KR20150079173A - Preparatiom method of polymer film and coextrusion film - Google Patents

Abstract

The present invention relates to a manufacturing method of a polymer film comprising a substrate film forming step of coextruding a first resin comprising a polyamide-based resin and a second comprising a copolymer comprising a polyamide-based segment and a poly-ether-based segment and to a coextrusion film comprising a substrate film containing a first resin layer comprising a polyamide-based resin and a second resin layer comprising a copolymer comprising a polyamide-based segment and a poly-ether-based segment.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of producing a polymer film and a coextrusion film,

The present invention relates to a method of producing a polymer film and a coextruded film, and more particularly, to a coextruded film which is used as an inner liner of a tire to realize excellent airtightness even in a thin thickness, Which is capable of securing high elasticity along with excellent durability and endothelium characteristics in the process of driving a vehicle, and a method of manufacturing a polymer film by implementing a thin airtightness, thereby improving the fuel efficiency of a vehicle by reducing the weight of the tire, The present invention relates to a coextruded film for an inner liner which is capable of securing a high elasticity together with an excellent durability and an endothelial characteristic even in a process or a running process of an automobile.

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 (or pneumatic tires), which are filled with high-pressure air of about 30 to 40 psi, are usually used without using a tube. In the course of vehicle operation, The inner liner having high airtightness is disposed in 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.

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, .

Recently, as oil prices have increased, interest in eco tires (eco-friendly tires) that can improve automobile fuel efficiency has increased, and attempts have been made to reduce the weight of tires or to reduce the ground area through changes in tire compounds or changes in tread design. I have been. However, according to the previously known method, there is a certain limit to improve the stability of the running stability and the shape stability of the tire, and to reduce the weight of the tire and to improve the automobile fuel economy.

The present invention realizes excellent airtightness even with a thin thickness, thereby making it possible to lighten the weight of the tire and improve the fuel efficiency of the automobile, and to provide a polymer film capable of securing high elasticity along with durability and endothelial property, Method.

In addition, the present invention realizes excellent airtightness even with a thin thickness, thereby making it possible to lighten the tire and improve the fuel economy of the automobile. Also, the present invention can provide a tire having excellent durability and endurance, Lt; RTI ID = 0.0 > coextrusion < / RTI > film for a liner.

The present invention also provides a pneumatic tire including the coextruded film for an inner liner.

The present invention relates to a polymer film comprising a first resin including a polyamide resin and a second resin including a copolymer including a polyamide segment and a polyether segment, Of the present invention.

The present invention also provides a resin composition comprising: a first resin layer containing a polyamide resin; And a substrate film containing a second resin layer containing a copolymer including a polyamide-based segment and a poly-ether-based segment. The present invention also provides a coextruded film for an inner liner.

The present invention also provides a pneumatic tire comprising the coextruded film for the inner liner.

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

In this specification, terms such as 'first' and 'second' are used to distinguish between an object or a constituent element, and are not construed to limit the specific order or importance.

Also, the term " segment " means a part or a specific part having the same physical property, which has the same chemical structure in a polymer or a compound. For example, the segment may be a specific repeating unit or a chemical structure in which these specific repeating units are assembled, or may be a part or residue derived from a reactant (monomer, oligomer, polymer, etc.) included in the final reaction product.

Also, 'residue' means a form or chemical structure in which a reactant participating in a chemical reaction is included in the final product, and may be a chemical structure, a functional group, a repeating unit, etc. derived from the reactant.

Also, alkylene means a divalent functional group derived from an alkane, arylene means a divalent functional group derived from arene, and aryl alkylene means a divalent functional group derived from an arene, Quot; means a divalent functional group derived from a compound including arene and an alkane.

According to an embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a base film forming step of pneumatically delivering a second resin containing a first resin including a polyamide resin and a copolymer including a polyamide segment and a polyether segment; A method of producing a polymer film including the polymeric film may be provided.

A base film obtained by co-extruding a first resin containing the polyamide-based resin and a second resin containing a copolymer containing the polyamide-based segment and a poly-ether-based segment as a polymer film for a tire innerliner It is possible to achieve high airtightness by thinning the tire to lighten the weight of the tire, improve the fuel efficiency of the vehicle, and achieve high durability and endurance characteristics and high elasticity in the tire manufacturing process and automobile driving process. And completed the invention.

The polymer film may be used as an inner liner of a tire, and the polymer film may be a film for an inner liner of a pneumatic tire.

By co-extruding the first resin and the second resin, it is possible to disperse the development speed applied to the film against impacts and stresses externally, to provide a buffering effect, and to prevent entanglement between the coextrusion layers And external stress and impact are dispersed even in the thickness direction of the film to improve the toughness and durability of the film.

The base film may have a laminated structure including at least two layers, and the polyamide-based segment and the poly-ether-based segment may be bonded together with the high airtightness realized from the first resin including the polyamide- And the elastomeric properties expressed from the second resin including the copolymer.

Specifically, the polymer film for inner liner provided according to the manufacturing method of one embodiment has an airtightness of about 10 to 30 times as compared with a butyl rubber generally used for a tire at an excellent airtightness, for example, at the same thickness, The film exhibits a modulus which is not high, so that the rigidity of the film can be inhibited from rising at a high temperature and can be prevented from being crystallized at a high temperature.

As described above, the base film may be formed by co-extruding the first resin and the second resin, and co-extruding the first resin and the second resin using at least one of the first resin and the second resin to form a laminate structure of two or more layers can do. That is, in the base film forming step, a base film having a multilayer structure containing at least two or more layers may be formed by co-extruding at least one of the first resin and at least one of the second resins.

That is, the base film forming step may further include co-extruding at least one of the first resin and at least one second resin to form a base film having a multilayer structure including at least two layers.

