JP6118492B2 - Tire manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a tire. By applying a gas barrier resin having high tension after molding, the gas barrier resin can be introduced into the barrier layer without being peeled off by expansion during molding, and the gas barrier property is provided. The present invention relates to a method for manufacturing a tire capable of improving the tire strength.

Conventionally, in order to improve the fuel consumption of a tire, development of reducing the weight of the tire has been performed. As a method for reducing the weight of a tire, there is a method using a film having gas barrier properties as an inner liner.
Usually, a film (inner liner) having gas barrier properties is disposed when a tire is molded. Here, some of the resins having good gas barrier properties cannot be used as the material of the inner liner because the resin layer peels off from the tire because the tension is too high to withstand the expansion at the time of molding the tire. There is a problem that the material of the inner liner is limited.
Moreover, as a film having gas barrier properties, when a metal vapor deposition film (for example, see Patent Document 1) is arranged at the time of tire molding, the film is cracked at the time of expansion at the time of tire molding (the film is cracked), There exists a problem that the effect (gas barrier property) as an inner liner will be lost.

Further, in order to solve the problem that it is difficult to paste a film having gas barrier properties on the tire inner surface forming a curved surface, it has been conventionally performed to apply a film having gas barrier properties in a solution state (for example, (See Patent Documents 2 and 3).
However, since the film having the gas barrier property has a single layer structure, there is a problem that the gas barrier property is lowered particularly when a flaw (crack) is entered.

Special table 2001-509111 gazette JP-A-5-318618 Japanese Patent Laid-Open No. 5-278409

  Therefore, an object of the present invention is to apply a gas barrier resin having high tension after molding, so that the gas barrier resin can be introduced into the barrier layer without being peeled off by expansion during molding, and the gas barrier property is improved. An object of the present invention is to provide a tire manufacturing method that can be used.

  As a result of intensive studies to solve the above problems, the present inventors formed a laminate including at least two barrier layers containing a gas barrier resin on the inner surface of the molded tire after molding the tire. Thus, by applying a gas barrier resin having high tension after molding, the gas barrier resin can be introduced into the barrier layer without being peeled off by expansion during molding, and the gas barrier property can be improved. It was found that the manufacturing method can be realized.

That is, the tire manufacturing method of the present invention includes a laminate forming step of forming a laminate including at least two barrier layers containing a gas barrier resin on the inner surface of the molded tire after the molding step of molding the tire. wherein, in the laminate forming step, the barrier layer is formed by coating, the solvent in the coating solution used for the coating is azeotropically evaporated at once, the boiling point of 120 ° C. or higher alcohol as including a mixed solvent It is a solvent that volatilizes at 120 ° C., the alcohol having a boiling point of 120 ° C. or higher is benzyl alcohol, and the content of the benzyl alcohol is 28.5% by volume to 35% by volume with respect to the solvent in the coating solution. It is characterized by.

Moreover, the vulcanization | cure process which vulcanizes the said tire is further included, and the said laminated body formation process can also be performed before this vulcanization | cure process.
Moreover, it is preferable that the said laminated body contains the elastic body layer adjacent to the said barrier layer.
Moreover, it is preferable that the said laminated body contains the said barrier layer and the said elastic body layer alternately.
The gas barrier resin contained in the barrier layer preferably has an air permeability coefficient at 20 ° C. and 65% RH of 800 × 10 ⁻¹² cm ³ · cm ² · sec · cmHg or less .

  According to the present invention, by applying a gas barrier resin having high tension after molding, the gas barrier resin can be introduced into the barrier layer without being peeled off by expansion during molding, and the gas barrier property is improved. It is possible to provide a method for manufacturing a tire that can be used.

It is a fragmentary sectional view showing an example of the tire manufactured by the manufacturing method of the tire of the present invention. It is a typical sectional view showing an example of a layered product in the present invention.

(Tire manufacturing method)
The tire manufacturing method of the present invention includes at least a molding step and a laminate forming step, and further includes other steps such as a vulcanization step as necessary.

<Tire>
Below, an example of the tire manufactured by the manufacturing method of the tire of the present invention is explained in detail using a drawing.

Hereinafter, as shown in FIG. 1, the tire includes, for example, a pair of bead portions 9 and a pair of sidewall portions 10, and a tread portion 11 connected to both sidewall portions 10. A carcass (carcass cord + carcass rubber) 12 extending in a toroid shape between them to reinforce each of these parts 9, 10 and 11, and two belt layers disposed on the outer side in the tire radial direction of the crown part of the carcass 12 And a bead filler 15 disposed on the outer side in the tire radial direction of a ring-shaped bead core 14 embedded in the bead portion 9, and an inner liner 16 is provided on the inner surface of the tire inside the carcass 12. Has been placed.
In the present invention, the inner liner 16 is constituted by a laminate including at least two barrier layers.

<Molding process>
The molding process is a process of molding a tire.

-Molding-
The molding of the tire is not particularly limited and can be appropriately selected according to the purpose. For example, several cords are wound, beads are wound on both sides of the cord, and then a tread is applied. Winding and forming a green tire (green tire), etc. are mentioned.

<Vulcanization process>
The vulcanization step is a step of vulcanizing the tire (raw tire) molded in the molding step.
-Vulcanization-
There is no restriction | limiting in particular as said vulcanization time, temperature, and pressure, According to the objective, it can select suitably.

<Laminated body formation process>
The laminate forming step is a step of forming a laminate including at least two barrier layers containing a gas barrier resin on the inner surface of the molded tire.
The laminate forming step may be performed before the vulcanization step or may be performed after the vulcanization step as long as it is performed after the molding step.
Here, if the laminate formation step is performed before the vulcanization step, there is a possibility that crystals will grow by a PCI treatment (post-cure inflator treatment) that cools while maintaining the shape of the vulcanized tire after the vulcanization step. And the barrier property may be improved.
When the laminated body is applied before vulcanization, the bladder and the laminated body may be in close contact with each other. In order to prevent this, a release agent may be applied.
When the laminate is applied after vulcanization, the laminate is in close contact with the bladder and there is no possibility of peeling after vulcanization.

-Barrier layer formation method-
There is no restriction | limiting in particular as a formation method of the said barrier layer, According to the objective, it can select suitably, For example, the method of forming a barrier layer by sticking, the method of forming a barrier layer by application | coating, etc. are mentioned.

--- Paste--
There is no restriction | limiting in particular as said sticking, According to the objective, it can select suitably, For example, adhere | attaching a gas barrier resin film on a tire inner surface using an adhesive agent etc. are mentioned. Here, the gas barrier resin film may be attached to the inner surface of the tire one by one to form two or more barrier layers, or a laminate including two or more barrier layers is prepared in advance. Two or more barrier layers may be formed by attaching the laminate to the inner surface of the tire.
Since the tire inner surface is curved, it may be difficult to attach the resin film. Efficiency can be improved by applying heat to the resin film in advance to form the inner surface of the tire and then attaching the film to the inner surface of the tire.

--- Application--
There is no restriction | limiting in particular as said application | coating, According to the objective, it can select suitably, For example, apply | coating the gas barrier resin made into solution state (molten state) to the tire inner surface etc. are mentioned. Here, in order to increase the thickness of the gas barrier resin layer, it may be overcoated.
Moreover, there is no restriction | limiting in particular as said application | coating system, According to the objective, it can select suitably, For example, spray application, brushing, etc. are mentioned.
Further, as a method of application, there is a method in which a gas barrier resin made into a solution is put on the inner surface of the tire and the tire is rotated to uniformly apply the solution.

The solvent in the coating solution used for the coating is not particularly limited as long as it is a solvent capable of dissolving the gas barrier resin and azeotropically evaporates at once, and may be appropriately selected according to the purpose. However, it is preferable to contain an alcohol having a boiling point of 120 ° C. or higher.
By containing an alcohol having a boiling point of 120 ° C. or higher as the solvent in the coating solution, the gas barrier resin layer becomes uniform, and the effects of improving gas barrier properties and crack resistance can be obtained.
Further, the solvent in the coating solution may be a single solvent or a mixed solvent composed of a plurality of solvents.

The content of the alcohol having a boiling point of 120 ° C. or higher is not particularly limited as long as it is 5% by volume to 50% by volume with respect to the solvent in the coating solution, and can be appropriately selected according to the purpose. 15 volume%-35 volume% are preferable.
When the content is less than 5% by volume or more than 50% by volume, the gas barrier resin cannot be uniformly applied. On the other hand, it is preferable in the said preferable range at the point from which the gas barrier resin layer becomes uniform and the effect of improving gas barrier property and crack resistance is acquired.

There is no restriction | limiting in particular as long as it is 120 degreeC as a boiling point of the said alcohol, Although it can select suitably according to the objective, 120 to 250 degreeC is preferable and 150 to 180 degreeC is more preferable.
If the boiling point of the alcohol is less than 120 ° C, the gas barrier resin cannot be applied uniformly, and if it exceeds 250 ° C, it may be difficult to evaporate the solvent. On the other hand, if it is within the more preferable range, it is preferable in that evaporation can be performed simultaneously with the (mixing) solvent for dissolving the gas barrier resin.
There is no restriction | limiting in particular as said alcohol, Although it can select suitably according to the objective, benzyl alcohol, ethylene glycol, etc. are preferable at the soluble point of gas barrier resin.

-Laminate-
The laminate includes at least two or more barrier layers, and further includes other layers such as an elastic layer as necessary.
Here, the laminate preferably includes an elastic layer adjacent to the barrier layer from the viewpoint of crack resistance, adhesion to the tire inner surface, and the like, and further improves crack resistance. From the viewpoint of improving the internal pressure retention, it is more preferable to include the barrier layers and the elastic layers alternately.
In addition, regarding the adhesion between the laminate and the tire inner surface, if the outermost layer of the laminate is a barrier layer, it is not possible to obtain adhesion with rubber on the tire inner surface, so an anchor coat or the like is considered necessary. The anchor coat is not particularly limited and may be appropriately selected depending on the intended purpose.For example, a rubber composition having an epoxy residue and an aliphatic unsaturated bond residue and urethane attached thereto may be mentioned. It is done.

Hereinafter, an example of the inner liner (laminated body) will be described in detail with reference to the drawings.
As shown in FIG. 2, the inner liner is, for example, a laminate having a five-layer structure in which barrier layers 23 and 25 containing a gas barrier resin and elastic layers 22, 24 and 26 containing an elastomer are alternately laminated. 21 and adhered to the tire 27. Here, the laminate in FIG. 2 has a five-layer structure in which barrier layers and elastic layers are alternately laminated, but the laminate in the present invention is not limited to this.

