KR102188026B1 - Copolymer andn polymer film - Google Patents

Abstract

The present invention, polyamide-based repeating unit 20% to 90% by weight; 2 to 45% by weight of linear or branched alkylene oxide repeating units having 2 to 10 carbon atoms; 0.001% to 10% by weight of arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and at least two acyl functional groups; And 4% to 38% by weight of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms, and a polymer film including a base film including the copolymer.

Description

Copolymer and polymer film {COPOLYMER ANDN POLYMER FILM}

The present invention relates to a copolymer and a polymer film, and more particularly, a copolymer capable of securing a relatively high level of impact strength and having high stability that does not change significantly in physical properties and shape at high temperatures, and excellent airtightness even with a thin thickness. When used as an inner liner film by implementing, it is possible to lighten the tire and improve the fuel economy of the vehicle, and to a polymer film having physical properties such as high durability, high heat resistance and high fatigue resistance along with excellent moldability.

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

Tread (1): A part that comes into contact with the road surface, provides frictional force necessary for braking and driving, has good wear resistance, must be able to withstand external shocks, and has low heat generation.

Body Ply (or Carcass) (6): A layer of cord inside the tire that supports loads, withstands impact, and has strong fatigue resistance against flexion movements while driving.

Belt (5): It is located between the body plies, and in most cases, it is composed of steel wire. It not only relieves external shocks, but also maintains a wide tread tread to provide excellent driving stability.

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

Inner Liner (7): It is located inside the tire instead of a tube, and it prevents air leakage to enable pneumatic tires.

BEAD (9): A square or hexagonal wire bundle coated with rubber on the wire, and plays a role of seating and fixing the tire on the rim.

CAP PLY (4): This is a special cordage located on the belt of radial tires for some passenger cars, and minimizes the movement of the belt while driving.

APEX (8): This is a triangular rubber filler used to minimize the dispersion of beads, protect the beads by mitigating external impacts, and prevent air inflow during molding.

Recently, tube-less tires (or pneumatic tires) injected with high-pressure air of 30 to 40 psi inside without using a tube are commonly used. In order to prevent leakage into the carcass, an inner liner with high airtightness is disposed on the inner layer of the carcass.

Previously, tire inner liners containing rubber components such as butyl rubber or halo butyl rubber, which have relatively low air permeability, were used as main components.In these inner liners, the content of rubber or the thickness of the inner liner had to be increased to obtain sufficient airtightness. . However, when the content of the rubber component and the tire thickness increase, there is a problem that the total weight of the tire increases and the fuel economy of the vehicle decreases.

In addition, the rubber components have relatively low heat resistance, so that air pockets are created between the inner rubber and the inner liner of the carcass layer during the vulcanization process of tires where repeated deformation occurs under high temperature conditions or during the operation of automobiles. There was a problem of changing shape or physical properties. In addition, in order to bind the rubber components to the kercus layer of the tire, a vulcanizing agent or a vulcanization process had to be applied, and it was difficult to secure sufficient adhesive strength by this.

However, any previously known method has limitations in maintaining excellent air permeability and moldability of a tire while sufficiently reducing the thickness and weight of the inner liner. In addition, the inner liner obtained by a previously known method has its own physical properties deteriorated or cracks occur in the film during the manufacturing process of tires in which high-temperature repetitive molding is performed or during the operation of automobiles where high heat is generated by repeated deformation. A lot of problems appeared.

Due to the recent rise in oil prices, interest in eco-tyres (eco-friendly tires) that can improve automobile fuel economy has increased, and attempts to reduce the weight of tires or reduce the folding area through changes in tire compounds or tread designs have been made. Have been. However, according to the previously known method, there is a certain limitation in reducing the weight of the tire and improving the fuel economy of the vehicle while improving the driving stability or the shape stability of the tire.

The present invention is to provide a copolymer capable of securing a relatively high level of impact strength with high stability that does not change significantly in physical properties and shape at high temperatures.

In addition, the present invention realizes excellent airtightness even with a thin thickness, so that when used as an inner liner film, it is possible to lighten the tire and improve the fuel efficiency of automobiles, and a polymer having physical properties such as high durability, high heat resistance and high fatigue resistance along with excellent formability It is to provide a film.

In the present specification, 20% to 90% by weight of polyamide repeating units; 2 to 45% by weight of linear or branched alkylene oxide repeating units having 2 to 10 carbon atoms; 0.001% to 10% by weight of arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and at least two acyl functional groups; And 4% to 38% by weight of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms.

In addition, in the present specification, a polymer film including a base film including the copolymer is provided.

