WO2008013183A1

WO2008013183A1 - Inner liner for pneumatic tire, method for producing the same and pneumatic tire

Info

Publication number: WO2008013183A1
Application number: PCT/JP2007/064527
Authority: WO
Inventors: Daisuke Nakagawa; Daisuke Nohara; Daisuke Katou; Yuwa Takahashi
Original assignee: Bridgestone Corporation
Priority date: 2006-07-24
Filing date: 2007-07-24
Publication date: 2008-01-31

Abstract

Disclosed is an inner liner for pneumatic tires which is obtained by joining a resin film layer (A)(9) with a rubber-like elastic layer (B)(10) through an adhesive layer (C)(11). At least the adhesive layer (C)(11) side surface of the resin film layer (A)(9) is surface-modified, and separation resistance between the resin film layer and the rubber-like elastic layer is improved. The inner liner for pneumatic tires has high breaking resistance at bending, and hardly suffers from cracks. It is preferable that at least the adhesive layer (C)(11) side surface of the resin film layer (A)(9) is subjected to surface oxidation.

Description

Specification

Inner liner for pneumatic tire, method for producing the same, and pneumatic tire

Technical field

TECHNICAL FIELD [0001] The present invention relates to an inner liner for a pneumatic tire, a method for producing the same, and a pneumatic tire including the inner liner. In particular, the present invention improves rupture resistance during bending and suppresses the occurrence of cracks. It relates to a possible inner liner for a pneumatic tire.

Conventionally, a rubber composition mainly composed of butyl rubber, halogenated butyl rubber or the like has been used for an inner liner disposed as an air barrier layer on the inner surface of the tire in order to maintain the internal pressure of the tire. However, since the rubber composition mainly composed of these butyl rubbers has a low air-nore property, when the rubber composition is used for the inner liner, the thickness of the inner liner is reduced. It was necessary to be around lmm. Therefore, the weight of the inner liner in the tire is about 5%, which is an obstacle to reducing the tire weight and improving the fuel efficiency of the car!

[0003] On the other hand, an ethylene butyl alcohol copolymer (hereinafter sometimes abbreviated as EVOH) is known to have excellent gas barrier properties. The EVOH has an air permeation amount that is 1/100 or less of the above-mentioned rubber composition for inner liners, so that it can greatly improve the tire internal pressure retention even at a thickness of 100 μm or less. In addition, the weight of the tire can be reduced.

[0004] There are many resins with lower air permeability than the above butyl rubber. If the air permeability is about one-tenth of that of a butyl inner liner, the internal pressure retention is not required unless the thickness exceeds 100 m. When the thickness exceeds 100 m, the effect of reducing the weight of the tire is small, and the deformation force when the tire is bent. The inner liner breaks or the inner liner cracks. It will occur and it will be difficult to maintain barrier properties. [0005] On the other hand, when the above EVOH is used, it can be used even with a thickness of 100 μm or less, so that it is difficult to break due to bending deformation at the time of tire rolling, and cracks are also difficult to occur. Therefore, it can be said that it is effective to use EVOH as the tire inner liner in order to improve the internal pressure retention of the pneumatic tire. For example, Japanese Unexamined Patent Application Publication No. 2004-176048 discloses a pneumatic tire provided with an inner liner made of specific EVOH.

[0006] Further, the inner liner disclosed in Japanese Patent Application Laid-Open No. 2004-176048 is used by being attached to an auxiliary layer made of an elastomer through an adhesive layer in order to improve the internal pressure retention of the tire. It is preferred to do, and it is said that.

Disclosure of the invention

[0007] However, the present inventors have examined an inner liner for a pneumatic tire using a resin film layer and a rubber-like elastic body layer. In general, the resin film layer and the rubber-like elastic body layer are different from each other. It was found that the resin film layer having low adhesion is easily peeled off from the rubber-like elastic layer. Here, even with the technique disclosed in JP-A-2004- 176048, and a still adhesion between the resin film layer and rubbery elastomer layer is susceptible force ^s for improvement in low immediately peeling strength .

[0008] Further, the inner liner disclosed in Japanese Patent Application Laid-Open No. 2004-176048 is a power that can improve the air permeability of a pneumatic tire, and the inner liner has a low adhesiveness. There is room for improvement in peel resistance.

[0009] Further, from the viewpoint of mainly improving water resistance and adhesion to rubber, a thermoplastic urethane elastomer may be disposed on the outer layer portion of the inner liner made of EVOH. As a result, it has been found that by using a specific adhesive composition, it is possible to provide good adhesion workability and peeling resistance after heat bonding.

[0010] Therefore, an object of the present invention is to improve the peel resistance between the resin film layer and the rubber-like elastic body layer, increase the fracture resistance at the time of bending, and prevent the occurrence of cracks. And providing a method for manufacturing the inner liner. Another object of the present invention is to improve the adhesive strength of the adhesive layer so that it has durability that can withstand expansion during molding of the tire and to improve the peel resistance after vulcanization. , Increase rupture resistance during bending, It is an object of the present invention to provide an inner liner for a pneumatic tire capable of suppressing the generation of squeeze and a method for manufacturing the inner liner. Furthermore, another object of the present invention is to provide a pneumatic tire provided with such an inner liner.

[0011] As a result of intensive studies to achieve the above object, the present inventors have found that an inner liner for a pneumatic tire in which a resin film layer and a rubber-like elastic body layer are joined via an adhesive layer. In one aspect, the surface of the resin film layer at least on the side of the adhesive layer is modified to provide a pneumatic tire having excellent peeling resistance, excellent rupture resistance when bent, and suppressing occurrence of cracks. And found that an inner liner can be obtained.

[0012] Further, as a result of further investigations, the present inventors have determined that at least one surface of the resin film layer in the inner liner for a pneumatic tire comprising a laminate having a resin film layer and an adhesive layer. By making the surface free energy above a certain value, it is possible to obtain an inner liner for tires that is durable enough to withstand expansion when molding tires, has excellent rupture resistance when bent, and suppresses the occurrence of cracks. As a result, the present invention has been completed.

That is, in the first inner liner for a pneumatic tire of the present invention, the resin film layer (A) and the rubber-like elastic body layer (B) are bonded via the adhesive layer (C). Become

The resin film layer (A) is characterized in that at least the surface on the adhesive layer (C) side is surface-modified.

[0014] In the first inner liner for a pneumatic tire of the present invention, it is preferable that at least a surface of the resin film layer (A) on the side of the adhesive layer (C) is subjected to surface oxidation treatment. Further, as the surface oxidation treatment, a corona discharge treatment is more preferable.

[0015] The second inner liner for a pneumatic tire of the present invention includes a resin film layer (A) and an adhesive layer (C) disposed on the resin film layer (A). The surface free energy of at least one surface of the resin film layer (A) is 50 mN / m or more.

[0016] In a preferred example of the inner liner for a pneumatic tire of the present invention, a modified ethylene butyl alcohol copolymer obtained by reacting the resin film layer (A) with an ethylene butyl alcohol copolymer ( At least a layer comprising D). Here, the resin film layer (A) includes at least a layer containing the modified butyl alcohol copolymer (D). It may have another layer which is preferable, or it may be composed only of a layer containing the above-mentioned modified butyl alcohol copolymer (D).