-Air permeability coefficient of the barrier resin contained in the laminate (barrier layer) The air permeability coefficient of the barrier resin contained in the laminate under the conditions of 20 ° C and 65% RH is not particularly limited. However, it is preferably 800 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less, preferably 8.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less. Is more preferably 5.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less, and most preferably 3.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less. When the air permeability coefficient at 20 ° C. and 65% RH exceeds 800 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg, the laminate must be thickened in order to increase the internal pressure retention of the tire. Therefore, the weight of the inner liner cannot be sufficiently reduced.

--- Layer structure of laminate--
There is no restriction | limiting in particular as long as it has two or more barrier layers as a layer structure of the said laminated body, Although it can select suitably according to the objective, It is more preferable to have seven or more barrier layers.
By having two or more barrier layers, even when a flaw (crack) occurs and a part of the function of the barrier layer is lost, the barrier layer that does not lose the function prevents air from passing through the inner liner. It is possible to prevent the property from being reduced (the tire internal pressure is reduced).

There is no restriction | limiting in particular as the total number of layers of the said barrier layer and the said elastic body layer, Although it can select suitably according to the objective, 2 layers or more are preferable, 3 layers or more are more preferable, 5 layers or more are More preferably, 21 layers or more are more preferable, 48 layers or more are more preferable, and 65 layers or more are particularly preferable. The laminate may be a multilayer structure, and the total number of the barrier layer and the elastic layer may be 128 layers or more, 256 layers or more, 512 layers or more, and 1024 layers or more.
By setting the total number of layers to 5 or more, it is possible to prevent the occurrence of defects such as pinholes and cracks continuously. As a result, it is possible to prevent breakage of all layers of the laminate, and high gas barrier properties and resistance. It has characteristics such as flexibility (crack resistance) and high internal pressure retention after running.

The laminate may have other layers (C layer) other than the barrier layer (A layer) and the elastic layer (B layer). In addition, as the stacking order of the barrier layer (A layer) and the elastic body layer (B layer), for example,
(1) A, B, A, B... A, B (that is, (AB) _n )
(2) A, B, A, B ... A (that is, (AB) _n A)
(3) B, A, B, A ... B (that is, (BA) _n B)
(4) A, A, B, B... A, A, B, B (that is, (AABB) _n )
A stacking order such as can be adopted. Moreover, when it has another layer (C layer), for example,
(5) A, B, C... A, B, C (that is, (A, B, C) _n )
A stacking order such as can be adopted.

As the stacking order of the barrier layer (A layer) and the elastic body layer (B layer), the barrier layer (A layer) and the elastic body layer as in (1), (2) or (3) above. (B layer) is preferably laminated alternately.
Furthermore, as the stacking order of the barrier layer (A layer) and the elastic body layer (B layer), both outermost layers of the stacked body are the elastic body layer (B layer) as described in (3) above. It is preferable. It is advantageous in terms of adhesiveness to the tire that both outermost layers of the laminate are the elastic body layers (B layers).

  In the laminate, support layers may be laminated on both sides or one side of a laminate comprising the barrier layer (A layer), the elastic body layer (B layer), and other layers (C layer). . The support layer is not particularly limited, and for example, a general synthetic resin layer, a synthetic resin film, or the like is also used.

  In the laminate, the average thickness of one layer of the barrier layer (A layer) and the elastic layer (B layer) is not particularly limited and may be appropriately selected depending on the intended purpose. 001 μm to 10 μm, preferably 0.001 μm to 40 μm. By setting the average thickness of one layer of the barrier layer (A layer) and the elastic layer (B layer) within the preferred range, the number of layers can be reduced even when the overall thickness of the laminate is the same. As a result, the gas barrier property, bending resistance, etc. of the laminate can be further improved.

  The laminate includes a gas barrier resin, and an elastic layer (B layer) containing an elastomer is laminated together with a barrier layer (A layer) having a thickness in the above range, so that the ductility of the gas barrier resin itself is increased. Even if it is low, the ductility of the barrier layer (A layer) which consists of a resin composition with low ductility can be improved. This is because the low ductility resin composition is in a highly ductile state by thinly laminating a barrier layer (A layer) made of a resin composition having low ductility on an elastic layer (B layer) having excellent ductility. This is thought to be due to metastasis. The barrier layer (A layer) is generally made of a material having low ductility. By making the thickness of each layer very thin in this way, the gas barrier property and the flex resistance required for the tire inner liner and the like are highly compatible. be able to. Therefore, the laminated body can maintain characteristics such as high gas barrier properties even when it is used after being deformed such as bending.

  The lower limit of the average thickness of one layer of the barrier layer (A layer) is not particularly limited and can be appropriately selected according to the purpose. As described above, 0.001 μm is preferable, and 0.01 μm is more preferable. 0.05 μm is particularly preferable. If the thickness is 0.001 μm or less, film formation stability cannot be obtained, and the probability of pinholes is increased, so that sufficient barrier properties may not be obtained. On the other hand, the upper limit of the average thickness of one layer of the barrier layer (A layer) is not particularly limited and can be appropriately selected according to the purpose. However, as described above, 10 μm is preferable, 7 μm is more preferable, and 5 μm is preferable. More preferably, 3 μm is more preferable, and 1 μm is most preferable. If the barrier layer is 10 microns or more, the bending fatigue property is lowered, and the internal pressure retention property after running may be significantly lowered.

  When the average thickness of one layer of the barrier layer (A layer) is smaller than the above lower limit, it becomes difficult to form with a uniform thickness, and the gas barrier property and the bending resistance of the laminate may be lowered. Conversely, if the average thickness of one layer of the barrier layer (A layer) exceeds the upper limit, the durability and crack resistance of the laminate may be reduced when the thickness of the entire laminate is the same. Moreover, when the average thickness of one layer of said barrier layer (A layer) exceeds the said upper limit, there exists a possibility that the ductility improvement of the said barrier layer (A layer) may not fully express. The average thickness of one barrier layer (A layer) refers to a value obtained by dividing the total thickness of all barrier layers (A layer) included in the laminate by the number of barrier layers (A layer).

  The lower limit of the average thickness of the elastic layer (B layer) is not particularly limited and may be appropriately selected depending on the intended purpose. However, when the elastic layer is thin, an effect of buffering the barrier layer is obtained. Therefore, 0.001 μm is preferable, 0.01 μm is more preferable, and 0.1 μm is particularly preferable. On the other hand, the upper limit of the average thickness of the elastic body layer (B layer) is not particularly limited and can be appropriately selected according to the purpose. However, if it is thick, the tire weight increases, which is not preferable. 30 μm is more preferable, and 20 μm is more preferable.

  When the average thickness of one layer of the elastic body layer (B layer) exceeds the above upper limit, the durability and crack resistance of the laminate may be lowered when the thickness of the entire laminate is the same. The average thickness of one elastic layer (B layer) is a value obtained by dividing the total thickness of all elastic layers (B layer) included in the laminate by the number of elastic layers (B layer). Say.

  Regarding the average thickness of the elastic layer (B layer), the ratio of the average thickness of the elastic layer (B layer) to the average thickness of the barrier layer (A layer) (B layer / A layer) Is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 1/3 or more, and more preferably 1/2 or more. Further, the ratio is 1 or more, that is, the average thickness of one layer of the elastic layer (B layer) is more preferably equal to or more than the average thickness of one layer of the barrier layer (A layer). More preferably, it is more preferably 3. By making the ratio of the thicknesses of the barrier layer (A layer) and the elastic body layer (B layer) in this way, the crack resistance of the barrier layer (A layer) is improved.

  Furthermore, the laminate is preferably crosslinked. If the laminate is not cross-linked, the laminate (inner liner) may be significantly deformed and non-uniform in the vulcanization process of the tire, which may deteriorate the gas barrier properties, flex resistance, and fatigue resistance of the laminate. is there. Here, as a crosslinking method, a method of irradiating energy rays is preferable. Examples of the energy rays include ionizing radiation such as ultraviolet rays, electron beams, X-rays, α rays, γ rays, and among these, electron beams are used. Particularly preferred. The electron beam irradiation is preferably performed after the barrier layer is processed into a molded body such as a film or sheet. Here, the dose of the electron beam is preferably in the range of 10 to 500 kGy, and more preferably in the range of 50 to 300 kGy. When the electron beam dose is less than 10 kGy, crosslinking is difficult to proceed. In addition, the barrier layer may be subjected to a surface treatment by an oxidation method, a concavo-convex method or the like in order to improve adhesiveness with other layers. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, and the like. Can be mentioned. Among these, corona discharge treatment is preferable.

  A radical crosslinking agent may be blended as a crosslinking aid in the gas barrier layer and elastic layer contained in the laminate. The gas barrier layer and elastic layer contain a radical cross-linking agent to increase the cross-linking effect during irradiation with active energy rays, further improve the interlayer adhesion of the multilayer structure, and suppress deformation of the laminate during the vulcanization process. Can do. Moreover, it is also possible to reduce the irradiation amount of an active energy ray compared with the case where a radical crosslinking agent is not contained. The content of the radical crosslinking agent is preferably 0.01 to 10% by mass.

  Examples of the radical crosslinking agent include trimethylolpropane trimethacrylate, triallyl isocyanurate, triallyl cyanurate, diethylene glycol diacrylate, neophenylene glycol diacrylate, and the like. In addition, these radical crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more type.

--- Barrier layer--
The barrier layer is a layer containing a gas barrier resin in order to realize the air barrier property of the inner liner (laminated body) and maintain the internal pressure of the tire. When the resin composition constituting the barrier layer contains a gas barrier resin, an inner liner (laminate) having excellent gas barrier properties can be obtained.

The gas barrier resin is a resin having a function of preventing gas permeation. There is no restriction | limiting in particular as an air permeability coefficient in 20 degreeC and 65% RH conditions of the said gas-barrier resin, Although it can select suitably according to the objective, 800 * 10 < ^-12 > cm < ³ > cm / cm < ² >.・ Sec · cmHg or less is preferable, 8.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less is more preferable, and 5.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less Is particularly preferable, and 3.0 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg or less is most preferable. When the air permeability coefficient at 20 ° C. and 65% RH exceeds 800 × 10 ⁻¹² cm ³ · cm / cm ² · sec · cmHg, the barrier layer must be thickened in order to enhance the internal pressure retention of the tire. Therefore, the weight of the inner liner cannot be sufficiently reduced.

