KR20170038401A - Polymer film and preparation method thereof - Google Patents

Abstract

The present invention relates to a polymer film and a production method thereof. The polymer film comprises a base material film layer including: at least two or more base films; and a bonding layer positioned between the adjacent base material films, wherein an included angle between the machine direction of the adjacent base material films is 60 to 120.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer film,

The present invention relates to a polymer film and a method of manufacturing a polymer film. More specifically, the present invention provides a polymer film and a polymer film having excellent airtightness even with a thin thickness, To a polymer film having high durability and endothelial property against external stress or repeated deformation, and a method for producing the polymer film.

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 a fiber / steel / rubber and 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, any previously known method has had a limitation in maintaining excellent air permeability and moldability of the tire while sufficiently reducing the thickness and weight of the inner liner. In addition, the inner liner obtained by the previously known method has a problem in that the properties of the inner liner itself deteriorate in the manufacturing process of the tire in which the high temperature repetitive molding is performed or the repeated process of deformation, .

The present invention realizes excellent airtightness even with a thin thickness, thereby making it possible to lighten the tire and improve the fuel efficiency of the automobile. It has uniform physical properties in all regions and all directions, and has high durability against endurance and repeated deformation, And a polymer film comprising the same.

The present invention also provides a method for producing the polymer film.

In the present specification, at least two substrate films; And a bonding layer positioned between adjacent base films, wherein a polymer film having an angle of 60 DEG to 120 DEG between machine directions of the adjacent base films is provided do.

Also, in the present specification, a substrate film layer forming step including a step of laminating at least two substrate films arranged so as to have an angle of 60 ° to 120 ° between machine directions via a bonding layer A method for producing a polymer film is provided.

Hereinafter, a method for producing a polymer film and a polymer film according to a specific embodiment of the present invention will be described in detail.

According to one embodiment of the invention, at least two substrate films; And a bonding layer positioned between adjacent base films, wherein a polymer film having an angle of 60 DEG to 120 DEG between machine directions of the adjacent base films is provided .

The inner liner deforms in various processes such as tire forming and vulcanization by air injection. In particular, the radial direction and the circumferential direction of the tire cause deformation Is particularly large. Generally, the deformation rate in the circumferential direction of the tire is much higher than the radial direction of the tire. As a result, there is a large difference in orientation between the two directions due to the deformation by the tire manufacturing process, Resulting in uneven physical properties and relatively poor physical properties. As the external stress concentrates on such a weak physical property, the inner liner may be damaged or broken, and it may become difficult to secure the durability and the endothelial characteristic required of the tire.

Thus, the present inventors have found that when two or more base films are crossed with each other in machine direction so that the angle between the machine direction of neighboring base films is 60 ° to 120 °, When the polymer film is used as an inner liner of a tire, it is possible to realize excellent airtightness even with a thin thickness to lighten the tire and improve the fuel efficiency of the automobile, and the polymer film has uniform physical properties in all regions and all directions, And it has high durability and endothelial characteristics against stress and repeated deformation.

The polymer film including the base film layer can have uniform modulus and heat shock resistance characteristics in all directions, maximizing the dispersion effect on the stress externally applied, and thus reducing heat generation and durability due to stress concentration Can be minimized. In particular, the polymer film of the embodiment can uniformly disperse the residual stress applied to the polymer film in all directions during the molding process and the vulcanization process due to the uniform modulus characteristic in all directions, A higher moldability can be secured in the tire manufacturing process.

In addition, the polymer film of one embodiment has a good dispersion effect on external stress, and has a uniform residual stress in all directions. Therefore, even when repeatedly deformed and subjected to a high temperature, It is possible to exhibit excellent durability and endothelial property by suppressing crack propagation and propagation of generated cracks.

Accordingly, the polymer film of the embodiment can exhibit a uniform thickness and physical properties without any difference in thickness or physical properties in a specific direction in the finished tire, and the elasticity is not significantly decreased, so that crystals are formed in the film, And the like can be prevented. That is, the polymer film can secure the mechanical properties, durability, or endothelial properties necessary for the tire manufacturing process and the vehicle running process.

As described above, the base film layer may include at least two or more base film, and the base films may be laminated via a bonding layer.

The angle between the machine directions of the adjacent base films among the base films included in the base film layer may be 60 ° to 120 °, or 80 ° to 100 °, or 90 °. That is, in the film for inner liers of the embodiment, two adjacent substrate films may be arranged such that the machine direction is perpendicular (90 °) to each other, or at an angle of up to 30 ° in the vertical (90 °) And can be arranged to be turned off.

The angle between the machine direction of two neighboring substrate films means an angle formed by the machine direction of one base film and the machine direction of the one base film and the neighboring base film. For example, as shown in FIG. 2, the angle a between the adjacent two substrate films may be defined as an angle between the machine direction of two adjacent substrate films.

The machine direction (MD) of the base film refers to a direction in which a raw material of the base film is melted and extruded and is discharged in the form of a film, and a direction perpendicular to the machine direction is referred to as a transverse direction Direction).

Generally, the mechanical and transverse directions of the base film differ in heat resistance modulus or heat-aged impact strength. The modulus of heat resistance and the heat-resistant impact strength were measured in the machine direction (MD) and the transverse direction (TD) of the substrate film immediately after heat treatment for 30 minutes and 1 hour at 170 占 폚 in a hot air oven, It may be measured by using an Instron and Impact Tester.

On the other hand, each of the base films may be a polyamide based resin; And a copolymer including a polyamide-based segment and a polyether-based segment; and at least one compound selected from the group consisting of: More specifically, each of the base films may comprise a polyamide based resin; And copolymers comprising polyamide-based segments and polyether-based segments.

The polyamide based resin may have a relative viscosity (96% sulfuric acid solution) of 2.5 to 4.0, or 3.2 to 3.8.

If the relative viscosity of the polyamide resin is less than 2.5, a sufficient elongation can not be secured due to a reduction in toughness, which may cause breakage during tire manufacturing or automobile operation, and the crystallization rate with respect to heat is increased, Brittleness) The effect of crystallization delay through the phenomenon control can not be fully demonstrated.

When the relative viscosity of the polyamide resin is more than 4.0, the modulus or viscosity of the base film to be produced may be unnecessarily high, the efficiency and economical efficiency of the production process may be deteriorated, It may be difficult to have elasticity, and miscibility with a copolymer containing a polyamide segment and a polyether segment may deteriorate, resulting in uneven physical properties of the base film.