[0017] In the inner liner for a pneumatic tire of the present invention, when the resin film layer (A) includes at least a layer containing the modified ethylene butyl alcohol copolymer (D), the ethylene butyl alcohol copolymer The ethylene content of the coalescence is preferably 25-50 mono%. Further, the saponification degree of the ethylene butyl alcohol copolymer is preferably 90% or more. Furthermore, it is preferable that the modified ethylene-butyl alcohol copolymer (D) is obtained by reacting 1 to 50 parts by mass of an epoxy compound with respect to 100 parts by mass of the ethylene-butyl alcohol copolymer. Furthermore, the layer containing the modified ethylene butyl alcohol copolymer (D) has a functional group that reacts with a hydroxyl group in the matrix made of the modified ethylene butyl alcohol copolymer (D), and has a Young's modulus of 500 MPa. The resin composition (F) in which the following flexible resin (E) is dispersed is preferable. In addition, the matrix here means a continuous phase.

[0018] In another preferable embodiment of the pneumatic tire for an inner liner aspect of the present invention, the resin film Lum layer (A), 20 ° C, the oxygen permeability at 65% RH is 3.0 X 10- ¹² cm ³ ' cm / cm ² • seccmHg¾T

In another preferred embodiment of the inner liner for a pneumatic tire of the present invention, the resin film layer (A) has a thickness of 100 Hm or less.

[0020] In another preferred embodiment of the inner liner for a pneumatic tire of the present invention, the resin film layer (A) is crosslinked! /.

[0021] In the inner liner for a pneumatic tire according to the present invention, when the resin film layer (A) includes at least a layer containing the modified ethylene butyl alcohol copolymer (D), the modified ethylene butyl alcohol copolymer is used. The polymer (D) is preferably crosslinked.

[0022] The inner liner 1 for a pneumatic tire according to the present invention includes the modified ethylene-bule alcohol when the resin film layer (A) includes at least the layer containing the modified ethylene butyalcohol copolymer (D). It is preferable to provide one or more auxiliary layers (G) that also have an elastomeric force adjacent to the layer containing the copolymer (D). Here, the auxiliary layer (G) More preferably, it includes a plastic urethane elastomer. The total thickness of the auxiliary layer (G) is more preferably in the range of 10 to 100 μm.

[0023] In another preferable example of the second inner liner for a pneumatic tire of the present invention, at least one surface of the coating liquid containing the adhesive composition (H) and the organic solvent is surface-modified. The surface of the resin film layer (A) is applied and dried to form the adhesive layer (C), and the rubber-like elastic layer (B) is further bonded to the surface of the adhesive layer (C). It is obtained by performing a sulfur treatment.

[0024] In another preferred embodiment of the second inner liner for a pneumatic tire of the present invention, the coating liquid containing the adhesive composition (H) and the organic solvent is used as the rubber-like elastic layer (B). The adhesive layer (C) is formed by coating and drying on the surface of the adhesive layer, and the resin film layer (A) having at least one surface modified is bonded to the surface of the adhesive layer (C) and added. It can be obtained by sulfur treatment.

[0025] In another preferred embodiment of the inner liner for a pneumatic tire of the present invention, the rubbery elastic layer (B) contains butyl rubber and / or halogenated butyl rubber.

[0026] A first method for producing an inner liner for a pneumatic tire according to the present invention includes the step of modifying the surface of the resin film layer (A) with a coating solution containing an adhesive composition (H) and an organic solvent. The coated layer is coated and dried to form an adhesive layer (C). Next, the rubber-like elastic layer (B) is bonded to the surface of the adhesive layer (C) with! /, And vulcanized. It is characterized by performing processing.

[0027] Further, in the second method for producing an inner liner for a pneumatic tire of the present invention, a coating liquid containing an adhesive composition (H) and an organic solvent is applied to the rubber-like elastic layer (B). ) Applied and dried to form an adhesive layer (C), and then the surface of the resin film layer (A) is bonded to the surface of the adhesive layer (C). The vulcanization treatment is performed.

[0028] A pneumatic tire according to the present invention is characterized by using the inner liner for a pneumatic tire.

[0029] According to the present invention, the resin film layer and the rubber-like layer are bonded to the rubber-like elastic body layer via the adhesive layer, with the resin film layer having at least the adhesive layer side surface modified. It is possible to provide an inner liner for a pneumatic tire which has excellent resistance to peeling from an elastic layer and which has high fracture resistance when bent, and suppresses the occurrence of cracks, and a method for producing the inner liner. it can. In addition, a laminate including a resin fine layer (A) having a surface free energy of at least a certain value or more on one side and an adhesive layer (B) disposed on the resin film (A) is used. Provides an inner liner for pneumatic tires that is durable enough to withstand expansion during molding of the tire, has excellent fracture resistance when bent, and suppresses the occurrence of cracks, and a method for manufacturing the inner liner can do. Further, it is possible to provide a pneumatic tire provided with an inner liner that is strong and capable.

Brief Description of Drawings

FIG. 1 is a partial cross-sectional view of an example of a pneumatic tire according to the present invention.

FIG. 2 is a partial cross-sectional view of an example of an inner liner for a pneumatic tire according to the present invention.

FIG. 3 is a partial cross-sectional view of another example of an inner liner for a pneumatic tire according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0031] The present invention is described in detail below. The first inner liner for a pneumatic tire according to the present invention is for a pneumatic tire in which a resin film layer (A) and a rubber-like elastic body layer (B) are bonded via an adhesive layer (C). It is an inner liner, and at least the surface of the resin film layer (A) on the adhesive layer (C) side is surface-modified. In the first inner liner for a pneumatic tire of the present invention, since the joint surface of the resin film layer (A) is surface-modified, the peel resistance is greatly improved. In addition, since the peeling of the resin film layer (A) is suppressed, the inner liner of the present invention also suppresses the generation of cracks having high rupture resistance during bending!

[0032] In the first inner liner for a pneumatic tire of the present invention, the resin film layer (A) is adhered to the adhesive layer (C) disposed on the surface of the resin film layer (A). In order to improve the property and, in turn, improve the peel resistance to the rubber-like elastic layer (B), surface modification is required. Here, as the method of surface modification, surface oxidation treatment is preferable. As the surface oxidation treatment, corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, etc. are preferable, among which the equipment is inexpensive. The corona discharge treatment is particularly preferable because it can be carried out in the atmosphere and at atmospheric pressure. When the resin film layer (A) is surface-modified, the surface-modified surface has high surface free energy. [0033] The second inner liner for a pneumatic tire of the present invention includes a resin film layer (A) and an adhesive layer (C) disposed on the resin film layer (A). The surface free energy of at least one surface of the resin film layer (A) is 50 mN / m or more. Here, in the inner liner for a pneumatic tire of the present invention, the surface free energy of at least one surface of the resin film layer (A) is 50 mN / m or more, so that the wettability is improved and the adhesive layer (C) The adhesive strength of can be improved. This improves the peel resistance between the rubber on the inner surface of the tire and the inner liner, and improves the shear adhesive strength of the joint (joint) where the inner liner is bonded in an annular shape in the tire manufacturing process. Therefore, in the second inner liner for a pneumatic tire of the present invention, the occurrence of cracks with high fracture resistance during bending is also suppressed.

[0034] In the resin film layer (A) of the second inner liner for a pneumatic tire of the present invention, the surface free energy on the surface on which the adhesive layer (C) is formed is set to 50 mN / m or more. Therefore, the peel resistance between the tire inner surface and the inner liner can be improved, and the surface free energy on the surface opposite to the surface on which the adhesive layer (C) is formed should be 50 mN / m or more. Therefore, it is possible to improve the shear adhesive strength of the joint where the inner liner is bonded in a ring shape. From the above, both effects can be obtained if the surface free energy on both surfaces of the resin film layer (A) is 50 mN / m or more.