Specifically, the substrate film obtained in the manufacturing method of one embodiment may have a two-layer structure in which a first resin layer formed from the first resin and a second resin layer formed from the second resin are laminated, Layer structure in which two second resin layers formed from the second resin are laminated on both surfaces of a first resin layer formed from the first resin, and on the contrary, a second resin layer formed from the second resin Layer structure in which two first resin layers formed from the first resin are laminated on both sides of the first resin layer. The base film may have a multilayer structure including two or more layers each of a first resin layer formed from the first resin and a second resin layer formed from the second resin.

Each of the first resin layer and the second resin layer may have a thickness of 0.1 mu m to 300 mu m, or 1 mu m to 250 mu m, or 2 mu m to 200 mu m. The base film comprising the first resin layer and the second resin layer has a thickness of 0.2 to 3,000 mu m, or 2 to 2,500 mu m, and 4 to 2,000 mu m. Or a thickness of 40 [mu] m to 400 [mu] m.

The base film forming step may further include forming a base film having a multi-layer structure including at least two layers using at least one of the first resin and the second resin.

In this case, the first resin may contain more polyamide resin than the one or more second resins, and the content (wt%) of the polyamide resin in the first resin may be greater than the content 5 wt.% To 85 wt.%, Or 10 wt.% To 85 wt.%, Or 25 wt.% To 80 wt.%, Respectively, relative to the content (wt.%) Of the polyamide based resin in the second resin.

For example, when the difference between the content (wt%) of the polyamide-based resin in the first resin and the content (wt%) of the polyamide-based resin in the second resin is in the range of 5 wt% to 85 wt% The first resin may comprise from 5% to 100% by weight or from 30% to 100% by weight of the polyamide based resin and from 0% to 95% by weight of the copolymer comprising the polyamide based segment and the poly-ether based segment, 0 wt% to 70 wt%, and the second resin comprises 0 wt% to 95 wt% or 0 to 80 wt% of the polyamide resin; And 5 to 100% by weight or 20 to 100% by weight of a copolymer containing the polyamide-based segment and poly-ether-based segment. That is, the content (wt%) of the polyamide based resin in the first resin is 5 wt% to 85 wt%, or 10 wt% (wt%) based on the content of the polyamide based resin % To 85 wt%, or 25 wt% to 80 wt%.

On the other hand, in the base film forming step, the first resin and at least one second resin containing less polyamide resin than the first resin are co-extruded to form a base film having a multilayer structure including at least two layers The method further comprising:

That is, it is preferable that one kind of the first resin and at least one of the polyamide-based resin (including the polyamide-based segment and the poly-ether-based copolymer) Or two or more kinds of second resins can be co-aggregated to form a base film having a multilayer structure of two or more layers.

Meanwhile, the process of co-extruding the first resin and the second resin may be performed at a temperature of 200 ° C to 300 ° C, or 230 ° C to 290 ° C. The co-extrusion temperature should be higher than the melting point of the polyamide compound. However, if the co-extrusion temperature is too high, carbonization or decomposition may occur to deteriorate the physical properties of the film and internal agglomeration or orientation occurs between the polyether segments contained in the second resin Which may be disadvantageous for producing an undrawn film.

Except for using the first resin and the second resin described above in the co-extrusion process, conventionally known co-extrusion methods and apparatuses can be used without any limitation. For example, it is possible to use a co-extruder including an extruder or a raw material injecting portion and a combining adapter in which raw materials transferred from the extruder or the raw material injecting portion are laminated in a molten state into a plurality of layers, The co-extruder may include two or more extruders or a raw material injection unit in accordance with the numbers of the first resin and the second resin used for producing the base film.

In the production method of the polymer film of the embodiment, the co-extrusion may use a feed block capable of forming a base film having a multi-layer structure. According to the use of such a feed block, the first resin and the second resin injected from the extruder or the raw material injecting portion or the melts thereof may be formed into a multilayer structure, and the substrate film thus produced may also be formed into a multilayer structure And the multilayer structure formed in the feed block is continuously discharged through the die to form a multilayer structure film.

FIG. 2 schematically shows a process for producing a multi-layered film using the feed block. The feed block can be used without any limitations as long as it is known to be usable in a polymer resin or a plastic product.

For example, in the feed block there is a flow-path in which the inlet tube and the molten polymers into which the polymer flows from the extruder can maintain individual flows, The feed block may include a melt flow distributor (Melt-Distributor) that forms a melt flow at a constant layer thickness ratio and then combines individual melt flows. By adjusting the spacing of the melt flow distributor, the thickness ratio of the layer in which each molten polymer is formed can be varied.

Specifically, the polymer melted from the extruder is injected into the feed block through a separate polymer inlet pipe and a polymer path, and then a polymer flow of a laminated structure having a constant thickness ratio is formed by a melt flow distributor And then extruded through a die to form a base film having a layer structure formed in the feed block.

However, the details of the feed block that can be used in the method of producing the polymer film of the embodiment are not limited to the above contents, and the feed block known to be used in the process of melting and molding a polymer resin can be used without any limit Do.

The step of forming the base film may further include layering the co-extruded resultant to form a multilayered base film. The resultant co-extruded product may have a multilayer structure of two or more layers, and the resultant co-extruded product may be divided into a predetermined thickness ratio and then laminated again to form a multilayer structure having four or more multilayer structures.

The apparatus and method that can be used in the step of laminating the co-extruded resultant and multilayering the base film are not limited to a wide range. For example, a device such as a separator (interfacial surface generator, or interface generator) The resultant co-extruded product can be laminated one or more times to form a multilayer structure.

