KR20160116860A - Inner liner film and preparation method of pneumatic tire - Google Patents

Abstract

The present invention relates to an inner liner film including a splice portion joining both ends of the inner liner film via a tie gum comprising 10 to 60 wt% of a butyl-based rubber, and to a producing method of a pneumatic tire comprising a step of raising the inner liner film on a tire forming drum.

Description

TECHNICAL FIELD [0001] The present invention relates to an inner liner film and a pneumatic tire,

The present invention relates to an inner liner film and a method for manufacturing a pneumatic tire

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 . However, when the content of the rubber component and the tire thickness are increased, the total weight of the tire is increased and the fuel economy of the automobile is lowered.

In addition, the rubber components have relatively low heat resistance, and air pockets are formed between the inner rubber of the carcass layer and the inner liner during the vulcanization process of the tire or the running of the vehicle in which repeated deformation occurs at high temperature, There is a problem that the shape and physical properties are changed. In order to bond the rubber components to the curl layer of the tire, a vulcanizing agent or a vulcanization process has to be applied.

Accordingly, various methods have been proposed to reduce the thickness and weight of the inner liner to reduce fuel consumption, and to reduce changes in the form and physical properties of the inner liner that occur during the molding or running of the tire. However, the inner liner obtained by the previously known method has problems such as a manufacturing process or repeated deformation of a tire in which repeated high temperature molding is performed, and the properties of the inner liner are degraded or cracks are generated in the running process of an automobile in which high heat is generated .

The present invention is to provide an inner liner film which has a uniform structure with excellent mechanical properties and a stable structure, and can secure excellent durability and air tightness even in a tire manufacturing process or a running process of an automobile.

Further, it is an object of the present invention to provide an inner liner film and an inner structure of a tire that are uniform in all directions, have a stable structure with excellent physical properties, have excellent mechanical properties, durability and endurance characteristics, The present invention provides a method for manufacturing a pneumatic tire which can secure a holding performance.

In this specification, there is provided an inner liner film including a splice portion for joining both ends of an inner liner film through a tie bar containing 10 to 60 wt% of a butyl rubber.

Further, in the present specification, there is provided a method of manufacturing a pneumatic tire including a step of raising the inner liner film on a tire building drum.

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

According to one embodiment of the present invention, an inner liner film may be provided which includes a splice portion for joining both ends of an inner liner film via a tie bar including 10 to 60 wt% of a butyl rubber.

In the tire manufacturing process, the end of the inner liner film is bonded with an adhesive, a rubber cement component, or the like in order to form a sheet-like inner liner film into a cylindrical shape so that the inner liner film can be wound around the molding drum. Air is structurally easily leaked from the rice part, and the air tightness of the used adhesive or rubber cement component is not sufficient, so that there is a limit in that the air pressure can not be maintained for a long time when using the finally manufactured tire.

Accordingly, the present inventors have found that the rubber composition of the present invention can be obtained by bonding both ends of an inner liner film through a tie gum comprising 10 to 60 wt% of a butyl rubber to form a splice portion, It is possible to prevent a phenomenon in which air is leaked to the splice portion or breakage occurs in the vicinity of the splice portion when the vehicle travels.

If the content of the butyl rubber in the tire gum is less than 10% by weight, it may be difficult to prevent the air from leaking to the splice part when the vehicle is driven while the tire is manufactured. Thus, Rapid reduction can result in increased deformation of the tire and significantly lower fuel economy. If the content of the butyl rubber in the tire gum is more than 60% by weight, the adhesive properties of the tire gum and the adhesion with the inner liner film are lowered, so that breakage or separation of the splice part during tire production and running And cracks and breakage phenomena may occur due to the degradation of the mechanical properties of the tie gauges.

The splice portion refers to a portion where both ends of the inner liner film are joined or overlapped. An example of a rough appearance of such a splice is as shown in FIG.

Specifically, in the splice portion, the tie gauge may be positioned between a portion of one side of one end of the inner liner film and a portion of one side of the other end opposite to the one side.

However, the splice portion refers to a portion where one end and the other end of the inner liner film are joined or overlapped, and is not limited to the portion or area where the tie gum is located. For example, it may be located over the entirety of the tie black splice portion, and may be located with a smaller area or a larger area than the splice portion.

In the inner liner film, the length of the peripheral portion of the tire in the circumferential direction or the circumferential direction of the tire building drum may be 10 mm to 60 mm.