[0035] The second inner liner for a pneumatic tire of the present invention requires that the surface free energy of at least one surface of the resin film layer (A) is 50 mN / m or more, and is 50 to 80 mN / m. Preferably there is. Here, in order to increase the surface free energy of the resin film layer (A) to 50 mN / m or more, it is preferable to modify the surface of the resin film layer (A). More preferably, the treatment is performed. Preferred examples of the surface oxidation treatment include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, etc. Among these, corona discharge treatment is particularly preferred.

[0036] The resin that can be used for the resin film layer (A) is not particularly limited, and may be a specific resin alone, or other materials are dispersed in the specific resin. It may be a compound. As the power and mulch compound, those that form sea-island structures are preferred. A thermoplastic resin is suitably used as the sea part of the sea-island structure. The thermoplastic resin preferably has a Young's modulus of more than 500 MPa at 23 ° C. Specifically, polyamide resins, polyvinylidene chloride resins, polyester resins, thermoplastic urethane elastomers, ethylene Examples thereof include a butyl alcohol copolymer resin, and among these, an ethylene-butyl alcohol copolymer resin is preferable. In general, ethylene-butyl alcohol copolymer-based resins have a low gas permeation and a very high gas barrier property. These thermoplastic resins may be used singly or in combination of two or more.

[0037] In addition, the resin film layer (A) has a surface free energy, and therefore it is preferable that an oxygen-containing group is present on the surface of the resin film layer (A). More preferably, a functional group is present. Such a functional group can improve the wettability of the resin film layer (A). Accordingly, it is preferable that the resin film layer (A) is a thermoplastic resin having an ethylene butyl alcohol copolymer-based resin. For example, a modified ethylene obtained by reacting an ethylene butyl alcohol copolymer with an epoxy compound. -More preferred is a butyl alcohol copolymer (D). Since such a modified ethylene butyl alcohol copolymer (D) has a lower elastic modulus than a normal ethylene butyl alcohol copolymer, the rupture resistance during bending is high and cracks are difficult to occur. .

Therefore, it is preferable that the resin film layer (A) includes at least a layer containing a modified ethylene butyl alcohol copolymer (D) obtained by reacting an ethylene butyl alcohol copolymer.

[0039] The ethylene Bulle alcohol copolymer, it forces S preferably ethylene content of 25 to 50 mol%, 30 to 48 mole ^_0/0, it is further preferred tool 35-45 mole ^_0/0 More preferably, it is. If the ethylene content is less than 25 mol%, the bending resistance, fatigue resistance, and melt moldability may deteriorate. On the other hand, if it exceeds 50 mol%, the gas barrier properties may not be sufficiently secured. Further, the ethylene-butyl alcohol copolymer preferably has a saponification degree of 90% or more, more preferably 95% or more, and still more preferably 99% or more. If the degree of saponification is less than 90%, gas barrier properties and Thermal stability at the time of molding may be insufficient. Further, the ethylene-butyl alcohol copolymer has a melt flow rate (MFR) of 190.degree. C. under a load of 2160 g, 0.;! To 30 g / 10 min. S, preferably 0.3 to 25 g / 10 min. More preferably it is.

[0040] In the present invention, although the method for producing the modified ethylene butyl alcohol copolymer (D) is not particularly limited, the production is a reaction in which an ethylene butyl alcohol copolymer and an epoxy compound are reacted in a solution. A method is preferably mentioned. More specifically, a modified ethylene-butyl alcohol copolymer (D) is added to an ethylene-vinyl alcohol copolymer solution in the presence of an acid catalyst or an alkali catalyst, preferably in the presence of an acid catalyst, and reacted. ) Can be manufactured. Examples of the reaction solvent include non-proton polar solvents such as dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Examples of the acid catalyst include P-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, sulfuric acid, and boron trifluoride. Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, and hydroxide. Examples include lithium and sodium methoxide. In addition, the catalyst amount is preferably in the range of 0.0001 to 10 parts by mass with respect to 100 parts by mass of the ethylene-butyl alcohol copolymer. Further, the modified ethylene-butyl alcohol copolymer (D) is formed into a film, a sheet or the like at a melting temperature of preferably 150 to 270 ° C. by melt molding, preferably extrusion molding such as T-die method or inflation method. And used as the resin film layer (A).

[0041] As the epoxy compound to be reacted with the ethylene butyl alcohol copolymer, a monovalent epoxy compound is preferable. Of the monovalent epoxy compounds, glycidol and epoxypropane are particularly preferred from the viewpoints of ease of production of the modified ethylene butyl alcohol copolymer, gas barrier properties, flex resistance and fatigue resistance. The epoxy compound is preferably 1 to 50 parts by mass, more preferably 2 to 40 parts by mass, and more preferably 5 to 35 parts by mass with respect to 100 parts by mass of the ethylene butyl alcohol copolymer. It is more preferable to react.

[0042] The modified ethylene butyl alcohol copolymer (D) is preferably crosslinked. If the modified ethylene-butyl alcohol copolymer (D) is not cross-linked, the resin film layer (A) will deform significantly and become non-uniform in the vulcanization process for producing pneumatic tires. Therefore, the gas barrier properties, flex resistance, and fatigue resistance of the inner liner may be deteriorated. In the method for producing the modified ethylene-butyalcohol copolymer (D), it is possible to crosslink the modified ethylene-butyalcohol copolymer (D) by using a divalent or higher valent epoxy compound.

[0043] The modified ethylene-butalcohol copolymer (D) preferably has a saponification degree of 90% or more, more preferably 95% or more, and even more preferably 99% or more. Is more preferable. If the saponification degree is less than 90%, the gas barrier property and the thermal stability during molding will be insufficient. The modified ethylene monobutyl alcohol copolymer (D) has a melt flow rate (MFR) of 190 ° C and a load of 2160g from the viewpoint of obtaining gas-noreness, bending resistance and fatigue resistance. Preferably 30-30 g / 10 min, more preferably 0.3-25 g / 10 min, and even more preferably 0.5-20 g / 10 min.

[0044] The layer containing the modified ethylene butyl alcohol copolymer (D) has a functional group that reacts with a hydroxyl group in a matrix composed of the modified ethylene butyl alcohol copolymer (D) and has a Young's modulus. It is preferable to use a resin composition (F) in which a flexible resin (E) of 500 MPa or less is dispersed. Dispersing the flexible resin (E) in a matrix that also has the modified ethylene-butyl alcohol copolymer (D) force significantly reduces the elastic modulus and suppresses the occurrence of breakage and cracks during bending. be able to. Here, since the flexible resin (E) has a functional group that reacts with a hydroxyl group, the flexible resin (E) is uniformly dispersed in the matrix. Examples of the functional group that reacts with a hydroxyl group include a maleic anhydride residue, a hydroxyl group, a carboxyl group, and an amino group. Specific examples of the flexible resin (E) having a functional group that reacts with a hydroxyl group include maleic anhydride-modified hydrogenated styrene ethylene-butadiene-styrene block copolymer, maleic anhydride-modified ultra-low density polyethylene, and the like. It is done. Further, when the Young's modulus of the flexible resin (E) is 500 MPa or less, the elastic modulus of the resin film layer (A) can be lowered, and as a result, the bending resistance can be improved.

[0045] Further, the ratio of the flexible resin (E) to the total of the modified ethylene butyl alcohol copolymer (D) and the flexible resin (E) is 10 to 10% from the viewpoint of improving the bending resistance and the gas barrier property. A range of 30% by weight is preferred. Furthermore, the flexible resin (E) has an average particle size of 2 The following is preferable. If the average particle size exceeds 2, the bending resistance may not be sufficiently improved, and the gas barrier property may be lowered. The average particle diameter of the flexible resin (E) in the resin composition (F) is observed, for example, by freezing the sample, cutting the sample with a microtome, and observing with a transmission electron microscope (TEM).