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

In the present specification, the arylene group refers to a divalent functional group derived from arene. In addition, in the present specification, the alkylene group refers to a divalent functional group derived from alkane.

According to an embodiment of the present invention, 20% to 90% by weight of a polyamide-based repeating unit; 2 to 45% by weight of linear or branched alkylene oxide repeating units having 2 to 10 carbon atoms; 0.001% to 10% by weight of arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and at least two acyl functional groups; And 4% to 38% by weight of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms; may be provided.

The present inventors conduct research on the material of the inner liner film to solve the limitations of previously used rubber components such as butyl rubber or halobutyl rubber, and the physical properties and shape do not change significantly even at room temperature as well as high temperature conditions. It has high stability, can secure a relatively high level of impact strength, and has synthesized a novel copolymer having excellent mechanical properties along with high elasticity and low modulus properties and completed the invention.

In particular, the copolymer includes a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms, has high stability that does not change significantly in physical properties and shape at high temperatures, and can secure a relatively high level of impact strength. As a result, the inner liner of the pneumatic tire provided using the copolymer secures high airtightness, while the change in physical properties and shape are not so large during the tire molding process or the driving process of the vehicle, thereby securing high durability and fatigue resistance properties. can do.

The copolymer may include 4 wt% to 38 wt%, or 5 wt% to 30 wt%, or 6 wt% to 20 wt% of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms.

If the content of the linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms in the copolymer is too small, it may be difficult to ensure that the heat resistance or thermal decomposition temperature of the copolymer is sufficiently high, and the copolymer at high temperature The retention rate of physical properties or shape may be significantly lowered before and after tensioning.

In addition, if the content of the linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms in the copolymer is too large, the dialkyl siloxane repeating unit, polyamide repeating unit and alkylene oxide in the process of synthesizing the copolymer Since the bonding between the repeating units is not smooth, synthesis into a copolymer may not be easy, and the flexibility of the copolymer may be greatly reduced.

Specifically, the linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms may include the repeating unit of Formula 4 below.

[Formula 4]

In Formula 3, R ₈ and R ₉ may be the same as or different from each other, and each is methyl or ethyl, and n is an integer of 5 to 50, or an integer of 10 to 30, or an integer of 13 to 27.

If n is too small among the repeating units of Formula 4, the flexibility of the copolymer decreases, and it is difficult to exhibit excellent elasticity in a wide temperature range. In addition, if n is too large among the repeating units of Formula 4, the ratio of maintaining the properties and shape of the copolymer of the embodiment at high temperature may be lowered, and phase separation may occur in the copolymer.

In addition, the copolymer includes an arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more, and has high heat resistance and heat resistance along with high airtightness and excellent moldability. Strength can be secured, and by minimizing the decrease in modulus properties due to heat in a high temperature environment, the effect of improving toughness properties and improving durability can be expressed. Accordingly, when the copolymer is applied as an inner liner of a pneumatic tire, the change in physical properties may not be very large even during the tire forming process or the driving process in which the tire is repeatedly deformed at high temperature, and the rate of crystallization at high temperature is relatively small. It is possible to prevent crystallization of the polymer structure itself due to the rise and breakage of the polymer structure accordingly.

The arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more is a dicarboxylic acid or poly-carboxylic acid including an arylene group having 6 to 20 carbon atoms. It may be derived from an acid, for example, may be derived from a raw material such as terephthalic acid or isophthalic acid used in the manufacture of the polymer film.

Specific examples of the arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more may include the repeating unit of Formula 5 below.

[Chemical Formula 5]

In Formula 5, Ar is an arylene group having 6 to 20 carbon atoms.

The copolymer may include 0.001 wt% to 10 wt%, or 0.005 to 5 wt% of the arylene acyl repeating unit.

If the content of the arylene acyl repeating unit in the copolymer is too small, the heat resistance or heat shock resistance of the copolymer itself or the polymer film obtained therefrom may not be sufficiently secured. When exposed to high temperature conditions of 100° C. or higher, the polymer The physical properties of the film can be greatly deteriorated. In addition, if the content of the arylene acyl repeating unit in the copolymer is too high, the content of the polyamide repeating unit or polyether repeating unit decreases, and the airtightness or durability of the copolymer itself or a polymer film obtained therefrom is reduced. It may be lowered or their modulus may be increased or the elasticity or formability may be lowered.

Meanwhile, the polyamide-based repeating unit may include a repeating unit of Formula 1 or Formula 2 below.