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).

Specific examples of the polyamide resin include nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, copolymers of nylon 6/66, nylon 6/66/610 copolymers, 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 may be preferably used.

In addition, the polyamide resin that may be contained in each of the base films may include a polyamide-based copolymer containing two or more different repeating units.

The polyamide-based copolymer may contain two or more different repeating units, and at least one of the repeating units of the polyamide-based copolymer may include a repeating unit represented by the following formula (1).

[Chemical Formula 1]

The polyamide-based copolymer may further include a repeating unit represented by the following general formula (2) or (3) other than the repeating unit represented by the general formula (1).

(2)

In Formula 2, R ₁ is a straight or branched alkylene group having 2 to 4 carbon atoms or 6 to 15 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a linear or branched alkylene group having 7 to 20 carbon atoms Alkylene group.

(3)

In Formula 3, R ₂ is an alkylene group of a straight-chain or branched-chain having 1 to 20 carbon atoms, R ₃ is arylene (arylene) group having 1 to 20 carbon atoms an alkylene group of a straight or branched, having from 6 to 20 carbon atoms group, or Chain or branched alkylene group having 7 to 20 carbon atoms.

The polyamide-based copolymer may contain 0.5 to 20% by weight or 1 to 18% by weight of the repeating unit represented by the formula (2).

In addition, the polyamide-based copolymer may contain 0.5 to 20% by weight, or 1 to 18% by weight, of the repeating unit represented by the formula (3).

The polyamide-based copolymer may be synthesized using two or more kinds of monomers or may be obtained by copolymerizing two or more kinds of polyamide-based polymers.

Specifically, the polyamide-based copolymer may contain, in addition to caprolactam, 2-azetidinone, 2-pyrrolidone, δ-Valerolactam, 1-Aza-2-Cyclooctanone, 2-Azacyclononanone, 10-Aminodecanoic acid, -Aminoundecanoic acid, Laurolactam, or a mixture thereof as a monomer, and may be synthesized by using a dicarboxylic acid and a diamine compound selectively.

Examples of usable carboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, isophtalic acid, terephthalic acid or a mixture thereof. Examples of the usable diamine compound include 1,4-diaminobutane, 1,5-diaminopentane, hexamethylene diamine, 1,7-diaminoheptane, 1,8-diaminooctane, 1,10-decanediamine, m- .

The polyamide-based copolymer may also be synthesized by copolymerizing a polymer containing a repeating unit of the formula (1) and a polymer containing a repeating unit of the formula (2) or (3).

On the other hand, the copolymer containing the polyamide segment and the polyether segment may have a weight average molecular weight of 30,000 to 500,000, or 70,000 to 300,000.

In the present specification, the weight average molecular weight refers to the weight average molecular weight in terms of polystyrene measured by the GPC method.

If the weight average molecular weight of the copolymer is less than 30,000, the polymer film may not have sufficient mechanical properties to be used as an inner liner. When the weight average molecular weight of the copolymer exceeds 500,000, The modulus or crystallinity of the polymer film may excessively increase and it may be difficult to ensure the elasticity or elastic recovery rate that the polymer film should have as an inner liner.

The polyamide segment of the copolymer may comprise repeating units of the following formula (11) or (12).

(11)

In Formula 11, 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.

[Chemical Formula 12]

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 arylene group having 6 to 20 carbon atoms, or a linear or branched alkylene group having 7 to 20 carbon atoms.

On the other hand, the polyether-based segment of the copolymer means a repeating unit containing an alkylene oxide ('-Akyl-O-') group, and is formed from a polyether-based resin participating in the polymerization reaction or a precursor thereof .

The polyether segment of the copolymer may be a main repeating unit that may be contained in the polyalkylene glycol resin or derivative thereof, wherein the polyalkylene glycol derivative is a polyalkylene glycol derivative in which the terminal of the polyalkylene glycol resin is an amine group, An isocyanate group or the like, preferably an amine group-substituted derivative. Preferably, the polyether segment of the copolymer is selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylenediamine, polyoxypropylenediamine, polyoxytetramethylenediamine, and copolymers thereof It may be a main repeating unit contained in one type of polyether resin.

In addition, the polyether segment of the copolymer may contain a repeating unit represented by the following formula (13).

[Chemical Formula 13]

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

Refers to a divalent functional group derived from an 'alkylene' group alkyl group, arylene refers to a divalent functional group derived from arene, and 'arylalkylene' Means a divalent functional group derived from an alkyl group into which an aryl group is introduced.

On the other hand, if the content of the polyether segment is 2 wt% to 40 wt%, or 3 wt% to 35 wt%, or 4 wt% to 30 wt%, or 5 wt%, based on the total weight of the base film included in the base film layer, By weight to 25% by weight. The content of the polyether segment relative to the total weight of the base film included in the base film layer is preferably in the range of 1 to 10 parts by weight based on the total weight of the base film included in the base film layer, As a ratio of the total weight of the resin particles.

 If the content of the polyether segment is less than 2% by weight of the total amount of the base film layer, the modulus of the base film layer or the polymer 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% by weight of the entirety of the base film layer, the airtightness of the polymer film may be lowered, and the elasticity of the base film layer may increase to make it difficult to produce a uniform film have.

The content of the polyether segment in each of the base films may be 2 to 40% by weight.

On the other hand, each of the base films may be a polyamide based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment, in a ratio of from 9: 1 to 1: 9, or from 8: 2 to 2: 8.

Each of the base films may have a thickness of 2 탆 to 400 탆, or 4 탆 to 200 탆, or 10 탆 to 150 탆.

Further, the thickness of the base film layer may be 5 占 퐉 to 1000 占 퐉, or 20 占 퐉 to 800 占 퐉, or 50 占 퐉 to 500 占 퐉.

The bonding layer is positioned between neighboring substrate films and serves to bond the two substrate films. As a specific material of the bonding layer, a common tire known to be usable for the production of a tire can be used.

For example, a coloring agent such as the tie black rubber, carbon black, and sulfur. Specific examples of the rubber included in the tie gums include natural rubber and synthetic rubber, and more specifically natural rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber, chloroprene rubber, styrene / butadiene / vinylpyridine A rubber containing one kind or a mixture of two or more kinds may be used. In addition to the coloring agent such as the tie black rubber and the carbon black, and the sulfur, it may further include an additive such as an adhesive, zincation, stearic acid or an antioxidant.