[0046] The resin film layer (A) preferably has a Young's modulus at 23 ° C of more than 500 MPa.

[0047] The resin film layer (A), the oxygen permeability at 20 ° C, 65% RH is ^{3.0 X 10- 12 cm 'cm /} cm' sec ' that mosquitoes preferably cmUg than, 1.0 X 10 cm' The force is more preferably cm / cm * sec'cmHg or less, and more preferably 5.0 × 10 cm'cm / cm'sec-cmHg or less. When the oxygen permeability at 20 ° C, 65% RH is more than ^{3.0 X 10- 12 cm cm / cm} sec 'cmHg, when used for the inner liner of all, in order to increase the internal pressure retainability of the tire, the resin film layer ( A) must be made thick, and the weight of the tire cannot be reduced sufficiently.

[0048] The thickness of the resin film layer (A) is preferably 100 m or less, more preferably the lower limit is 0.1 m; and the range is from! To 40 m. More preferred is the range of 5-30 am! If the thickness of the resin film layer (A) exceeds 100 μm, the effect of reducing the weight will be less than that of a conventional butyl rubber-based inner liner when used for an inner liner, and the bending resistance and Fatigue resistance is reduced, and it is easy for fractures / cracks to occur due to bending deformation during rolling of the tire, and because the cracks are likely to extend, the internal pressure retention of the tire may be reduced compared to before use. On the other hand, if it is less than O.l ^ m, the gas barrier property is insufficient, and the tire internal pressure retention may not be sufficiently secured.

[0049] Further, the resin film layer (A) is preferably crosslinked! /, Preferably! /. If the resin film layer (A) is cross-linked! /, N! /, The inner liner is significantly deformed and becomes non-uniform during the vulcanization process of the tire, and the gas barrier properties, flex resistance, and fatigue resistance of the inner liner are reduced. Sexuality may worsen. Here, as the crosslinking method, the method of irradiating energy rays is preferred. Examples of the energy rays include ionizing radiation such as ultraviolet rays, electron beams, X-rays, α-rays, γ-rays. Lines are particularly preferred. The electron beam irradiation is preferably performed after the resin film layer (層) is processed into a molded body such as a film sheet. Where the electron beam dose Is preferably in the range of 10-60 Mrad, more preferably in the range of 20-50 Mrad. When the electron beam dose is less than lOMrad, crosslinking is difficult to proceed, whereas when it exceeds 60 Mrad, the deterioration of the compact tends to proceed.

[0050] The inner liner for a pneumatic tire according to the present invention has a resin film layer (A) that preferably uses the above-mentioned modified ethylene-butyl alcohol copolymer (D) for the resin film layer (A). A multilayered film including a layer containing the modified ethylene butyl alcohol copolymer (D) may be used. Here, as a method of multilayering, for example, a method of co-extrusion of the resin composition (F) containing the modified ethylene butyl alcohol copolymer (D) and another resin, etc. can be mentioned. Is a thermoplastic urethane elastomer

[0051] In the inner liner 1 for a pneumatic tire of the present invention, as an example in which the resin film layer (A) is multilayered, the resin film layer (A) is further adjacent to the layer containing the modified ethylene butyl alcohol copolymer (D). One provided with one or more auxiliary layers (G) made of an elastomer is preferably mentioned. Here, since the auxiliary layer (G) uses an elastomer, it has high adhesion to the hydroxyl group of the modified ethylene-vinyl alcohol copolymer (D) and is difficult to peel off. Therefore, even if a layer containing the modified ethylene butyl alcohol copolymer ( _D ) breaks or cracks, it is difficult for the cracks to extend, so that adverse effects such as large breaks and cracks are suppressed and the internal pressure of the tire is maintained. Sex can be sufficiently maintained.

[0052] The elastomer used for the auxiliary layer (G) is preferably a thermoplastic urethane elastomer from the viewpoint of water resistance and adhesion to rubber. In addition, when the thermoplastic urethane elastomer is used for the auxiliary layer (G), the generation and extension of cracks can be suppressed while making the auxiliary layer (G) thinner. Here, the thermoplastic urethane-based elastomer is obtained by a reaction of a polyol, an isocyanate compound, and a short chain diol. Polyol and short chain diol form a linear polyurethane by addition reaction with an isocyanate compound. The polyol becomes a flexible part in the thermoplastic urethane elastomer, and the isocyanate compound and the short chain diol become a hard part. Note that the properties of the thermoplastic elastomeric elastomer can be changed over a wide range by changing the type of raw material, blending amount, polymerization conditions, and the like. As a powerful thermoplastic urethane elastomer, Preferred examples include polyether urethane.

[0053] The total thickness of the auxiliary layer (G) is preferably in the range of 10 to 100 m. If the thickness of the auxiliary layer is less than lO ^ m, the effect of disposing the auxiliary layer (G) is small. If it exceeds lOO ^ m, the weight of the tire cannot be reduced sufficiently.

[0054] In the second inner liner for a pneumatic tire of the present invention, a rubber-like elastic layer (B) is further provided on the surface of the adhesive layer (C) opposite to the resin film layer (A). It is preferable that the laminated body is provided. Here, by disposing the rubber-like elastic layer (B), the workability when the inner liner of the present invention is attached to the inner surface of the tire is greatly improved.

[0055] In the case where the inner liner for a pneumatic tire of the present invention includes the rubber-like elastic body layer (B), the rubber-like elastic body layer (B) includes butyl rubber and / or halogenated butyl rubber as a rubber component. It is preferable to contain. Here, examples of the halogenated butyl rubber include chlorinated butyl rubber, brominated butyl rubber, and modified rubbers thereof. The halogenated butyl rubber may be a commercially available product, such as “Enjay Butyl HT10-66” (registered trademark) [Chlorinated butyl rubber manufactured by ENGAI Chemical Co., Ltd.], “Bromob utyl 2255” (registered) Trademarks) [manufactured by JSR, brominated butylene rubber], “Bromobutyl 2244” (registered trademark) [manufactured by JSR, brominated butyl rubber] and the like. Examples of the chlorinated or brominated modified rubber include “Expro50” (registered trademark) [manufactured by Exxon].

[0056] The content of butyl rubber and / or halogenated butyl rubber in the rubber component in the rubber-like elastic layer (B) is preferably 50% by mass or more from the viewpoint of improving air permeation resistance. 70 to 100% is more preferable. Here, as the rubber component, in addition to butyl rubber and halogenated butyl rubber, it is possible to use gen-based rubber, epic chlorohydrin rubber, or the like. These rubber components may be used singly or in combination of two or more.

[0057] In addition to the rubber component, the rubber-like elastic layer (B) contains a compounding agent usually used in the rubber industry, such as a reinforcing filler, a softening agent, an anti-aging agent, a vulcanizing agent, A rubber vulcanization accelerator, a scorch inhibitor, zinc white, stearic acid and the like can be appropriately blended depending on the purpose. As these compounding agents, commercially available products can be suitably used. [0058] In the adhesive layer (C) of the inner liner for a pneumatic tire of the present invention, the maleimide derivative and poly- having two or more reactive sites in the molecule with respect to 100 parts by mass of the rubber component (I). It is preferable to use an adhesive composition (H) containing at least 0.1 part by mass of at least one kind of P-dinitrosobenzene. By using the maleimide derivative and / or poly-P-dinitrosobenzene in the adhesive composition (H), the adhesive layer (C) with respect to the resin film layer (A) and the rubber-like elastic body layer (B) The adhesiveness is improved, and the peel resistance between the resin film layer (A) and the rubber-like elastic layer (B) can be improved.