The layer separating device may include a laminate inlet port through which the coextruded laminate flows, a channel dividing the laminate, and a stacking part for re-stacking the divided laminate, The structure of the laminate introduced into the layer separating device is divided by a channel, and then laminated again in the lamination part, so that the multilayered structure can be obtained. The number of layers of the final multilayered laminate can be adjusted according to the number of layers (number of layers) and the number of channels of the coextruded laminate introduced into the layer separating device.

For example, if the coextruded laminate introduced into the layer separating apparatus has a three-layer structure, and the channel of the layer separating apparatus is two, the three-layer laminate is divided into the upper channel and the lower channel, A three-layer laminate of the upper channel and a three-layer laminate of the lower channel are stacked together to form a six-layer laminate, and when the layer separator is further applied continuously, To form a laminate.

However, the details of the layer separating apparatus usable in the method of manufacturing the polymer film of the embodiment are not limited to the above contents, and the layer separating apparatus known to be usable in the process of melting and molding the polymer resin is not limited Available

The base film forming step may include extruding the co-extruded product or the multilayered co-extruded product into a film form. In the extrusion process, an extrusion die known to be usable for extruding a polymer resin can be used without any limitations. However, in order to make the thickness of the base film more uniform or prevent orientation from occurring in the base film, Is preferably used.

On the other hand, the base film formed may be an unoriented film. 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. Further, since the crystallization phenomenon hardly occurs in the unstretched film, damage such as cracks can be prevented even by repeated deformation. Further, since the unoriented film does not have a large variation in orientation and physical properties in a specific direction, an inner liner having uniform physical properties can be obtained.

Specifically, the base film forming step may be performed so as not to stretch the co-extruded product of the first resin and the second resin in machine direction (MD) or transverse direction (TD). Accordingly, the produced polymer film for inner liner may include a coextruded unstretched base film.

Extruding the resultant co-extruded product of the first resin and the second resin to form a base film in the form of a film having a thickness of from 0.2 mu m to 3,000 mu m, or from 2 mu m to 2500 mu m, or from 4 mu m to 2,000 mu m thick have. The melt extrudate obtained in the above co-extrusion step can be formed into a film having a uniform thickness while being cooled to a predetermined temperature.

For example, the resultant product of the co-extrusion process may be cooled at room temperature or solidified in a cooling unit maintained at a temperature of 5 ° C to 40 ° C.

On the other hand, in the step of forming the base film, the thickness of the molten resin sheet to be discharged is adjusted by combining the extruder discharge amount, the width or gap of the die, and the winding speed of the cooling roll, The thickness of the base film can be adjusted to 0.2 탆 to 3,000 탆, or 2 탆 to 2,500 탆, or 4 탆 to 2,000 탆 by uniformly adhering closely to each other using an electrostatic edge pinning apparatus.

Meanwhile, in the method for producing a polymer film of the embodiment, the first resin may contain only the polyamide-based resin as an essential component, and the second resin may include the polyamide-based segment and the polyether- Based segment may be included as an essential component.

The first resin may further include a copolymer including a polyamide-based segment and a poly-ether-based segment in addition to the polyamide-based resin described above.

The second resin may further include a polyamide-based resin in addition to the copolymer including the polyamide-based segment and the poly-ether-based segment described above.

The first resin may further comprise a copolymer including a polyamide segment and a polyether segment, and when the second resin further comprises a polyamide resin, The first resin may contain more polyamide based resin than the first resin.

By co-extruding the above-mentioned first resin and the second resin described above, it is possible to produce a polyamide-based resin which exhibits high airtightness, and which is produced from a copolymer containing the polyamide-based segment and a poly- Gt; elastomeric < / RTI > properties.

The difference between the content (wt%) of the polyamide resin in the first resin and the content (wt%) of the polyamide resin in the second resin is 5 wt% to 85 wt%, or 10 wt% By weight, or from 25% by weight to 80% by weight.

If the difference between the content (wt%) of the polyamide-based resin in the first resin and the content (wt%) of the polyamide-based resin in the second resin is in the range of 5 wt% to 85 wt% The coextruded film provided according to the production method can have higher airtightness and durability and at the same time the content of the polyether segment contained in the first resin and the second resin is adjusted to an appropriate range Therefore, the co-extruded film may have properties such as high moldability and elasticity.

Specifically, the difference between the content (wt%) of the polyamide-based resin in the first resin and the content (wt%) of the polyamide-based resin in the second resin is within the range of 5 wt% to 85 wt% Wherein the first resin comprises 5 to 100% by weight or 30 to 100% by weight of the polyamide based resin and 0 to 95% by weight of a copolymer containing the polyamide based segment and a poly-ether based segment, Or 0 wt% to 70 wt%, and the second resin comprises 0 wt% to 95 wt% or 0 to 80 wt% of the polyamide resin; And 5 to 100% by weight or 20 to 100% by weight of a copolymer containing the polyamide-based segment and poly-ether-based segment.

In addition, in the method of manufacturing a polymer film according to one embodiment of the present invention, two second resin layers formed from the second resin may be laminated on both sides of the first resin layer formed from the first resin, A base film layer having a laminated structure can be formed. In addition, the three-layer laminated structure may be repeatedly laminated to form a base film layer having a multilayer structure of more than three layers.

When the polymer film for inner liner including the base film layer having three or more laminated structure thus manufactured is applied to the pneumatic tire, the first resin layer located between the two second resin layers causes a higher Airtightness can be achieved, but the two second resin layers ensure higher elasticity and lower modulus, so that the inner-liner polymer film can exhibit a modulus not so high and the rigidity of the film increases at a high temperature And can be prevented from being crystallized at a high temperature.

On the other hand, the polyamide resin included in the first resin or included in the second resin may have a relative viscosity (96% sulfuric acid solution) of 2.5 to 4.0 or 3.0 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).

The polyamide resin contained in the first resin or contained in the second resin can be used without limitation of a specific kind as long as it has a relative viscosity of 2.5 to 4.0 (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.