When an example of the specific composition of the tire gum is shown, 25 to 60% by weight of natural rubber; 0 to 15 wt% of styrene / butadiene rubber, 0 to 20 wt% of butyl rubber, 20 to 40 wt% of carbon black, 2 to 5 wt% of process oil, 1 to 3 wt% of a pressure sensitive adhesive, 1 to 5 wt% 0.1 to 0.5% by weight, and 1 to 5% by weight of other compounding agents (zincification, stearic acid, antioxidant, etc. used in conventional rubber formulations). However, the tie black of such a specific component is merely an example of a known tie gum component, and the specific components of the tie gum usable in the polymer film of this embodiment are not limited thereto.

The bonding layer may have a thickness of 1 to 200 mu m, or 10 to 150 mu m, or 20 to 100 mu m.

Each of the base films may further include at least one additive selected from the group consisting of a heat resistant agent, a cross-linking agent, and an antioxidant. Such an additive may be contained in each of the base films in an amount of 0.001 wt% to 5 wt%.

The base film may be an unstretched film that is not substantially stretched. When the base film is in the form of an unstretched film, it can be suitably applied to a tire forming process in which high expansion occurs due to low modulus and high strain. Since the crystallization phenomenon hardly occurs in the unstretched film, it is possible to prevent damage such as cracking even by repeated deformation, and since the orientation and physical property deviations in specific directions are not large, the inner liner Can be obtained.

The polymer film may further include an adhesive layer formed on at least one surface of the base film and including a resorcinol-formalin-latex (RFL) -based adhesive.

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

The above-mentioned resorcinol-formalin-latex (RFL) -based adhesive is capable of crosslinking between latex and rubber to exhibit adhesion performance. Since it is a latex polymeric material physically, it has low hardenability and can have a flexible property like rubber. Chemical bonding between the methylol end group of the kn-formalin polymer and the substrate film is possible. Accordingly, when the above-mentioned resorcinol-formalin-latex (RFL) -based adhesive is applied to the base film, it is possible to realize a satisfactory adhesive property and high moldability and elasticity.

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

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

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

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

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 polymer film As shown in FIG. When the thickness of the adhesive layer is too thin, the adhesive layer itself may become thinner when the tire expands, and the crosslinking adhesion between the carcass layer and the base film or between the base film included in the base film layer may be lowered, So that the fatigue characteristics can be lowered. In addition, if the adhesive layer is too thick, the interface separation in the adhesive layer may occur and the fatigue characteristics may be deteriorated.

In order to adhere the inner liner film to the carcass layer of the tire, an adhesive layer is generally formed on one surface of the base film. However, in the case of the polymer film of the embodiment in which the inner liner film is applied to multiple layers, An adhesive layer may be formed on both surfaces of the base film for securing adhesion with the bonding layer.

According to another embodiment of the present invention, there is provided a method for manufacturing a base film, comprising the steps of: laminating at least two base films through a bonding layer such that an angle between the machine directions is 60 ° to 120 °; ; And a method of producing a polymer film.

The polymer film including the base film layer prepared by arranging the two substrate films adjacent to each other such that the angle between the machine direction of the two base film films is 60 ° to 120 ° and laminating them via the bonding layer, The polymer film is uniform in physical properties in all regions and all directions and has high durability and endurance characteristics against external stress or repeated deformation. .

As in the method of manufacturing the polymer film of the embodiment, the angle between the machine directions of the adjacent base films is 60 ° to 120 °, or 80 ° to 100 °, or 90 °, Therefore, the polymer film including the base film layer can have uniform modulus and heat-resistant impact strength characteristics in all directions, maximizing the dispersion effect on the stress externally applied, and thereby improving heat generation and durability So that the degradation can be minimized. Specifically, the polymer film provided according to the above manufacturing method can uniformly disperse the residual stress applied to the polymer film during the molding process and the vulcanization process due to the uniform modulus characteristic in all directions , So that higher moldability can be secured in the tire manufacturing process.

In addition, the polymer film provided according to the above-described method has an excellent dispersion effect against external stress and has a uniform residual stress in all directions. As a result, It is possible to suppress the occurrence of cracks due to heat generation and the propagation of generated cracks, thereby exhibiting excellent durability and endothelial property.

 In the film for inner liers provided according to the above manufacturing method, two adjacent substrate films are arranged so that the machine direction is perpendicular (90 DEG) to each other, or an angle of at most 30 DEG in the vertical (90 DEG) As shown in FIG.

The definition of the angle between the machine direction of two neighboring substrate films includes the above-mentioned content regarding the polymer film of the embodiment.

The base film layer forming step may include sequentially or at least two or more of the at least two base film layers. That is, in the base film layer formation step, two or more base film layers can be sequentially laminated via a bonding layer, and two or more base film layers are arranged at an angle between the machine directions described above, Whereby a base film layer can be formed.

The bonding layer serves to bond the two base films to each other between adjacent base films, and as a specific material of the bonding layer, a common tire known to be usable for the production of a tire can be used .

The specific composition of the tie gauge includes the above-mentioned contents with respect to the polymer film of the embodiment.

In addition, the base film layer forming step may further include laminating a base film having a thickness of 1 to 200 탆 between at least two base films.

That is, in the process of arranging the at least two base films so that the angle between the machine directions is 60 ° to 120 ° and laminating the base films through the bonding layer, Such tie bars may be in the form of sheets commonly known.

An example of a step of laminating a base film having a thickness of 1 占 퐉 to 200 占 퐉 between the at least two base films is as follows:

The tie gum is laminated with a base film at room temperature to form a bonding layer on one side of the base film and is cut to fit the tire molding size and then the base layer film is laminated on the basis of the machine direction of the base film of the first layer And the machine direction of the base film of the second layer is sequentially laminated, wherein the angle between the base film of the first layer and the machine direction of the base film of the second layer is 60 to 120 degrees And a laminate is formed so that only one bonding layer exists between the base films. When the base film of the third layer is continuously laminated, the angle between the machine direction and the machine direction (Machine Direction) is 60 to 120 °, and the base film of the second layer and the third layer And lamination is performed so that only one bonding layer exists between the base films. A base film layer can be produced by laminating a base film by the same method as described above. At this time, a bonding layer is present on one surface of the laminated base film layer, and a tire of the base film layer is brought into contact with the carcass layer of the tire during the production of the tire. Also, the present invention can be applied to a tire after joining a base film that is not laminated with a bonding layer on a bonding layer present in the base film layer so that the bonding layer does not exist on both sides of the final base film layer.

