KR102031788B1 - Preparatiom method of polymer film and coextrusion film - Google Patents

Abstract

The present invention includes a substrate film forming step of co-extrusion of a first resin including a polyamide-based resin and a second resin including a copolymer including a polyamide-based segment and a polyether-based segment. A first resin layer comprising a method for producing the same and a polyamide-based resin; And it relates to a coextrusion film comprising a base film containing a second resin layer comprising a copolymer comprising a polyamide segment and a poly-ether segment.

Description

Manufacturing Method and Coextrusion Film of Polymer Film {PREPARATIOM METHOD OF POLYMER FILM AND COEXTRUSION FILM}

The present invention relates to a method for manufacturing a polymer film and a coextrusion film, and more particularly, it is used as an inner liner of a tire to realize excellent airtightness even at a thin thickness, thereby making the tire lighter and improving automobile fuel economy, and producing a tire. In addition to the excellent durability and fatigue resistance in the process of driving a car, a method of manufacturing a polymer film capable of securing high elasticity and excellent airtightness even at a thin thickness can reduce tire weight and improve fuel efficiency of a car. The present invention relates to a coextrusion film for innerliner that can secure high elasticity with excellent durability and fatigue resistance even in a process or a car driving process.

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

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

Body Ply (or Carcass) (6): A layer of cord inside the tire, which must support loads, withstand impacts, and be resistant to fatigue during rolling.

Belt (5): Located between the body plies, consisting of steel wires in most cases to mitigate external shocks and maintain a wide tread ground to provide excellent driving stability.

Side Wall (3): refers to the rubber layer between the lower part of the shoulder (2) from the bead (9) and serves to protect the body ply (6) inside.

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

BEAD (9): A square or hexagonal wire bundle with rubber coating on the wire that rests and secures the tire to the rim.

CAP PLY (4): A special cord paper placed on the belt of some passenger radial tires that minimizes belt movement when driving.

APEX (8): A triangular rubber filler used to minimize the dispersion of beads, to mitigate external impacts, to protect the beads, and to prevent the ingress of air during molding.

Recently, tube-less tires (or pneumatic tires) in which 30 to 40 psi of high-pressure air is injected without using tubes are generally used. An airtight inner liner is disposed in the carcass inner layer to prevent leakage to the carcass.

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

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

However, any previously known method has had a limit in maintaining excellent air permeability and tire formability while sufficiently reducing the thickness and weight of the innerliner. In addition, the innerliner obtained by the previously known method may be deteriorated in its physical properties or cracks in the film during the manufacturing process of a tire that is repeatedly formed at a high temperature, or during the driving process of a vehicle in which high heat is generated. Many problems have appeared.

With the recent rise in oil prices, interest in eco tires (environmental tires), which can improve automobile fuel economy, has increased, and attempts to reduce the weight of the tire or reduce the ground area by changing tire compounds or changing tread design, etc. Has been. However, by the previously known methods, there are certain limitations in reducing the weight of tires and improving automobile fuel efficiency while improving driving stability and shape stability of tires.

The present invention can realize a high airtightness even in a thin thickness to reduce the weight of the tire and improve the fuel economy of the automobile, and also to produce a polymer film that can ensure high elasticity with excellent durability and fatigue resistance in the tire manufacturing process or automobile driving process It is to provide a method.

In addition, the present invention implements excellent airtightness even at a thin thickness to lighten the tires and improve the fuel economy of the car, and also to ensure high elasticity with excellent durability and fatigue resistance in the tire manufacturing process or automobile driving process It is to provide a coextrusion film for a liner.

In addition, the present invention is to provide a pneumatic tire including the co-extrusion film for the inner liner.

The present invention includes a substrate film forming step of co-extrusion of a first resin including a polyamide-based resin and a second resin including a copolymer including a polyamide-based segment and a polyether-based segment. It provides a method for producing.

In addition, the present invention is a first resin layer containing a polyamide-based resin; And a base film including a second resin layer including a copolymer including a polyamide-based segment and a polyether-based segment.

In addition, the present invention provides a pneumatic tire comprising the co-extrusion film for the inner liner.

Hereinafter, a method of manufacturing 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 the present specification, terms such as 'first' and 'second' are used to distinguish an object or a component to which they refer, and are not limited to specifying a certain order or importance.

In addition, "segment" means a part having the same chemical structure or a specific part having the same physical properties in the polymer or compound. For example, a segment may be a specific repeating unit or a chemical structure in which these specific repeating units are aggregated, or may be a moiety or moiety derived from a reactant (monomer, oligomer, polymer, etc.) included in the final reaction product.

In addition, "residue" means a form or chemical structure in which the reactants participating in the chemical reaction are included in the final result, and may be a chemical structure, a functional group, a repeating unit, and the like derived from the reactants.

In addition, alkylene refers to a divalent functional group derived from alkane, arylene refers to a divalent functional group derived from arene, and aryl alkylene Means a divalent functional group derived from a compound including arene and alkane.

According to one embodiment of the invention, the substrate film forming step of co-extrusion a second resin including a first resin containing a polyamide-based resin and a copolymer comprising a polyamide-based segment and a polyether-based segment; It can be provided a method for producing a polymer film comprising a.

A base film obtained by coextrusion of a first resin including the polyamide resin and a second resin including a copolymer including the polyamide segment and a polyether segment is used as a polymer film for tire innerliner. When applied, it is possible to realize excellent airtightness even at a thin thickness to make tires lighter and improve fuel efficiency, and to secure high elasticity with excellent durability and fatigue resistance even during tire manufacturing or driving. Confirmed through and completed the invention.

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

As the first resin and the second resin are co-extruded, the spreading speed applied to the film can be dispersed, the buffering effect can be dispersed, and the entanglement between co-extrusion layers can be solved. By inducing and dispersing external stress and impact in the film thickness direction can improve the toughness and durability of the film.

The base film may have a laminated structure including two or more layers, and the polyamide-based segment and the polyether-based segment may be formed together with a high airtightness implemented from the first resin including the polyamide-based resin. It may have an elastomeric property expressed from the second resin including the copolymer.

Specifically, the polymer film for innerliner provided according to the manufacturing method of the embodiment shows excellent airtightness, for example, about 10 to 30 times the airtightness compared to butyl rubber generally used in tires at the same thickness, and the like. It can exhibit a modulus that is not high and can suppress the rise of the stiffness of the film at a high temperature and can prevent crystallization at a high temperature.