In addition, the polyamide-based resin contained in the first resin or included in the second resin 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 include 0.5 to 20% by weight or 1 to 18% by weight of the repeating unit represented by the formula (2).

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-based segment and the poly-ether-based segment contained in the first resin or contained in the second resin may have a weight average molecular weight of 50,000 to 500,000, or 70,000 to 250,000 have. If the weight average molecular weight of the copolymer is less than 50,000, the prepared base film may not have sufficient mechanical properties to be used for the polymer film for inner liner, and if the weight average molecular weight of the copolymer exceeds 500,000, The modulus or degree of crystallization of the base material film excessively increases and it may be difficult to secure the elasticity or elastic recovery rate to be possessed as the polymer film for 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 may be a main repeating unit that may be contained in a polyalkylene glycol resin or a derivative thereof. In the polyalkylene glycol derivative, the terminal of the polyalkylene glycol resin may be an amine group, a carboxyl group or an isocyanate group , Preferably an amine group-substituted derivative. Preferably, the polyether-based segment is at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylenediamine, polyoxypropylenediamine, polyoxytetramethylenediamine, and copolymers thereof And may be a main repeating unit contained in the polyether-based 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, R ₆ and R ₇ may be the same or different and are each a direct bond, -O- , -NH-, -COO- or -CONH-.

The total content of the polyether segments in the base film obtained in the above production method may be 2 to 40% by weight, or 3 to 30% by weight, or 4 to 20% by weight. If the content of the polyether segment is less than 2% by weight based on the total weight of the base film, the modulus of the base film or the polymer film for inner liner becomes high, so that the moldability of the tire is deteriorated, have. If the content of the polyether segment exceeds 40% by weight of the total amount of the base film, the airtightness of the polymer film for inner liner may be deteriorated and the reactivity to the adhesive may be lowered so that the inner liner easily adheres to the carcass layer And the elasticity of the base film may increase, so that it may not be easy to produce a uniform film.

Within the range in which the content ratio of the polyether segment in the base film is in the range of 2 to 40% by weight, the copolymer contains the polyamide segment and the polyether segment in a predetermined weight ratio .

For example, the copolymer comprising the polyamide-based segment and the polyether-based segment may comprise the polyamide-based segment and the polyether-based segment in a ratio of 1: 9 to 9: 1, or 2: 8 to 8: 3: 7 to 7: 3.

The first resin and the second resin may be mixed in a ratio of from 9: 1 to 2: 3, preferably from 2: 1 to 4: 1, 1: 9, or 8: 2 to 2: 8 by weight.

Further, it is preferable that the first resin further comprises a copolymer containing a polyamide segment and a poly-ether segment, or the second resin further comprises a polyamide resin, The weight ratio of the first resin and the second resin may be controlled so that the content ratio of the polyether segments in the base film [2 wt% to 40 wt%, or 4 to 20 wt%] is maintained.

Each of the first resin and the second resin may further include at least one additive selected from the group consisting of a heat resisting agent, a crosslinking agent, and an antioxidant. Such an additive may be contained in an amount of 0.001 wt% to 10 wt% in each of the first resin and the second resin.

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

Preferably, the step of forming such an adhesive layer may be performed by coating a resorcinol-formalin-latex (RFL) -based adhesive on one surface or both surfaces of the formed substrate film, followed by drying. The formed adhesive layer may have a thickness of 0.1 to 20 占 퐉, preferably 0.1 to 10 占 퐉. The resorcinol-formalin-latex (RFL) based adhesive 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. Specific details of the resorcinol-formalin-latex (RFL) -based adhesive will be described later.

According to another embodiment of the present invention, there is provided a resin composition comprising: a first resin layer containing a polyamide resin; And a substrate film containing a second resin layer containing a copolymer containing a polyamide-based segment and a poly-ether-based segment, may be provided.

As described above, when the first resin containing the polyamide resin and the second resin containing the copolymer containing the polyamide segment and the polyether segment are co-extruded, the first resin layer and the second resin layer, A coextruded film for an inner liner containing a base film containing a second resin layer can be produced.

Such a coextruded film for an inner liner has a high airtightness realized from a first resin layer containing the polyamide resin and a second water containing a copolymer containing the polyamide segment and the polyether segment And may have elastomeric properties expressed from the strata.

Accordingly, the coextruded film for inner liner has excellent airtightness even with a thin thickness, which can reduce the weight of the tire and improve the fuel efficiency of the automobile. In addition, the tire has excellent durability and endurance characteristics in tire manufacturing process and automobile driving process, . Specifically, the coextruded film for an inner liner of the embodiment exhibits excellent airtightness, for example, an airtightness of about 10 to 20 times that of a butyl rubber generally used in a tire at the same thickness, but exhibits a modulus not so high, It is possible to prevent the rigidity of the film from rising and to prevent crystallization at a high temperature.

The base film may have a multilayer structure of two or more layers including at least one of the first resin layer and at least one second resin layer.

By including the substrate film comprising the first resin layer and the second resin layer, the coextruded film for the inner liner of the embodiment can have a high elasticity and a low modulus characteristic while securing a further improved airtightness.

In particular, the coextruded film for an inner liner of the above embodiment of the present invention is superior in terms of adhesion to the polymer film, in comparison with the polymer film of the equivalent thickness comprising the polyamide-based resin and a copolymer containing the polyamide-based segment and poly- High durability with high airtightness can be achieved.

The first resin layer may contain only the polyamide-based resin as an essential component, and the second resin layer may include only the copolymer as an essential component.

In addition, the first resin layer may further include a copolymer including a polyamide-based segment and a poly-ether-based segment in addition to the polyamide-based resin described above.

The second resin layer may further include a polyamide-based resin in addition to the copolymer including the polyamide-based segment and the poly-ether-based segment.