The content of each of the base film, the content of the base film layer, the specific content of the polyamide-based resin and the copolymer containing the polyamide-based segment and the polyether-based segment will be described in detail with reference to the polymer film of the embodiment As shown above.

On the other hand, the method for producing the polymer film of the embodiment is a polyamide-based resin; And a copolymer including a polyamide-based segment and a polyether-based segment; and melting and extruding at least one compound selected from the group consisting of a polyamide-based segment and a polyether-based segment at 200 to 300 ° C to form a base film.

The melting temperature should be higher than the melting point of the polyamide compound. However, if the melting temperature is too high, carbonization or decomposition may occur to deteriorate the physical properties of the film, and bonding or orientation between the polyether resin may occur to produce an unstretched film It can be disadvantageous.

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

On the other hand, the step of forming the base film may include a step of extruding the mixture into a film having a thickness of 2 m to 400 m. The thickness of the produced film may be controlled by controlling the extrusion conditions such as the extruder discharge amount or the gap of the extrusion die, or by changing the winding speed of the extrudate during the cooling process or the recovery process.

The die gap of the extrusion die may be adjusted to 0.3 to 1.5 mm in order to more uniformly control the thickness of the base film in the range of 2 to 400 탆. In the step of forming the base film, if the die gap is too small, the die shear pressure of the melt extrusion process becomes too high and the shear stress becomes high, so that it is difficult to form a uniform film of the extruded film, If the die gap is too large, stretching of the melt-extruded film becomes too high and orientation may occur, and the difference between the longitudinal and transverse properties of the base film to be produced may become large.

Further, in the above-mentioned method for producing a polymer film, the thickness of the base film produced by the above-mentioned step is continuously measured, and the result of the measurement is fed back so that the portion of the extrusion die corresponding to the position where the uneven thickness appears, -Die's lip gap adjustment bolt can be adjusted to reduce the deviation of the base film to obtain a film having a more uniform thickness. In addition, automated process steps can be configured by using an automated system, such as an Auto Die system, to control the thickness of the film-feedback-extrusion die.

Meanwhile, the method for producing a polymer film may further include solidifying the base film formed by melting and extrusion in a cooling part maintained at a temperature of 5 to 40, preferably 10 to 30.

The base film formed by the melt and extrusion may be solidified in a cooling portion maintained at the temperature of 5 to 40 to be provided as a film having a more uniform thickness. The base film obtained by melting and extruding can be grounded or brought into close contact with the cooling section maintained at the above-mentioned appropriate temperature, so that the stretching can be substantially prevented, and the base film can be provided as an unstretched film.

Specifically, the solidifying step may be performed by using the air knife, the air nozzle, the vacuum-box, the electrostatic application device (Edge-Pinning device) Lt; RTI ID = 0.0 > and / or < / RTI >

As the base film formed by melting and extruding is adhered to the cooling roll by using an air knife, an air nozzle, a vacuum box, an electrostatic application device (edge-pinning device), or a combination thereof in the solidification step, It is possible to prevent the phenomenon that the film is blown out in the air or partially unevenly cooled in the air after the extrusion and thus a film having a more uniform thickness can be formed and the film is relatively thicker Some thin regions may not be substantially formed.

On the other hand, the step of forming the base film may further include a step of adding a heat resistant agent to at least one compound selected from the group consisting of the polyamide based resin and a copolymer containing a polyamide based segment and a polyether based segment .

The heat resistant agent may be melted and extruded sequentially or simultaneously with a polyamide based resin and / or a copolymer including a poly-amide based segment and a poly-ether based segment. Further, the heat resistant agent may be mixed by a simple branding mixing method or a compounding method at 200-300.

The method for producing a polymer film may further include forming an adhesive layer having a thickness of 0.1 to 20 탆 on at least one surface of the base film, each of the adhesive layers including a resorcinol-formalin-latex (RFL) have.

The adhesive layer containing the resorcinol-formalin-latex (RFL) adhesive may be formed by applying a resorcinol-formalin-latex (RFL) adhesive to at least one side of the base film, And an adhesive film containing a formalin-latex (RFL) -based adhesive may be laminated on at least one side of the base film, respectively.

Preferably, the step of forming the adhesive layer may be carried out by coating a resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film and drying the same. The adhesive layer formed on at least one surface of the base film And may have a thickness of 0.1 to 20 mu m, preferably 0.1 to 10 mu m. The resorcinol-formalin-latex (RFL) based adhesive may comprise 2 to 32% by weight of a condensate of resorcinol and formaldehyde and 68 to 98% by weight, preferably 80 to 90% by weight of latex.

Specific details regarding the resorcinol-formalin-latex (RFL) -based adhesive of the above specific composition include the above-mentioned contents regarding the polymer film of the embodiment.

The application of the adhesive may be carried out by any conventional coating or coating method or apparatus without limitation, but it may be applied by a knife coating method, a bar coating method, a gravure coating method, a spraying method, Can be used. However, it is preferable to use a knife coating method, a gravure coating method or a bar coating method in terms of uniform application and coating of the adhesive.

After the adhesive layer is formed on at least one side of the base film, the drying and the adhesive reaction may be carried out at the same time. However, considering the reactivity of the adhesive, it may be divided into a drying step and a heat treatment reaction step. In order to apply a multi-layered adhesive, the above-described adhesive layer formation, drying and reaction steps may be applied several times. Further, the heat treatment reaction may be performed by applying the adhesive to the base film and then solidifying and reacting at 100 to 150 for about 30 seconds to 3 minutes under heat treatment conditions.

According to the present invention, it is possible to realize excellent airtightness even with a thin thickness, to lighten the tire, to improve the fuel economy of the automobile, to have uniform physical properties in all regions and all directions, And a pneumatic tire including the polymer film may be provided.

Fig. 1 schematically shows the structure of a pneumatic tire.
2 schematically shows an example of the angle between the machine directions of two adjacent substrate films.

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

[ Example : Production of polymer film]

< Example 1 >

(1) Production of base film

(nylon 6) having a relative viscosity (3.6% solution of sulfuric acid) of 3.6 prepared from? -caprolactam and a copolymer resin having a weight average molecular weight of about 85,000 (copolymer having a main chain of polytetramethylene oxide 25% by weight of a polyether segment and 75% by weight of a polyamide segment derived from? -Caprolactam) was mixed at a weight ratio of 4: 6, and 0.5 part by weight of an oxazoline compound relative to 100 parts by weight of the mixture And 0.4 parts by weight of a heat resisting agent (a mixture of copper iodide and potassium iodide - 7% by weight of copper (Cu) in the mixture) were added to prepare a mixture for producing a base film.