[Formula 1]

In Formula 1, R ₁ is a straight or branched alkylene group having 1 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a straight or branched arylalkylene group having 7 to 20 carbon atoms. More preferably, in Formula 1, R ₁ may be an alkylene group having 3 to 6 carbon atoms.

[Formula 2]

In Formula 2, R ₂ is a straight or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms, and R ₃ is a linear or branched alkylene group having 1 to 20 carbon atoms, It is a C6-C20 arylene group or a C7-C20 linear or branched arylalkylene group.

The content of the polyamide-based repeating unit in the copolymer may be determined in consideration of the physical properties or final use of the final copolymer or a polymer film manufactured using the copolymer. Specifically, the copolymer is a C2 to C10 linear or branched alkylene oxide repeating unit and the C1 to C4 linear or branched dialkyl siloxane repeating unit and the remaining amount excluding components that may be optionally included The content may include a polyamide-based repeating unit, and specifically, 20 to 90% by weight, 55 to 85% by weight; may be.

The linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms may include the repeating unit of Formula 3 below.

[Chemical Formula 3]

In Formula 3, R ₅ is a straight or branched alkylene group having 2 to 10 carbon atoms, n is an integer of 5 to 150, R ₆ and R ₇ may be the same as or different from each other, and each of a direct bond, -O -, -NH-, -COO- or -CONH-.

The linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms may be derived from a monomer, oligomer or polymer having a weight average molecular weight of 500 to 10,000, preferably 1,000 to 3,000.

If n among the repeating units of Formula 3 is too small, the copolymer may not properly function such as suppressing the growth of large crystals at high temperature or lowering the modulus. If n is too high among the repeating units of Formula 3, the durability of the copolymer may decrease, and the gas permeability of the polymer film prepared using the copolymer may be greatly increased.

The copolymer of the embodiment may contain 2% to 45% by weight, or 5% to 40% by weight, or 8% to 35% by weight of a linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms. I can.

If the content of the linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms in the copolymer is too low, the modulus of the copolymer and the polymer film prepared using the copolymer increases, so that the The physical properties of the copolymer or polymer film may be greatly deteriorated. In addition, if the content of the linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms in the copolymer is too high, the elasticity of the copolymer may be excessively increased, making it difficult to prepare a uniform film. , The polymer film prepared from the copolymer has poor gas barrier properties required as a tire inner liner, so tire performance may be degraded. Since the reactivity to the adhesive is lowered, it may be difficult for the polymer film to easily adhere to the carcass layer by the inner liner.

The copolymer may have a weight average molecular weight of 50,000 to 300,000, or 70,000 to 250,000, or 90,000 to 200,000. The weight average molecular weight of the copolymer is less than 50,000, and sufficient mechanical properties or heat resistance to use the copolymer as a material for an inner liner of a pneumatic tire may not be secured. In addition, if the weight average molecular weight of the copolymer exceeds 300,000, the modulus or crystallinity of the copolymer is excessively increased when heated to a high temperature, so it may be difficult to secure the elasticity or elastic recovery rate that should be obtained as an inner liner film.

The copolymer may further include an alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and an acyl functional group having at least two or more. The alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and an acyl functional group having at least 2 or more is a dicarboxylic acid or poly-carboxylic acid including an alkylene group having 1 to 10 carbon atoms. It may be derived from an acid, for example, may be derived from a raw material such as adipic acid used in the manufacture of the copolymer.

Specific examples of the alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and an acyl functional group having at least 2 or more may include the repeating unit of Formula 6 below.

[Chemical Formula 6]

In Formula 6, R ₁₀ is a linear or branched alkylene group having 1 to 10 carbon atoms.

The copolymer may further include 0.001 wt% to 10 wt%, or 0.005 to 5 wt% of the alkylene acyl repeating unit.

If the content of the alkylene acyl repeating unit in the copolymer is too small, heat resistance or thermal shock resistance may not be sufficiently secured, and when exposed to high temperature conditions of 100° C. or higher, physical properties of the copolymer may be greatly deteriorated. In addition, if the content of the alkylene acyl repeating unit in the copolymer is too high, the content of the polyamide repeating unit or the polyether repeating unit decreases, and the airtightness of the copolymer or the polymer film prepared from the copolymer Durability may decrease, the modulus of the copolymer or the polymer film may increase, or elasticity or moldability may decrease.

In particular, the copolymer may include an arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more; And an alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and an acyl functional group having at least two or more; high airtightness and excellent molding when applied to a tire inner liner In addition to the performance, high heat resistance and heat resistance can be secured, and accordingly, the change in physical properties may not be very large even in the tire forming process or the driving process of automobiles where repeated deformation is performed at high temperature, and the rate of crystallization at high temperature is relatively small, so the temperature rises. It is possible to prevent the crystallization of the film itself and the damage of the film accordingly.