Here, specific examples of the gas barrier resin are not particularly limited and may be appropriately selected according to the purpose. Examples thereof include ethylene-vinyl alcohol copolymer (EVOH) and modified ethylene-vinyl alcohol copolymer. (Modified EVOH), polyamide resin, polyester resin, polyvinylidene chloride (PVDC), acrylonitrile copolymer, polyacrylonitrile, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl alcohol, polyacrylic acid (PMA), polymethacrylic acid (PMMA), polyacrylic acid ester, polymethacrylic acid ester and the like. These may be used individually by 1 type and may use 2 or more types together. Further, a modified (modified) gas barrier resin may be used.
Among these, an ethylene-vinyl alcohol copolymer (EVOH), a modified ethylene-vinyl alcohol copolymer (modified EVOH), a polyamide-based resin, and a polyester resin are preferable in terms of gas barrier properties. Polymer (EVOH), modified ethylene-vinyl alcohol copolymer (modified EVOH), polyacrylic acid ester, polymethacrylic acid ester, and polyvinylidene chloride are melt moldable and soluble in solvents Particularly preferred in terms. The modified ethylene-vinyl alcohol copolymer (modified EVOH) is, for example, a compound obtained by reacting an epoxy compound or the like with an ethylene-vinyl alcohol copolymer (EVOH). The elastic modulus is lower than that of the polymer (EVOH). For this reason, the elasticity modulus of a barrier layer can be reduced and durability, such as crack resistance, can also be improved.

--- Ethylene-vinyl alcohol copolymer (EVOH) and modified ethylene-vinyl alcohol copolymer (modified EVOH) ---
The ethylene-vinyl alcohol copolymer (EVOH) has an ethylene unit and a vinyl alcohol unit as structural units, and usually saponifies the resulting ethylene-vinyl ester copolymer by polymerizing ethylene and vinyl ester. Can be obtained.
The ethylene-vinyl alcohol copolymer has an ethylene content (monomer unit in EVOH) from the viewpoint of improving gas barrier properties, bending fatigue resistance, melt moldability, solubility in solvents and interlayer adhesion of the inner liner. The ratio of the number of ethylene with respect to the total number of is preferably 3 to 70 mol%, more preferably 10 to 60 mol%, still more preferably 20 to 55 mol%, and more preferably 25 to 50 mol%. It is particularly preferred that If the ethylene content is less than 3 mol%, the water resistance, hot water resistance, gas barrier properties and melt moldability at high humidity of the inner liner may be reduced, while if it exceeds 70 mol%, the gas barrier of the inner liner may be reduced. May decrease.

  The ethylene-vinyl alcohol copolymer has a saponification degree (the number of vinyl alcohol units relative to the total number of vinyl alcohol units and vinyl ester units in EVOH from the viewpoint of improving gas barrier properties, moisture resistance and interlayer adhesion of the inner liner. %) Is preferably 80% or more, more preferably 90% or more, still more preferably 95% or more, and particularly preferably 99% or more. On the other hand, the saponification degree of the ethylene-vinyl alcohol copolymer is preferably 99.99% or less. If the saponification degree of EVOH is less than 80%, the melt moldability, gas barrier property, coloration resistance and moisture resistance of the inner liner may be lowered.

  The ethylene-vinyl alcohol copolymer has a melt flow rate (MFR) of 0.1 to 30 g / 10 min under a load of 190 ° C. and 21.18 N from the viewpoint of obtaining gas barrier properties, flex resistance and fatigue resistance. It is preferable that it is 0.3 to 25 g / 10 min.

The ethylene-vinyl alcohol copolymer has a content G (mol%) of 1,2-glycol bond structural units of the following formula:
G ≦ 1.58−0.0244 × E
[Wherein, G is the content (mol%) of 1,2-glycol bond structural unit, E is the ethylene unit content (mol%) in EVOH, where E ≦ 64) And the intrinsic viscosity is preferably in the range of 0.05 to 0.2 L / g. By using such an ethylene-vinyl alcohol copolymer, the resulting inner liner (laminate) has a gas barrier property that is less dependent on humidity, has good transparency and gloss, and is made of another resin. Lamination into layers is also facilitated. The content of the 1,2-glycol-bonded structural unit was determined by changing the EVOH sample to a dimethyl sulfoxide solution according to the method described in “S. Aniya et al., Analytical Science Vol. 1, 91 (1985)”. It can be measured by nuclear magnetic resonance at 90 ° C.

  The modified ethylene-vinyl alcohol copolymer (modified EVOH) contains, in addition to ethylene units and vinyl alcohol units, other repeating units (hereinafter also referred to as structural units), for example, repeating units derived from these units. It is a polymer having a seed or plural kinds. The preferred ethylene content, degree of saponification, melt flow rate (MFR), content of 1,2-glycol bond structural unit and intrinsic viscosity of the modified EVOH are the same as those of the above-mentioned EVOH.

上記式（Ｉ）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立して、水素原子、炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基、炭素数６〜１０の芳香族炭化水素基又はヒドロキシ基を表す。また、Ｒ^１、Ｒ^２及びＲ^３のうちの一対が結合していてもよい（但し、Ｒ^１、Ｒ^２及びＲ^３のうちの一対が共に水素原子の場合は除く）。また、前記炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基は、ヒドロキシ基、カルボキシ基又はハロゲン原子を有していてもよい。一方、上記式（ＩＩ）中、Ｒ^４、Ｒ^５、Ｒ^６及びＲ^７は、それぞれ独立して、水素原子、炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基、炭素数６〜１０の芳香族炭化水素基又はヒドロキシ基を表す。また、Ｒ^４とＲ^５又はＲ^６とＲ^７は結合していてもよい（但し、Ｒ^４とＲ^５又はＲ^６とＲ^７が共に水素原子の場合は除く）。また、前記炭素数１〜１０の脂肪族炭化水素基、炭素数３〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基は、ヒドロキシ基、アルコキシ基、カルボキシ基又はハロゲン原子を有していてもよい。 The modified EVOH preferably has, for example, at least one structural unit selected from the structural units (I) and (II) shown below, and the structural unit is 0.5 to 30 mol% based on the total structural units. It is more preferable to contain in the ratio. Such a modified EVOH can improve the flexibility and processing characteristics of the resin or resin composition, and the interlayer adhesion, stretchability, and thermoformability of the inner liner.

In the above formula (I), R ¹ , R ² and R ³ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, An aromatic hydrocarbon group or hydroxy group having 6 to 10 carbon atoms is represented. In addition, a pair of R ¹ , R ² and R ³ may be bonded (except when a pair of R ¹ , R ² and R ³ are both hydrogen atoms). The aliphatic hydrocarbon group having 1 to 10 carbon atoms, the alicyclic hydrocarbon group having 3 to 10 carbon atoms, or the aromatic hydrocarbon group having 6 to 10 carbon atoms includes a hydroxy group, a carboxy group, or a halogen atom. You may have. On the other hand, in said formula (II), R < ⁴ >, R < ⁵ >, R < ⁶ > and R <^7> are respectively independently a hydrogen atom, a C1-C10 aliphatic hydrocarbon group, and a C3-C10 alicyclic ring. A formula hydrocarbon group, a C6-C10 aromatic hydrocarbon group, or a hydroxy group is represented. R ⁴ and R ⁵ or R ⁶ and R ⁷ may be bonded to each other (except when R ⁴ and R ⁵ or R ⁶ and R ⁷ are both hydrogen atoms). Moreover, the said C1-C10 aliphatic hydrocarbon group, a C3-C10 alicyclic hydrocarbon group, or a C6-C10 aromatic hydrocarbon group is a hydroxy group, an alkoxy group, a carboxy group, or It may have a halogen atom.

  In the modified EVOH, the lower limit of the content of the structural unit (I) and / or (II) with respect to all the structural units is preferably 0.5 mol%, more preferably 1 mol%, further 1.5 mol%. preferable. On the other hand, in the modified EVOH, the upper limit of the content of the structural unit (I) and / or (II) with respect to all the structural units is preferably 30 mol%, more preferably 15 mol%, still more preferably 10 mol%. By containing the structural units (I) and / or (II) in the specified proportions, the flexibility and processing characteristics of the resin or resin composition, and the interlayer adhesion, stretchability and thermoformability of the inner liner can be achieved. Can be improved.

  In the structural units (I) and (II), examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include an alkyl group and an alkenyl group, and examples of the alicyclic hydrocarbon group having 3 to 10 carbon atoms include cyclohexane. An alkyl group, a cycloalkenyl group, etc. are mentioned, A phenyl group etc. are mentioned as a C6-C10 aromatic hydrocarbon group.

In the structural unit (I), R ¹ , R ² and R ³ are preferably each independently a hydrogen atom, a methyl group, an ethyl group, a hydroxy group, a hydroxymethyl group or a hydroxyethyl group. Among these, a hydrogen atom, a methyl group, a hydroxy group, or a hydroxymethyl group is more preferable. With such R ¹ , R ² and R ³ , the stretchability and thermoformability of the inner liner can be further improved.

  The method for incorporating the structural unit (I) in EVOH is not particularly limited and may be appropriately selected depending on the intended purpose. For example, in the copolymerization of ethylene and vinyl ester, the structural unit (I) And a method of copolymerizing monomers derived from the above. Examples of the monomer derived from the structural unit (I) include alkene such as propylene, butylene, pentene, hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, 3-acyloxy-1 -Butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3-acyloxy-4 -Methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-hydroxy-1 -Pentene, 5-hydroxy-1-pentene, 4,5-dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, , 5-diacyloxy-1-pentene, 4-hydroxy-3-methyl-1-pentene, 5-hydroxy-3-methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5,6 -Dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5-hydroxy-1-hexene, 6-hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy Alkenes having a hydroxy group or an ester group such as -1-hexene and 5,6-diacyloxy-1-hexene are exemplified. Among these, from the viewpoint of copolymerization reactivity and gas barrier properties of the resulting inner liner, propylene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene, and 3, 4-diacetoxy-1-butene is preferred. Specifically, propylene, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene, and 3,4-diacetoxy-1-butene are more preferable, and 3,4-diacetoxy- 1-butene is particularly preferred. In addition, when using the alkene which has ester, it is induced | guided | derived to the said structural unit (I) in the case of saponification reaction.

In the structural unit (II), R ⁴ and R ⁵ are preferably both hydrogen atoms. In particular, it is more preferable that R ⁴ and R ⁵ are both hydrogen atoms, one of the R ⁶ and R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and the other is a hydrogen atom. The aliphatic hydrocarbon group in the structural unit (II) is preferably an alkyl group or an alkenyl group. Further, from the viewpoint of particularly emphasizing the gas barrier property of the inner liner (laminate), it is preferable that one of R ⁶ and R ⁷ is a methyl group or an ethyl group, and the other is a hydrogen atom. Furthermore, it is also preferable that one of R ⁶ and R ⁷ is a substituent represented by (CH ₂ ) _h OH (where h is an integer of 1 to 8) and the other is a hydrogen atom. In the substituent represented by (CH ₂ ) _h OH, h is preferably an integer of 1 to 4, more preferably 1 or 2, and particularly preferably 1.