Then, the mixture was extruded at 240 to maintain a uniform molten resin flow through a T-die (Die Gap - 0.6 mm), using an air knife on the surface of the cooling roll adjusted to 18, And cooled and solidified on a film of 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 15 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 base 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.

(3) Bonding layer  Produce

(Zincation, stearic acid, and antioxidant) 2 wt.% Of natural rubber, 30 wt.% Of carbon black (N330), 4 wt.% Of process oil, 2.5 wt.% Of adhesive, 2 wt.% Of vulcanization accelerator, % Were mixed in a Banbury mixer and then released at 160 캜. The compounded rubber composition was passed through an extruder to prepare a rubber sheet having a thickness of 100 탆 and used as a bonding layer.

(4) Film layer  formation

The bonding layer in the form of a rubber sheet was laminated on one surface of an unstretched base film having an adhesive layer on both surfaces thereof by a roll-to-roll method to prepare a base film laminated with the bonding layer.

Two pieces of the substrate film laminated with the bonding layer were cut in a machine direction (Machine Direction) and a transverse direction (1.5 m x 1.5 m) respectively. At this time, in order to avoid confusion in the lamination, the surface having the bonding layer in the " Laminating base material film "is designated as the" A " The laminated substrate film laminated on the substrate laminate is referred to as a " first layer ", and the "laminating base film" 2nd floor ".

When the "substrate film laminated with the bonding layer" is laminated by the above-described method, the substrate film side of the first layer located at the lowermost position is referred to as "1B" and the bonding layer side of the first layer is referred to as "1A" , The surface of the substrate film of the second layer continuously laminated thereon was designated as "2B ", and the bonding layer surface of the second layer was designated as" 2A ".

The two cut pieces of the "laminated substrate film" were laminated to prepare a base film layer. In the lamination of the "base film on which the bonding layer was laminated," The film was placed and laminated so as to form a shape of "1B / 1A / 2B / 2A" based on the lowermost end so that the bonding layer was positioned between the base films. At this time, the base film layers having a total thickness of 410 mu m were formed by laminating the first and second base film layers so that the angle between the machine direction (Machine Direction) was 90 DEG.

< Example 2 >

Production of a base film, application of an adhesive, and a bonding layer were carried out in the same manner as in Example 1 except for the formation of a base film layer, and a "base film in which a bonding layer was laminated was prepared.

In forming the base film layer, the "base film in which the bonding layer was laminated" was cut into three pieces each having a size of 2.5 m × 2.5 m in the machine direction and transverse direction, respectively, And then laminated in the same manner as in Example 1 to form a base film layer.

The "second layer" and the "third layer" were continuously laminated on the basis of the "first layer" in the formation of the base film layer, and "1B / 1A / 2B / 2A / 3B / 3A ".

At this time, the angle between the machine direction of the base film and the machine direction of the first layer and the second layer base film in the clockwise direction with reference to the machine direction of the first layer base film Layer direction so that the angle between the machine direction of the second and third layer base films is 60 ° in the clockwise direction on the basis of the machine direction of the second layer base film, To thereby form a base film layer having a total thickness of 615 mu m.

< Example 3 >

(1) Production of base film

(Synthesized by using? -Caprolactam and "Hexametylene diamine and adipic acid" in a weight ratio of 94: 6) of a polyamide-based copolymer resin having a relative viscosity of 96% (sulfuric acid solution) And a copolymer resin having a weight average molecular weight of about 102,000 (30% by weight of a polyether segment having an amine terminal group as a main chain of polytetramethylene oxide as a main chain and 70% by weight of a polyamide segment derived from? -Caprolactam) ) Was mixed at a weight ratio of 2: 8, and 0.4 part by weight of the oxazoline compound and 0.3 part by weight of the heat resistant agent (copper (Cu) content in the mixture of copper iodide and potassium iodide - mixture) Was added to prepare a mixture for producing the first base film.

Further, a polyamide-based resin (nylon 6) having a relative viscosity of 3.8 (a 96% solution of sulfuric acid) prepared from epsilon -caprolactam and a copolymer resin having a weight-average molecular weight of about 102,000 (a polyether- 30% by weight of a polyether segment and 70% by weight of a polyamide segment derived from? -Caprolactam) were mixed at a weight ratio of 4: 6, and the oxazoline compound 0.4 , And 0.3 parts by weight of a heat resistant agent (a mixture of copper iodide and potassium iodide - a copper (Cu) content in a mixture of 7% by weight) was added to prepare a mixture for preparing a second base film.

The mixture for preparing the first base film was extruded at 230 from a T-die (Die Gap - 0.5 mm) while maintaining a uniform molten resin flow, and an Air Knife was used on the surface of the cooled roll adjusted to 15 The molten resin was cooled and solidified on a film having a uniform thickness. Then, a first base film having an unstretched thickness of 50 탆 was obtained at a speed of 18 m / min without passing through a stretching and heat treatment zone.

Further, the mixture for preparing the second base film was extruded at 235 while maintaining a uniform molten resin flow through a T-die (Die Gap - 0.5 mm), and an Air Knife And the molten resin was cooled and solidified on a film having a uniform thickness. Then, an unoriented second base film having a thickness of 100 탆 was obtained at a speed of 18 m / min without passing through the stretching and heat treatment sections.

(2) Application of adhesive

An adhesive layer was formed in the same manner as in Example 1, except that an adhesive layer having a thickness of 3 mu m was formed on both surfaces of the unstretched first base film and the second base film.

(3) Bonding layer  Produce

A bonding layer was prepared in the same manner as in Example 1, except that a rubber sheet having a thickness of 20 탆 was prepared and used as a bonding layer.

(4) Film layer  formation

The first base film and the second base film were laminated with the bonding layer in the same manner as in Example 1 to obtain a first base film laminated with the bonding layer and a second base film laminated with the bonding layer, Base film "

Two pieces of the first substrate film laminated with the bonding layer were cut in a machine direction (Machine Direction) and a transverse direction (2.5 mx 2.5 m) respectively in order to form a base film layer, The second substrate film laminated with the bonding layer was cut into 2.5.times.2.5 m pieces in the machine direction and the transverse direction and cut into one piece, To thereby form a base film layer.