Specifically, an arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more; And the molar ratio of the alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and at least two acyl functional groups may be 1:1 to 1:7, or 1:1.1 to 1:5. have.

An alkylene group having 1 to 10 carbon atoms and an acyl functional group having at least 2 carbon atoms compared to the arylene acyl repeating unit including the arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more If the molar ratio of the alkylene acyl repeating unit including a is less than 1, it may be difficult to secure high heat resistance and heat shock resistance.

In addition, an alkylene group having 1 to 10 carbon atoms and an acyl having at least 2 carbon atoms compared to the arylene acyl repeating unit including the arylene group having 6 to 20 carbon atoms and at least two acyl functional groups If the molar ratio of the alkylene acyl repeating unit including the functional group is more than 7, the elastic properties may be deteriorated due to the high rigidity properties.

On the other hand, the method of synthesizing the copolymer is not largely limited, the polyamide-based repeating unit; A linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms; Arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more; And a precursor or a reactant capable of forming a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms at a reaction temperature of 100° C. or higher. In addition, in the process of synthesizing the copolymer, a precursor or a reactant capable of forming an arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more is further used. I can.

Meanwhile, according to another embodiment of the present invention, a polymer film including a base film including the above-described copolymer may be provided.

As described above, the copolymer comprises 20% to 90% by weight of polyamide-based repeating units; 2 to 45% by weight of linear or branched alkylene oxide repeating units having 2 to 10 carbon atoms; 0.001 wt% to 10 wt%, or 0.005 wt% to 5 wt% of arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and at least two acyl functional groups; And 4% to 38% by weight of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms.

In addition, the copolymer is 0.001% to 10% by weight, or 0.005% to 5% by weight of an alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and at least two acyl functional groups. Can include.

The polyamide repeating unit, a linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms, a straight or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms, an arylene group having 6 to 20 carbon atoms And an arylene acyl repeating unit including at least two acyl functional groups, an alkylene group having 1 to 10 carbon atoms, and an alkylene acyl repeating unit including at least two acyl functional groups and a copolymer. Specific details include the above-described contents with respect to the copolymer of the embodiment.

The polymer film including the base film containing the copolymer has high stability that does not change significantly in physical properties and shape at room temperature as well as at high temperature, and can secure a relatively high level of impact resistance, and while securing high airtightness, the tire forming process However, even in the process of driving a vehicle, changes in physical properties and changes in shape are not so large, so high durability and fatigue resistance can be secured.

The polymer film may be used as an inner liner for a pneumatic tire.

On the other hand, when the deformation test of elongating the base film by 10% to 30% in the temperature range of -75 °C to -25 °C is repeatedly performed, the rate of change of the area under the stress strain curve of the base film The shape recovery, defined as, may be 55% or more, or 60% to 95%. The deformation test may be repeated 10 or more times, or 10 to 100 times.

In addition, when the deformation test of elongating the base film by 10% to 30% was repeatedly performed in a temperature range of -75 °C to -25 °C, the rate of change in plastic strain (εp) of the base film was 25%. Or less, or may be 5% to 25%.

That is, the polymer film including the base film does not have a large rate of change in physical properties or shape even in a wide range of low-temperature regions, for example, in the temperature range of -75°C to -25°C, and the recovery rate thereof is also relatively high.

The high recovery rate exhibited by the polymer film at low temperatures seems to be due to the polymer structure of the above-described copolymer, and specifically, the copolymer is the dialkyl siloxane repeating unit and the aryl repeating unit together with the polyamide repeating unit and the alkylene oxide repeating unit. It appears to be due to the inclusion of the renacyl repeating unit, and as the alkyleneacyl repeating unit is selectively further included in addition to the arylene acyl repeating unit, the effect may be more clearly shown.

The polymer film may have a thickness of 30 to 300 μm, preferably 40 to 250 μm, more preferably 40 to 200 μm. Accordingly, the polymer film of one embodiment of the present invention may have a lower air permeability, for example, an oxygen permeability of 200 cc/(m 2 ·24 hr·atm) or less while having a thin thickness compared to previously known ones. Specifically, the oxygen permeability of the polymer film of the embodiment measured for 24 hours through the ASTM D 1434 method at a temperature of 23°C and a relative humidity of 55RH% is 200 cc/(m²·24hr·atm) or less, or 20 To 200 cc/(m2·24hr·atm), or 30 to 120 cc/(m2·24hr·atm).