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

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

Specifically, the base film obtained in the manufacturing method of the embodiment may have a two-layer structure in which the first resin layer formed from the first resin and the second resin layer formed from the second resin are laminated. The second resin layer may be a three-layered structure in which two second resin layers formed from the second resin are laminated on both surfaces of the first resin layer formed from the first resin, on the contrary, and a second resin layer formed from the second resin. It may have a three-layer structure in which two first resin layers formed from the first resin on each side of the stack. The base film may have a multilayer structure including two or more layers 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 μm to 300 μm, or 1 μm to 250 μm, or 2 μm to 200 μm. The base film including the first resin layer and the second resin layer has a thickness of 0.2 μm to 3,000 μm, or 2 μm to 2,500 μm, and 4 μm to 2,000 μm. Or 40 μm to 400 μm.

The forming of the base film may further include forming a base film having a multilayer structure including at least two layers by using one or more types of the first resin and the second resin.

In this case, the first resin may include more polyamide-based resins than the one or more types of the second resins, and the content (wt%) of the polyamide-based resins in the first resins may be 5 wt% to 85 wt%, alternatively 10 wt% to 85 wt%, or 25 wt% to 80 wt% of the polyamide-based resin in the second resin, respectively.

For example, 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% by weight to 85% by weight. The first resin is 5 wt% to 100 wt% of the polyamide resin, or 30 wt% to 100 wt%, and 0 wt% to 95 wt% of the copolymer including the polyamide segment and the polyether segment. 0 wt% to 70 wt%, and the second resin includes 0 wt% to 95 wt% or 0 to 80 wt% of the polyamide resin; And 5 wt% to 100 wt% or 20 wt% to 100 wt% of the copolymer including the polyamide-based segment and the polyether-based segment. That is, the content (wt%) of the polyamide-based resin in the first resin is 5% to 85% by weight, or 10% by weight, compared to the content (wt%) of the polyamide-based resin in the two second resins, respectively. % To 85% by weight, or 25% to 80% by weight can be large.

On the other hand, the step of forming the base film is a multi-layered base film comprising at least two layers by co-extrusion of at least one or more types of second resins containing less polyamide-based resin than the first resin and the first resin It may further comprise the step of forming.

That is, at least 1 containing less polyamide-based resins (including more copolymers including the polyamide-based segments and polyether-based segments) than one kind of the first resin and the first resin. The base film which has a multilayer structure of two or more layers can be formed by carrying out the co-extrusion of 2 or more types or 2 or more types of 2nd resin.

On the other hand, the process of coextrusion of the first resin and the second resin may be carried out at a temperature of 200 ℃ to 300 ℃, or 230 ℃ to 290 ℃. The coextrusion temperature should be higher than the melting point of the polyamide-based compound, but if it is too high, carbonization or decomposition may occur and the physical properties of the film may be inhibited, and internal aggregation or orientation may occur between the polyether-based segments included in the second resin. This can be disadvantageous for producing unstretched films.

In the co-extrusion process, a conventionally known co-extrusion method and apparatus may be used without any limitation except that the above-described first and second resins are used. For example, a coextruder including an extruder or a raw material injection unit and a combining adapter in which raw materials transferred from the extruder or raw material injection unit are laminated in a plurality of layers in a molten state may be used. The coextruder may include two or more extruders or raw material injection parts according to the number of the first resin and the second resin used in the production of the base film.

In the method of manufacturing the polymer film of the above embodiment, the coextrusion may use a feed block capable of forming a base film having a multilayer structure. As the feed block is used, the first resin and the second resin or a melt thereof thereof injected from the extruder or the raw material injection part may be formed in a multilayer structure, and the base film thus manufactured may also be formed in a multilayer structure. The multilayer structure formed in the feed block may be continuously discharged through a die to form a multilayer structure film.

2 schematically shows a process of manufacturing a multilayer structure film using the feed block. The feed block can be used without any limitation as long as it is known that the feed block can be used in a polymer resin or a plastic product.

For example, in the feed block, there is a polymer flow path through which an inflow pipe from which an polymer is introduced from an extruder and a molten polymer can maintain a separate flow. The feed block may include a melt flow distributor (Melt-Distributor) that serves to combine the individual melt flows after forming the melt flow in a constant layer thickness ratio. By adjusting the spacing of the melt flow distributors it is possible to vary the thickness ratio of the layers on which each molten polymer is formed.

Specifically, the molten polymers from the extruder are injected into the feed block through individual polymer inflow pipes and polymer paths, and then a melt flow distributor forms a polymer flow having a uniform thickness ratio by using a melt-distributor. Thereafter, it is extruded through a die to form a layered base film formed in the feed block.

However, the specific details of the feed block that can be used in the manufacturing method of the polymer film of the embodiment is not limited to the above content, the feed block known to be used in the process of melting and molding the polymer resin can be used without great limitation Do.

The forming of the base film may further include stacking the coextruded result to multilayer the base film. The coextruded result may have a multilayer structure of two or more layers, and the coextruded result may be multi-layered to have a multilayer structure of four or more layers by dividing the coextruded result into a predetermined thickness ratio and then stacking again.

The apparatus or method which can be used in the step of stacking the coextruded result to multiply the base film is not limited to a large number, and for example, an apparatus such as an interfacial surface generator or an interface generator as shown in FIG. 3. The coextruded result through can be laminated one or more times to be multi-layered.

The layer separation apparatus may include a stack inlet into which the coextruded stack flows, a channel for dividing the stack, and a stacking part for stacking the divided stack again. Since the structure of the stack introduced into the layer separation apparatus is divided by a channel, the stack is stacked again in the stacking unit, thereby enabling multilayering. The number of layers of the final multilayered stack may be adjusted according to the number of layers and the number of channels of the coextruded stack introduced into the layer separation apparatus.

For example, if the coextruded laminate flowing into the delamination apparatus has a three-layer structure, and the channel of the delamination apparatus has two channels, the three-layer laminate is separated into an upper channel and a lower channel, respectively. Then, in the stacking portion, the three-layer stack of the upper channel and the three-layer stack of the lower channel are stacked together to form a stack of six-layer structure. It will form a stack of.

However, the details of the layer separation apparatus that can be used in the method of manufacturing the polymer film of the embodiment are not limited to the above contents, and the layer separation apparatus known to be used in the process of melting and molding the polymer resin is not particularly limited. Available

The forming of the base film may include extruding the coextruded product or the multilayered coextrusion product into a film form. In the extrusion process, an extrusion die known to be used for extrusion of a polymer resin may be used without particular limitation, but a T-type die may be used to make the thickness of the base film more uniform or to prevent orientation of the base film. Preference is given to using.

Meanwhile, the formed base film may be an unstretched film. When the base film is in the form of an unstretched film, it has a low modulus and a high strain rate and can be suitably applied to a tire forming process in which high expansion occurs. In addition, since crystallization hardly occurs in the unstretched film, damage such as cracks can be prevented even by repeated deformation. In addition, since the unstretched 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 forming of the base film may be performed so as not to stretch the coextrusion result of the first resin and the second resin in a machine direction (MD) or a transverse direction (TD). Accordingly, the polymer film for the inner liner manufactured may include a coextruded unstretched base film.