The first substrate film laminated with the bonding layer was laminated so as to be located at the positions of the "first layer" and the "third layer" in the formation of the base film layer, and the "second base film laminated with the bonding layer" Film "was placed at the position of the" second layer ".

That is, the base film layer was formed so as to be in the form of "1B / 1A / 2B / 2A / 3B / 3A" with reference to the base film surface of the lowermost "first layer".

In this case, the angle between the machine direction of the substrate films is set to be the angle between the machine direction of the first and second layer base films in a clockwise direction based on the machine direction of the first layer substrate film 90 °, and laminated so that the angle between the machine direction of the second and third layer base films was 90 ° in the clockwise direction on the basis of the machine direction of the second layer base film in succession Thereby forming a base film layer having a total thickness of 278 mu m.

< Example 4 >

(1) Production of base film

The same procedure as in Example 3 was carried out except that the thickness of the first base film and the second base film was adjusted to 30 μm by adjusting the discharge amount of the extruder during the production of the base film, A film was prepared.

 (2) Application of adhesive

An adhesive layer was formed in the same manner as in Example 3 above.

(3) Bonding layer  Produce

A bonding layer was prepared in the same manner as in Example 1 except that a rubber sheet having a thickness of 15 탆 was prepared and used as a bonding layer.

(4) Film layer  formation

The first base film and the second base film were laminated with the bonding layer in the same manner as in Example 1 to obtain a first base film laminated with the bonding layer and a second base film laminated with the bonding layer, Base film "

Three sheets of the "first base film laminated with the bonding layer" were cut in a machine direction (Machine Direction) and a transverse direction (2.5 mx 2.5 m) respectively in order to form a base film layer, The second substrate film laminated with the bonding layer was cut into two pieces each having a size of 2.5 mx 2.5 m in the machine direction and transverse direction and cut in the same manner as in Example 1, To thereby form a base film layer.

The first base film laminated with the bonding layer was laminated so as to be located at the positions of the first layer, the third layer and the fifth layer in the formation of the base film layer, and the bonding layer was laminated ) Was laminated so as to come to the positions of "2nd layer" and "fourth layer ".

That is, the base film layer was formed so as to be in the form of "1B / 1A / 2B / 2A / 3B / 3A / 4B / 4A / 5B / 5A" with reference to the base film surface of the lowermost "first layer".

At this time, the angle between the machine direction of the base film and the machine direction of the first layer and the second layer base film in the clockwise direction with reference to the machine direction of the first layer base film Was 72 °, and the laminate was laminated so that the angle between the machine direction of the second and third layer base films was 72 ° in the clockwise direction on the basis of the machine direction of the second layer base film in succession And in the same manner, the angle between the machine direction of the third and fourth layer base films was 72 ° in the clockwise direction on the basis of the machine direction of the third layer base film. The machine direction of the multilayer substrate film was laminated in the clockwise direction so that the angle between the machine direction of the 4th and 5th layer base films was 72 °, To form a base film layer having a thickness 255㎛.

< Example 5 >

(1) Production of base film

(Synthesized by using? -Caprolactam and "Hexametylene diamine and adipic acid" in a weight ratio of 94: 6) of a polyamide-based copolymer resin having a relative viscosity of 96% (sulfuric acid solution) And a copolymer resin having a weight average molecular weight of about 78,000 (15% by weight of a polyether segment based on polytetramethylene oxide having an amine terminal group as a main chain and 85% by weight of a polyamide segment derived from? -Caprolactam as a main chain) ) Were mixed at a weight ratio of 25:75, and 0.4 part by weight of an oxazoline compound and 0.3 part by weight of a heat resisting agent (copper (Cu) content in a mixture of copper iodide and potassium iodide - mixture) Was added to prepare a mixture for producing the first base film.

Further, a polyamide-based copolymer resin [ε-caprolactam and "hexamethylene diamine and adipic acid") having a relative viscosity of 3.8 (96% solution of sulfuric acid) was used in a weight ratio of 94: 6 And a copolymer resin having a weight average molecular weight of about 95,000 (20% by weight of a polyether-based segment having a main chain of polytetramethylene oxide at the amine terminal end and 80% by weight of a polyamide-based segment derived from? -Caprolactam as the main chain) ) Was mixed at a weight ratio of 3: 7, and 0.4 part by weight of an oxazoline compound and 100 parts by weight of the above mixture were mixed with 7% by weight of a heat-resistant agent (copper (Cu) content in a mixture of copper iodide and potassium iodide- ] Was added to prepare a mixture for preparing the second base film.

The mixture for preparing the first base film was extruded at 230 from a T-die (Die Gap - 0.5 mm) while maintaining a uniform molten resin flow, using an Air Knife on the surface of the cooled roll adjusted to 20 The molten resin was cooled and solidified on a film having a uniform thickness. Then, a first base film having an unoriented thickness of 25 mu m was obtained without passing through a stretching and heat treatment section at a speed of 17 m / min.

Further, the mixture for preparing the second base film was extruded at 235 while maintaining a uniform molten resin flow through a T-die (Die Gap - 0.5 mm), and an Air Knife And the molten resin was cooled and solidified on a film having a uniform thickness. Then, a second base film having an unoriented thickness of 25 mu m was obtained without passing through the stretching and heat treatment sections at a speed of 17 m / min.

(2) Application of adhesive

The mixture of resorcinol and formaldehyde was mixed at a molar ratio of 1: 2.5, followed by condensation reaction to obtain a condensate of resorcinol and formaldehyde. 20% by weight of the condensate of resorcinol and formaldehyde and 80% by weight of styrene / butadiene-1,3 / vinylpyridine latex were mixed to obtain a resorcinol-formalin-latex (RFL) adhesive having a concentration of 30%.

The resorcinol-formalin-latex (RFL) -based adhesive was coated on both sides of the base film using a gravure coater and dried and reacted at 150 ° C for 1.5 minutes to form adhesive layers each having a thickness of 5 μm on both sides.

(3) Bonding layer  Produce

A bonding layer was prepared in the same manner as in Example 1, except that a rubber sheet having a thickness of 10 탆 was prepared and used as a bonding layer.