Meanwhile, the polymer film may further include a polyamide resin having a relative viscosity (sulfuric acid 96% solution) of 3.0 to 4.0, or 3.2 to 3.5, optionally together with the above-described copolymer.

If the viscosity of the polyamide-based resin is less than 3.0, sufficient elongation may not be secured due to the decrease in the toughness of the polymer film, and thus damage may occur during tire manufacturing or driving, and the polymer film should have as an inner liner film. It may be difficult to secure physical properties such as airtightness or moldability. In addition, when the viscosity of the polyamide-based resin exceeds 4.0, the modulus or viscosity of the polymer film to be produced may be unnecessarily increased, and it may be difficult to have appropriate moldability or elasticity as a tire inner liner.

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

Polyamide resins that can be used in the polymer film include polyamide resins such as 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 copolymer, nylon 66/PP copolymer and nylon 66/PPS copolymer; Or N-alkoxyalkylated products thereof, such as 6-nylon methoxymethylated, 6-610-nylon methoxymethylated or 612-nylon methoxymethylated, nylon 6, nylon 66 or nylon It is preferable to use 46.

In addition, the polyamide resin may be included in the polymer film not only by using the resin itself, but also by preparing a polymer film using a monomer of the polyamide resin or a precursor of the polyamide resin.

The polymer film may be mixed with a polyamide-based resin having a relative viscosity (sulfuric acid 96% solution) of 3.0 to 4.0 in consideration of the specific physical properties or shape of the finally produced inner liner film and the copolymer in an appropriate ratio. , For example, a polyamide resin having a relative viscosity of 3.0 to 4.0 (a 96% sulfuric acid solution): the weight ratio of the copolymer may be 7:3 to 1:9.

Meanwhile, the polymer film may further include 10 to 500 ppmw of a heat resistant agent. If the content of the heat-resistant agent is less than 10 ppmw of the polymer film, the effect of improving heat resistance may be insignificant, and if it exceeds 500 ppmw, the physical properties of the polymer film may be deteriorated, and there is substantially no effect of improving heat resistance according to the amount used. It can unnecessarily increase the price of the final product. As a specific example of such a heat resistant agent, an aromatic amine compound, a hindered phenol compound, a phosphorus compound, an inorganic compound, a polyamide compound, a polyether compound, or a mixture of two or more thereof may be used.

Meanwhile, the polymer film of the embodiment may further include an adhesive layer formed on at least one surface of the polymer film and comprising a resorcinol-formalin-latex (RFL)-based adhesive.

The adhesive layer including the resorcinol-formalin-latex (RFL)-based adhesive enables the polymer film to have excellent adhesion and adhesion retention performance even to the tire carcass layer, and accordingly, in the manufacturing process or driving process of a tire By preventing breakage of the interface between the inner liner film and the carcass layer generated by heat generated or repeated deformation, the polymer film of one embodiment can have sufficient fatigue resistance when applied as an inner liner film.

The main characteristics of the above-described adhesive layer appear to be due to the inclusion of a specific resorcinol-formalin-latex (RFL)-based adhesive having a specific composition. Previously, rubber-type tie gum was used as an adhesive for tire inner liner, and accordingly, an additional vulcanization process was required. In contrast, the adhesive layer includes a resorcinol-formalin-latex (RFL)-based adhesive of a specific composition, and has high reactivity and adhesion to the polymer film, and is compressed under high temperature heating conditions without increasing the thickness. The polymer film and the tire carcass layer can be firmly bonded.

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

The condensation product 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 a condensation reaction. In addition, the condensate of resorcinol and formaldehyde may be included in an amount of 2% by weight or more with respect to the total amount of the adhesive layer in terms of chemical reaction for excellent adhesion, and less than 32% by weight to secure appropriate 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 an amount of 68% by weight or more based on the total amount of the adhesive layer for the flexibility of the material and effective crosslinking reaction with the rubber, and 98% by weight or less for the chemical reaction with the base film and the rigidity of the adhesive layer.

The adhesive layer may have a thickness of 0.1 to 20 µm, preferably 0.1 to 10 µm, more preferably 0.2 to 7 µm, even more preferably 0.3 to 5 µm, and on one or both surfaces of the polymer film Can be formed in

If the thickness of the adhesive layer is too thin, the adhesive layer itself may become thinner during tire expansion, the crosslinking adhesion between the carcass layer and the base film may be lowered, and stress may be concentrated in a part of the adhesive layer to lower fatigue properties. In addition, if the adhesive layer is too thick, interfacial separation in the adhesive layer may occur, resulting in poor fatigue properties.