The method may further include cooling the coextruded product of the first resin and the second resin to form a base film in the form of a film having a thickness of 0.2 μm to 3,000 μm, or 2 μm to 2,500 μm, or 4 μm to 2,000 μm. have. The melt extrudate obtained in the coextrusion step described above may be formed into a film having a uniform thickness while being cooled to a predetermined temperature.

The specific apparatus or method that can be used in the cooling process is not particularly limited, and for example, the result of the coextrusion 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, by adjusting the thickness of the molten resin sheet discharged by combining the extruder discharge amount, the width or gap of the die, the winding speed of the cooling roll, or the like, the air knife and air nozzle, vacuum apparatus and The thickness of the base film may be adjusted to 0.2 μm to 3,000 μm, or 2 μm to 2,500 μm, or 4 μm to 2,000 μm by cooling by uniformly adhering and cooling using an electrostatic edge pinning device.

On the other hand, in the manufacturing method of the polymer film of the embodiment, the first resin may include only the polyamide resin as an essential component, the second resin is the polyamide segment and poly-ether (poly-ether) Only the copolymer including the system segment may be included as an essential component.

In addition, the first resin may further include a copolymer including a polyamide segment and a polyether segment in addition to the polyamide 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 polyether-based segment.

In addition, when the first resin further comprises a copolymer including a polyamide-based segment and a polyether-based segment, and the second resin further includes a polyamide-based resin, In comparison, the first resin may include more polyamide-based resin.

As the first resin and the second resin described above are co-extruded, they are expressed from a copolymer including the polyamide-based segment and the polyether-based segment with high airtightness realized from the polyamide-based resin. It can have a combination of elastomeric properties.

On the other hand, 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% to 85% by weight, or 10% to 85% by weight Weight percent, or 25 weight percent to 80 weight percent.

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% by weight to 85% by weight, the polymer film of the embodiment The coextruded film provided according to the manufacturing method may have a higher airtightness and durability, and at the same time the content of the poly-ether segment contained in the first resin and the second resin is adjusted to an appropriate range. Therefore, the coextrusion film may have characteristics 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% to 85% by weight, The first resin is 5% to 100% by weight of the polyamide-based resin, or 0 to 95% by weight of the copolymer including the polyamide-based segment and the polyether-based segment Or 0 wt% to 70 wt%, and the second resin includes 0 wt% to 95 wt% or 0 wt% to 80 wt% of the polyamide resin; And 5 wt% to 100 wt% or 20 wt% to 100 wt% of the copolymer including the polyamide-based segment and the polyether-based segment.

In addition, in the method of manufacturing the polymer film of the embodiment, 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, and thus, three layers may be laminated. A base film layer having a laminated structure can be formed. In addition, since the laminated structure of the three layers formed is repeatedly stacked, a base film layer having a multilayer structure of more than three layers may be formed.

When the polymer film for innerliner including a base film layer having three or more laminated structures manufactured as described above is applied to a pneumatic tire, it is higher due to the first resin layer positioned between the two second resin layers. While airtightness can be achieved, the two second resin layers can ensure higher elasticity and low modulus characteristics, so that the polymer film for the innerliner may exhibit a not very high modulus, and the rigidity of the film increases at high temperatures. It can suppress and crystallize at high temperature.

On the other hand, the polyamide-based resin included in the first resin or the second resin may have a relative viscosity (96% solution of sulfuric acid) of 2.5 to 4.0 or 3.0 to 3.8. When the relative viscosity of the polyamide-based resin is less than 2.5, sufficient elongation may not be secured due to a decrease in toughness, which may cause damage during tire manufacturing or driving a vehicle, and speed up crystallization of heat to increase rigidity of the base film. Brittleness) The effect of delaying crystallization through phenomenon control cannot be sufficiently exhibited. When the relative viscosity of the polyamide-based resin is more than 4.0, the modulus or viscosity of the substrate film to be manufactured may be unnecessarily high, and the efficiency and economic efficiency of the manufacturing process may be lowered, and the tire innerliner may have appropriate moldability or It may be difficult to have elasticity, and the compatibility with the copolymer including the polyamide-based segment and the polyether-based segment may be deteriorated, which may cause physical property unevenness of the base film.

The relative viscosity of the polyamide-based resin refers to the relative viscosity measured using a 96% sulfuric acid solution at room temperature. Specifically, a sample of a certain polyamide-based resin (for example, 0.025 g of specimen) is dissolved in 96% sulfuric acid solution at different concentrations to prepare two or more measurement solutions (for example, a polyamide-based resin specimen). Dissolve in 96% sulfuric acid to make concentrations of 0.25 g / dL, 0.10 g / dL, and 0.05 g / dL, and make three measuring solutions), and the relative viscosity of the measuring solution using a viscosity tube at 25 ° C. (for example, , The ratio of the average passage time of the measurement solution to the viscosity tube passage time of 96% sulfuric acid solution can be obtained.

The polyamide-based resin contained in the first resin or the second resin may be used without any particular kind as long as it has a relative viscosity of 2.5 to 4.0 (96% sulfuric acid solution). Specific examples of the polyamide-based resin include nylon 6, nylon 66, nylon 46, nylon 11, nylon 12, nylon 610, nylon 612, nylon 6/66 copolymer, nylon 6/66/610 copolymer, nylon MXD6, nylon 6T, nylon 6 / 6T copolymers, nylon 66 / PP copolymers and nylon 66 / PPS copolymers; Or N-alkoxyalkylates thereof, for example, methoxymethylate of 6-nylon, methoxymethylate of 6-610-nylon or methoxymethylate of 612-nylon.

In addition, the polyamide-based resin contained in the first resin or the second resin may include a polyamide-based copolymer including two or more different repeating units.

The polyamide-based copolymer may include two or more different repeating units, and at least one of the repeating units of the polyamide-based copolymer may include a repeating unit of Formula 1 below.

[Formula 1]

In addition, the polyamide-based copolymer may further include repeating units of the following Formula 2 or Formula 3 in addition to the repeating units of Formula 1.

[Formula 2]

In Formula 2, R ₁ is a straight or branched chain 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 straight or branched chain aryl having 7 to 20 carbon atoms. Alkylene group.

[Formula 3]

In Formula 3, R ₂ is a linear or branched alkylene group having 1 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 C7-C20 linear or branched arylalkylene group.

The polyamide-based copolymer may include 0.5 wt% to 20 wt% or 1 to 18 wt% of the repeating unit of Formula 2.