上記式（ＩＩＩ）〜（ＩＸ）中、Ｒ^８、Ｒ^９、Ｒ^１０、Ｒ^１１及びＲ^１２は、水素原子、炭素数１〜１０の脂肪族炭化水素基（アルキル基又はアルケニル基等）、炭素数３〜１０の脂環式炭化水素基（シクロアルキル基又はシクロアルケニル基等）又は炭素数６〜１０の芳香族炭化水素基（フェニル基等）を表す。なお、Ｒ^８及びＲ^９又はＲ^１１及びＲ^１２は、同一であってもよく、異なっていてもよい。また、ｉ、ｊ、ｋ、ｐ及びｑは、１〜８の整数を表す。 The method for incorporating the structural unit (II) in EVOH is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a monovalent epoxy compound is added to EVOH obtained by a saponification reaction. The method of making it react is mentioned. Preferred examples of the monovalent epoxy compound include compounds represented by the following formulas (III) to (IX).

In the above formulas (III) to (IX), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms (such as an alkyl group or an alkenyl group), An alicyclic hydrocarbon group having 3 to 10 carbon atoms (such as a cycloalkyl group or a cycloalkenyl group) or an aromatic hydrocarbon group having 6 to 10 carbon atoms (such as a phenyl group) is represented. R ⁸ and R ⁹ or R ¹¹ and R ¹² may be the same or different. Moreover, i, j, k, p, and q represent the integer of 1-8.

  The monovalent epoxy compound represented by the formula (III) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, epoxy ethane (ethylene oxide), epoxy propane, 1,2-epoxybutane 2,3-epoxybutane, 3-methyl-1,2-epoxybutane, 1,2-epoxypentane, 2,3-epoxypentane, 3-methyl-1,2-epoxypentane, 4-methyl-1, 2-epoxypentane, 4-methyl-2,3-epoxypentane, 3-ethyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3- Methyl-1,2-epoxyhexane, 4-methyl-1,2-epoxyhexane, 5-methyl-1,2-epoxyhexane, 3-ethyl-1, -Epoxyhexane, 3-propyl-1,2-epoxyhexane, 4-ethyl-1,2-epoxyhexane, 5-methyl-1,2-epoxyhexane, 4-methyl-2,3-epoxyhexane, 4- Ethyl-2,3-epoxyhexane, 2-methyl-3,4-epoxyhexane, 2,5-dimethyl-3,4-epoxyhexane, 3-methyl-1,2-epoxyheptane, 4-methyl-1, 2-epoxyhexane, 5-methyl-1,2-epoxyheptane, 6-methyl-1,2-epoxyheptane, 3-ethyl-1,2-epoxyheptane, 3-propyl-1,2-epoxyheptane, 3 -Butyl-1,2-epoxyheptane, 4-ethyl-1,2-epoxyheptane, 4-propyl-1,2-epoxyheptane, 6-ethyl-1,2-epoxy Siheptane, 4-methyl-2,3-epoxyheptane, 4-ethyl-2,3-epoxyheptane, 4-propyl-2,3-epoxyheptane, 2-methyl-3,4-epoxyheptane, 5-methyl- 3,4-epoxyheptane, 5-ethyl-3,4-epoxyheptane, 2,5-dimethyl-3,4-epoxyheptane, 2-methyl-5-ethyl-3,4-epoxyheptane, 1,2- Epoxyheptane, 2,3-epoxyheptane, 3,4-epoxyheptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 3,4-epoxyoctane, 4,5-epoxyoctane, 1,2-epoxy Nonane, 2,3-epoxynonane, 3,4-epoxynonane, 4,5-epoxynonane, 1,2-epoxydecane, 2,3-epoxydecane, 3, 4-epoxydecane, 4,5-epoxydecane, 5,6-epoxydecane, 1,2-epoxyundecane, 2,3-epoxyundecane, 3,4-epoxyundecane, 4,5-epoxyundecane, 5,6 -Epoxyundecane, 1,2-epoxydodecane, 2,3-epoxydodecane, 3,4-epoxydodecane, 4,5-epoxydodecane, 5,6-epoxydodecane, 6,7-epoxydodecane, epoxyethylbenzene, 1 -Phenyl-1,2-propane, 3-phenyl-1,2-epoxypropane, 1-phenyl-1,2-epoxybutane, 3-phenyl-1,2-epoxypentane, 4-phenyl-1,2- Epoxypentane, 5-phenyl-1,2-epoxypentane, 1-phenyl-1,2-epoxyhexane, 3-phenyl Le-1,2 epoxy hexane, 4-phenyl-1,2-epoxy hexane, 5-phenyl-1,2-epoxy hexane, 6-phenyl-1,2-epoxy hexane, and the like.

  The monovalent epoxy compound represented by the above formula (IV) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, methyl glycidyl ether, ethyl glycidyl ether, n-propyl glycidyl ether, isopropyl glycidyl Ether, n-butyl glycidyl ether, isobutyl glycidyl ether, tert-butyl glycidyl ether, 1,2-epoxy-3-pentyloxypropane, 1,2-epoxy-3-hexyloxypropane, 1,2-epoxy-3- Heptyloxypropane, 1,2-epoxy-4-phenoxybutane, 1,2-epoxy-4-benzyloxybutane, 1,2-epoxy-5-methoxypentane, 1,2-epoxy-5-ethoxypentane, 1 , 2-Epoxy-5-propoxypentane 1,2-epoxy-5-butoxypentane, 1,2-epoxy-5-pentyloxypentane, 1,2-epoxy-5-hexyloxypentane, 1,2-epoxy-5-phenoxypentane, 1,2- Epoxy-6-methoxyhexane, 1,2-epoxy-6-ethoxyhexane, 1,2-epoxy-6-propoxyhexane, 1,2-epoxy-6-butoxyhexane, 1,2-epoxy-6-heptyloxy Hexane, 1,2-epoxy-7-methoxyheptane, 1,2-epoxy-7-ethoxyheptane, 1,2-epoxy-7-propoxyheptane, 1,2-epoxy-7-butoxyheptane, 1,2- Epoxy-8-methoxyoctane, 1,2-epoxy-8-ethoxyoctane, 1,2-epoxy-8-butoxyoctane, Ricidol, 3,4-epoxy-1-butanol, 4,5-epoxy-1-pentanol, 5,6-epoxy-1-hexanol, 6,7-epoxy-1-heptanol, 7,8-epoxy-1 -Octanol, 8,9-epoxy-1-nonanol, 9,10-epoxy-1-decanol, 10,11-epoxy-1-undecanol, and the like.

  The monovalent epoxy compound represented by the above formula (V) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene glycol monoglycidyl ether, propanediol monoglycidyl ether, butanediol monoglycidyl Examples include ether, pentanediol monoglycidyl ether, hexanediol monoglycidyl ether, heptanediol monoglycidyl ether, octanediol monoglycidyl ether, and the like.

  The monovalent epoxy compound represented by the formula (VI) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 3- (2,3-epoxy) propoxy-1-propene, 4 -(2,3-epoxy) propoxy-1-butene, 5- (2,3-epoxy) propoxy-1-pentene, 6- (2,3-epoxy) propoxy-1-hexene, 7- (2,3 -Epoxy) propoxy-1-heptene, 8- (2,3-epoxy) propoxy-1-octene, and the like.

  The monovalent epoxy compound represented by the formula (VII) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 3,4-epoxy-2-butanol, 2,3-epoxy- 1-butanol, 3,4-epoxy-2-pentanol, 2,3-epoxy-1-pentanol, 1,2-epoxy-3-pentanol, 2,3-epoxy-4-methyl-1-pen Tanol, 2,3-epoxy-4,4-dimethyl-1-pentanol, 2,3-epoxy-1-hexanol, 3,4-epoxy-2-hexanol, 4,5-epoxy-3-hexanol, 1 , 2-epoxy-3-hexanol, 2,3-epoxy-4,4-dimethyl-1-hexanol, 2,3-epoxy-4,4-diethyl-1-hexanol, 2,3-epoxy-4- Til-4-ethyl-1-hexanol, 3,4-epoxy-5-methyl-2-hexanol, 3,4-epoxy-5,5-dimethyl-2-hexanol, 3,4-epoxy-2-heptanol, 2,3-epoxy-1-heptanol, 4,5-epoxy-3-heptanol, 2,3-epoxy-4-heptanol, 1,2-epoxy-3-heptanol, 2,3-epoxy-1-octanol, 3,4-epoxy-2-octanol, 4,5-epoxy-3-octanol, 5,6-epoxy-4-octanol, 2,3-epoxy-4-octanol, 1,2-epoxy-3-octanol, 2,3-epoxy-1-nonanol, 3,4-epoxy-2-nonanol, 4,5-epoxy-3-nonanol, 5,6-epoxy-4-nonano 3,4-epoxy-5-nonanol, 2,3-epoxy-4-nonanol, 1,2-epoxy-3-nonanol, 2,3-epoxy-1-decanol, 3,4-epoxy-2- Decanol, 4,5-epoxy-3-decanol, 5,6-epoxy-4-decanol, 6,7-epoxy-5-decanol, 3,4-epoxy-5-decanol, 2,3-epoxy-4- Examples include decanol and 1,2-epoxy-3-decanol.

  The monovalent epoxy compound represented by the above formula (VIII) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1 , 2-epoxycycloheptane, 1,2-epoxycyclooctane, 1,2-epoxycyclononane, 1,2-epoxycyclodecane, 1,2-epoxycycloundecane, 1,2-epoxycyclododecane, etc. It is done.

  The monovalent epoxy compound represented by the formula (IX) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, 3,4-epoxycyclopentene, 3,4-epoxycyclohexene, 3, 4-epoxycycloheptene, 3,4-epoxycyclooctene, 3,4-epoxycyclononene, 1,2-epoxycyclodecene, 1,2-epoxycycloundecene, 1,2-epoxycyclododecene, etc. Is mentioned.

  Among the monovalent epoxy compounds, epoxy compounds having 2 to 8 carbon atoms are preferable. In particular, from the viewpoint of easy handling of the compound and reactivity with respect to EVOH, the carbon number of the monovalent epoxy compound is more preferably 2 to 6, and further preferably 2 to 4. The monovalent epoxy compound is particularly preferably a compound represented by the formula (III) or (IV) among the compounds represented by these formulas. Specifically, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane, and glycidol are preferable from the viewpoint of reactivity to EVOH and gas barrier properties of the resulting inner liner, and among these, epoxypropane And glycidol are particularly preferred.

  In the present invention, the ethylene-vinyl alcohol copolymer is obtained, for example, by polymerizing ethylene and a vinyl ester to obtain an ethylene-vinyl ester copolymer, and saponifying the ethylene-vinyl ester copolymer. . Further, as described above, the modified ethylene-vinyl alcohol copolymer is obtained by (1) copolymerizing a monomer derived from the structural unit (I) in the polymerization of ethylene and vinyl ester, or (2) It is obtained by reacting a monovalent epoxy compound with EVOH obtained by a saponification reaction. Here, the polymerization method of the ethylene-vinyl alcohol copolymer and the modified ethylene-vinyl alcohol copolymer is not particularly limited, and for example, any of solution polymerization, suspension polymerization, emulsion polymerization, and bulk polymerization may be used. Moreover, any of a continuous type and a batch type may be sufficient.