The length of the circumferential portion of the tire in the circumferential direction or the circumferential direction of the tire building drum is too short and the sufficient adhesion between films can not be provided during the production of the tire, The inner air of high pressure from the pneumatic tire can easily flow out to the outside through the short splice portion, which is technically disadvantageous.

If the length of the peripheral portion of the tire in the circumferential direction or the circumferential direction of the tire building drum is too long, the weight of the tire may be increased to reduce the weight saving effect due to application of the film, Stress or deformation is concentrated on the splice part when the vehicle is driven, thereby increasing the noise and vibration during running and increasing the possibility of breakage, which is technically disadvantageous.

On the other hand, the tie black may have a thickness of 0.1 mm to 2 mm.

If the thickness of the tie gauges is too thick, the high-pressure internal air in the finally produced pneumatic tires can easily flow out to the outside on the widened splice portion, and the tie sword of the splice during the tire forming and vulcanization process is high Temperature, and pressure, and may hinder the formation of a uniform shape of the tire.

In addition, if the thickness of the tie gauge is too thin, the adhesive force and the adhesive force for bonding the film in the molding and vulcanization process of the tire are lowered, and the film is widened, making it difficult to manufacture the tire. The breakage is likely to occur at the splice portion, and it is difficult to manufacture uniformly thin tie gauge due to elastic recovery due to the characteristics of the tie gauge.

As described above, it can be located over the entirety of the tie black splice portion, and can be located with a small area or a larger area than the splice portion. Specifically, the length of the tie gauge in the circumferential direction of the tire or the circumferential direction of the tire building drum may be 0.8 to 3 times the length of the splice portion.

10 to 60% by weight of the tie black butyl rubber, 10 to 70% by weight of other rubber components and 1 to 30% by weight of an additive.

The butyl rubber may be a butyl rubber of a kind known to be used for a tire or a tire used for a tire. Specific examples of the butyl rubber include brominated butyl rubber (Br-IIR), chlorinated butyl rubber (Cl-IIR) Halogenated butyl rubber (X-IIR), and non-halogenated butyl rubber (IIR).

Specific examples of such other rubber components include natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), and the like. , Epoxidized natural rubber (ENR), styrene-isoprene-butadiene copolymer rubber (SIBR), or a mixture of two or more thereof.

The additive may include at least one member selected from the group consisting of inorganic fillers, tackifiers, antioxidants, vulcanization accelerators and oils. As the inorganic filler, carbon black, silica, or the like can be used. The tackifier may be a non-reactive phenolic resin, an aromatic hydrocarbon resin, an aliphatic hydrocarbon resin, or a mixture of two or more thereof.

The specific composition of the inner liner film is not limited. For example, the inner liner film may include at least one of a polyamide resin, an elastomer containing a polyamide repeating unit, and the like.

However, it is possible to realize excellent airtightness even with a thin thickness, thereby making it possible to lighten the tire and improve the fuel efficiency of automobile. Also, it has mechanical properties such as excellent moldability, high durability and fatigue resistance, low modulus property and high elasticity In order to secure the elastic recovery rate, the inner liner film is preferably a laminated film of a polyamide resin; A copolymer comprising a polyamide-based segment and a poly-ether-based segment; And an olefin-based polymer compound.

The base film may have low modulus and high toughness at a low temperature, but may have a low modulus and high toughness at a high temperature, so that stress concentration concentration due to an external impact is significantly lowered, And can have excellent endothelial performance even when the propagation speed of cracks is low, such as during winter or when the temperature is low, such as polar regions.

Also, by using the olefin-based polymer compound together with the copolymer comprising the polyamide-based resin and the polyamide-based segment and the polyether-ether-based segment, the base film of the inner liner film It is possible to prevent the phenomenon of crystallization due to high temperature, external impact or deformation, and to maintain the mechanical properties of the inner liner film at a level equal to or higher than that of the inner liner film, to lower the modulus characteristic or to increase the elasticity, Can be improved.

Specifically, the olefin-based polymer compound can improve the softness of the base film and improve the ability to absorb external impact, and can also significantly reduce the modulus of the base film, It is possible to prevent the phenomenon that the internal structure of the compound or the polymer contained in the polymer is changed to crystallize.

