.0-2.0 at the shear rate of 100s <^-1> and 260 degreeC.
15. The method of claim 14,
The manufacturing method of the film for tire innerliners whose ratio of the melt viscosity of the said copolymer with respect to the melt viscosity of the said polyamide resin is 1.0-2.0 at the shear rate of 500s-1 and the temperature of 260 degreeC.
15. The method of claim 14,
A method for producing a film for tire innerliner having an absolute weight average molecular weight of 50,000 to 300,000 of the copolymer including the polyamide segment and the polyether segment.
15. The method of claim 14,
The method of manufacturing a film for a tire innerliner further comprising the step of mixing the polyamide-based resin and the copolymer in a weight ratio of 6: 4 to 3: 7.
15. The method of claim 14,
The copolymer is a method for producing a film for tire innerliner comprising 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 base film layer,
Method of producing a film for a tire innerliner comprising the step of extruding the mixture into a film having a thickness of 30 to 300 ㎛.
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,
Wherein the step of forming the adhesive layer comprises:
2 to 30% by weight of a condensate of resorcinol and formaldehyde on at least one surface of the base film layer; And applying an adhesive comprising a latex 68 to 98% by weight to a thickness of 0.1 to 20 μm.

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