  There is no restriction | limiting in particular as vinyl ester which can be used for the said superposition | polymerization, According to the objective, it can select suitably, For example, fatty acid vinyl, such as vinyl acetate, vinyl propionate, and vinyl pivalate, etc. are mentioned.

  Moreover, when manufacturing a modified ethylene-vinyl alcohol copolymer, the monomer which can be copolymerized with these monomers other than ethylene and vinyl ester may be used preferably in a small amount. This copolymerizable monomer includes, in addition to the monomer derived from the above structural unit (I), other alkenes such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itaconic acid. Saturated carboxylic acid or its anhydride, salt, monoalkyl ester or dialkyl ester, etc .; Nitriles such as acrylonitrile and methacrylonitrile; Amides such as acrylamide and methacrylamide; Olefins such as vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid Examples thereof include sulfonic acid or a salt thereof; alkyl vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, and the like. Moreover, a vinyl silane compound can also be used as a monomer, and the amount of the vinyl silane compound introduced into the copolymer is preferably 0.0002 mol% or more and 0.2 mol% or less. Examples of the vinylsilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, γ-methacryloyloxypropylmethoxysilane, and the like. Among these vinylsilane compounds, vinyltrimethoxysilane and vinyltriethoxysilane are preferable.

  The solvent that can be used for the polymerization is not particularly limited as long as it is an organic solvent that can dissolve ethylene, vinyl ester, and ethylene-vinyl ester copolymer. Specific examples of the solvent include alcohols such as methanol, ethanol, propanol, n-butanol and tert-butanol; dimethyl sulfoxide, and the like. Among these, methanol is particularly preferable because removal and separation after the reaction is easy.

  There is no restriction | limiting in particular as an initiator which can be used for superposition | polymerization, According to the objective, it can select suitably, For example, 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4 Azonitrile-based initiators such as -dimethylvaleronitrile), 2,2'-azobis- (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis- (2-cyclopropylpropionitrile); Isobutyryl peroxide, cumylperoxyneodecanoate, diisopropylperoxycarbonate, di-n-propylperoxydicarbonate, t-butylperoxyneodecanoate, lauroyl peroxide, benzoyl peroxide, t-butylhydro And organic peroxide initiators such as peroxides.

  The polymerization temperature is usually about 20 ° C to 90 ° C, preferably 40 ° C to 70 ° C. The polymerization time is usually about 2 hours to 15 hours, preferably 3 hours to 11 hours. The polymerization rate is usually about 10% to 90%, preferably 30% to 80% with respect to the vinyl ester charged. The resin content in the solution after polymerization is about 5% to 85% by mass, preferably 20% to 70% by mass.

  After polymerization for a predetermined time or after reaching a predetermined polymerization rate, a polymerization inhibitor is added to the resulting copolymer solution as necessary, and unreacted ethylene gas is removed by evaporation. Remove. As a method for removing unreacted vinyl ester, for example, a copolymer solution is continuously supplied from the upper part of the tower filled with Raschig rings at a constant rate, and an organic solvent vapor such as methanol is blown from the lower part of the tower, A method may be employed in which a vapor mixture of an organic solvent such as methanol and unreacted vinyl ester is distilled from the top, and a copolymer solution from which unreacted vinyl ester has been removed is removed from the bottom of the column.

  Next, an alkali catalyst is added to the copolymer solution to saponify the copolymer present in the solution. The saponification method can be either a continuous type or a batch type. There is no restriction | limiting in particular as said alkali catalyst, According to the objective, it can select suitably, For example, sodium hydroxide, potassium hydroxide, an alkali metal alcoholate, etc. are mentioned. The saponification conditions are, for example, in the case of batch type, the concentration of the alkali catalyst in the copolymer solution is about 10% to 50% by mass, the reaction temperature is about 30 ° C. to 65 ° C., and the amount of catalyst used is vinyl ester. It is preferable that about 0.02 mol to 1.0 mol per mol of the structural unit and the saponification time is about 1 hour to 6 hours.

  The (modified) EVOH after the saponification reaction contains an alkali catalyst, by-product salts such as sodium acetate and potassium acetate, and other impurities. Therefore, it is preferable to remove these by neutralization and washing as necessary. . Here, when the (modified) EVOH after the saponification reaction is washed with water containing almost no metal ions such as ion-exchanged water, chloride ions, etc., part of sodium acetate, potassium acetate, etc. may remain. .

--- Polyamide resin (PA) ---
The polyamide resin (PA) is a general term for polymer compounds having an amide bond formed by a reaction between an acid and an amine, and has good mechanical properties and is resistant to tension, compression, bending, and impact. From the viewpoint of improving gas barrier properties, melt moldability, and interlayer adhesion of the inner liner, the polyamide resin (PA) is 100 g / 10 minutes at a melt flow rate JIS K 7210 1999 (230 ° C. 21.18 N). Is preferable, and it is still more preferable that it is 30 g / 10min.
The polyamide resin can be obtained by ring-opening polymerization of lactam or polycondensation of aminocarboxylic acid or diamine and carboxylic acid.

  The lactam is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ε-caprolactam and ω-laurolactam.

  The aminocarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and paraaminomethylbenzoic acid. It is done.

  There is no restriction | limiting in particular as said diamine, According to the objective, it can select suitably, For example, tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4-trimethylhexamethylene diamine 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (amino-3-aminomethyl-3,5,5-trimethylcyclohexane, Bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine, etc. .

  The dicarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, cyclohexane Dicarboxylic acid, decalin dicarboxylic acid, norbornane dicarboxylic acid, tricyclodecane dicarboxylic acid, pentacyclododecanedicarboxylic acid, isophorone dicarboxylic acid, 3,9-bis (2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5] Undecane, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, terephthalic acid, isophthalic acid, phthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, tetralindicarboxylic acid, etc. To mention That.

  The polycondensation method for synthesizing the polyamide resin is not particularly limited and can be appropriately selected depending on the purpose. For example, a polycondensation method in a molten state or a low polycondensation method once in a molten state. An example is a method (so-called solid phase polymerization) in which after the viscosity polyamide is obtained, heat treatment is performed in a solid phase state. The polycondensation method in the solution state is not particularly limited and can be appropriately selected depending on the purpose. For example, an aqueous solution of a nylon salt of diamine and dicarboxylic acid is heated under pressure to remove water and condensed water. Examples thereof include a method of polycondensation in a molten state, a method of directly adding diamine to a dicarboxylic acid in a molten state, and polycondensing under normal pressure.

  The specific polyamide resin that is a polycondensate such as the compound is not particularly limited and may be appropriately selected depending on the purpose. For example, polycaprolactam (nylon 6), polylaurolactam (nylon 12), Polyhexamethylenediadipamide (nylon 66), polyhexamethylene azelamide (nylon 69), polyhexamethylene sebamide (nylon 610), nylon 46, nylon 6/66, nylon 6/12, 11-aminoundecanoic acid Polyamide resin (nylon 11) and other aliphatic polyamide resins; polyhexamethylene isophthalamide (nylon 6IP), metaxylenediamine / adipic acid copolymer (nylon MXD6), metaxylenediamine / adipic acid / isophthalic acid co Aromatic polyamide resins such as polymers, etc. That. These may be used individually by 1 type and may use 2 or more types together.

  Among these polyamide resins, nylon MXD6 having excellent gas barrier properties is preferable. As a diamine component of this nylon MXD6, it is preferable that 70 mol% or more of metaxylylenediamine is contained, and as a dicarboxylic acid component, it is preferable that 70 mol or more of adipic acid is contained. By obtaining nylon MXD6 from a monomer having the above blending range, more excellent gas barrier properties and mechanical performance can be exhibited.

--- Polyester resin ---
The polyester resin is a polymer having an ester bond and can be obtained by polycondensation of a polyvalent carboxylic acid and a polyol. There is no restriction | limiting in particular as a polyester resin used as a gas barrier resin of the said laminated body, According to the objective, it can select suitably, For example, a polyethylene terephthalate (PET), polyglycolic acid (PGA), an aromatic liquid crystal And polyester. These may be used individually by 1 type and may use 2 or more types together. Among these polyester resins, polyglycolic acid (PGA) and wholly aromatic liquid crystal polyesters are preferable from the viewpoint of high gas barrier properties.

---- Polyglycolic acid (PGA) ----
The polyglycolic acid (PGA) is a homopolymer or a copolymer having a structural unit (GA) represented by —O—CH ₂ —CO—. There is no restriction | limiting in particular as a content rate of the said structural unit (GA) in the said polyglycolic acid (PGA), Although it can select suitably according to the objective, 60 mass% or more is preferable and 70 mass% or more is more. Preferably, 80% by mass or more is particularly preferable, and 100% by mass or less is preferable. When the content ratio of the structural unit (GA) is less than 60% by mass, the gas barrier property may not be sufficiently exhibited.

  There is no restriction | limiting in particular as a manufacturing method of the said polyglycolic acid (PGA), According to the objective, it can select suitably, For example, (2) Method of synthesize | combining by dehydration polycondensation of glycolic acid, (2) Glycolic acid Examples thereof include a method of synthesis by dealcoholization polycondensation of an alkyl ester, and a method of synthesis by (3) ring-opening polymerization of glycolide (1,4-dioxane-2,3-dione).

  The method for synthesizing polyglycolic acid (PGA) as a copolymer is not particularly limited and may be appropriately selected depending on the purpose. For example, in each of the above synthesis methods, as a comonomer, for example, oxalic acid Ethylene (1,4-dioxane-2,3-dione), lactide, lactones (for example, β-propiolactone, β-butyrolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valero) Lactone, ε-caprolactone, etc.), cyclic monomers such as trimethylene carbonate, 1,3-dioxane; hydroxy such as lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6-hydroxycaproic acid Carboxylic acid or alkyl ester thereof; ethylene glycol, 1,4-butane A substantially equimolar mixture of an aliphatic diol such as diol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof; and the like, in combination with glycolide, glycolic acid or glycolic acid alkyl ester as appropriate The method of copolymerizing is mentioned.

  As a specific method of the ring-opening polymerization of (3), glycolide is used in the presence of a small amount of a catalyst (for example, a cationic catalyst such as tin organic carboxylate, tin halide, antimony halide, etc.). A method of heating to a temperature of ° C. can be mentioned. This ring-opening polymerization is preferably performed by a bulk polymerization method or a solution polymerization method.

  In the ring-opening polymerization, glycolide used as a monomer can be obtained by a sublimation depolymerization method or a solution phase depolymerization method of a glycolic acid oligomer.

  The high-boiling polar organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include bis (alkoxyalkyl esters) phthalates such as di (2-methoxyethyl) phthalate; diethylene glycol dibenzoate and the like. Alkylene glycol dibenzoates; aromatic carboxylic acid esters such as benzyl butyl phthalate and dibutyl phthalate; aromatic phosphoric acid esters such as tricresyl phosphate; In addition to the high-boiling polar organic solvent, polypropylene glycol, polyethylene glycol, tetraethylene glycol, or the like can be used in combination as an oligomer solubilizer as necessary.