For the application of the adhesive, a commonly used application or coating method or device may be used without any particular limitation, but a knife coating method, a bar coating method, a gravure coating method or a spray method, or an immersion method may be used. Can be used. However, it is preferable to use a knife (Knife) coating method, a gravure coating method, or a bar coating method in terms of uniform application and coating of the adhesive.

In addition, the method of manufacturing the polymer film is not subject to great limitation, and a method of manufacturing a polymer film known in general may be used.

For example, a raw material including the above-described copolymer or a raw material optionally additionally including a polyamide resin is supplied to an extrusion die, and melted and extruded at 200°C or higher or 230°C to 300°C to form a polymer film. I can. The temperature at which the raw material is melted may be 230 to 300 °C, preferably 240 to 280 °C. The melting temperature should be higher than the melting point of the polyamide-based compound, but if it is too high, carbonization or decomposition may occur, thereby impairing the physical properties of the film, and bonding between the polyether-based repeat units may occur or orientation may occur in the fiber arrangement direction. .

The extrusion die can be used without any other limitation as long as it is known that it can be used for extrusion of a polymer resin, but a T-type die is used to make the thickness of the polymer film more uniform or prevent orientation in the polymer film. It is desirable.

Meanwhile, forming the polymer film may include extruding the melt-extruded raw material into a film having a thickness of 30 to 300 μm. Control of the thickness of the produced film may be achieved by adjusting extrusion conditions, for example, an extruder discharge amount or a gap of an extrusion die, or by changing a winding speed of a cooling process or a recovery process of the extrudate.

In order to more uniformly control the thickness of the polymer film layer in the range of 30 to 300 μm, the die gap of the extrusion die may be adjusted to 0.3 to 1.5 mm. In the step of forming the polymer film, if the die gap is too small, the die shear pressure in the melt extrusion process becomes too high and the shear stress increases, making it difficult to form a uniform shape of the extruded film and decrease productivity. If the die gap is too large, the elongation of the melt-extruded film may be too high to cause orientation, and the difference in physical properties between the longitudinal and transverse directions of the polymer film to be produced may increase.

In addition, in the manufacturing method of the polymer film, the thickness of the polymer film manufactured by the above-described steps is continuously measured, and the measurement result is fed back to the portion of the extrusion die corresponding to the position where the uneven thickness appears, for example, T -By adjusting the die's lip gap adjustment bolt, it is possible to obtain a film having a more uniform thickness by reducing the deviation of the manufactured polymer film. In addition, it is possible to configure an automated process step by using an automated system, such as an Auto Die system, for the thickness measurement of the film, feedback, and control of the extrusion die.

According to the present invention, a copolymer capable of securing a relatively high level of impact resistance and a copolymer capable of securing a relatively high level of impact resistance and excellent airtightness even with a thin thickness, so as to reduce tire weight when used as an inner liner film. And it is possible to improve fuel efficiency of automobiles, and a polymer film having physical properties such as high durability, high heat resistance, and high fatigue resistance along with excellent moldability can be provided.

The polymer film is used as a tire inner liner film to ensure high airtightness and excellent moldability, as well as high heat resistance and heat resistance. Accordingly, changes in physical properties are not very likely in the tire forming process or the vehicle driving process in which repeated deformation at high temperature is performed. It may not be large, and since the rate of crystallization at high temperature is relatively small, crystallization of the film itself due to an increase in temperature and thus damage of the film can be prevented.

1 schematically shows the structure of a tire.
2 shows 1H NMR data of the copolymer synthesized in Example 1.

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

[ Example And Comparative example : Synthesis of copolymer and production of polymer film]

Example One

(1) Synthesis of copolymer

In a 2L reactor, 700 g of ε-caprolactam, 250 g of polyoxytetramethylenediamine (molecular weight approx. 1,000), 50 g of hydroxy terminated polydimethylsiloxane, hydroxy terminated, 1000 g/mol of weight average molecular weight, 21.9 g of isophthalic acid, After adding 24.9 g of adipic acid, 14 g of water was added, followed by stirring at 150° C. at 80 rpm.

Then, the temperature of the reactor was increased to 250° C. to maintain a pressure of 0.33 MPa and reacted at 80 rpm for 1 hour. Thereafter, the pressure of the reactor was gradually removed for 30 minutes to create atmospheric pressure, and the reaction was completed in this state, and the final reaction result was prepared in the form of chips. The chip prepared above was washed with water at 95° C. for 24 hours to remove unreacted substances, and then vacuum dried at 100° C. for 20 hours. 1H NMR data of the final synthesized copolymer by vacuum drying are as shown in FIG. 2.