In addition, the polyamide-based copolymer may include 0.5 to 20% by weight or 1 to 18% by weight of the repeating unit of 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 is 2-Azetidinone, 2-Pirrolidone, δ-Valerolactam, 1-Aza-2-Cyclooctanone, 2-Azacyclononanone, 10-Aminodecanoic acid, 11 in addition to caprolactam -Aminoundecanoic acid, Laurolactam or a mixture thereof can be synthesized as a monomer, and can be synthesized using a dicarboxylic acid and a diamine compound selectively.

The usable carboxylic acid may include Malonic acid, Succinic acid, Glutaric acid, Adipic acid, Pimelic acid, Suberic acid, Azelaic acid, Sebacic acid, Dodecanedioic acid, Isophtalic acid, Terephtalic acid, or mixtures thereof. In addition, the usable diamine compounds include 1,4-Diaminobutane, 1,5-Diaminopentane, Hexametylene diamine, 1,7-Diaminoheptane, 1,8-Diaminooctane, 1,10-Decanediamine, m-Xylene diamine or mixtures thereof Can be mentioned.

In addition, the polyamide-based copolymer may be synthesized by copolymerizing a polymer including a repeating unit of Formula 1 and a polymer including a repeating unit of Formula 2 or Formula 3.

Meanwhile, the copolymer including the polyamide-based segment and the polyether-based segment included in the first resin or 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 substrate film to be produced may not secure sufficient mechanical properties for use in the polymer film for innerliner, and if the weight average molecular weight of the copolymer is more than 500,000, it is heated to a high temperature. As the modulus or crystallinity of the base substrate film is excessively increased, it may be difficult to secure elasticity or elastic recovery rate to have as the polymer film for innerliner.

The polyamide-based segment of the copolymer may include a repeating unit of Formula 11 or Formula 12 below.

[Formula 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 arylalkylene group having 7 to 20 carbon atoms.

[Formula 12]

In 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, Arylene groups having 6 to 20 carbon atoms or straight or branched arylalkylene groups having 7 to 20 carbon atoms.

Meanwhile, the polyether segment of the copolymer refers to a repeating unit including an alkylene oxide ('-Akyl-O-') group, and is formed from a polyether resin or a precursor thereof that participates in a polymerization reaction. Can be.

The polyether segment may be a main repeating unit that may be included in a polyalkylene glycol resin or a derivative thereof. In this case, the polyalkylene glycol derivative may have an amine group, a carboxyl group, or an isocyanate group at the terminal of the polyalkylene glycol resin. It may be a derivative substituted with, preferably substituted with an amine group. Preferably, the polyether segment is one selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene diamine, polyoxypropylene diamine, polyoxytetramethylene diamine, and copolymers thereof. It may be a main repeating unit included in the polyether resin.

In addition, the polyether segment of the copolymer may include a repeating unit represented by the following Formula 13.

[Formula 13]

In Formula 13, R ₅ is a linear or branched alkylene group having 1 to 10 carbon atoms, n is an integer of 1 to 100, R ₆ and R ₇ may be the same or different from each other, and are a direct bond, -O- , -NH-, -COO- or -CONH-.

The total content of the polyether segment in the base film obtained in the manufacturing 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-based segment is less than 2% by weight of the entire base film, the modulus of the base film or the polymer film for the inner liner is increased to reduce the moldability of the tire or to significantly decrease the physical properties due to repeated deformation. have. When the content of the polyether-based segment exceeds 40% by weight of the entire base film, the airtightness of the polymer film for the inner liner may be lowered, the reactivity to the adhesive is lowered, the inner liner is easily adhered to the carcass layer The following may be difficult, and the elasticity of the base film may be increased, and thus it may not be easy to prepare a uniform film.

Within the range in which the content ratio [2 wt% to 40 wt%] of the polyether segment in the base film is maintained, the copolymer may include the polyamide segment and the polyether segment in a predetermined weight ratio. Can be.

For example, the copolymer including the polyamide-based segment and the polyether-based segment may include the polyamide-based segment and the polyether-based segment in a range of 1: 9 to 9: 1, or 2: 8 to 8: 2, or It may be included in the weight ratio of 3: 7 to 7: 3.

In addition, the first resin and the second resin in the range of the content ratio [2% by weight to 40% by weight, or 4 to 20% by weight of the polyether-based segment in the above-described base film, from 9: 1 to 9: It can be coextruded using a weight ratio of 1: 9 or 8: 2 to 2: 8.

In addition, even when the first resin further comprises a copolymer including a polyamide-based segment and a polyether-based segment, or the second resin further comprises a polyamide-based resin, The content ratio [2% by weight to 40% by weight, or 4 to 20% by weight] of the polyether-based segment in the base film may be coextruded by adjusting the use weight ratio of the first resin and the second resin.

Meanwhile, each of the first and second resins may further include at least one additive selected from the group consisting of a heat resistant agent, a crosslinking agent, and an antioxidant. Such additives may be included in an amount of 0.001% by weight to 10% by weight in each of the first and second resins.

The method may further include forming an adhesive layer including a resorcinol-formalin-latex (RFL) adhesive on at least one surface of the base film. The adhesive layer including the resorcinol-formalin-latex (RFL) -based adhesive may be formed by coating a resorcinol-formalin-latex (RFL) -based adhesive on one surface of the base film layer, and the resorcinol- It can also be formed by laminating an adhesive film comprising a formalin-latex (RFL) -based adhesive on one surface of the base film layer.

Preferably, the forming of the adhesive layer may be performed by coating a resorcinol-formalin-latex (RFL) -based adhesive on one or both surfaces of the formed base film and then drying. The formed adhesive layer may have a thickness of 0.1 to 20 ㎛, preferably 0.1 to 10 ㎛. The resorcinol-formalin-latex (RFL) -based adhesive may be 2 to 32% by weight, preferably 10 to 20% by weight and latex 68 to 98% by weight, preferably 80 to 80%, of a condensate of resorcinol and formaldehyde. 90 weight percent. More specific information about the specific components of the resorcinol-formalin-latex (RFL) adhesive and the like will be described later.

On the other hand, according to another embodiment of the invention, the first resin layer containing a polyamide-based resin; And a base film including a second resin layer including a copolymer including a polyamide-based segment and a polyether-based segment.

As described above, when the first resin including the polyamide-based resin and the second resin including the copolymer including the polyamide-based segment and the polyether-based segment are coextruded, the first resin layer and The coextrusion film for innerliner containing the base film containing a 2nd resin layer can be manufactured.

The coextruded film for the inner liner may include a second water including a copolymer including the polyamide-based segment and the polyether-based segment together with high airtightness implemented from the first resin layer including the polyamide-based resin. It may have the elastomeric properties expressed from the strata.