The base film may contain 3 wt% to 35 wt%, or 10 wt% to 30 wt% of the olefin-based polymer compound. If the content of the olefin-based polymer compound is too small, the degree of action and effect of the olefin-based polymer compound may be insignificant. If the content of the olefinic polymer compound is too large, the physical properties and effects expressed by the polyamide resin and the copolymer can be reduced. In the case of applying the inner liner film of the embodiment, A decrease in physical properties due to heat may occur.

The olefin-based polymer compound may include an olefin-based polymer or copolymer grafted with an olefin-based polymer, an olefin-based copolymer, a dicarboxylic acid or an acid anhydride thereof, or a mixture of two or more thereof.

The olefin-based polymer may include polyethylene, polypropylene or a mixture thereof.

The olefin-based copolymer may be an ethylene-propylene copolymer or an ethylene-acrylic ester-maleic anhydride terpolymer, an acrylic ester-maleic anhydride copolymer, maleic anhydride functionalized polyolefin, ethylene-butyl acrylate-glycidyl methacrylate (GMA) terpolymer of ethylene, butylacrylate (BA) and glycidylmethacrylate (GMA).

As described above, the olefin-based polymer compound may include an olefin-based polymer or copolymer grafted with a dicarboxylic acid or an acid anhydride thereof. The dicarboxylic acid may be selected from the group consisting of maleic acid, phthalic acid, itaconic acid, , Alkenyl succinic acid, cis-1,2,3,6 tetrahydrophthalic acid, 4-methyl-1,2,3,6 tetrahydrophthalic acid, or a mixture of two or more thereof, and the dicarboxylic acid May be a dicarboxylic acid dianhydride of the above-mentioned examples.

The content of the grafted dicarboxylic acid or its acid anhydride in the olefinic polymer or copolymer grafted with the dicarboxylic acid or an acid anhydride thereof may be 0.3% by weight or more, preferably 0.5% by weight to 3.0% by weight %. ≪ / RTI >

The grafting ratio of the dicarboxylic acid or its acid anhydride can be determined from the results obtained by acid-base titration of the olefinic polymer. For example, about 1 g of the olefin-based polymer compound is placed in 150 ml of xylene saturated with water and refluxed for about 2 hours. A small amount of a 1% by weight thymol blue-dimethylformamide solution is added, and a 0.05 N sodium hydroxide-ethyl alcohol solution To obtain a solution of a dark blue solution. The resulting solution was again in a 0.05N hydrochloric acid / isopropyl alcohol solution until the solution turned yellow to determine its acid value. From this, the dicarboxylic acid grafted to the olefinic polymer compound The amount of acid can be calculated.

The olefin-based polymer compound may have a density of 0.77 g / cm 3 to 0.95 g / cm 3, or 0.80 g / cm 3 to 0.93 g / cm 3.

 On the other hand, the base film may include the polyamide-based resin and a copolymer including the polyamide-based segment and poly-ether-based segment, and may have a relatively low air permeability and a relatively low modulus. Specifically, due to the inherent molecular chain characteristics of the polyamide resin contained in the base film, the inner liner film of the embodiment has an airtightness of about 10 to 20 times at the same thickness as the butyl rubber generally used in a tire And the copolymer is present in a state of being bonded or dispersed among the polyamide based resins to lower the modulus of the base film and to prevent the rigidity of the base film from increasing, It is possible to prevent crystallization.

The polyamide based resin may have a relative viscosity (96% solution of sulfuric acid) of 2.5 to 4.0, preferably 3.2 to 3.8. 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 polyamide based resins usable in the base film include polyamide based resins such as copolymers 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.

On the other hand, the weight average molecular weight of the copolymer including the polyamide segment and the polyether segment may be 30,000 to 500,000, or 70,000 to 300,000, or 90,000 to 200,000. If the weight average molecular weight of the copolymer is less than 30,000, the prepared base film may not have sufficient mechanical properties for use in the inner liner film, and the inner liner film may be difficult to ensure sufficient gas barrier . If the absolute weight average molecular weight of the copolymer exceeds 500,000, the modulus or degree of crystallization of the base film may excessively increase during heating at a high temperature, and it may be difficult to secure the elasticity or elastic recovery rate to be provided as the inner liner film.

The content of the polyether segment in the base film may be 2 wt% to 40 wt%, 3 wt% to 35 wt%, or 4 wt% to 30 wt%.