(2) Preparation of polymer film

The dried chips were extruded with a melt extruder at a temperature of 250° C. and a polymer film of 120 μm was prepared through a T-die.

Example 2 to 4

change the amount of ε-caprolactam A copolymer was synthesized in the same manner as in Example 1, except that hydroxy group-terminated polydimethylsiloxane, isophthalic acid, and adipic acid were used as shown in Table 1 below, and a polymer film of 120 μm was prepared.

Comparative Example 1

Instead of using the hydroxy group-terminated polydimethylsiloxane (Poly (dimethylsiloxane), hydroxy terminated, weight average molecular weight 1000 g/mol), an additional 50 g of polyoxytetramethylenediamine was used instead, and isophthalic acid and adipic acid were not used. Except for the point, a copolymer was synthesized in the same manner as in Example 1 and a polymer film of 120 μm was prepared.

Comparative Example 2

In a 2L reactor, 700 g of ε-caprolactam, 270 g of polyoxytetramethylenediamine (molecular weight: 1,000), 30 g of hydroxy terminated polydimethylsiloxane, hydroxy terminated, weight average molecular weight of 1000 g/mol), and isophthalic acid _21.9_g , A copolymer was synthesized in the same manner as in Example 1, except that 24.9 g of adipic acid was added, and a polymer film of 120 μm was prepared.

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[ Experimental example : Measurement of polymer film properties]

Experimental Example 1 : shape Recovery rate ( shape recovery ) Measure

(1) Form at room temperature Recovery rate Measure

The polymer film obtained in the above Examples and Comparative Examples was subjected to a simple stretch cyclic test in which 20% elongation was performed 50 times using a universal material evaluation equipment (manufacturer Instron, equipment name 5566) at 25°C, and then form at room temperature. The recovery rate was measured. The shape recovery rate may be defined as a rate of change of an area under a stress strain curve of the base film during a simple stretch cyclic test on the base film.

(2) Form at low temperature Recovery rate Measure

The polymer film obtained in Examples and Comparative Examples was subjected to a simple stretch cyclic test in which 20% elongation was performed 50 times using a universal material evaluation equipment (manufacturer Instron, equipment name 5566) at -50°C. The morphology recovery rate at was measured. The shape recovery rate may be defined as a rate of change of an area under a stress strain curve of the base film during a simple stretch cyclic test on the base film.

Experimental Example 2 : Plastic deformation during elongation (εp, plastic strain ) Of change rate measurement

(1) Plastic deformation at room temperature (εp, plastic strain ) Of change rate measurement

The polymer films obtained in Examples and Comparative Examples were fired at room temperature after performing a simple stretch cyclic test in which 20% elongation was performed 50 times using a universal material evaluation equipment (manufacturer Instron, equipment name 5566) at 25°C. The rate of change of the strain (εp, plastic strain) was measured.

(2) plastic deformation at low temperature (εp, plastic strain ) Of change rate measurement

The polymer film obtained in Examples and Comparative Examples was subjected to a simple stretch cyclic test in which 20% elongation was performed 50 times using a universal material evaluation equipment (manufacturer Instron, equipment name 5566) at -50°C. The rate of change in plastic strain (εp, plastic strain) was measured.

Experimental Example 3 : Heat-resistant impact strength ( KJ /g)

The specimens (width 15 mm) of each of the polymer films obtained in Examples and Comparative Examples were set to a gauge length of 50 mm according to ASTM 882, and then a speed of 50 mm/min was applied to measure the thermal impact strength (KJ/g).

Experimental Example 4 : Oxygen permeability

After mounting each of the polymer films obtained in Examples 1 to 2 and Comparative Examples 1 to 2 in an oxygen permeability measuring device (Mocon's Ox-Tran 2/20), oxygen and carrier gas (nitrogen 98% + hydrogen 2%) While maintaining the relative humidity of 55%, oxygen permeability was measured at a temperature of 23° C. for 24 hours.

The results of Experimental Examples 1 to 4 are shown in Tables 1 and 2 below.

As shown in Table 1 above, the polymer film obtained in Examples maintains high elastic recovery power and shape recovery rate of the elastomer within a wide temperature range from room temperature to -50°C compared to the polymer film obtained in Comparative Example. Confirmed.

In addition, it was confirmed that the polymer film obtained in the example has a thermal impact resistance of 2200 KJ/g or more and a thermal impact resistance retention rate of 60% or more even after the heat treatment. On the other hand, it was confirmed that the polymer film of Comparative Example had a thermal shock resistance drop to less than 2200 KJ/g after the heat treatment and a thermal shock resistance retention rate of less than 60%.