(4) Film layer  formation

The first base film and the second base film were laminated with the bonding layer in the same manner as in Example 1 to obtain a first base film laminated with the bonding layer and a second base film laminated with the bonding layer, Base film "

Two pieces of the first substrate film laminated with the bonding layer were cut in a machine direction (Machine Direction) and a transverse direction (2.5 mx 2.5 m) respectively in order to form a base film layer, The second substrate film laminated with the bonding layer was cut into two pieces each having a size of 2.5 mx 2.5 m in the machine direction and transverse direction and cut in the same manner as in Example 1, To thereby form a base film layer.

The first substrate film laminated with the bonding layer was laminated so as to be located at the positions of the "first layer" and the "third layer" in the formation of the base film layer, and the "second base film laminated with the bonding layer" Film "was laminated so as to be located at the positions of" second layer "and" fourth layer ".

That is, the base film layer was formed so as to be in the form of "1B / 1A / 2B / 2A / 3B / 3A / 4B / 4A" with reference to the base film surface of the lowermost "first layer".

At this time, the angle between the machine direction of the base film and the machine direction of the first layer and the second layer base film in the clockwise direction with reference to the machine direction of the first layer base film Layer direction so that the angle between the machine direction of the second and third layer base films is 60 ° in the clockwise direction on the basis of the machine direction of the second layer base film, And the machine direction of the third and fourth layer base films was 60 ° in the clockwise direction on the basis of the machine direction of the third layer base film so that the angle between the machine direction and the machine direction was 60 °, Thereby forming a base film layer.

[ Comparative Example : Production of polymer film]

 (1) Production of base film

(nylon 6) having a relative viscosity (3.8% solution of sulfuric acid) of 3.8 produced from? -caprolactam and a copolymer resin having a weight average molecular weight of about 58,000 (a poly (methylene oxide) 13% by weight of an ether-based segment and 87% by weight of a polyamide-based segment derived from? -Caprolactam) was mixed at a weight ratio of 9: 1 to prepare a mixture for producing a base film.

A substrate film having a thickness of 100 탆 was prepared in the same manner as in Example 1, except that the extrusion temperature was set at 255 캜.

(2) Application of adhesive

Resorcinol-formalin-latex (RFL) -based adhesive was coated on both sides of the base film using a gravure coater and dried and reacted at 150 ° C for 1 minute in the same manner as in Example 1, .

(3) Preparation of bonding layer

A rubber sheet having a thickness of 100 탆 was prepared in the same manner as in Example 1 and used as a bonding layer.

(4) Formation of base film layer

A base film and a bonding layer were laminated together in the same manner as in Example 1 to prepare a "substrate film laminated with a bonding layer ".

In order to form the base film layer, two pieces of the "laminating base film with the bonding layer" were cut in a machine direction (Machine Direction) and a transverse direction (Transverse Direction) And laminated in the same manner to form a base film layer.

At this time, the base film layer was formed so as to be in the form of "1B / 1A / 2B / 2A" with reference to the base film surface of the lowermost "first layer", and between the machine direction of the first and second base film So as to have an angle of 20 DEG, thereby forming a base film layer having a total thickness of 410 mu m.

< Experimental Example >

Experimental Example 1 : Oxygen permeability experiment

Using the gas transmission rate tester (Model BR-1 / BT-1, manufactured by Toyoseiki Seisaku-Sho) in accordance with ASTM D 1434 for the base film layers obtained in the above Examples and Comparative Examples, The permeability was measured.

Experimental Example  2: Modulus balance (Modulus Balance) Experiment

The base film layers obtained in the above Examples and Comparative Examples were left to stand at 23 DEG C and 50% RH for 24 hours, one end of the base film layer was suspended in a 170 DEG C hot air oven, Immediately after leaving for a minute, the machine direction (MD) of the base film layer was measured using a universal tensile tester (Instron, Tensile test machine) with a sample length of 30 mm and a sample width of 30 mm and a tensile speed of 300 mm / ) And the tensile strength at 25% elongation to transverse direction (TD) were measured 10 times, and the average value of the eight values excluding the maximum value and the minimum value was used as the machine direction (MD) And the modulus at 25% elongation at a high temperature (170 ° C) against the transverse direction (TD).

The ratio of the modulus value at 25% elongation at high temperature (170 DEG C) to the machine direction (MD) and the transverse direction (TD) (Modulus Balance) can be confirmed, and it is calculated in the same manner as in Formula 1 below.

&Lt; General Formula 1 &

Experimental Example 3 : Heat resistance Impact strength ratio (MD / TD) experiment

The heat-resistant impact strength of the base film layer obtained in the above Examples and Comparative Examples was measured as follows.

The thermal shock resistance was measured by applying the ISO 8256 Method A method and a cutting device (ISO 8256 Type 4) was applied to the machine direction (MD) and the transverse direction (TD) Were used to collect 10 specimens for evaluation.

At this time, the shape of the specimen for evaluation (specimen length x shoulder width x parallel specimen length x specimen width) is cut to 60 mm x 10 mm x 25 mm x 3 mm in accordance with ISO 8256 type 4, and the specimen cut according to the standard is heated at 23 ° C and 50% After standing for 24 hours, one end of the substrate film layer was suspended in a hot air oven at 170 占 폚 and heat-treated for 1 hour in a no-load and no-contact state, and then subjected to heat treatment at 23 占 폚 and 50% relative humidity in accordance with ISO 8256 Method A, (MD) and transverse direction (TD) of the heat-treated base film layer by using a thermal impact tester (Pendulum Impact Tester, Zwick / Roell, Model HIT 5.5P) And the average value was obtained for eight values excluding the maximum value and the minimum value.

In order to minimize the variation caused by the external environment during the measurement of the heat-resisting impact strength, the test specimens were cut to a size necessary for the measurement before the heat treatment. After the heat treatment, the measurement was completed within 15 minutes after the heat treatment in order to minimize changes in properties.

The heat-resistant impact strength of the base film layer with respect to the machine direction (MD) and the transverse direction (TD) was obtained by the following general formula (2).

&Lt; General Formula 2 &

Thermal shock resistance (kJ / m ² ) = impact energy (kJ) / [film thickness (m) ⅹ specimen width (0.003 m)]

(Here, the width of the specimen for evaluation is fixed at 3 mm)

The heat-resistant impact strength ratio was calculated by the following general formula (3).

&Lt; General Formula 3 &

Experimental Example 4 : Measurement of ease of molding

The base film layers of the examples and comparative examples were applied as inner liners to produce 100 tires of the 205R / 65R16 standard. After manufacturing the green tire during the tire manufacturing process, the manufacturability and appearance were evaluated, and the final appearance of the tire was examined after vulcanization.