If the content of the polyether segment is less than 2% by weight of the total amount of the base film, the modulus of the base film or the inner liner film becomes high, so that the moldability of the tire may deteriorate or the physical properties may deteriorate due to repeated deformation. If the content of the polyether segment exceeds 40 wt% of the entire film, the gas barrier required for the tire inner liner is poor, and the tire performance may deteriorate. 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 is increased, so that it may not be easy to produce a uniform film.

The polyamide-based segment of the copolymer may comprise repeating units 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, an arylene group having 6 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 or an arylene group having 6 to 20 carbon atoms, R ₃ is a linear or branched alkylene group having 1 to 20 carbon atoms, an alkylene group having 6 to 20 carbon atoms Or a linear or branched alkylene group having 7 to 20 carbon atoms.

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-.

In the base film, the polyamide based resin and the copolymer comprising the polyamide based segment and the poly-ether based segment may be used in a ratio of 9: 1 to 1: 9, or 2: 8 to 8: 2 By weight. If the content of the polyamide resin is too small, the density or airtightness of the base film may be lowered. If the content of the polyamide resin is too large, the modulus of the base film may be excessively high or the moldability of the tire may be deteriorated. In a high temperature environment occurring in a tire manufacturing process or an automobile running process, And a crack can be generated by repeated deformation.

The base film may have a thickness of 30 to 300 mu m, preferably 40 to 250 mu m, more preferably 40 to 200 mu m. Accordingly, the inner liner film of one embodiment of the invention may have a low air permeability, for example, an oxygen permeability of 200 cm 3 / (m 2 24 hr 揃 atm) or less, while being thinner than previously known.

On the other hand, the base film may further include a heat resistant agent. As the base film further includes a heat resistant agent, it is possible to prevent chain breakage of the polymer due to the heat involved in the film production process or the tire production process and to inhibit radical generation by pyrolysis, Even if it is left for a long time or exposed, the physical properties thereof are not significantly deteriorated.

The base film may contain 0.005 wt% to 2.50 wt% of the heat resistant agent, or 0.01 wt% to 1.00 wt%. If the content of the heat resistant agent is too small, the effect of improving heat resistance may be insignificant. If the content of the heat resisting agent is too large, the physical properties of the base film may be deteriorated, and the effect of improving the heat resistance depending on the content of the base film may be substantially lowered, thereby unnecessarily raising the price of the final product.

Specific examples of such heat resisting agents include aromatic amine compounds, hindered phenol compounds, phosphorus compounds, inorganic compounds, polyamide compounds, polyether compounds, or a mixture of two or more thereof. Such a heat resisting agent may be applied in the form of a powder or a liquid in the manufacturing method described later.

Specific examples of the hindered phenol compound include N, N'-hexamethylenebis (3,5-ditertiary-4-hydroxy-hydrosinamide) or pentaerythritol tetrakis 3- (3,5- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate as a commercially available product, and Irganox 1010 as a commercially available product. Examples of possible hindered phenol compounds are not limited thereto.

Specific examples of the aromatic amine compound include 2,2,4-trimethyl-1,2-dihydroquinoline or a polymer thereof, phenyl? -Naphthylamine, phenyl-? -Naphthylamine, aldol-? -Naphthylamine N, N'-bis (1-ethyl-3-methylphenyl) -p-phenylenediamine, p-iso-propoxyldi Phenylamine, 6-ethoxy-2,2,4-trimethyl 1,2-dihydroquinoline, N-phenyl-N'-isopropyl-para-phenylenediamine, di-beta-naphthyl- (3, 3, 5-di-tert-butyl) -4- (4-methylphenyl) Hydroxyphenyl-propionamide) or a mixture of two or more thereof. However, examples of the aromatic amine compound usable as the heat resisting agent are not limited thereto.

Specific examples of the phosphorus compound include triphenyl phosphate (TPP), triaryl phosphate, aromatic phosphate ester, 2-ethylhexyldiphenyl phosphate, triethylene phosphate, tricresyl phosphate (TCP), cresylphenyl phosphate, chlorethyl phosphate , Tris-β-chloropropyl phosphate, tris-dichloropropyl phosphate, halogen-containing condensed phosphate esters, aromatic condensed phosphoric acid esters, polyphosphates, red phosphorus or a mixture of two or more thereof. Examples of the phosphorus compounds usable as the heat resisting agent But is not limited thereto.