---- Fully aromatic liquid crystal polyester ----
The wholly aromatic liquid crystal polyester is a liquid crystalline polyester in which both a polyvalent carboxylic acid as a monomer and a polyol are aromatic compounds. This wholly aromatic liquid crystalline polyester can be obtained by polymerizing by a known method in the same manner as ordinary polyester.

  The aromatic polyvalent carboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. 1,4-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 3,3′-biphenyldicarboxylic acid, 4,4′-methylenedibenzoic acid, diphenic acid, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The aromatic polyol is not particularly limited and may be appropriately selected depending on the intended purpose. For example, hydroquinone, methylhydroquinone, 4,4′-dihydroxydiphenyl, resorcinol, phenylhydroquinone, 3,4′-bisphenol A, etc. are mentioned.

  Further, the wholly aromatic liquid crystalline polyester is obtained by polymerizing an aromatic compound having a hydroxy group and a carboxy group such as hydroxybenzoic acid and hydroxynaphthoic acid, or the above aromatic polyvalent carboxylic acid and aromatic type. It can also be obtained by copolymerization with a polyol.

--- Polyvinyl alcohol resin (PVA) ---
The polyvinyl alcohol resin (PVA) is a kind of synthetic resin and can be obtained by saponifying polyvinyl acetate obtained by polymerizing a vinyl acetate monomer.

--- Additives in resin composition for forming barrier layer ---
Depending on the embodiment, the resin composition forming the barrier layer may contain one or more compounds selected from a phosphoric acid compound, a carboxylic acid, and a boron compound. By including such a phosphoric acid compound, carboxylic acid or boron compound in the resin composition of the barrier layer, various performances of the multilayer structure can be improved.

  Specifically, by including a phosphoric acid compound in the resin composition of the barrier layer containing EVOH or the like, the thermal stability during melt molding of the multilayer structure can be improved. It does not specifically limit as a phosphoric acid compound, For example, various acids, such as phosphoric acid and phosphorous acid, its salt, etc. are mentioned. The phosphate may be contained in any form of, for example, a first phosphate, a second phosphate, and a third phosphate, and is not particularly limited as a counter cation species, but an alkali metal ion Or alkaline earth metal ions are preferred. In particular, sodium dihydrogen phosphate, potassium dihydrogen phosphate, sodium hydrogen phosphate, or potassium hydrogen phosphate is preferred because of its high thermal stability improving effect.

  As a minimum of content of a phosphoric acid compound (phosphoric acid radical conversion content of a phosphoric acid compound in a dry resin composition of a barrier layer), 1 mass ppm is preferred, 10 mass ppm is more preferred, and 30 mass ppm is still more preferred. . On the other hand, the upper limit of the content of the phosphoric acid compound is preferably 10,000 ppm by mass, more preferably 1,000 ppm by mass, and even more preferably 300 ppm by mass. If the content of the phosphoric acid compound is less than the above lower limit, coloring during melt molding may become intense. In particular, since the tendency is remarkable when the heat history is accumulated, a molded product obtained by molding the resin composition pellet may be poor in recoverability. On the other hand, if the content of the phosphoric acid compound exceeds the above upper limit, there is a risk that gels and blisters during molding are likely to occur.

  Moreover, by containing carboxylic acid in the resin composition of a barrier layer containing EVOH etc., there exists an effect which controls the pH of a resin composition, prevents gelatinization, and improves thermal stability. As the carboxylic acid, those having a pKa at 25 ° C. of 3.5 or more are preferable. When a carboxylic acid such as oxalic acid, succinic acid, benzoic acid, citric acid or the like having a pKa at 25 ° C. of less than 3.5 is contained, it becomes difficult to control the pH of the resin composition containing EVOH and the like, and resistance to coloring. And the interlayer adhesion may be unsatisfactory. In particular, as the carboxylic acid, acetic acid or lactic acid is preferable from the viewpoint of cost and the like.

  As a minimum of content of carboxylic acid (content of carboxylic acid in the dry resin composition of a barrier layer), 1 mass ppm is preferred, 10 mass ppm is more preferred, and 50 mass ppm is still more preferred. On the other hand, the upper limit of the carboxylic acid content is preferably 10,000 mass ppm, more preferably 1,000 mass ppm, and even more preferably 500 mass ppm. If the carboxylic acid content is less than the lower limit, coloring may occur during melt molding. Conversely, if the content of carboxylic acid exceeds the above upper limit, the interlayer adhesion may be insufficient.

Furthermore, the inclusion of a boron compound in the resin composition of the barrier layer containing EVOH or the like has an effect of improving thermal stability. Specifically, when a boron compound is added to a resin composition composed of EVOH or the like, it is considered that a chelate compound is generated between the EVOH or the like and the boron compound, and by using such EVOH or the like, it is more effective than ordinary EVOH or the like. It is possible to improve thermal stability and mechanical properties. The boron compound is not particularly limited, and examples thereof include boric acids, boric acid esters, borates, and hydrogenated boric acids. Specifically, examples of boric acids include orthoboric acid (H ₃ BO ₃ ), metaboric acid, and tetraboric acid, and examples of boric acid esters include triethyl borate and trimethyl borate. Examples of the borate include alkali metal salts, alkaline earth metal salts, and borax of the various boric acids. Of these, orthoboric acid is preferred.

  As a minimum of content of a boron compound (boron conversion content of a boron compound in a dry resin composition of a barrier layer), 1 mass ppm is preferred, 10 mass ppm is more preferred, and 50 mass ppm is still more preferred. On the other hand, the upper limit of the boron compound content is preferably 2,000 mass ppm, more preferably 1,000 mass ppm, and even more preferably 500 mass ppm. If the boron compound content is less than the above lower limit, the effect of improving the thermal stability by adding the boron compound may not be obtained. On the contrary, when the content of the boron compound exceeds the above upper limit, gelation tends to occur and there is a risk of forming defects.

  The method for containing the phosphoric acid compound, carboxylic acid or boron compound in a resin composition containing EVOH or the like is not particularly limited. For example, when preparing pellets of a resin composition containing EVOH or the like, A method of adding to the product and kneading is preferably employed. The method of adding to the resin composition is not particularly limited, but the method of adding as a dry powder, the method of adding in a paste impregnated with a solvent, the method of adding in a suspended state in a liquid, or dissolving in a solvent. The method of adding as a solution is illustrated. From the viewpoint of homogeneous dispersion in these, a method of dissolving in a solvent and adding as a solution is preferable. The solvent used in these methods is not particularly limited, but water is preferably used from the viewpoints of solubility of the additive, cost merit, ease of handling, completeness of work environment, and the like. At the time of these additions, a resin other than the metal salt and EVOH described later, other additives, and the like can be added simultaneously.

  In addition, as a method of containing a phosphoric acid compound, a carboxylic acid, and a boron compound, a method in which pellets or strands obtained by an extruder or the like after the saponification are immersed in a solution in which those substances are dissolved is homogeneously dispersed. It is preferable at the point which can be made. Also in this method, water is preferably used as the solvent for the same reason as described above. By dissolving a metal salt described later in this solution, the metal salt can be contained simultaneously with the phosphoric acid compound and the like.

  The resin composition of the barrier layer preferably contains a compound having a conjugated double bond having a molecular weight of 1,000 or less. By containing such a compound, the hue of the resin composition of the barrier layer is improved, so that a multilayer structure having a good appearance can be obtained. Examples of such a compound include a conjugated diene compound having a structure in which at least two carbon-carbon double bonds and one carbon-carbon single bond are alternately connected, and three carbon-carbon double bonds. A triene compound having a structure in which two carbon-carbon single bonds are alternately connected; a conjugated polyene compound having a structure in which a larger number of carbon-carbon double bonds and carbon-carbon single bonds are alternately connected; Examples thereof include conjugated triene compounds such as 2,4,6-octatriene. The compound having a conjugated double bond may include a plurality of conjugated double bonds independently in one molecule, for example, a compound having three conjugated trienes in the same molecule such as tung oil. It is.

  Examples of the compound having a conjugated double bond include a carboxy group and a salt thereof, a hydroxyl group, an ester group, a carbonyl group, an ether group, an amino group, an imino group, an amide group, a cyano group, a diazo group, a nitro group, a sulfone group, and a sulfoxide. It may have other various functional groups such as a group, sulfide group, thiol group, sulfonic acid group and salt thereof, phosphoric acid group and salt thereof, phenyl group, halogen atom, double bond and triple bond. Such a functional group may be directly bonded to the carbon atom in the conjugated double bond, or may be bonded to a position away from the conjugated double bond. The multiple bond in the functional group may be in a position capable of conjugating with the above conjugated double bond. For example, 1-phenylbutadiene having a phenyl group and sorbic acid having a carboxy group also have the conjugated double bond referred to herein. Included in compounds. Specific examples of this compound include, for example, 2,4-diphenyl-4-methyl-1-pentene, 1,3-diphenyl-1-butene, 2,3-dimethyl-1,3-butadiene, 4-methyl-1 , 3-pentadiene, 1-phenyl-1,3-butadiene, sorbic acid, myrcene and the like.

  The conjugated double bond in the compound having a conjugated double bond is not only an aliphatic conjugated double bond such as 2,3-dimethyl-1,3-butadiene and sorbic acid, but also 2,4-diphenyl. Aliphatic and aromatic conjugated double bonds such as -4-methyl-1-pentene and 1,3-diphenyl-1-butene are also included. However, from the viewpoint of obtaining a multilayer structure having a more excellent appearance, a compound containing a conjugated double bond between the above aliphatic groups is preferred, and a conjugated double bond having a polar group such as a carboxy group and a salt thereof, or a hydroxyl group. Also preferred are compounds comprising. Further, a compound having a polar group and containing an aliphatic conjugated double bond is particularly preferable.

The molecular weight of the compound having a conjugated double bond is preferably 1,000 or less. When the molecular weight exceeds 1,000, the surface smoothness and extrusion stability of the multilayer structure may be deteriorated. The lower limit of the content of the compound having a conjugated double bond having a molecular weight of 1,000 or less is preferably 0.1 mass ppm, more preferably 1 mass ppm, more preferably 3 mass ppm from the viewpoint of the effect exerted. Further preferred is 5 ppm by mass or more. On the other hand, the upper limit of the content of this compound is preferably 3,000 ppm by mass, more preferably 2,000 ppm by mass, further preferably 1,500 ppm by mass, from the viewpoint of the effect exerted. ppm is particularly preferred.
As a method for adding the compound having a conjugated double bond, it is preferable to add after the polymerization as described above and before the saponification from the viewpoint of improving the surface smoothness and the extrusion stability. Although the reason for this is not necessarily clear, it is considered that the compound having a conjugated double bond has an effect of preventing alteration such as EVOH before saponification and / or during the saponification reaction.