[0059] Examples of the rubber component (I) used in the adhesive composition (H) include chlorosulfonated polyethylene, butyl rubber, halogenated butyl rubber, and Gen rubber. Among these, chlorosulfonated polyethylene, and Butyl rubber and / or halogenated butyl rubber is preferred. The above chlorosulfonated polyethylene is a synthetic rubber having a saturated main chain structure obtained by chlorination and chlorosulfonization of polyethylene using chlorine and sulfurous acid gas, and is weather resistant, ozone resistant, heat resistant. Excellent gas barrier properties. In addition, as the chlorosulfonated polyethylene, a commercially available product can be used, and examples thereof include trade name “HIVALON” [manufactured by DuPont]. Furthermore, the content of the chlorosulfonated polyethylene in the rubber component (I) is preferably 10% by mass or more from the viewpoint of improving the peeling resistance. On the other hand, butyl rubber and halogenated butyl rubber are as described in the rubber-like elastic layer (B), and the content of butyl rubber and / or halogenated butyl rubber in the rubber component (I) is 50% by mass. % Or more is preferable. The rubber component (I) may be used alone or in combination of two or more.

[0060] The adhesive composition (H) is a maleimide derivative having two or more reactive sites in the molecule and / or as a crosslinking agent and a crosslinking aid in order to improve the peel resistance after heat treatment. Includes poly-P-dinitrosobenzene, and examples of the maleimide derivative include 1,4-phenylene dimaleimide, among which 1,4-phenylene dimaleimide is preferable. One of these crosslinking agents and crosslinking assistants may be used alone, or two or more thereof may be used in combination. The blending amount of the maleimide derivative and / or poly-P-dinitrosobenzene in the adhesive composition (H) is preferably 0.1 parts by mass or more with respect to 100 parts by mass of the rubber component (1). Yes. If the blending amount of the maleimide derivative and / or poly-p-dinitrosobenzene is less than 0.1 parts by mass, the peeling resistance after vulcanization cannot be sufficiently improved! /.

[0061] The adhesive composition (H) preferably further contains a rubber vulcanization accelerator, a filler, a tackifier such as a resin and a low molecular weight polymer, and the like. In addition, for example, a softening agent, an anti-aging agent, a vulcanizing agent, an anti-scorch agent, zinc white, stearic acid and the like may be appropriately blended according to the purpose! /.

[0062] As a method for producing an inner liner for a pneumatic tire of the present invention, for example, at least one surface of a coating liquid in which the adhesive composition (H) is dispersed or dissolved in an organic solvent is surface-modified. The adhesive layer (C) is formed by coating and drying on the surface of the resin film layer (A), preferably the resin film layer (A) having at least one surface subjected to surface oxidation treatment, and then the adhesive layer Examples thereof include a method in which the rubber-like elastic layer (B) is bonded to the surface of (C) and vulcanized. In the method for producing an inner liner for a pneumatic tire according to the present invention, the coating liquid is applied to the surface of the rubber-like elastic layer (B) and dried to form an adhesive layer (C). The surface of the agent layer (C) is laminated with the surface of the resin film layer (A) whose surface has been modified on at least one side, and preferably the surface of the resin film layer (A) which has been subjected to surface oxidation treatment on at least one side. Processing may be performed. Here, in order to manufacture the first inner liner for a pneumatic tire of the present invention, it is necessary that at least the surface of the resin film layer (A) on the adhesive layer (C) side is surface-modified. The vulcanization temperature is preferably 120 to 120 ° C or more, more preferably 125 to 200 ° C, more preferably 130 to 180 ° C.

[0063] The method of mixing the adhesive composition (H) and the organic solvent is carried out by a conventional method !, and the concentration of the adhesive composition (H) in the coating solution prepared by such a method is 5 The range of ˜50 mass% is preferred, and the range of 10-30 mass% is more preferred. Here, examples of the organic solvent include toluene, xylene, n-hexane, cyclohexane, black mouth form, methyl ethyl ketone, and the like. These organic solvents may be used individually by 1 type, and 2 or more types may be mixed and used for them. In the organic solvent, the Hildebrand solubility parameter (δ value) is preferably in the range of 14 to 20 MPa ^1/2 . Here, when the Hildebrand solubility parameter (δ value) is within the specific range, the affinity between the organic solvent and the rubber component (I). Becomes higher.

[0064] The pneumatic tire of the present invention is characterized by using the above-described inner liner for a pneumatic tire. Hereinafter, the pneumatic tire of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional view of an example of the pneumatic tire of the present invention. The tire shown in FIG. 1 has a pair of bead portions 1 and a pair of sidewall portions 2, and a tread portion 3 connected to both sidewall portions 2, and extends in a toroidal shape between the pair of bead portions 1. The carcass 4 is composed of one or more carcass plies that reinforce these parts 1, 2, and 3, and an inner liner 5 is disposed on the inner surface of the tire inside the carcass 4.

[0065] In the illustrated example of the tire, the carcass 4 includes a main body portion extending in a toroidal shape between a pair of bead cores 6 embedded in the bead portion 1 and the inner side in the tire width direction around each bead core 6. The force composed of the folded portion wound outward in the radial direction toward the outside In the pneumatic tire of the present invention, the number of plies and the structure of the carcass 4 are not limited thereto.

[0066] Further, in the illustrated tire, a belt 7 composed of two belt layers is disposed on the outer side in the tire radial direction of the crown portion of the carcass 4, and the belt 7 in the illustrated example includes two sheets. In the pneumatic tire of the present invention, the number of belt layers constituting the belt 7 is not limited to this. Here, the belt layer is usually composed of a rubberized layer of a cord extending obliquely with respect to the tire equatorial plane, and the two belt layers have the cords constituting the belt layer intersecting each other across the equator plane. The belt 7 is thus laminated. Furthermore, the illustrated tire has a force S including a belt reinforcing layer 8 disposed so as to cover the entire belt 7 outside the belt 7 in the tire radial direction, and the pneumatic tire of the present invention has a belt reinforcing layer 8. The belt reinforcing layer having another structure may be provided. Here, the belt reinforcing layer 8 is usually composed of a rubberized layer of cords arranged substantially parallel to the tire circumferential direction.

It should be noted that the inner liner 1 described above is applied to the inner liner 5 in the illustrated tire. Hereinafter, the inner liner 1 of the present invention used for the pneumatic tire will be described in detail with reference to the drawings. FIG. 2 is a partial cross-sectional view of an example of an inner liner for a pneumatic tire according to the present invention. The inner liner shown in Fig. 2 The rum layer (A) 9 and the rubber-like elastic layer (B) 10 are joined via the adhesive layer (C) 11. Here, the rubber-like elastic layer (B) 10 is joined to the tire inner surface inside the carcass 4 in the pneumatic tire. The illustrated inner liner 1 has a force S including the rubber-like elastic layer (B) 10, and the second inner liner 1 for a pneumatic tire according to the present invention does not have the rubber-like elastic layer. May be. In this case, the adhesive layer (C) 11 is directly bonded to the inner surface of the tire inside the carcass 4.

[0068] In the illustrated inner liner, the resin film layer (A) 9 has only one layer containing, for example, a modified ethylene butyl alcohol copolymer (D). One may have other layers as shown in FIG.

FIG. 3 is a partial cross-sectional view of another example of the inner liner 1 of the present invention. The inner liner of the illustrated example includes, as a resin film layer (A) 12, a layer 13 containing the modified ethylene-butyl alcohol copolymer (D) and two layers of heat disposed adjacent to the layer 13. And a layer 14 made of a plastic urethane elastomer. The same reference numerals as those in Fig. 2 indicate the same members.