The first resin layer may further include a copolymer including a polyamide segment and a polyether segment, the second resin layer may further include a polyamide resin, The first resin layer may contain more polyamide resin than the stratum.

The difference between the content (wt%) of the polyamide resin in the first resin layer and the content (wt%) of the polyamide resin in the second resin layer is 5 wt% to 85 wt%, or 10 wt% To 85% by weight, or from 25% by weight to 80% by weight.

If the difference between the content (wt%) of the polyamide resin in the first resin layer and the content (wt%) of the polyamide resin in the second resin layer is in the above range, And the durability of the co-extruded film can be improved. At the same time, the content of the poly-ether-based segment contained in the first resin layer and the second resin layer is adjusted to an appropriate range, And the like.

Specifically, the first resin layer may contain 5 wt% to 100 wt% or 30 wt% to 100 wt% of the polyamide based resin, 0 wt% of the copolymer containing the polyamide based segment and the polyether based segment, To 95% by weight or 0% by weight to 70% by weight. The second resin layer may contain 0 to 95% by weight or 0 to 80% by weight of the polyamide resin; And 5 to 100% by weight or 20 to 100% by weight of a copolymer containing the polyamide-based segment and poly-ether-based segment.

On the other hand, the base film may have a multilayer structure of two or more layers including at least one second resin layer containing less polyamide resin than the first resin layer and the first resin layer.

That is, as described above, it is preferable that one kind of the first resin and a copolymer containing less polyamide resin than the first resin (the polyamide-based segment and the polyether-based segment-containing copolymer And more than two kinds of second resins are included in the second resin layer to form a base film having a multilayer structure of two or more layers. Thus, compared to one first resin layer and the first resin layer, A substrate film comprising at least one second resin layer containing less polyamide based resin may be formed.

On the other hand, the total content of the polyether segments in the base film may be 2 to 40 wt%, or 3 to 30 wt%, or 4 to 20 wt%. The total content of the polyether segments in the base film is a ratio of the sum of the weights of the polyether segments in the copolymer that can be contained in the second resin layer and the first resin layer with respect to the total weight of the base film Can be obtained.

 If the content of the polyether segment is less than 2% by weight based on the total weight of the base film, the modulus of the base film or the polymer film for inner liner becomes high, so that the moldability of the tire is deteriorated, have. If the content of the polyether segment exceeds 40% by weight of the total amount of the base film, the airtightness of the polymer film for inner liner may be deteriorated and the reactivity to the adhesive may be lowered so that the inner liner easily adheres to the carcass layer And the elasticity of the base film may increase, so that it may not be easy to produce a uniform film.

In addition, in the coextruded film of one embodiment, two of the second resin layers may be laminated on both sides of the first resin layer, so that a base film layer having a laminated structure of three layers may be formed. In addition, the three-layer laminated structure may be repeatedly laminated to form a base film layer having a multilayer structure of more than three layers.

When the polymer film for inner liner including the base film layer having three or more laminated structure thus manufactured is applied to the pneumatic tire, the first resin layer located between the two second resin layers causes a higher Airtightness can be achieved, but the two second resin layers ensure higher elasticity and lower modulus, so that the inner-liner polymer film can exhibit a modulus not so high and the rigidity of the film increases at a high temperature And can be prevented from being crystallized at a high temperature.

The polyamide resin contained in the first resin layer and the copolymer contained in the second resin layer can undergo a chemical reaction during the co-extrusion process, whereby the first resin layer and the second resin layer are cross- And an interface layer containing a crosslinking reaction product between the polyamide resin and the copolymer may be formed between the first resin layer and the second resin layer.

Each of the first resin layer and the second resin layer may have a thickness of 0.1 mu m to 300 mu m, or 1 mu m to 250 mu m, or 2 mu m to 200 mu m. The base film including the first resin layer and the second resin layer may have a thickness of 0.2 mu m to 3,000 mu m, or 2 mu m to 2,500 mu m, or 4 mu m to 2,000 mu m, or 40 mu m to 400 mu m.

The polyamide resin contained in the first resin layer or optionally included in the second resin layer may have a relative viscosity (sulfuric acid 96% solution) of 2.5 to 4.0. The relative viscosity and the specific kind of the above-mentioned polyamide-based resin are as described above.

The copolymer comprising the polyamide-based segment and the poly-ether-based segment which are contained in the second resin layer or alternatively can be contained in the first resin layer may have a weight average molecular weight of 50,000 to 500,000 have. The details of the weight average molecular weight of the copolymer are as described above.

Each of the first resin layer and the second resin layer may further include at least one additive selected from the group consisting of a heat resistant agent, a crosslinking agent, and an antioxidant. Such an additive may be included in the first resin layer and the second resin layer in an amount of 0.001 wt% to 10 wt%, respectively.

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.

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

The adhesive layer containing the resorcinol-formalin-latex (RFL) adhesive has excellent adhesion and adhesive holding performance to the base film and the tire carcass layer, and accordingly, the heat generated in the process of manufacturing or running the tire Or interfacial layer between the polymer film for inner liner and the carcass layer caused by repeated deformation is prevented so that the polymer film for inner liner has sufficient fatigue resistance.

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

In addition, the above-mentioned resorcinol-formalin-latex (RFL) -based adhesive is capable of crosslinking between latex and rubber to exhibit adhesive performance, and since it is a latex polymeric material physically, , Chemical bonding between the methylol end group of the resorcinol-formalin polymer and the substrate film is possible. Accordingly, when the above-mentioned resorcinol-formalin-latex (RFL) -based adhesive is applied to the base film, 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 from 0.1 to 20 占 퐉, preferably from 0.1 to 10 占 퐉, more preferably from 0.2 to 7 占 퐉, even more preferably from 0.3 to 5 占 퐉, and the surface of one side of the coextruded film for inner liner Or may be formed on both surfaces. If the thickness of the adhesive layer is too thin, the adhesive layer itself may become thinner when the tire is inflated, the crosslinking adhesive force between the carcass layer and the base film may be lowered, and the stress may concentrate on a part of the adhesive layer. In addition, if the adhesive layer is too thick, the interface separation in the adhesive layer may occur and the fatigue characteristics may be deteriorated.