  The resin composition of the barrier layer is not limited to the above-described additives, and other resins other than EVOH, etc., or various other materials such as heat stabilizers, ultraviolet absorbers, antioxidants, colorants, fillers, etc. The additive may be included. When the resin composition of the barrier layer contains additives other than the above additives, the amount is preferably 50% by mass or less, more preferably 30% by mass or less, based on the total amount of the resin composition, It is especially preferable that it is 10 mass% or less.

The resin composition of the barrier layer has a viscosity behavior stability (M ₁₀₀ / M ₂₀ , where M ₂₀ is 20 minutes from the start of kneading) in the relationship between the melt kneading time and torque at at least one point at a temperature 10 to 80 ° C. higher than the melting point. The value of the subsequent torque (M ₁₀₀ represents the torque 100 minutes after the start of kneading) is preferably in the range of 0.5 to 1.5. The viscosity behavior stability value closer to 1 indicates that the viscosity change is smaller and the thermal stability (long run property) is more excellent.

-Elastic layer-
The elastic body layer constituting the inner liner (laminate) is a layer containing an elastomer, and any other configuration is not particularly limited as long as it is a layer containing an elastomer. For example, the layer which consists of an elastomer, or the layer which consists of an elastomer composition in which this elastomer exists as a matrix, etc. are mentioned. The matrix means a continuous phase.
When the resin composition which comprises the said elastic body layer contains an elastomer, the ductility of the said laminated body can be improved and bending resistance can be improved. Further, by laminating an elastic body layer made of a resin composition containing this elastomer together with a barrier layer having a predetermined thickness, the ductility of the barrier layer can be increased even when the resin composition of the barrier layer is low.
The elastic layer may contain various additives such as a filler and a plasticizer in addition to the elastomer.
The elastomer refers to a composition having elasticity at around room temperature, and has a Young's modulus at 23 ° C. smaller than that of the gas barrier resin. More specifically, it has the property of stretching to 2 times under the condition of room temperature (20 ° C.), holding in that state for 1 minute, and then shrinking to less than 1.5 times the original length within 1 minute. Refers to resin. The elastomer is structurally usually a polymer having a polymer chain having a glass transition temperature of room temperature or lower and a crosslinking point, or a polymer having a hard segment and a soft segment in the polymer chain. is there.

The elastomer contained in the elastic layer constituting the inner liner preferably has a Young's modulus at 23 ° C. of 200 MPa or less, more preferably 100 MPa or less, and even more preferably 50 MPa or less. The air permeability coefficient at 20 ° C. and 65% RH of the elastomer contained in the elastic layer is preferably 5 × 10 ⁻⁸ cm ³ · cm ² · sec · cmHg or less. This is because if it exceeds 5 × 10 ⁻⁸ cm ³ · cm / cm ² · sec · cmHg, sufficient internal pressure retention may not be ensured even when the barrier layer is provided.

  There is no restriction | limiting in particular as an elastomer used for the said elastic body layer, According to the objective, it can select suitably, For example, a polystyrene-type elastomer, a polyolefin-type elastomer, a polydiene-type elastomer, a polyvinyl chloride-type elastomer, a chlorinated polyethylene type | system | group Examples include elastomers, polyurethane elastomers, polyester elastomers, polyamide elastomers, fluororesin elastomers, natural rubber, polybutadiene rubber, styrene-butadiene copolymer, isobutylene rubber, brominated isobutylene rubber, and chloroprene rubber. Among these, polystyrene elastomer, polyolefin elastomer, polydiene elastomer, polyurethane elastomer, polyester elastomer, polyamide elastomer and natural rubber, polybutadiene rubber, isobutylene rubber from the viewpoint of ease of molding and solubility in solvents. At least one selected from the group consisting of brominated isobutylene rubbers is preferred, and polyurethane elastomers are more preferred.

  Moreover, there is no restriction | limiting in particular as such an elastomer, Although it can select suitably from well-known thermoplastic elastomers and non-thermoplastic elastomers, it is possible to use a thermoplastic elastomer for melt molding. preferable.

  The thermoplastic elastomer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polystyrene-based thermoplastic elastomer, a polyolefin-based thermoplastic elastomer, a polydiene-based thermoplastic elastomer, and a polyvinyl chloride-based thermoplastic elastomer. Chlorinated polyethylene-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, fluororesin-based thermoplastic elastomer, and the like. Among these, from the viewpoint of ease of molding, a group consisting of a polystyrene-based thermoplastic elastomer, a polyolefin-based thermoplastic elastomer, a polydiene-based thermoplastic elastomer, a polyurethane-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, and a polyamide-based thermoplastic elastomer. At least one selected from more preferable is preferable, and a polyurethane-based thermoplastic elastomer is more preferable.

--- Polystyrene thermoplastic elastomer ---
The polystyrene-based thermoplastic elastomer has an aromatic vinyl polymer block (hard segment) and a rubber block (soft segment), and the aromatic vinyl polymer portion forms a physical cross-link and becomes a crosslinking point. On the other hand, the rubber block imparts rubber elasticity.
The polystyrene-based thermoplastic elastomer can be classified according to the arrangement pattern of soft segments in the molecule. For example, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene -Isobutylene-styrene block copolymer (SIBS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), etc. Block copolymer of crystalline polyethylene and ethylene / butylene-styrene random copolymer obtained by hydrogenating block copolymer of butadiene-styrene random copolymer, polybutadiene or ethylene-butadiene random copolymer Obtain a block copolymer of the body and the polystyrene by hydrogenating, for example, also include diblock copolymer of crystalline polyethylene and polystyrene. These polystyrene-based thermoplastic elastomers may be modified products such as maleic anhydride modified.
Among these, styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene from the balance of mechanical strength, heat stability, weather resistance, chemical resistance, gas barrier properties, flexibility, workability, etc. / Butylene-styrene block copolymer (SEBS) and styrene-ethylene / propylene-styrene block copolymer (SEPS) are preferred.

---- Polyolefin thermoplastic elastomer ---
The polyolefin-based thermoplastic elastomer includes a thermoplastic elastomer having a polyolefin block such as polypropylene or polyethylene as a hard segment and a rubber block such as an ethylene-propylene-diene copolymer as a soft segment. Such thermoplastic elastomer includes a blend type and an implant type. Examples of the polyolefin-based thermoplastic elastomer include maleic anhydride-modified ethylene-butene-1 copolymer, maleic anhydride-modified ethylene-propylene copolymer, halogenated butyl rubber, modified polypropylene, and modified polyethylene. You can also.

---- Polydiene thermoplastic elastomer ---
Examples of the polydiene-based thermoplastic elastomer include 1,2-polybutadiene-based TPE, trans 1,4-polyisoprene-based TPE, hydrogenated conjugated diene-based TPE, and epoxidized natural rubber (ENR). The 1,2-polybutadiene-based TPE is a polybutadiene containing 90% or more of 1,2-bonds in the molecule, and is crystalline syndiotactic 1,2-polybutadiene as a hard segment and amorphous as a soft segment. It consists of 1,2-polybutadiene. Trans 1,4-polyisoprene-based TPE is polyisoprene having a trans 1,4 structure of 98% or more in the molecule, and includes crystalline trans 1,4 segments as hard segments and soft segments as soft segments. It consists of amorphous trans 1,4 segments.

--- Polyvinyl chloride thermoplastic elastomer (TPVC) ---
The polyvinyl chloride thermoplastic elastomer (TPVC) is generally roughly classified into the following three types. Note that this TPVC may also be a modified product such as maleic anhydride-modified PVC.
Type 1: High molecular weight polyvinyl chloride (PVC) / plasticized polyvinyl chloride (PVC) blend type TPVC
It is a thermoplastic elastomer made of high molecular weight PVC for the hard segment and PVC plasticized with a plasticizer for the soft segment. In addition, by using high molecular weight PVC for the hard segment, the function of a crosslinking point is given to the microcrystal part.
Type 2: Partially cross-linked PVC / plasticized PVC blend type TPVC
It is a thermoplastic elastomer using PVC in which a partially crosslinked or branched structure is introduced into a hard segment and PVC plasticized with a plasticizer in a soft segment.
Type 3: PVC / elastomer alloy TPVC
It is a thermoplastic elastomer that uses PVC for the hard segment and rubber such as partially crosslinked nitrile butadiene rubber (NBR) or TPE such as polyurethane TPE and polyester TPE for the soft segment.

--- Polychlorinated polyethylene (CPE) thermoplastic elastomer ---
The chlorinated polyethylene-based thermoplastic elastomer is a soft resin obtained by reacting polyethylene with chlorine gas in an aqueous suspension or a solvent such as carbon tetrachloride, and a crystalline polyethylene block is a soft segment in the hard segment. A chlorinated polyethylene (CPE) block is used for the segment. In the CPE block, both components of polyethylene and chlorinated polyethylene are mixed as a mixture having a multi-block or random structure.
Polychlorinated polyethylene (CPE) has different molecular properties such as chlorine content, blockiness and residual crystallinity depending on the type of raw polyethylene, chlorination degree, production conditions, etc., and as a result, a wide range from resin to rubber The product having the same property as that of the vulcanized rubber is also possible, and the product can be modified by maleic anhydride modification.

---- Polyester thermoplastic elastomer (TPEE) ---
The polyester-based thermoplastic elastomer (TPEE) is a multi-block copolymer using polyester as a hard segment in a molecule and polyether or polyester having a low glass transition temperature (Tg) as a soft segment. TPEE can be divided into the following types according to the difference in molecular structure, and polyester / polyether type TPEE and polyester / polyester type TPEE dominate.
(1) Polyester / polyether type TPEE
Generally, it is a thermoplastic elastomer using aromatic crystalline polyester as a hard segment and polyether as a soft segment.
(2) Polyester / Polyester type TPEE
A thermoplastic elastomer using an aromatic crystalline polyester as a hard segment and an aliphatic polyester as a soft segment.
(3) Liquid crystalline TPEE
It is a thermoplastic elastomer using rigid liquid crystal molecules as hard segments and aliphatic polyester as soft segments.

---- Polyamide thermoplastic elastomer (TPA) ---
The polyamide-based thermoplastic elastomer (TPA) is a multi-block copolymer using polyamide as a hard segment and polyether or polyester having a low Tg as a soft segment. The polyamide component constituting the hard segment is selected from nylon 6, 66, 610, 11, 12 and the like, and nylon 6 and nylon 12 are mainly used. As the constituent material of the soft segment, a long-chain polyol such as polyether diol or polyester diol is used. Representative examples of polyether polyols include diol poly (oxytetramethylene) glycol (PTMG), poly (oxypropylene) glycol, and the like. Representative examples of polyester polyols include poly (ethylene adipate) glycol, poly (butylene- 1,4 adipate) glycol and the like.