[0070] The pneumatic tire of the present invention can be manufactured by a conventional method using the inner liner 1 described above. In the pneumatic tire of the present invention, as the gas filled in the tire, it is possible to use normal air or air having a changed oxygen partial pressure, or an inert gas such as nitrogen.

EXAMPLES The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples.

[0072] (Synthesis Example of Modified Ethylene Bull Alcohol Copolymer (D))

In a pressurized reactor, ethylene-butyl alcohol copolymer with an ethylene content of 44 mol% and a saponification degree of 99.9% (190 ° C, MFR under 216 Og load: 5.5 g / 10 min) 2 parts by mass and N- 8 parts by mass of methyl-2-pyrrolidone was charged, and heated and stirred at 120 ° C for 2 hours to completely dissolve the ethylene-vinyl alcohol copolymer. To this was added 0.4 parts by mass of epoxypropane as an epoxy compound, and then heated at 160 ° C. for 4 hours. After heating, precipitate in 100 parts by weight of distilled water, and use a large amount of distilled water to sufficiently dissolve N-methyl-2-pyrrolidone and unreacted ether. Poxypropane was washed to obtain a modified ethylene-butyl alcohol copolymer (D). Furthermore, after the obtained modified ethylene butyl alcohol copolymer (D) was vigorously reduced to a particle size of about 2 mm with a pulverizer, it was thoroughly washed again with a large amount of distilled water. The washed particles were vacuum-dried at room temperature for 8 hours and then melted at 200 ° C. using a twin-screw extruder to be pelletized. The resulting modified ethylene butyl alcohol copolymer (D) had a Young's modulus of 1300 MPa at 23 ° C.

[0073] The Young's modulus at 23 ° C of the modified ethylene-butyl alcohol copolymer (D) was measured by the following method.

[0074] (1) Measurement of Young's modulus

Using the obtained pellets, a single-layer film having a thickness of 20 m was produced using a twin-screw extruder manufactured by Toyo Seiki Co., Ltd. under the following extrusion conditions. Next, using this film, a strip-shaped test piece having a width of 15 mm was prepared and left in a temperature-controlled room at 23 ° C. and 50% RH for one week, and then autograph [AG- A500] was used to measure the S-S curve (stress-strain curve) at 23 ° C and 50% RH under conditions of chuck spacing of 50 mm and tensile speed of 50 mm / min. Young's modulus was determined.

[0075] Screw: 20mm φ, full flight

Cylinder, die temperature setting: C1 / C2 / C3 / die = 200/200/200/200 (.C)

[0076] Further, the ethylene content and the saponification degree of the above ethylene butyl alcohol copolymer were determined by ¹ H-NMR measurement using deuterated dimethyl sulfoxide as a solvent [JN M-GX-500 type manufactured by JEOL Ltd.] Is a value calculated from the spectrum obtained in [Use]. Furthermore, the melt flow rate (MFR) of the above ethylene monobutyl alcohol copolymer was measured at 190 ° C by filling a sample into a cylinder with an inner diameter of 9.55 mm and a length of 162 mm of a melt indexer L244 [manufactured by Takara Kogyo Co., Ltd.] After melting, an even load is applied using a plunger with a weight of 2160g and a diameter of 9.48mm, and the amount of resin extruded per unit time from a 2.1mm diameter orifice provided in the center of the cylinder (g / 10 Min). However, when the melting point of the ethylene-butyl alcohol copolymer is around 190 ° C or exceeds 190 ° C, measurement is made at multiple temperatures above the melting point under a load of 2160g. The logarithm of MFR is plotted on the vertical axis, and the value calculated by adding it to 190 ° C is the melt flow rate (MF R).

[0077] (Synthesis example of flexible resin (E))

Maleic anhydride-modified hydrogenated styrene ethylene butadiene styrene block copolymer was synthesized by a known method and pelletized. The resulting maleic anhydride-modified hydrogenated styrene ethylene butadiene styrene block copolymer had a Young's modulus power of 3 MPa, a styrene content of 20%, and a maleic anhydride content of 0.3 meq / g. The Young's modulus of the maleic anhydride-modified hydrogenated styrene ethylene butadiene styrene block copolymer was measured by the above method.

[0078] (Preparation of film A1)

Using the pellets of the modified ethylene butyl alcohol copolymer (D) obtained in the synthesis example, a 40πιιη φ extruder [PLABOR 0-c. 40-8] manufactured by the Institute of Plastics Engineering, and a film-forming machine that also has the power of Ding. And a film was formed under the following extrusion conditions to obtain a single-layer film having a thickness of 20 πι.

[0079] Format: Single screw extruder (non-vent type)

L / D: 24

Diameter: 40mm φ

Screw: single-flight full flight type, surface nitrided steel

Screw rotation speed: 40rpm

Dice: 550mm wide coat nonga die

Lip gap: 0.3mm

Cylinder, die temperature setting: C1 / C2 / C3 / Adapter / Die = 180/200/210 / 210/210 (° C)

[0080] (Preparation of film B1)

The resin composition (F) was prepared by kneading the modified ethylene butyl alcohol copolymer (D) obtained in the synthesis example and the flexible resin (E) with a twin-screw extruder, in the same manner as the production of the film A1. A monolayer film having a thickness of 20 m was obtained. Here, the content of the flexible resin (E) in the resin composition (F) is 20% by mass. In addition, the average particle diameter of the flexible resin (E) in the resin composition (F) is determined by freezing a sample of the obtained resin composition (F) and then cutting the sample with a microtome. It was 1.0 when measured with a transmission electron microscope.

[0081] (Preparation of film A2)

Using the modified ethylene butyl alcohol copolymer (D) pellets obtained in the synthesis example and thermoplastic polyurethane [Kuraray 3190, Kuraray Co., Ltd.], the following co-extrusion equipment was used. A three-layer film (thermoplastic polyurethane layer / modified EVOH (D) layer / thermoplastic polyurethane layer, thickness: 20 ^ m / 20 μm / 20 μm) was prepared under extrusion molding conditions.

[0082] Extrusion temperature of each resin: C1 / C2 / C3 / die = 170/170/200/200 ° C

Extruder specifications for each resin:

Thermoplastic polyurethane: 25mm φ Extruder —25—18 AC [Osaka Seiki Co., Ltd.

]

Modified EVOH (D): 20mm φ Extruder Lab Machine ME Type CO—EXT [Toyo Seiki Co., Ltd.]

T-die specification: 500mm width, 2 types, 3 layers [Plastic Engineering Laboratory Co., Ltd.] Cooling roll temperature: 50 ° C

Pickup speed: 4m / min

[0083] (Preparation of film B2)

Using the resin composition (F) prepared in the production of the film B1 and the thermoplastic polyurethane [Kuraray Co., Ltd. Kuramylon 3190], the three-layer film (thermoplastic polyurethane layer) was produced in the same manner as the production of the film A2. / Resin composition (F) layer / thermoplastic polyurethane layer, thickness: 20 m / 20 μm / 20 μm).

[0084] The oxygen permeability coefficient of the film obtained as described above was evaluated by the following method. The results are shown in Table 1.

[0085] (2) Measurement of oxygen permeability coefficient of film

The film was conditioned at 20 ° C. and 65% RH for 5 days. Using the two humidity-adjusted films obtained, using MOCON OX—TRAN2 / 20, manufactured by Modern Control, in compliance with JIS K7126 (isobaric method) at 20 ° C and 65% RH Then, the oxygen transmission coefficient was measured and the average value was obtained. [0086]

(Example of production of rubber-like elastic layer (B) 1)

Butyl rubber SR Co., Ltd., Butyl 268] 100 parts by mass, GPF carbon black [Asahi Carbon Co., Ltd., # 55] 60 parts by mass, SUNPAR2280 [Nihon Sun Sekiyu Co., Ltd.] 7 parts by mass, Stearic acid [Asahi Denka Kogyo Co., Ltd.] 1 part by mass, Noxeller DM [Ouchi Shinsei Chemical Co., Ltd.] 1.3 parts by mass, Zinc oxide [Shiramizu Chemical Co., Ltd.] 3 parts by mass and sulfur [ Tsurumi Chemical Co., Ltd.] A rubber composition was prepared by blending 0.5 part by mass, and an unvulcanized rubber-like elastic layer (B) having a thickness of 500 am was produced using the rubber composition. .