In order to adhere the polymer film for inner liner to the carcass layer of the tire, an adhesive layer is generally formed on one surface of the base film. However, when a polymer film for inner liner is applied in a multilayer structure or when a polymer film for an inner liner It is preferable to form an adhesive layer on both sides of the base film when adhesion to rubber is required on both sides according to the tire molding method and structure design such as wrapping.

According to another embodiment of the present invention, a pneumatic tire including the coextruded film for the inner liner may be provided.

As described above, since the above-described coextruded film for inner liner can realize excellent airtightness even with a thin thickness, the pneumatic tire can be lightened as compared with the pneumatic tire known previously, and thus the fuel economy of the automobile can be improved.

In addition, the co-extruded film for inner liner has high elasticity and durability, so that the film itself can be crystallized even in a tire manufacturing process in which a large deformation is made under a high temperature condition, or in a car running process in which repetitive deformation is continuously applied, It is possible to prevent the occurrence of damage such as cracks and the like, so that the pneumatic tire can secure high running stability and shape stability.

The pneumatic tire may have the structure of a conventional pneumatic tire except that it comprises a coextruded film for the inner liner described above.

For example, the pneumatic tire may comprise a tread portion; A pair of shoulder portions which are respectively continuous on both sides around the tread portion; A pair of side wall portions continuous with each of the shoulder portions; A pair of bead portions continuous to each of the side wall portions; A body fly portion formed on the inner side of the tread portion, the shoulder portion, the side wall portion and the bead portion; A belt portion and a cap ply portion sequentially stacked between the inner side surface of the tread portion and the body ply portion; And a coextrusion film for an inner liner coupled to the inside of the body ply portion.

According to the present invention, it is possible to realize excellent airtightness even with a thin thickness, thereby reducing the weight of the tire and improving the fuel efficiency of the automobile. Further, the present invention can provide a tire having excellent durability and endurance, A pneumatic tire including a coextrusion film for a liner, a production method capable of providing the coextrusion film for the inner liner, and a coextrusion film for the inner liner may be provided.

By using the coextruded film for inner liner, it is possible to improve the automobile fuel economy by lowering the total weight of the tire without changing the tire compound or changing the tread design, and it is possible to improve the stability of the running of the vehicle and the stability of the shape of the tire.

Fig. 1 schematically shows the structure of a pneumatic tire.
Fig. 2 schematically shows a process of producing a multi-layered film using a feed block in the embodiment.
3 schematically shows an interfacial surface generator used in the embodiment.

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 : For inner liner  Preparation of polymer film]

< Example 1 >

(1) Production of base film

&lt; RTI ID = 0.0 &gt; epsilon -caprolactam &lt; A nylon 6 resin having a relative viscosity of 3.6 (a solution of sulfuric acid of 96%), a polyether-based segment having a polypropylene oxide as a main chain at the amine terminal and a polyamide-based segment derived from? -Caprolactam (Polyether-based segments: polyamide-based segments in a weight ratio of 1: 3) at a weight ratio of 6: 4 to prepare a first resin. Then, a nylon 6 resin having a relative viscosity of 3.6 (96% solution of sulfuric acid) and the above copolymer having a weight average molecular weight of 110,000 were mixed at a weight ratio of 4: 6 to prepare a second resin.

After drying the first resin and the second resin, a base film was prepared using two extruders and a three-layered feed block. The first extruder was constituted by a first resin layer (layer B) The second resin, which is a raw material of the second resin layer (A layer), was added to the second extruder and extruded at 260 ° C.

As shown schematically in FIG. 2, in order to form a multilayer structure, a feed block having a three-layer structure is provided on the extrusion die, and a first resin layer (B layer) forms a core layer (Second resin layer (A layer) / first resin layer (B layer) / second resin layer (A layer) of the multilayered film having a three-layer structure in which the second resin layer (A layer) forms a skin layer 2 resin layer (A layer)].

The molten resin flow of the multilayered film formed in the above-described structure and composition was extruded through a T-die (Die Gap - 1.5 mm), and the molten resin Was cooled and solidified in the form of a film having a uniform thickness to obtain an unstretched substrate film of a three-layer structure having a thickness of 100 mu m at a speed of 15 m / min. At this time, one second resin layer (A layer) occupied 10% of the entire substrate film thickness, and the first resin layer (B layer) occupied 80% of the entire substrate film thickness.

(2) Application of adhesive

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

The resulting resorcinol-formalin-latex (RFL) -based adhesive was coated on the non-stretched substrate film of the obtained three-layer structure using a gravure coater and dried and reacted at 150 ° C for 1 minute to form an adhesive layer .

< Example 2 >

(1) Production of base film

(relative viscosity (96% solution of sulfuric acid) 3.8) synthesized using 95% by weight of? -caprolactam and 5% by weight of 2-azacyclononanone and a polypropylene oxide (Polyether segment: polyamide segment: 1: 4) having a weight average molecular weight of 100,000 and containing a polyether segment derived from ? -Caprolactam and a polyether segment derived from ? -Caprolactam in a weight ratio of 7: 3 to prepare a first resin.

Then, a second resin was prepared by mixing the polyamide-based resin [3.8] (relative viscosity (96% solution of sulfuric acid)] and the copolymer having the weight average molecular weight of 100,000 in a weight ratio of 4: 6.