Accordingly, the coextrusion film for the inner liner realizes excellent airtightness even at a thin thickness, thereby making it possible to reduce tire weight and improve fuel efficiency of a vehicle, and have high elasticity as well as excellent durability and fatigue resistance in a tire manufacturing process or a vehicle driving process. Can be secured. Specifically, the co-extruded film for the inner liner of the embodiment has excellent airtightness, for example, 10 to 20 times the airtightness compared to butyl rubber generally used in tires at the same thickness, but not very high modulus to show a high temperature The increase in the rigidity of the film can be suppressed and the crystallization at high temperature can be prevented.

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 of the second resin layers.

As the base film including the first resin layer and the second resin layer is included, the coextrusion film for the innerliner of the embodiment may have high elasticity and low modulus characteristics while ensuring improved airtightness.

In particular, the coextrusion film for innerliner of the above embodiment is more effective than the polymer film of the same thickness including the polyamide-based resin and the copolymer including the polyamide-based segment and the polyether-based segment together. Improved durability can be achieved with high airtightness.

The first resin layer may include 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 polyether-based segment in addition to the aforementioned polyamide-based resin.

The second resin layer may further include a polyamide resin in addition to the copolymer including the polyamide segment and the polyether segment.

The first resin layer further includes a copolymer including a polyamide-based segment and a polyether-based segment, and the second resin layer further includes a polyamide-based resin. Compared with the ground layer, the first resin layer may include more polyamide-based resin.

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

When the difference between the content (wt%) of the polyamide-based resin in the first resin layer and the content (wt%) of the polyamide-based resin in the second resin layer is within the above range, the coextrusion film of the embodiment may have a higher airtightness. The coextruded film may have high moldability and elasticity as the content of the polyether-based segment included in the first resin layer and the second resin layer is adjusted to an appropriate range. And the like.

Specifically, the first resin layer is 5% to 100% by weight of the polyamide-based resin or 30 to 100% by weight and 0% by weight of the copolymer including the polyamide-based segment and polyether-based segment To 95% by weight or 0% to 70% by weight. In addition, the second resin layer is 0% to 95% or 0 to 80% by weight of the polyamide resin; And 5 wt% to 100 wt% or 20 wt% to 100 wt% of the copolymer including the polyamide-based segment and the polyether-based segment.

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

That is, as described above, the copolymer further includes one kind of the first resin and less polyamide-based resin (the polyamide-based segment and the polyether-based segment than the first resin). It is possible to form a base film having a multilayer structure of two or more layers by co-extracting at least one or more kinds or two or more kinds of second resins, and thus, compared with one first resin layer and the first resin layer. A base film including one or more second resin layers containing less polyamide-based resin may be formed.

On the other hand, the total content of the polyether segment in the base film may be 2 to 40% by weight, or 3 to 30% by weight, or 4 to 20% by weight. The total content of the polyether-based segments in the base film is a ratio of the sum of the weights of the polyether-based segments in the copolymer which may be included in the second resin layer and the first resin layer relative to the total weight of the base film. Can be saved.

 If the content of the polyether-based segment is less than 2% by weight of the entire base film, the modulus of the base film or the inner liner polymer film is increased to reduce the moldability of the tire or to significantly decrease the physical properties due to repeated deformation. have. When the content of the polyether-based segment exceeds 40% by weight of the entire base film, the airtightness of the polymer film for the inner liner may be lowered, the reactivity to the adhesive is lowered, the inner liner is easily adhered to the carcass layer The following may be difficult, and the elasticity of the base film may be increased, and thus it may not be easy to prepare a uniform film.

In addition, in the coextrusion film of the embodiment, two second resin layers may be laminated on both surfaces of the first resin layer, and thus a base film layer having a three-layer laminated structure may be formed. In addition, since the laminated structure of the three layers formed is repeatedly stacked, a base film layer having a multilayer structure of more than three layers may be formed.

When the polymer film for innerliner including a base film layer having three or more laminated structures manufactured as described above is applied to a pneumatic tire, it is higher due to the first resin layer positioned between the two second resin layers. While airtightness can be achieved, the two second resin layers can ensure higher elasticity and low modulus characteristics, so that the polymer film for the innerliner may exhibit a not very high modulus, and the rigidity of the film increases at high temperatures. It can suppress and crystallize at high temperature.

The polyamide-based resin included in the first resin layer and the copolymer included in the second resin layer may chemically react in the coextrusion process, and thus the first resin layer and the second resin layer may be crosslinked. An interfacial layer including a crosslinking reaction between the polyamide-based 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 μm to 300 μm, or 1 μm to 250 μm, or 2 μm to 200 μm. The base film including the first resin layer and the second resin layer may have a thickness of 0.2 μm to 3,000 μm, or 2 μm to 2,500 μm, or 4 μm to 2,000 μm, or 40 μm to 400 μm.

The polyamide-based resin that may be included in the first resin layer or optionally included in the second resin layer may have a relative viscosity of 2.5 to 4.0 (96% sulfuric acid solution). The content regarding the relative viscosity and specific types of the polyimide-based resin is as described above.

The copolymer including the polyamide segment and the polyether segment, which may be included in the second resin layer or optionally included in the first resin layer, may have a weight average molecular weight of 50,000 to 500,000. have. More specific information on the weight average molecular weight of the copolymer is 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 an amount of 0.001% by weight to 10% by weight in each of the first resin layer and the second resin layer.

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 has a low modulus and a high strain rate and can be suitably applied to a tire forming process in which high expansion occurs. In addition, since the crystallization phenomenon hardly occurs in the unstretched film, damage such as cracks can be prevented even by repeated deformation, and the inner liner having uniform physical properties because the variation in the orientation and physical properties in a specific direction is not large. Can be obtained.

The coextrusion film for the 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 including the resorcinol-formalin-latex (RFL) -based adhesive has excellent adhesion and adhesion retention performance to the base film and the tire carcass layer, and thus, heat generated during tire manufacturing or driving Alternatively, the inner liner polymer film may have sufficient fatigue resistance by preventing fracture of the interface between the inner liner polymer film and the carcass layer caused by repeated deformation.

The main properties of the adhesive layer described above appear to be due to the inclusion of certain resorcinol-formalin-latex (RFL) based adhesives having a specific composition. As the adhesive for the inner liner, a rubber type tie gum or the like was used, and thus an additional vulcanization process was required. In contrast, the adhesive layer includes a resorcinol-formalin-latex (RFL) -based adhesive having a specific composition, and has high reactivity and adhesion to the base film, and is compressed under high temperature heating conditions without increasing the thickness. The base film and the tire carcass layer may be firmly bonded. Accordingly, it is possible to reduce the weight of the tire and to improve the fuel efficiency of the automobile, and to prevent the phenomenon of separating the carcass layer and the inner liner layer or the base film and the adhesive layer even during repeated deformation in the tire manufacturing process or the automobile driving process. Can be. In addition, since the adhesive layer may exhibit high fatigue resistance against physical and chemical deformations that may be applied during tire manufacturing or driving, the adhesive force may be applied even during the manufacturing process under high temperature conditions or during the driving of a vehicle in which mechanical deformation is applied for a long time. The degradation of other physical properties can be minimized.