[0088] (Production Example 2 of Rubber Elastic Body Layer (B))

An unvulcanized rubber-like elastic layer with a thickness of 500 m was used in the same manner as in Preparation Example 1 except that brominated butyl rubber SR, Bromobutyl 2 244] was used instead of the butyl rubber of Preparation Example 1. B) was prepared.

[0089] (Preparation of adhesive composition (H))

Brominated butyl rubber [JSR Co., Ltd., Bromobutyl 2244] 100 parts by mass of carbon black [Tokai Carbon Co., Ltd., Seast NB] 10 parts by mass, phenolic resin [Sumitomo Beichikrite Co., Ltd., PR-SC-400] 20 parts by mass, stearic acid manufactured by Nippon Rika Co., Ltd., 50S] 1 part by mass, zinc oxide [by Hakutech Co., Ltd.] 3 parts by mass, poly-P-dinitrosobenzene [Ouchi Shinsei Chemical Industry Co., Ltd., Barnock DNB] 3 parts by mass, 1,4-phenylene dimaleimide [Ouchi Shinsei Chemical Co., Ltd., Barnock PM] 3 parts by mass, vulcanization accelerator ZTC [Ouchi Eshin Chemical Industry Co., Ltd., Noxeller ZTC, Zinc dibenzyldithiocarbamate] 1 part by mass, Vulcanization accelerator DM [Ouchi Shinsei Chemical Co., Ltd., Noxeller DM, Di-2-benzothiazolyl disulfide ] 0.5 parts by mass, vulcanization accelerator D [Ouchi Shinsei Chemical Co., Ltd., Noxeller D, 1,3-Diphenyl Dani Down] 1 part by mass and sulfur [Tsurumi Chemical Co., Ltd., Jinhua mark micronized sulfur] 1.5 An adhesive composition (H) was prepared by blending parts by mass.

[0090] (Example 1-1)

Using a Nisshin Noise Voltage Co., Ltd. electron beam irradiation device “Curetron EBC200-100 for production”, film A1 was irradiated with an electron beam under the conditions of a quick calorie voltage of 200 kV and an irradiation energy of 30 Mrad to perform crosslinking treatment. After that, on the surface of the obtained cross-linked film, a corona discharge treatment device “Corona Master PS-1M” manufactured by Shinko Electric Instruments Co., Ltd. was used under the conditions of electrode spacing lm m, discharge voltage 7 kV, frequency 15 kHz. Corona discharge treatment (surface oxidation treatment) was performed. Next, 100 parts by mass of the adhesive composition (H) was added to 1000 parts by mass of toluene (δ value: 18.2 MPa ^1/2 ), and dispersed or dissolved to prepare a coating solution. The obtained coating liquid is applied to one side of an oxidized film and then dried to form an adhesive layer (C). The rubber-like elastic body of Production Example 1 is formed on the surface of the adhesive layer (C). After laminating layer (B), vulcanization was performed at 160 ° C for 15 minutes to produce an inner liner having the structure shown in FIG. Using the obtained inner liner, a pneumatic tire for passenger cars of size 195 / 65R15 with the structure shown in FIG. 1 was produced according to a conventional method.

[0091] (Examples 1-2 to 1-8)

A pneumatic tire was produced in the same manner as in the above Example; 1-1 except that the resin film layer (A) and rubber-like elastic layer (B) shown in Table 2 were used.

[0092] (Examples 1-9 to 1-10)

The resin film layer (A) and rubber-like elastic layer (B) shown in Table 2 were used, and instead of the corona discharge treatment as a surface oxidation treatment, a plasma irradiation surface modification device manufactured by Kasuga Electric Co., Ltd. A pneumatic tire was produced in the same manner as in the above Example; 1-1 except that the plasma discharge treatment was performed under the condition of an output of 10 kV using “PS-601C type”.

[0093] (Comparative Example 1-1)

A pneumatic tire was produced in the same manner as in the above Example; 1-1 except that the surface oxidation treatment was not performed.

[0094] (Comparative Examples 1-2 and 1-4; 1-4)

A pneumatic tire was produced in the same manner as in Comparative Example 1-1, except that the resin film layer (A) and rubber-like elastic layer (B) shown in Table 2 were used. [0095] Next, a durability test of the obtained tire was performed by the following method to evaluate the presence or absence of a failure. The results are shown in Table 2.

[0096] (3) Tire durability test

Each prototype tire is assembled with a rim, the internal pressure is 175 kPa, the load is 4.5 kN, the speed is 80 km / h, the temperature is 20 ° C, and the drum running test is performed. After running 10,000 km, the inner liner appearance of the tire is visually observed. Observed. By visual observation, the case where no failure was detected was determined to be good, and the case where cracks or cracks occurred, or peeling or lifting was determined to be defective.

[0097] ^

[0098] As is apparent from Table 2, in the tires of the examples, peeling and lifting were observed regardless of which resin film layer (A) and rubber-like elastic body layer (B) were used as the inner liner. It can be seen that the peel resistance between the resin film layer (A) and the rubber-like elastic layer (B) is high. In addition, since no cracks or cracks are generated, the inner liner of the present invention has excellent breaking resistance at the time of bending.

[0099] (Example 2-;! To 2-8 and Comparative Example 2-;! To 2-3)

Using a Nisshin Noi Voltage Co., Ltd. electron beam irradiation device “Curetron EBC200-100 for production”, film A2 was irradiated with an electron beam under the conditions of a quick calorie voltage of 200 kV and an irradiation energy of 30 Mrad, and then subjected to crosslinking treatment. After that, on the surface of the obtained crosslinked film, Shinko Electric Meter Using a corona discharge treatment device “Corona Master PS-1M” (electrode spacing lmm, frequency 15kHz) manufactured by Sou Co., Ltd., surface oxidation treatment was performed on at least one side of the crosslinked film under the conditions shown in Tables 3-4. did. Next, 100 parts by mass of the above adhesive composition (H) was added to 1000 parts by mass of toluene (δ value: 18.2 MPa ¹⁷² ), and dispersed or dissolved to prepare a coating solution. The obtained coating solution was applied to one side of an oxidized film and then dried to form an adhesive layer (C). The rubber-like elastic body of Production Example 1 was formed on the surface of the adhesive layer (C). After laminating layer (B), a vulcanization treatment was performed at 160 ° C. for 15 minutes to produce an inner liner having the structure shown in FIG. Next, using the obtained inner liner, a pneumatic tire for a passenger car having a size of 195 / 65R15 having the structure shown in FIG. 1 was produced according to a conventional method.

[0100] With respect to the film obtained by subjecting at least one surface of the crosslinked film to surface oxidation treatment, the surface free energy was measured by the following method. In this case, the surface of the film on which the adhesive layer (C) was formed was designated as A-2, and the surface opposite to the surface on which the adhesive layer (C) was formed was designated as A-1. The results are shown in Tables 3-4.