The copolymer having the weight average molecular weight of 100,000 was used alone as another second resin.

Then, using the first resin and the second kind of the second resin, three extruders, a three-layered feed block and two two-channel interfacial surface generators To prepare a base film.

Specifically, a first resin obtained by mixing the polyamide based resin and the copolymer having the weight average molecular weight of 100,000 in a weight ratio of 7: 3 was dried and then extruded at 255 캜. The second extruder The other one of the second resins (copolymer having a weight average molecular weight of 100,000) was dried and then extruded at 260 ° C. In the third extruder, the polyamide resin and the copolymer having the weight average molecular weight of 100,000 were mixed in a ratio of 4: 6 The second resin mixed in a weight ratio was dried, then charged, and extruded at 260 캜.

After the extrusion, in order to form a multi-layer structure, a core layer is formed from the resultant extruded from the first extruder in a three-layered feeder block provided on the two-layer separator (B Layer) A skin layer was formed from each of the extruded products in the second extruder and the third extruder to form a molten resin flow having three layers (A layer and C layer) (layer A / layer B / layer C) C floor].

In the three-layer structure of the &quot; A layer / B layer / C layer &quot; formed in the feed block, the thickness of the A layer accounts for 5% of the total thickness of the three-layer structure and the thickness of the B layer corresponds to the total thickness of the three- And 85%, and the layer structure was constructed such that the thickness of the C layer occupies 10% of the total thickness of the three-layer structure.

In order to continuously laminate the three-layered molten resin flow into thinner layers, the layers were separated and laminated by using a 2-channel interfacial surface generator connected to the feed block. That is, the three-layer structure of the "A layer / B layer / C layer" formed in the feed block is passed through a first two-channel interfacial surface generator to separate and laminate the three- (A / B / C / A / B / C) and then passed through a second 2-channel interfacial surface generator to separate and laminate the six- (A / B / C / A / B / C / A / B / C / A / B / C).

The molten resin flow of the multilayered film formed in the above-described structure and composition was extruded through a T-die (Die Gap - 1.5 mm), and the molten resin Was cooled and solidified in the form of a film having a uniform thickness to obtain an unstretched multilayered substrate film having a thickness of 100 mu m 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.

Then, the resorcinol-formalin-latex (RFL) -based adhesive was coated on the above-obtained 12-layer structure unstretched base film using a gravure coater and dried and reacted at 150 ° C for 1 minute to obtain a 5 μm thick adhesive layer .

< Experimental Example >

Experimental Example 1 : Heat Resistance Toughness

The heat resistance toughness of the base film obtained in the above Examples was measured as follows.

The substrate film was allowed to stand in a hot air oven at 170 캜 for one hour, left at 100 캜 in a hot air oven for 1 hour, and then allowed to stand at 23 캜 for 50 hours under a relative humidity of 50% (Machine Direction (MD)) of the substrate film heat-treated with a universal tensile tester (Instron, Tensile tester) at a tensile speed of 300 mm / min and a sample length of 30 mm and a sample width of 30 mm, ) And transverse direction (TD) were measured ten times, respectively, and the average values of eight values excluding the maximum value and the minimum value were obtained.

In order to minimize deviations caused by external environment during the heat treatment, tensile test specimens were cut to the size required for measurement before heat treatment, minimized changes in properties after heat treatment, and completed within 15 minutes after heat treatment.

The heat resistance toughness of the base film in the longitudinal direction (MD) and in the transverse direction (TD) was determined by using the breaking strength and the elongation at break of the base film after the heat treatment as shown in the following general formula (1).

&Lt; General Formula 1 &

Toughness (MPa) = breaking strength (MPa) x SQRT (elongation at break (%))

(Where SQRT stands for Square Root).

Experimental Example 2 : Oxygen permeability experiment

Using the gas transmission rate tester (Model BR-1 / BT-2, manufactured by Toyoseiki Seisaku-Sho) in accordance with the ASTM D 1434 method for the tire innerliner polymer film obtained in the above example, oxygen The permeability was measured.

Experimental Example 3 : Measurement of ease of molding

The tire innerliner polymer film of the above example was applied to produce 205 tires in accordance with 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 polymer inner film for a tire innerliner of the above example, and the ease of molding was determined as shown in the following Formula 2.

&Lt; General Formula 2 &

Experimental Example 4 : Durability measurement experiment

The durability of the tire prepared in Experimental Example 3 was experimentally evaluated by increasing the load using the FMVSS139 tire durability measurement method. This durability measurement was performed by two methods of step load method: endurance test which increases the load and high speed method which increases the speed. By checking whether there is a crack inside the tire, it is confirmed that there is 'good' when there is no crack, '.

The final appearance of the tire was evaluated by the method of Experimental Example 3, and an endurance test and a high-speed test were performed for each of 10 tires, The durability of the tire according to the Endurance Test and the High Speed Test was determined as shown in the following Equation 3 with respect to the number of tires which did not occur after the durability test.

&Lt; General Formula 3 &

Experimental Example 5 : Air pressure maintenance performance measurement

The tires produced in Experimental Example 3 were compared and evaluated 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 general formula (4).

 &Lt; General Formula 4 &

The results of Experimental Examples 1 to 5 are shown in Table 1 below.

Example 1 Example 2 Oxygen permeability [cc / (m 2 · 24 hr · atm)] 58 45 Base film
Heat Resistance Toughness (MPa) Longitudinal direction (MD) 1,652 1,587 In the transverse direction (TD) 1,399 1,250 Ease of molding (%) 100 99 Tire durability
(%) Endurance Test 100 100 High Speed Test 100 100 Air pressure retention ratio (%) 97.1 97.8

As shown in Table 1, the polymer film for inner liner obtained in the above example exhibited an oxygen permeability of 60 cc / (m 2 · 24 hr · atm) or less even at a thickness of about 103 μm to 105 μm, It is possible to obtain a high durability when applied to a tire and to have a heat resistance toughness of 1250 MPa or more in both the longitudinal direction and the transverse direction of the base film.