At this time, when the green tire or the vulcanized tire had no distortion, and the standard deviation of the diameter was within 5%, it was evaluated as "good". And, when the tire was not made properly due to the occurrence of distortion in the green tire or the vulcanized tire, or when the inner liner inside the tire was melted or torn and broken, or when the standard deviation of the diameter exceeded 5%, it was evaluated as "poor".

The ease of molding was evaluated by confirming the number of tires having a good appearance for 100 tires manufactured by applying the base film layers of the examples and comparative examples as tire inner liners, and the easiness of molding was calculated as shown in the following formula 4 .

&Lt; General Formula 4 &

Experimental Example 5 : Durability measurement experiment

The durability of the tire manufactured in Experimental Example 4 was experimentally evaluated by increasing the load using the FMVSS139 tire durability measurement method. This durability measurement is performed by two methods of step load method: endurance test which increases the load and high speed method which increases the speed. By checking the presence or absence of cracks in the tire, it is confirmed that there is 'good' '.

The final appearance of the tire was evaluated by the method of Experimental Example 4 to check whether there was a 'crack' by conducting the Endurance Test and the High Speed Test for each 10 pieces of the tires having the 'good' appearance, The durability of the tire according to the endurance test and the high speed test was determined as shown in the following general formula 5 with respect to the number of 'good' tires having no 'cracks' after the durability measurement.

&Lt; General Formula 5 &

Experimental Example 6 : Air pressure maintenance performance measurement

The tire manufactured in Experimental Example 4 was subjected to comparative evaluation by measuring the internal pressure retention (IPR) for 90 days at a temperature of 21 DEG C and a pressure of 101.3 kPa using the ASTM F1112-06 method as shown in the following Formula 6.

 &Lt; General Formula 6 >

The results of Experimental Examples 1 to 6 are shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example Oxygen permeability [cc / (m &lt; 2 &gt; 24 hratm)] 37 24 59 75 89 13 Modulus Balance (MD / TD) 1.13 1.07 1.03 1.02 1.05 1.35 Thermal Impact Strength Ratio (MD / TD) 1.25 1.38 1.57 1.33 1.45 2.58 Ease of molding (%) 100 98 100 100 100 21 Tire durability (%) Endurance Test 100 100 100 100 100 0 High Speed Test 100 100 100 100 100 30 Air pressure retention ratio (%) 98.2 98.7 98.0 97.7 97.4 98.8

** MD and TD were based on the machine direction and transverse direction of the first base film, respectively

As shown in Table 1, the base film layer of the examples prepared by laminating the two or more neighboring base films so that the angle between the machine directions was 60 ° to 120 °, The heat shock resistance is not only uniform but also adjusted to an appropriate range, for example, 1.20 or less in the case of the modulus balance and 1.75 or less in the case of the balance of the thermal shock resistance. Accordingly, when the base film layer of the above embodiment is used, not only the moldability in the tire manufacturing process is excellent, but also the effect of dispersing the stress externally is maximized, so that cracking due to stress concentration phenomenon and crack growth Can be suppressed, and it has been confirmed that excellent durability and endothelial property can be realized.

Claims (24)

At least two substrate films; And a bonding layer positioned between adjacent substrate films,
Wherein an angle between the machine direction of the adjacent base films is 60 ° to 120 °.
The method according to claim 1,
Wherein an angle between the machine direction of the adjacent base films is 80 ° to 100 °.
The method according to claim 1,
Wherein each of the base films comprises a polyamide based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment; and a polymer film comprising at least one compound selected from the group consisting of polyolefin-based segments and polyether-based segments.
The method of claim 3,
Wherein the polyamide based resin has a relative viscosity (96% solution of sulfuric acid) of 2.5 to 4.0.
The method of claim 3,
Wherein the copolymer comprising the polyamide-based segment and the poly-ether-based segment has a weight average molecular weight of 30,000 to 500,000.
The method of claim 3,
Wherein the content of the polyether segment is 2 to 40% by weight based on the total weight of the base film included in the base film layer.
The method of claim 3,
Wherein each of the base films comprises a polyamide based resin; And a copolymer comprising a polyamide-based segment and a polyether-based segment, in a ratio of from 9: 1 to 1: 9.
The method of claim 3,
Wherein the content of the polyether segment in each of the base films is 2 to 40 wt%.
The method according to claim 1,
Wherein the base film has a thickness of 2 to 400 占 퐉.
The method according to claim 1,
Wherein the base film layer has a thickness of 5 占 퐉 to 1000 占 퐉.
The method according to claim 1,
Wherein the bonding layer comprises tie gauze.
12. The method of claim 11,
The tie black rubber, carbon black, and sulfur,
The method according to claim 1,
Wherein the bonding layer has a thickness of 1 占 퐉 to 200 占 퐉.
The method according to claim 1,
Further comprising an adhesive layer formed on at least one side of the base film and having a thickness of 0.1 mu m to 20 mu m including a resorcinol-formalin-latex (RFL) adhesive.
The method according to claim 1,
Polymer film used as an inner liner of tires.
And a base film layer formation step comprising a step of laminating at least two base films through a bonding layer such that an angle between the machine directions is 60 ° to 120 °.
17. The method of claim 16,
Wherein an angle between the machine direction of the adjacent base films of the at least two base films is 80 ° to 100 °.
17. The method of claim 16,
Wherein the base film layer forming step comprises sequentially laminating or simultaneously laminating the at least two or more base film layers.
17. The method of claim 16,
Wherein the base film layer forming step further comprises laminating a base film having a thickness of 1 占 퐉 to 200 占 퐉 between at least two base films.
17. The method of claim 16,
Wherein the base film layer forming step includes sequentially laminating a base film laminated with a tie gum on at least one surface thereof and a base film laminated with another tie gum.
17. The method of claim 16,
Polyamide based resin; And a copolymer comprising a polyamide segment and a polyether segment, and melting and extruding at least one compound selected from the group consisting of a polyether-based segment and a polyether-based segment at 200 to 300 ° C to form a base film .
22. The method of claim 21,
Wherein the base film has a thickness of 2 to 400 mu m, A method for producing a polymer film.
17. The method of claim 16,
Further comprising the step of forming an adhesive layer having a thickness of 0.1 mu m to 20 mu m containing at least one resorcinol-formalin-latex (RFL) -based adhesive on at least one surface of the base film.
17. The method of claim 16,
Wherein the polymer film to be produced is used as an inner liner of a tire.

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