[0101] (4) Surface free energy

Using DropMaster700 manufactured by Kyowa Interface Science Co., Ltd., the contact angles of water, jodomethane and n_hexadecane were measured, and the surface free energy was calculated / calculated from these contact angles using the following formula.

d I p h

γ = γ ten γ ten γ

36.4 (l + cos θ Η) = (29.1 γ d) 1/2 + (1.3 γ Ρ) 1/2 + (42.4 γ h) 1/2

25.4 (l + cos θ ') = (46.8 γ ^d ) ^1/2 + (4 γ ^ρ ) ^1/2

13.8 (l + cos 0 ^D ) = (27.6 y ^d ) ^1/2

Where γ is the surface free energy (mN / m), _y ^d is the surface free energy dispersive component (mN / m), and γ ^Ρ is the surface free energy dipole attractive component (mN / m) ), Γ ¹¹ is the hydrogen bond component of surface free energy (mN / m), θ ^H is the contact angle of water (°), Θ ¹ is the contact angle of jode methane (°), e ^D is the contact angle (°) of n-hexadecane.

[0102] Next, a characteristic test of the obtained tire was performed and evaluated by the following method. The results are shown in Tables 3-4. [0103] (5) Test for confirming peeling of joint portion of inner liner due to expansion during molding Prepare 100 tires each having an inner liner prepared under each condition, and leave the tire at room temperature for one day. The joint properties of the inner liner of the tire inner surface were visually confirmed and evaluated according to the following criteria.

Of the 100 tires, all tires for which no joint peeling was confirmed

“◯”, “△” means that the joint part was confirmed to be peeled off on one tire, and “X” means that the joint part was confirmed to be peeled off on four or more tires.

[0104] (6) Tire durability test

Each prototype tire was assembled on a rim, the internal pressure was 175 kPa, the load was 4.5 kN, the speed was 80 km / h, the temperature was 20 ° C, and the drum running test was performed. After running 10,000 km, the inner surface of the tire was visually inspected. . When no failure was found by visual observation, “◯” was assigned, and when cracks or cracks were observed, or when peeling or lifting was observed, “X” was assigned.

Table 3

S star

From Tables 3 and 4, the tire inner liners of Examples 2-3 to 2-7 have a surface free energy of 50 mN / m or more on the A-1 surface of the resin film layer (A). It can be seen that it has the durability to withstand the expansion of. Also, Example 2-;! To 2-2 and 2-8 The inner liner of this tire has a force that the surface free energy on the A-1 surface of the resin film layer (A) is less than 50 mN / m, and the surface free energy on the A-2 surface is 50 mN / m or more. The adhesive strength of the agent layer (C) has been improved, and it has the durability that can be produced without any problem as a tire!

Since the inner liners of tires of Examples 2-;! To 2-3 and 2-6 to 2-8 have a surface free energy force of ¾0 mN / m or more on the A-2 surface of the resin film layer (A), It can be seen that the peeling resistance between the inner surface of the tire and the inner liner is excellent.

Claims

The scope of the claims

[1] An inner liner for a pneumatic tire in which a resin film layer (A) and a rubber-like elastic body layer (B) are joined via an adhesive layer (C),

An inner liner for a pneumatic tire, wherein at least a surface of the resin film layer (A) on the side of the adhesive layer (C) is surface-modified.

[2] The inner liner for a pneumatic tire according to claim 1, wherein at least a surface of the resin film layer (A) on the side of the adhesive layer (C) is subjected to surface oxidation treatment! one.

[3] The inner liner for a pneumatic tire according to claim 2, wherein the surface oxidation treatment is a corona discharge treatment.

[4] A laminate comprising a resin film layer (A) and an adhesive layer (B) disposed on the resin film layer (A),

An inner liner for a pneumatic tire, wherein a surface free energy of at least one surface of the resin film layer (A) is 50 mN / m or more.

[5] The resin film layer (A), comprising at least a layer containing a modified ethylene butyl alcohol copolymer (D) obtained by reacting an ethylene ethylene butyl alcohol copolymer. An inner liner for a pneumatic tire as described in 1.

6. The inner liner for a pneumatic tire according to claim 5, wherein the ethylene content of the ethylene butyl alcohol copolymer is 25 to 50 mol%.

7. The inner liner for a pneumatic tire according to claim 5, wherein the ethylene butyl alcohol copolymer has a saponification degree of 90% or more.

[8] The modified ethylene butyl alcohol copolymer (D) is obtained by reacting 1 to 50 parts by mass of an epoxy compound with 100 parts by mass of the ethylene butyl alcohol copolymer. 5. An inner liner for a pneumatic tire according to 5.

[9] The layer containing the modified ethylene butyl alcohol copolymer (D) has a functional group that reacts with a hydroxyl group in the matrix composed of the modified ethylene butyl alcohol copolymer (D). 6. The inner liner for a pneumatic tire according to claim 5, comprising a resin composition (F) in which a flexible resin (E) having a power of ^ OOMPa or less is dispersed.

[10] The resin film layer (A), 20 ° C, the oxygen permeability at 65% RH is 3.0 X 10- ¹² ^{^{cm 3 'cm / cm 2'}} sec ' claim 1 or 4 empty pneumatic tire for an inner liner one described, characterized in that cmHg or less.

[11] The inner liner for a pneumatic tire according to [1] or [4], wherein the thickness of the resin film layer (A) is 100 m or less.

[12] The inner liner for a pneumatic tire according to claim 1 or 4, wherein the resin film layer (A) is crosslinked.

[13] The tire inner liner according to [5], wherein the modified ethylene butyl alcohol copolymer (D) is crosslinked.

[14] The resin film layer (A) is further provided with one or more auxiliary layers (G) made of an elastomer adjacent to the layer containing the modified ethylene-butyl alcohol copolymer (D). The inner liner for a pneumatic tire according to claim 5.

15. The auxiliary layer (G) includes a thermoplastic urethane elastomer.

14. An inner liner for a pneumatic tire according to 14.

[16] The inner liner for a pneumatic tire according to claim 14, wherein the total force S of the thicknesses of the auxiliary layers (G) is in the range of 10 to 100.

[17] A coating liquid containing an adhesive composition (H) and an organic solvent is applied to the surface of the resin film layer (A) whose surface has been modified on at least one side and dried to form the adhesive layer (C 5. The air according to claim 4, which is obtained by forming a rubber elastic body layer (B) on the surface of the adhesive layer (C) and performing a vulcanization treatment. Inner liner for entering tires

Yes

[18] A coating liquid containing the adhesive composition (H) and an organic solvent is applied to the surface of the rubber-like elastic layer (B) and dried to form the adhesive layer (C). 5. The adhesive layer (C) according to claim 4, wherein the resin film layer (A) having at least one surface modified is bonded to the surface of the adhesive layer (C) and vulcanized. Inner liner for pneumatic tires.

[19] The inner liner for a pneumatic tire according to [1], [17] or [18], wherein the rubber-like elastic layer (B) force includes butyl rubber and / or halogenated butyl rubber.

[20] A coating solution containing the adhesive composition (H) and an organic solvent is applied to the surface-modified surface of the resin film layer (A) and dried to form an adhesive layer (C). Next! /, Of the adhesive layer (C) 19. The method for manufacturing an inner liner for a pneumatic tire according to claim 1, 17 or 18, wherein the rubber-like elastic layer (B) is bonded to a surface and vulcanization is performed.

[21] A coating solution containing the adhesive composition (H) and an organic solvent is applied to the surface of the rubber-like elastic layer (B) and dried to form an adhesive layer (C). The surface of the adhesive layer (C) is bonded to the surface of the adhesive layer (C) with /, and a vulcanization treatment is performed. Method for manufacturing an inner liner for a pneumatic tire according to claim

Yes

[22] A pneumatic tire comprising the inner liner for a pneumatic tire according to any one of claims! To 19! /.