Specific examples of the inorganic compound include iodinated compounds such as Mg (OH) 2, Al (OH) 2, Sb2O3, guanidine salt, Sb2O5, zinc borate, molybdenum compound, zinc stearate, CuI or KI, .

Even when a mixture of CuI and KI is used as the heat resisting agent, the heat resistance of the base film can be greatly improved, and even when exposed to a high temperature for a long time or exposed, the change in physical properties of the base film itself is not large.

When a mixture of CuI and KI is used as the heat resisting agent, 0.05 to 0.6% by weight of the mixture may be used. And, the content of copper (Cu) in the mixture of CuI and KI may be 5 to 10 wt%.

Even when a mixture of CuI and KI is used, the content of the heat resisting agent used can be greatly reduced (for example, 0.05 to 0.6% by weight in the base film) Heat resistance can be greatly improved.

Meanwhile, the inner liner film of one embodiment may further include an adhesive layer formed on at least one side of the base film and including a resorcinol-formalin-latex (RFL) -based adhesive.

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 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 one surface or both surfaces of the inner liner film Lt; / RTI >

According to another embodiment of the present invention, there is provided a method of manufacturing a pneumatic tire including a step of raising the above-described inner liner film on a tire building drum.

As described above, the inner liner film of the one embodiment may have a cylindrical shape by including a splice portion for joining both ends of the inner liner film through a tie bar containing 10 to 60 wt% of butyl rubber , The pneumatic tire can be manufactured by raising such an inner liner film on a tire building drum.

In the step of raising the inner liner film on the tire building drum, the inner liner film is formed by laminating a cylindrical inner liner including a splice portion for joining both ends of the inner liner film via a tie bar containing 10 to 60 wt% The step of raising the film on a forming drum or the step of wrapping the inner liner film on the forming drum and bonding both ends of the inner liner film to each other via a tyram containing 10 to 60% by weight of a butyl rubber .

That is, in the method of manufacturing the pneumatic tire, the inner liner film may be placed on the molding drum in a state in which the splice portion is formed, and the splice portion may be formed after the inner liner film is wrapped around the molding drum.

According to the manufacturing method of the pneumatic tire, the inner liner film and the inner structure of the tire are uniform, excellent in physical properties and stable structure in all directions, and the pneumatic tires manufactured in the tire manufacturing process It is possible to secure physical properties, durability, endothelial characteristics and improved air pressure maintenance performance.

The method of manufacturing the pneumatic tire may use the method, condition, and apparatus used in a conventional pneumatic tire manufacturing process without any limitation, except that the inner liner film is used.

The method of manufacturing an air-inlet tire includes the steps of: forming a carcass layer on the inner liner film; Attaching a bead wire to an end of the laminate including the inner liner and the carcass layer in the width direction of the forming drum; Forming a belt portion on the tire building drum raised laminate; Forming a cap ply on the belt portion; And forming a rubber layer for forming a tread portion, a shoulder portion, and a side wall portion on the formed belt portion.

According to the present invention, there is provided an inner liner film which has a uniform structure with excellent mechanical properties and a stable structure and which can ensure excellent durability and air tightness even in a tire manufacturing process or a running process of an automobile, and an inner liner film and an inner structure of a tire The present invention provides a method for manufacturing a pneumatic tire capable of securing uniform mechanical properties along with good physical properties and stable structure and securing excellent mechanical properties, durability, endurance characteristics and improved air pressure maintenance performance in tire manufacturing process and automobile driving process .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a step of forming a splice portion of an inner liner film of an example of the invention.
Fig. 2 schematically shows the structure of a pneumatic 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  And Comparative Example : Inner liner  Preparation of film]

< Example 1 >

(One) Preparation of base film

(nylon 6) having a relative viscosity of 3.4 (96% solution of sulfuric acid) prepared from epsilon -caprolactam and a copolymer resin having a weight average molecular weight of about 95,000 (copolymer having a poly (tetramethylene oxide) (0.7 weight%) ethylene-propylene copolymer (density: 0.870 g / cm &lt; 3 &gt;) grafted with maleic anhydride) 1 part by weight of the oxazoline compound and 10 parts by weight of the heat resisting agent [copper (Cu) content in the mixture of copper iodide and potassium iodide - 7% by weight] relative to 100 parts by weight of the mixture] Was added to prepare a mixture for preparing a base film.