In addition, the resorcinol-formalin-latex (RFL) -based adhesives are capable of crosslinking between latex and rubber, thereby exhibiting adhesive performance, and because they are physically latex polymers, have low curing properties and thus have flexible properties such as rubber. , Chemical bonding between the metirol end of the lesosinol-formalin polymer and the base film is possible. Accordingly, when the resorcinol-formalin-latex (RFL) -based adhesive is applied to the base film, high moldability and elasticity may be realized together with sufficient adhesive performance.

The resorcinol-formalin-latex (RFL) -based adhesive may be 2 to 32% by weight, preferably 10 to 20% by weight and latex 68 to 98% by weight, preferably 80 to 80%, of a condensate of resorcinol and formaldehyde. 90 weight percent.

The condensate of resorcinol and formaldehyde may be obtained by mixing the resorcinol and formaldehyde in a molar ratio of 1: 0.3 to 1: 3.0, preferably 1: 0.5 to 1: 2.5, and then condensation reaction. In addition, the condensate of the resorcinol and formaldehyde may be included in more than 2% by weight relative to the total amount of the adhesive layer in terms of chemical reaction for excellent adhesion, and may be included in less than 32% by weight in order to secure proper fatigue resistance properties. have.

The latex may be one or a mixture of two or more selected from the group consisting of natural rubber latex, styrene / butadiene rubber latex, acrylonitrile / butadiene rubber latex, chloroprene rubber latex and styrene / butadiene / vinylpyridine rubber latex. The latex may be included in more than 68% by weight relative to the total amount of the adhesive layer for the flexibility of the material and the effective crosslinking reaction with the rubber, it is included in 98% by weight or less for the chemical reaction with the base film and the rigidity of the adhesive layer.

In addition, the adhesive layer may further include one or more additives such as a surface tension modifier, a heat resistant agent, an antifoaming agent, and a filler, together with a condensate and latex of resorcinol and formaldehyde. At this time, the surface tension modifier of the additive is applied for uniform application of the adhesive layer, but may cause a problem of the adhesive force drop when the excessive input, it is less than 2% by weight or 0.0001 to 2% by weight based on the total amount of the adhesive layer, preferably May be included in an amount of 1.0 wt% or less or 0.0001 to 0.5 wt%. In this case, the surface tension modifiers sulfonate anionic surfactant, sulfate ester salt anionic surfactant, carboxylate anionic surfactant, phosphate ester salt anionic surfactant, fluorine-based surfactant, silicone-based surfactant and polysiloxane-based surfactant One or more selected from the group consisting of can be used.

The adhesive layer may have a thickness of 0.1 to 20 μm, preferably 0.1 to 10 μm, more preferably 0.2 to 7 μm, even more preferably 0.3 to 5 μm, and one surface of the coextrusion film for innerliner. Or on both surfaces. If the thickness of the adhesive layer is too thin, the adhesive layer itself may be thinner when the tire is inflated, the crosslinking adhesive force between the carcass layer and the base film may be lowered, and stress may be concentrated on a part of the adhesive layer, thereby reducing fatigue characteristics. In addition, when the adhesive layer is too thick, interfacial separation may occur in the adhesive layer, thereby reducing fatigue characteristics.

And, in order to adhere the polymer film for innerliner to the carcass layer of the tire, it is common to form an adhesive layer on one surface of the base film, but in the case of applying a multilayer polymer film for innerliner or the polymer film for innerliner According to the tire forming method and structural design such as wrapping, it is preferable to form an adhesive layer on both sides of the base film when rubber and adhesion are required on both sides.

On the other hand, according to another embodiment of the invention, a pneumatic tire including the co-extrusion film for the inner liner may be provided.

As described above, since the above-described coextrusion film for innerliner can realize excellent airtightness even with a thin thickness, the pneumatic tire can be lighter than the previously known pneumatic tire to improve the fuel efficiency of the automobile.

In addition, the co-extruded film for the inner liner ensures high elasticity and durability, so that the film itself crystallizes or the inside of the film even during a tire manufacturing process in which a large deformation is made under high temperature conditions or a vehicle driving process in which repeated deformation is continuously applied. The occurrence of damage such as cracks can be prevented, and accordingly, the pneumatic tire can secure high running stability and shape stability.

The pneumatic tire may have a structure of a commonly known pneumatic tire except for including the above-described coextrusion film for the inner liner.

For example, the pneumatic tire is a tread portion; A pair of shoulder parts each connected to both sides about the tread part; A pair of sidewall portions continuous to each of the shoulder portions; A pair of bead portions continuous to each of the sidewall portions; A body fly part formed inside the tread part, the shoulder part, the side wall part, and the bead part; A belt portion and a cap fly portion sequentially stacked between the tread portion inner surface and the body fly portion; And it may include a co-extrusion film for the inner liner coupled to the inside of the body fly.

According to the present invention, it is possible to realize excellent airtightness even at a thin thickness to lighten the tire and improve the fuel efficiency of the car, and to secure high elasticity with excellent durability and fatigue resistance in the tire manufacturing process or the driving process of the car. A pneumatic tire including a co-extrusion film for a liner, a manufacturing method capable of providing the co-extrusion film for the inner liner, and the co-extrusion film for the inner liner may be provided.

By using the co-extrusion film for the innerliner, it is possible to improve the vehicle fuel efficiency by reducing the overall tire weight without changing the tire compound or the tread design, and improve the vehicle running stability or the shape stability of the tire.

1 schematically shows the structure of a pneumatic tire.
Figure 2 schematically shows a process of manufacturing a multilayer structure film using a feed block in the embodiment.
Fig. 3 schematically shows an interfacial surface generator used in the embodiment.

The invention is explained in more detail in the following examples. However, the following examples are merely to illustrate the invention, but the content of 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

prepared from ε-caprolactam Weight average molecular weight 110,000 comprising a nylon 6 resin having a relative viscosity of 3.6% solution (96% sulfuric acid solution) and a polyether-based segment having a polypropylene oxide at the end of the amine group and a polyamide-based segment derived from ε-caprolactam The first resin was prepared by mixing a copolymer of (polyether-based segment: polyamide-based segment weight ratio of 1: 3) in a weight ratio of 6: 4. In addition, a second resin was prepared by mixing a nylon 6 resin having a relative viscosity (3.6% solution of sulfuric acid) of 3.6 and the copolymer having the weight average molecular weight of 110,000 in a weight ratio of 4: 6.