Claims (35)

A base film forming step of pneumatically delivering a first resin containing a polyamide resin and a second resin containing a copolymer containing a polyamide segment and a polyether segment, Gt;
The method according to claim 1,
Wherein the polymer film to be produced is used as an inner liner of a tire.
The method according to claim 1,
Wherein the first resin further comprises a copolymer including a polyamide-based segment and a poly-ether-based segment.
The method according to claim 1,
Wherein the second resin further comprises a polyamide based resin.
The method according to claim 1,
Wherein the first resin further comprises a copolymer comprising a polyamide-based segment and a poly-ether-based segment,
Wherein the second resin further comprises a polyamide based resin,
Wherein the first resin contains more polyamide resin than the second resin.
6. The method of claim 5,
Wherein the difference between the content (wt%) of the polyamide-based resin in the first resin and the content (wt%) of the polyamide-based resin in the second resin is 5 wt% to 85 wt%.
The method according to claim 6,
Wherein the first resin comprises from 5% to 100% by weight of the polyamide based resin and from 0% to 95% by weight of the copolymer comprising the polyamide based segment and the poly-ether based segment,
The second resin comprises 0% to 95% by weight of the polyamide resin; And 5 to 100% by weight of a copolymer comprising the polyamide-based segment and the poly-ether-based segment.
The method according to claim 1,
Wherein the polyamide based resin has a relative viscosity (96% solution of sulfuric acid) of 2.5 to 4.0.
The method according to claim 1,
Wherein the copolymer comprising the polyamide-based segment and the poly-ether-based segment has a weight average molecular weight of 50,000 to 500,000.
The method according to claim 1,
Wherein the base film forming step further comprises co-extruding at least one of the first resin and at least one second resin to form a base film having a multilayer structure including at least two layers, .
6. The method of claim 5,
The base film forming step
Extruding the first resin and at least one second resin containing less polyamide resin than the first resin to form a base film having a multilayer structure of two or more layers, Gt;
The method according to claim 10 or 11,
Wherein said co-extrusion uses a feed block capable of forming a base film of a multi-layer structure.
The method according to claim 1,
Wherein the base film forming step further comprises laminating the co-extruded resultant to form a multilayered base film.
The method according to claim 1,
Wherein the co-extrusion is carried out at a temperature of 200 ° C to 300 ° C.
The method according to claim 1,
Wherein the base film forming step is performed so as not to stretch the co-extruded product of the first resin and the second resin in machine direction (MD) or transverse direction (TD).
The method according to claim 1,
And cooling the co-extruded result of the first resin and the second resin to form a base film in the form of a film having a thickness of 4 to 2,000 mu m.
The method according to claim 1,
Wherein each of the first resin and the second resin further comprises at least one additive selected from the group consisting of a heat resistant agent, a cross-linking agent, and an antioxidant.
The method according to claim 1,
Further comprising the step of forming an adhesive layer comprising a resorcinol-formalin-latex (RFL) -based adhesive on at least one side of the base film.
A first resin layer containing a polyamide resin; And a substrate film containing a second resin layer containing a copolymer including a polyamide-based segment and a poly-ether-based segment.
20. The method of claim 19,
Wherein the first resin layer further comprises a copolymer comprising a polyamide-based segment and a poly-ether-based segment.
20. The method of claim 19,
Wherein the second resin layer further comprises a polyamide based resin.
20. The method of claim 19,
Wherein the base film has a multilayer structure of two or more layers including at least one of the first resin layer and at least one second resin layer.
20. The method of claim 19,
Wherein each of the first resin layer and the second resin layer has a thickness of 0.1 mu m to 300 mu m.
20. The method of claim 19,
Wherein the polyamide resin contained in the first resin layer has a relative viscosity of 2.5 to 4.0 (96% solution of sulfuric acid).
20. The method of claim 19,
Wherein the copolymer containing the polyamide segment and the polyether segment contained in the second resin layer has a weight average molecular weight of 50,000 to 500,000.
20. The method of claim 19,
Wherein the first resin layer further comprises a copolymer including a polyamide-based segment and a poly-ether-based segment,
Wherein the second resin layer further comprises a polyamide resin
Wherein the first resin layer contains more polyamide resin than the second resin layer.
27. The method of claim 26,
Wherein the difference between the content (wt%) of the polyamide resin in the first resin layer and the content (wt%) of the polyamide resin in the second resin layer is 5 wt% to 85 wt%.
27. The method of claim 26,
Wherein the first resin layer comprises 5 wt% to 100 wt% of the polyamide resin,
And the second resin layer comprises 0 to 95 wt% of the polyamide resin.
26. The method according to claim 19 or 26,
Wherein the total content of the polyether segments in the base film is from 2 to 40% by weight,
27. The method of claim 26,
Wherein the base film has at least one second resin layer containing less polyamide resin than the first resin layer and the first resin layer Coextruded film having two or more layers of multilayer structure.
20. The method of claim 19,
Wherein the base film is an unstretched film substantially not stretched.
20. The method of claim 19,
Further comprising an adhesive layer formed on at least one side of the base film and comprising a resorcinol-formalin-latex (RFL) based adhesive.
33. The method of claim 32,
Wherein the adhesive layer has a thickness of 0.1 占 퐉 to 20 占 퐉.
20. The method of claim 19,
Wherein each of the first resin layer and the second resin layer further comprises at least one additive selected from the group consisting of a heat resistant agent, a crosslinking agent, and an antioxidant.
A pneumatic tire comprising the coextruded film of claim 19 as an inner liner.

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