Then, the mixture was extruded at 255 DEG C while maintaining a uniform molten resin flow through a T-die (Die Gap - 0.9 mm), and melted on a surface of a cooling roll controlled at 20 DEG C using an air knife The resin was cooled and solidified on a film having a uniform thickness. Then, an unoriented base film having a thickness of 100 mu m was obtained without passing through a stretching and heat treatment section at a speed of 10 m / min.

(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. A resorcinol-formalin-latex (RFL) -based adhesive having a concentration of 25% was obtained by mixing 15% by weight of the condensate of resorcinol and formaldehyde and 85% by weight of styrene / butadiene-1,3 / vinylpyridine latex.

The resorcinol-formalin-latex (RFL) -based adhesive was coated on both sides of the unstretched substrate film using a gravure coater and dried and reacted at 150 ° C for 1 minute to form an adhesive layer having a thickness of 2.5 μm on both sides To prepare an inner liner film.

(3) Formation of the splice portion

Using a 0.5 mm thick tie gauge, a splice portion was formed so that both ends of the prepared inner liner film were overlapped by 15 mm. At this time, 20 wt% of the tie black butyl rubber, 40 wt% of natural rubber, 27 wt% of carbon black, 1 wt% of paraffin oil, 1 wt% of zinc oxide, and 1 wt% of stearic acid were included.

(4) Manufacture of pneumatic tire

The inner liner film having the cylindrical portion formed with the spit portion is sandwiched between the drum for tire molding and the rubber for forming the carcass layer, the bead wire, the belt portion, the cap fly portion and the outer rubber layer are laminated successively, Of the inner liner film was placed on a molding drum, and a splice portion was formed thereon to prepare a tire. The manufactured tires were 225 / 45R17 riding tires. Nylon 66 1260/2 was used as the body fly and polyester 1300De '/ 2 and cap fly.

Example 2

Except that 30 g of butyl rubber, 30 g of natural rubber, 27% of carbon black, 1 wt% of paraffin oil, 1 wt% of zinc oxide and 1 wt% of stearic acid was used. An inner liner film was produced in the same manner and a splice portion was formed, and a pneumatic tire was produced.

Example 3

An inner liner film was produced in the same manner as in Example 1 except that a splice portion was formed so that both ends of the prepared inner liner film were overlapped with each other by using a 0.5 mm thick tie gum to form a splice portion And pneumatic tires were produced.

Example 4

An inner liner film was prepared in the same manner as in Example 1 except that a splice portion was formed so that both ends of the prepared inner liner film were overlapped with each other using a 1.0 mm thick tie gum to form a splice portion And pneumatic tires were produced.

Example 5

The resulting inner liner film was overlapped with 15 mm at both ends (splice portion), and a tie having a thickness of 0.5 mm was formed so as to expose the tie gauge to a portion of 10 mm in the circumferential direction standard length of the tire continuously to the splice portion An inner liner film was produced in the same manner as in Example 1 except that an inner liner film was bonded using a sword, and a splice portion was formed to produce a pneumatic tire.

Comparative Example 1

An inner liner film was produced in the same manner as in Example 1 except that 60 g of natural rubber, 37 g of carbon black, 1 wt% of paraffin oil, 1 wt% of zinc oxide and 1 wt% of stearic acid were used. To form a splice portion, and pneumatic tires were produced.

Comparative Example 2

An inner liner film was prepared in the same manner as in Example 1, except that a tie gum consisting of 97 wt% of butyl rubber, 1 wt% of paraffin oil, 1 wt% of zinc oxide and 1 wt% of stearic acid was used and a splice portion was formed And pneumatic tires were produced.

Reference example

An inner liner compound containing 50 wt% of butyl rubber, 27 wt% of carbon black, 20 wt% of fiber filler and 1 wt% of paraffin oil, 1 wt% of zinc oxide and 1 wt% of stearic acid was rubber- A film was prepared, placed on a molding drum, and then a 15 mm splice portion was formed through pressure without using a tie gauge.

Then, a carcass layer or the like was bonded to produce the same tire standard as in Example 1.

< Experimental Example : Inner liner  Measurement of physical properties of film>

Experimental Example 1 : Air pressure maintenance performance

Using the ASTM F1112 manufactured tire, air pressure of 40 psi was injected into three tires for each of the examples and comparative examples, and the amount of air loss was measured for 3 months, and the average value of the air pressure reduction percentage was obtained.