After drying the first resin and the second resin, respectively, a base film was manufactured by using two extruders and a feed block having a three-layer structure, and a first resin layer (B layer) was formed in the first extruder. The first resin, which is a raw material, was added and extruded at 255 ° C, and the second extruder, which was a raw material constituting the second resin layer (A layer), was extruded at 260 ° C.

As schematically shown in Figure 2, to form a multi-layer structure, a three-layer feed block (Feed Block) was installed on the extrusion die, the first resin layer (B layer) forms an inner layer (Core-Layer) Melt flow of the multilayer film having a three-layer structure in which the second resin layer (A layer) forms a surface layer (Skin-Layer) [second resin layer (A layer) / first resin layer (B layer) / agent 2 resin layer (A layer)] was produced.

The molten resin flow of the multilayer film formed with the structure and composition as described above is extruded through a T-type die (die gap [1.5 mm]), and molten resin is used on the surface of the cooling roll controlled at 20 ° C. using air knife. Was cooled and solidified into a film of uniform thickness to obtain a three-layer unstretched base film having a thickness of 100 μm at a speed of 15 m / min. At this time, one second resin layer (A layer) accounted for 10% of the total base film thickness, and the first resin layer (B layer) occupied 80% of the total base film thickness.

(2) application of adhesive

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

Then, the resorcinol-formalin-latex (RFL) -based adhesive was coated on the obtained non-stretched base film of the three-layer structure by using a gravure coater, dried and reacted at 150 ° C. for 1 minute, and then the adhesive layer having a thickness of 3 μm Formed.

< Example 2 >

(1) Production of base film

Polyamide-based resin [relative viscosity (96% solution of sulfuric acid solution 3.8)] synthesized using 95% by weight of ε-caprolactam and 5% by weight of 2-azacyclononanone and polypropylene oxide at the amine group end A copolymer having a weight average molecular weight of 100,000 including a polyether-based segment having a main chain and a polyamide-based segment derived from ε- caprolactam (the weight ratio of the polyether-based segment: polyamide-based segment is 1: 4) 7: Mixing at a weight ratio of 3 to prepare a first resin.

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

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

Then, using the first resin and the two kinds of second resins, three extruders, a three-layered feed block, and two serially connected two-channel separators (2 channel interfacial surface generators) are used. To prepare a base film.

Specifically, in the first extruder, after drying the first resin mixed with the polyamide-based resin and the copolymer having a weight average molecular weight of 100,000 at a weight ratio of 7: 3, the mixture was introduced and extruded at 255 ° C. Another second resin (copolymer having a weight average molecular weight of 100,000) was dried and extruded at 260 ° C. The third extruder contained a 4: 6 copolymer of the polyamide-based resin and the weight average molecular weight of 100,000. After drying the second resin mixed by weight ratio, it was added and extruded at 260 ℃.

After the extrusion, a core layer is formed from the resultant extruded by the first extruder in a feeder block having a three-layer structure installed on the two-layer separation device to form a multilayer structure (B Layer) Skin layers (Skin-Layer) were formed from the resultant extruded in the second extruder and the third extruder (A layer and C layer) to form a molten resin stream having a three-layer structure [A layer / B layer / C floor].

In the three-layer structure of “A layer / B layer / C layer” formed from the feed block, the thickness of the layer A accounts for 5% of the total thickness of the three layer structure, and the thickness of the layer B is the total thickness of the three layer structure. Accounted for 85%, and the layer structure was constructed such that the thickness of the C layer accounted for 10% of the total thickness of the three-layer structure.

In order to successively multiply the melt flow of the three-layer structure to a thinner thickness, the layers were separated and stacked by using a 2-channel interfacial surface generator continuously connected to a feed block. That is, the three-layer structure of “A layer / B layer / C layer” formed from the feed block is passed through the first 2-channel interfacial surface generator to separate and stack the three layer structure to form a six layer structure ( Multi-layered with “A / B / C / A / B / C”), successively passed through a second 2-channel interfacial surface generator to separate and stack the six-layer structure in the same way. A layer structure (“A / B / C / A / B / C / A / B / C / A / B / C”) was formed.

The molten resin flow of the multilayer film formed with the structure and composition as described above is extruded through a T-type die (Die Gap-1.5 mm), and the molten resin is used by using an air knife on the surface of a cooling roll controlled at 18 ° C. Was cooled and solidified into a film with a uniform thickness to obtain an unstretched base film having a multilayer structure having a thickness of 100 μm at a rate of 10 m / min.

 (2) application of adhesive

Resorcinol and formaldehyde were mixed in a molar ratio of 1: 2, and then condensation reaction was carried out to obtain a condensate of resorcinol and formaldehyde. 15% by weight of the condensate of resorcinol and formaldehyde and 85% by weight of styrene / butadiene-1,3 / vinylpyridine latex were mixed to obtain a resorcinol-formalin-latex (RFL) adhesive having a concentration of 25%.

In addition, the resorcinol-formalin-latex (RFL) -based adhesive was coated on the obtained non-stretched base film having a 12-layer structure using a gravure coater, dried and reacted at 150 ° C. for 1 minute to form an adhesive layer having a thickness of 5 μm. Formed.

< Experimental Example >

Experimental Example 1 Heat resistance

The heat toughness of the base film obtained in the said Example was measured as follows.

After leaving the substrate film at 23 ° C. and 50% relative humidity for 24 hours, immediately after being left at 170 ° C. hot air oven for 1 hour, immediately after being left at 100 ° C. hot air oven for 1 hour, at 23 ° C. and 50% relative humidity environment. The length of the substrate film heat treated using a universal tensile tester (Tensile test machine, Instron, Inc.) at a sample length of 30 mm and a sample width of 30 mm and a tensile speed of 300 mm / min under ) Tensile strength and elongation at break in 10) and transverse directions (TD) were measured 10 times, respectively, and averaged over 8 values except the maximum and minimum values.

In order to minimize the deviation caused by the external environment during the heat treatment, the tensile test specimen was cut to the size necessary for measurement before heat treatment, after the heat treatment to minimize the change of physical properties, and the measurement was completed within 15 minutes after the heat treatment.

After the heat treatment, the thermal toughness of the base film (MD) and the transverse direction (TD) of the base film was determined using the breaking strength and the breaking elongation value of the base film.

<Formula 1>

Base Film Toughness (MPa) = Breaking Strength (MPa) x SQRT [Elongation at Break (%)]

(SQRT stands for Square Root.)

Experimental Example 2 : Oxygen Permeability Experiment

The polymer film for tire innerliner obtained in the above example was subjected to ASTM D 1434 method using a gas transmission rate tester (Model BR-1 / BT-2, manufactured by Toyoseiki Seisaku-Sho) in oxygen at 25 degrees 60 RH% atmosphere. Permeability was measured.