That is, the polymer film of the above embodiment secures high heat resistance and heat resistance, so that when applied as an inner liner film, the change in physical properties may not be very large even in the tire forming process or the automobile driving process in which repeated deformation at high temperature. Since the ratio is relatively small, crystallization of the film itself due to an increase in temperature and damage of the film can be prevented.

Claims (18)

20% to 90% by weight of polyamide repeating units;
2 to 45% by weight of linear or branched alkylene oxide repeating units having 2 to 10 carbon atoms;
0.001% to 10% by weight of arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and at least two acyl functional groups; And
4% to 38% by weight of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms; comprising a base film including a copolymer,
The arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more is a repeating unit of Formula 5 below,
Defined as the rate of change of the area under the stress strain curve of the base film when a deformation test of 10% to 30% elongation of the base film is repeatedly performed in a temperature range of -75 °C to -25 °C That the shape recovery is more than 55%,
Polymer film:
[Chemical Formula 5]

In Formula 5, Ar is an arylene group having 6 to 20 carbon atoms.
The method of claim 1,
The polyamide-based repeating unit comprises a repeating unit of the following Formula 1 or Formula 2, a polymer film:
[Formula 1]

In Formula 1, R ₁ is a C 1 to C 20 linear or branched alkylene group, a C 6 to C 20 arylene group, or a C 7 to C 20 linear or branched arylalkylene group,
[Formula 2]

In Formula 2, R ₂ is a straight or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms, and R ₃ is a linear or branched alkylene group having 1 to 20 carbon atoms, It is a C6-C20 arylene group or a C7-C20 linear or branched arylalkylene group.
The method of claim 1,
The linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms comprises a repeating unit of Formula 3 below:
[Chemical Formula 3]

In Chemical Formula 3,
R ₅ is a C 2 to C 10 linear or branched alkylene group,
n is an integer from 5 to 150,
R ₆ and R ₇ may be the same as or different from each other, and each is a direct bond, -O-, -NH-, -COO- or -CONH-.
The method of claim 1,
The linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms comprises a repeating unit of Formula 4 below:
[Formula 4]

In Chemical Formula 4,
R ₈ and R ₉ may be the same as or different from each other and each is methyl or ethyl, and n is an integer from 5 to 50.
delete The method of claim 1,
The copolymer comprises 0.001% to 10% by weight of an alkyleneacyl repeating unit including an alkylene group having 1 to 10 carbon atoms and an acyl functional group having at least 2 or more; Further comprising a polymer film.
The method of claim 6,
The alkylene acyl repeating unit including an alkylene group having 1 to 10 carbon atoms and an acyl functional group of at least two or more comprises a repeating unit of Formula 6 below:
[Chemical Formula 6]

In Formula 6, R ₁₀ is a linear or branched alkylene group having 1 to 10 carbon atoms.
The method of claim 6,
An arylene acyl repeating unit including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more; And an alkylene group having 1 to 10 carbon atoms and an alkylene acyl repeating unit including at least two acyl functional groups having a molar ratio of 1:1 to 1:7.
The method of claim 1,
The copolymer,
55% to 85% by weight of polyamide repeating units;
8% to 35% by weight of a linear or branched alkylene oxide repeating unit having 2 to 10 carbon atoms;
0.005% to 5% by weight of arylene acyl repeating units including an arylene group having 6 to 20 carbon atoms and an acyl functional group having at least 2 or more; And
5% to 30% by weight of a linear or branched dialkyl siloxane repeating unit having 1 to 4 carbon atoms; containing, a polymer film.
delete delete The method of claim 1,
When the deformation test of elongating the base film by 10% to 30% was repeatedly performed in a temperature range of -75 °C to -25 °C, the rate of change of the plastic strain (εp, plastic strain) of the base film is 25% or less, Polymer film.
The method of claim 1,
Polymer film used as an inner liner for pneumatic tires.
The method of claim 1,
The base film has a thickness of 30 μm to 300 μm, a polymer film.
The method of claim 1,
The base film further comprises a polyamide-based resin having a relative viscosity of 3.0 to 4.0 (96% sulfuric acid solution), a polymer film.
The method of claim 15,
The polyamide-based resin: the weight ratio of the copolymer is 7:3 to 1:9, a polymer film.
The method of claim 1,
A polymer film formed on at least one surface of the base film and further comprising an adhesive layer comprising a resorcinol-formalin-latex (RFL)-based adhesive.
The method of claim 17,
The adhesive layer has a thickness of 0.1 μm to 20 μm, a polymer film.

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