Experimental Example 2 : Tire Weight Index

The weight of the manufactured tire was measured, and when the general butyl rubber inner liner used in the reference example was used, the weight was expressed as 100, and the tire weight index of the tire of the other examples and the comparative example was added to 100 as compared with the comparative example.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Reference example tire
Weight index 108 108 107.5 107.5 108 108 Tire manufacturing failure 100 windage
Maintenance performance 180 190 200 150 200 105 Tire manufacturing failure 100

- The reference tire weight is 10.8 kg.

As shown in Table 1, in Examples 1 to 5, it was confirmed that the application of the inner liner film of the thin film showed a reduction in weight of the entire tire by about 8% as compared with the application of the butyl rubber inner liner of Reference Example . On the other hand, even in the case of using the same inner liner film as in Example 1, in Comparative Example 1 where only natural rubber was used for tire gum without using butyl rubber, the air pressure holding performance was not sufficiently improved, In the case of Comparative Example 2 composed of only rubber, it was confirmed that sufficient adhesion / adhesion was not exhibited and tire production was impossible.

That is, as can be seen from the results of the experiment on the pneumatic tire to which the inner liner film of Examples 1 to 5 was applied, it was confirmed that the length of 10 mm in the circumferential direction of the tire building drum was 10 It is confirmed that the channel or part through which the air passes in the pneumatic tire is minimized and the air pressure holding performance is dramatically increased.

Claims (17)

And a splice portion for joining both ends of the inner liner film via a tie bar including 10 to 60 wt% of butyl rubber.
The method according to claim 1,
Wherein the tie gum is positioned between a portion of one surface of one end of the inner liner film and a surface of the other surface opposite to the one surface of the inner liner film in the splice portion.
The method according to claim 1,
Wherein an inner circumferential direction of the tire or a length of a splice portion in the circumferential direction of the tire building drum is 10 mm to 60 mm.
The method according to claim 1,
Wherein the length of the tie gauge in the circumferential direction of the tire or the circumferential direction of the tire building drum is 0.8 to 3 times the length of the splice portion.
The method according to claim 1,
Said inner liner film having a thickness of from 0.1 mm to 2 mm.
The method according to claim 1,
10 to 60 wt.% Of the tie black butyl rubber, 10 to 70 wt.% Of other rubber components and 1 to 30 wt.% Of an additive.
The method according to claim 6,
The other rubber component is composed of natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), epoxidized natural rubber (ENR), and styrene-isoprene-butadiene copolymer rubber Lt; RTI ID = 0.0 &gt; liner &lt; / RTI &gt; film.
The method according to claim 6,
Wherein the additive comprises at least one member selected from the group consisting of an inorganic filler, a tackifier, an antioxidant, a vulcanization accelerator and an oil.
The method according to claim 1,
Wherein the inner liner film comprises a polyamide based resin; A copolymer comprising a polyamide-based segment and a poly-ether-based segment; And an olefin-based polymer compound.
10. The method of claim 9,
Wherein the content of the polyether segment in the base film is 2% by weight to 40% by weight.
10. The method of claim 9,
Wherein the relative viscosity (96% solution of sulfuric acid) of the polyamide resin is 2.5 to 4.0.
10. The method of claim 9,
Wherein the copolymer comprising the polyamide-based segment and the polyether-based segment has a weight average molecular weight of 30,000 to 500,000.
10. The method of claim 9,
Wherein the olefinic polymer compound comprises at least one compound selected from the group consisting of an olefinic polymer, an olefinic copolymer, and an olefinic polymer or copolymer grafted with a dicarboxylic acid or an acid anhydride thereof.
10. The method of claim 9,
Wherein the inner liner film comprises 3 to 35% by weight of the olefin-based polymer compound.
10. The method of claim 9,
Further comprising an adhesive layer formed on at least one side of the inner liner film and comprising a resorcinol-formalin-latex (RFL)
A method for manufacturing a pneumatic tire, comprising the step of raising the inner liner film of claim 1 on a tire building drum.
17. The method of claim 16,
Forming a carcass layer on the inner liner film;
Attaching a bead wire to an end of the laminate including the inner liner and the carcass layer in the width direction of the forming drum;
Forming a belt portion on the tire building drum raised laminate;
Forming a cap ply on the belt portion; And
And forming a rubber layer for forming a tread portion, a shoulder portion, and a side wall portion on the formed belt portion.

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