Experimental Example 3 : Easy measurement of molding

By applying the polymer film for tire inner liner of the above embodiment, 100 tires were manufactured in 205R / 65R16 specifications. After the production of the green tire during the tire manufacturing process, the ease of manufacture and appearance were evaluated, and the final appearance of the tire after vulcanization was then examined.

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

With respect to 100 tires manufactured by applying the polymer film for tire innerliner of the above embodiment, the number of tires having a good appearance was confirmed to evaluate molding ease, and molding ease was obtained as in the following general formula (2).

<Formula 2>

Experimental Example 4 Durability Measurement Experiment

The FMVSS139 tire durability measurement method was used to increase the load and to evaluate the durability of the tire manufactured in Experimental Example 3. This durability measurement is performed by two methods, Endurance Test which increases the load by using the Step Load method and High Speed Test which increases the speed, and checks whether there is a crack inside the tire. '

By evaluating the final appearance of the tire by the method of Experimental Example 3, 20 tires were selected for each appearance, and each of the ten tires was subjected to an endurance test and a high speed test. After the durability measurement, ten tires were used as the number of tires without any occurrence of durability, and the tire durability according to Endurance Test and High Speed Test was calculated as in the following general formula (3).

<Formula 3>

Experimental Example 5 : Air pressure holding performance measurement

The tire produced in Experimental Example 3 was evaluated by measuring the internal pressure retention (IPR: Internal Pressure Retention) for 90 days as shown in the following general formula (4) under the pressure of 101.3kPa at 21 ℃ temperature using ASTM F1112-06 method.

 <Formula 4>

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

Example 1 Example 2 Oxygen Permeability [cc / (㎡ · 24hr · atm)] 58 45 Base Film
Heat Toughness (MPa) Longitudinal direction (MD) 1,652 1,587 Transverse (TD) 1,399 1,250 Moldability (%) 100 99 Tire durability
(%) Endurance Test 100 100 High Speed Test 100 100 Air pressure retention rate (%) 97.1 97.8

As shown in Table 1, the polymer film for innerliner obtained in the above embodiment exhibits an oxygen permeability of 60 cc / (m 2 · 24hr · atm) or less even at a thickness of about 103 μm to 105 μm, thereby providing excellent airtightness even at a thin thickness. It can be realized, it can be ensured high durability when applied to the tire with excellent moldability, and both the longitudinal and transverse direction of the base film can be confirmed that it can have a heat resistance of 1250 MPa or more.

Claims (35)

First resin comprising 5% to 100% by weight of polyamide-based resin, 0% to 95% by weight of copolymer including polyamide-based segment and polyether-based segment, and 0% by weight of polyamide-based resin And a substrate film forming step of co-extruding a second resin including 5 wt% to 100 wt% of the copolymer including% to 95 wt% and a polyamide-based segment and a polyether-based segment.
The difference between the content of the polyamide-based resin in the first resin (wt%) and the content of the polyamide-based resin in the second resin (wt%) is 5% to 85% by weight, used as an inner liner of the tire Method for producing a polymer film.
delete delete delete delete delete delete The method of claim 1,
The polyamide-based resin has a relative viscosity (96% solution of sulfuric acid) of 2.5 to 4.0, the method for producing a polymer film.
The method of claim 1,
The copolymer comprising the polyamide-based segment and the polyether-based segment has a weight average molecular weight of 50,000 to 500,000.
The method of claim 1,
The forming of the base film further includes forming a base film having a multilayer structure including at least two layers by co-extrusion of at least one or more of the first resin and at least one or more second resins. .
The method of claim 1,
The base film forming step
Co-extruding at least one or more types of second resins containing less polyamide-based resin than the first resin and the first resin to form a base film having a two-layer or more multilayer structure, the polymer film Manufacturing method.
The method according to claim 10 or 11, wherein
The said coextrusion uses the feed block which can form the base film of a multilayer structure, The manufacturing method of a polymer film.
The method of claim 1,
The base film forming step further comprises the step of stacking the co-extruded result to multi-layer the base film, a method for producing a polymer film.
The method of claim 1,
The coextrusion is carried out at 200 ° C to 300 ° C, method for producing a polymer film.
The method of claim 1,
The forming of the base film may be performed such that the coextrusion products of the first resin and the second resin are not stretched in a machine direction (MD) or in a transverse direction (TD).
The method of claim 1,
Cooling the co-extrusion product of the first resin and the second resin further comprises the step of forming a base film in the form of a film having a thickness of 4 ㎛ to 2,000 ㎛, a method for producing a polymer film.
The method of claim 1,
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 crosslinking agent and an antioxidant, wherein the polymer film production method.
The method of claim 1,
Forming an adhesive layer comprising a resorcinol-formalin-latex (RFL) -based adhesive on at least one side of the base film, a method for producing a polymer film.
A first resin layer comprising 5 wt% to 100 wt% of a polyamide resin and 0 wt% to 95 wt% of a copolymer including a polyamide segment and a polyether segment; And a second resin layer comprising 0 wt% to 95 wt% of polyamide-based resin and 5 wt% to 100 wt% of a copolymer including a polyamide-based segment and a polyether-based segment. Including,
The difference between the content (wt%) of the polyamide-based resin in the first resin layer and the content (wt%) of the polyamide-based resin in the second resin layer is 5% to 85% by weight,
Coextrusion film for inner liner.
delete delete The method of claim 19,
The base film has a two or more multilayer structure comprising at least one of the first resin layer and at least one of the second resin layer, co-extrusion film.
The method of claim 19,
The first resin layer and the second resin layer each has a thickness of 0.1 ㎛ to 300 ㎛ coextrusion film.
The method of claim 19,
The polyamide-based resin contained in the first resin layer has a relative viscosity (96% solution of sulfuric acid) of 2.5 to 4.0, the coextrusion film.
The method of claim 19,
The copolymer including the polyamide-based segment and the polyether-based segment included in the second resin layer has a weight average molecular weight of 50,000 to 500,000.
delete delete delete The method of claim 19,
Coextrusion film, wherein the total content of the polyether-based segment in the base film is 2 to 40% by weight
The method of claim 19,
The base film may include at least one or more types of second resin layers containing less polyamide-based resin than the first resin layer and the first resin layer. The coextrusion film which has a multilayer structure of two or more layers containing.
The method of claim 19,
The coextrusion film, wherein the base film is an unstretched film that is not substantially stretched.
The method of claim 19,
A co-extrusion film formed on at least one side of the base film and further comprising an adhesive layer comprising a resorcinol-formalin-latex (RFL) -based adhesive.
33. The method of claim 32,
The adhesive layer has a thickness of 0.1 ㎛ to 20 ㎛, co-extrusion film.
The method of claim 19,
Each of the first resin layer and the second resin layer further includes 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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