---- Fluoroplastic thermoplastic elastomer ---
The fluororesin-based thermoplastic elastomer is an ABA type block copolymer made of fluororesin as a hard segment and fluororubber as a soft segment. Tetrafluoroethylene-ethylene copolymer or polyvinylidene fluoride (PVDF) is used for the fluororesin constituting the hard segment, and vinylidene fluoride-hexafluoropropylene-tetrafluoro is used for the fluororubber constituting the soft segment. An ethylene terpolymer or the like is used. More specifically, it includes vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, tetrafluoroethylene-perfluoromethyl vinyl ether rubber, phosphazene fluororubber, fluoropolyether, fluoronitroso rubber, perfluorotriazine. And the like. In addition, fluororesin TPE is microphase-separated like other TPE, and the hard segment forms the crosslinking point.

--- Polyurethane thermoplastic elastomer (TPU) ---
The polyurethane-based thermoplastic elastomer (TPU) includes (1) a polyurethane obtained by a reaction of a short-chain glycol and an isocyanate as a hard segment, and (2) a polyurethane obtained by a reaction of a long-chain glycol and an isocyanate as a soft segment. Is a linear multi-block copolymer. Here, polyurethane is a general term for compounds having a urethane bond (—NHCOO—) obtained by polyaddition reaction (urethanization reaction) of isocyanate (—NCO) and alcohol (—OH). In the innerliner of the present invention, if the elastomer forming the elastic layer is TPU, the stretchability and thermoformability can be improved by laminating the elastic layer. In addition, since the inner liner can improve the interlayer adhesion between the elastic layer and the barrier layer, the inner liner has high durability such as crack resistance, and even when the inner liner is used by being deformed, the gas barrier property and stretchability are improved. Can be maintained.

  The TPU is composed of a polymer polyol, an organic polyisocyanate, a chain extender and the like. The polymer polyol is a substance having a plurality of hydroxy groups, and is obtained by polycondensation, addition polymerization (for example, ring-opening polymerization), polyaddition or the like. Examples of the polymer polyol include polyester polyol, polyether polyol, polycarbonate polyol, or a cocondensate thereof (for example, polyester-ether-polyol). Among these, polyester polyol or polycarbonate polyol is preferable, and polyester polyol is particularly preferable. In addition, these polymer polyols may be used individually by 1 type, and may be used in combination of 2 or more type.

  Here, for example, according to a conventional method, the polyester polyol may be obtained by condensing a compound capable of forming an ester such as a dicarboxylic acid, an ester thereof, or an anhydride thereof and a low molecular polyol by a direct esterification reaction or an ester exchange reaction. Alternatively, it can be produced by ring-opening polymerization of a lactone.

  It does not specifically limit as dicarboxylic acid which can be used for the production | generation of the said polyester polyol, The dicarboxylic acid generally used in manufacture of polyester is mentioned. Specific examples of the dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, methylsuccinic acid, 2-methylglutaric acid, trimethyladipic acid, 2- C4-C12 aliphatic dicarboxylic acids such as methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid Examples thereof include aromatic dicarboxylic acids such as acid, orthophthalic acid, and naphthalenedicarboxylic acid. These dicarboxylic acids may be used individually by 1 type, and 2 or more types may be mixed and used for them. Among these, an aliphatic dicarboxylic acid having 6 to 12 carbon atoms is preferable, and adipic acid, azelaic acid or sebacic acid is particularly preferable. These dicarboxylic acids have a carbonyl group that is more likely to react with a hydroxy group, and can greatly improve interlayer adhesion with the barrier layer.

  It does not specifically limit as a low molecular polyol which can be used for the production | generation of the said polyester polyol, The low molecular polyol generally used in manufacture of polyester is mentioned. Specific examples of the low molecular polyol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,3-butylene glycol, 1, 4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,8-octane Diol, 2,7-dimethyl-1,8-octanediol, 1,9-nonanediol, 2-methyl-1,9-nonanediol, 1,10-decanediol, 2,2-diethyl-1,3- C2-C15 aliphatic diol such as propanediol; 1,4-cyclohexanediol, cyclo Cyclohexanedicarboxylic methanol, cyclooctane dimethanol, an alicyclic diol such as dimethyl cyclooctane dimethanol; 1,4-bis (beta-hydroxyethoxy) aromatic dihydric alcohols such as benzene. These low molecular polyols may be used alone or in a combination of two or more. Among these, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 2,7-dimethyl-1,8-octanediol, 1,9-nonanediol, 2,8- C5-C12 aliphatic diols having a methyl group in the side chain such as dimethyl-1,9-nonanediol are preferred. The polyester polyol obtained using such an aliphatic diol is likely to react with a hydroxy group, and can greatly improve the interlayer adhesion with the barrier layer. Furthermore, a small amount of a trifunctional or higher functional low molecular polyol can be used in combination with the low molecular polyol. Examples of the trifunctional or higher functional low molecular polyol include trimethylolpropane, trimethylolethane, glycerin, 1,2,6-hexanetriol, and the like.

  Examples of the lactone that can be used to produce the polyester polyol include ε-caprolactone and β-methyl-δ-valerolactone.

  Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene) glycol, and the like. These polyether polyols may be used individually by 1 type, and 2 or more types may be mixed and used for them. Among these, polytetramethylene glycol is preferable.

  Examples of the polycarbonate polyol include fats having 2 to 12 carbon atoms such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol. Preferable examples include compounds obtained by polycondensation of a group diol or a mixture thereof by the action of diphenyl carbonate or phosgene.

  The polymer polyol preferably has a lower limit of number average molecular weight of 500, more preferably 600, and still more preferably 700. On the other hand, the upper limit of the number average molecular weight of the polymer polyol is preferably 8,000, more preferably 5,000, and still more preferably 3,000. If the number average molecular weight of the polymer polyol is smaller than the lower limit, the compatibility with the organic polyisocyanate is too high, and the elasticity of the resulting TPU becomes poor. May decrease. On the other hand, if the number average molecular weight of the polymer polyol exceeds the above upper limit, the compatibility with the organic polyisocyanate is lowered, and mixing in the polymerization process becomes difficult. There is a possibility that a stable TPU cannot be obtained. The number average molecular weight of the polymer polyol is a number average molecular weight measured based on JIS-K-1577 and calculated based on the hydroxy group value.

  It does not specifically limit as said organic polyisocyanate, The well-known organic diisocyanate generally used for manufacture of TPU can be used. Examples of the organic diisocyanate include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, 3,3′-dichloro-4,4′-diphenylmethane diisocyanate, and toluic acid. Examples include aromatic diisocyanates such as diisocyanates; aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate. Among these, 4,4'-diphenylmethane diisocyanate is preferable from the viewpoint of improving the strength and flex resistance of the obtained inner liner. These organic polyisocyanates may be used alone or in combination of two or more.

  The chain extender is not particularly limited, and a known chain extender generally used in the production of TPU can be used, and the molecular weight is 300 having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule. The following low molecular weight compounds are preferably used. Examples of the chain extender include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol, and the like. . Among these, 1,4-butanediol is particularly preferable from the viewpoint of further improving the stretchability and thermoformability of the obtained inner liner. These chain extenders may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  Examples of the method for producing the TPU include a production method that uses the polymer polyol, the organic polyisocyanate, and a chain extender and that utilizes a known urethanization reaction technique, and uses either a prepolymer method or a one-shot method. May be. In particular, it is preferable to perform melt polymerization in the substantial absence of a solvent, and it is more preferable to perform continuous melt polymerization using a multi-screw extruder.

  In the TPU, the ratio of the mass of the organic polyisocyanate to the total mass of the polymer polyol and the chain extender [isocyanate / (polymer polyol + chain extender)] is preferably 1.02 or less. When the ratio exceeds 1.02, long-term operation stability during molding may be deteriorated.

  The nitrogen content of the TPU is determined by appropriately selecting the use ratio of the polymer polyol and the organic diisocyanate, but is practically in the range of 1% by mass to 7% by mass.

  Moreover, the resin composition of the said elastic body layer may use the suitable catalyst etc. which accelerate reaction of organic polyisocyanate and polymer polyol as needed. Furthermore, the resin composition of the elastic layer contains various additives such as a resin other than an elastomer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, and a filler as long as the object of the present invention is not impaired. You may go out. When the resin composition of the elastic layer contains an additive, the amount thereof is preferably 50% by mass or less, more preferably 30% by mass or less, and more preferably 10% by mass with respect to the total amount of the resin composition. % Or less is particularly preferable.

-Tire inner surface-
As shown in FIG. 2, the tire inner surface is a rubber member 21 that is bonded to the laminate 21 in the tire.
The rubber component constituting the tire 27 is preferably a rubber composition made of natural rubber, butadiene rubber, styrene-butadiene copolymer, butyl rubber, or halogenated butyl rubber.

  In addition to the rubber component, the rubber composition includes compounding agents commonly used in the rubber industry, such as reinforcing fillers, softeners, anti-aging agents, vulcanizing agents, vulcanization accelerators for rubber, scorch An 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.

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

<Preparation of film 1>
An ethylene-vinyl alcohol copolymer [manufactured by Kuraray; E105] and a maleic anhydride-modified ethylene butene copolymer [manufactured by Mitsui Chemicals; MH7010] were kneaded in a pellet twin-screw extruder mixed at 1: 1 to obtain a resin composition. Got. Using the obtained resin composition and thermoplastic polyurethane (TPU) [manufactured by Kuraray; Clamiron 3190], a five-layer film was formed using a two-kind five-layer coextrusion apparatus. The thicknesses of the barrier layer and the elastic layer of the obtained film were 20 μm and 20 μm, respectively.

<Preparation of film 2>
An ethylene-vinyl alcohol copolymer (EVOH) [manufactured by Kuraray; E105] and a thermoplastic polyurethane (TPU) [Kuraray Co., Ltd. Kuramylon 3190] were used, and 8 EVOH layers and 9 TPU layers were used. A 17-layer feed block was supplied to the co-extruder as a molten state at 210 ° C. so as to form a laminate, and co-extrusion was performed to join them to form a multilayer laminate. The melt of EVOH and TPU that merges changes the thickness of each layer of the extruded laminate uniformly by gradually changing the thickness of each layer flow path from the surface side toward the center side in the feed block. Extruded to be In addition, the slit shape was designed so that the layer thickness of the adjacent EVOH layer and the TPU layer was substantially the same. The thus obtained laminate comprising a total of 17 layers was rapidly cooled and solidified on a casting drum to which a surface temperature was maintained at 25 ° C. and electrostatically applied. The cast film obtained by rapid cooling and solidification was pressure-bonded onto a release paper and wound up. The flow path shape and the total discharge amount were set so that the time from when the melt of EVOH and TPU merged to when rapidly solidified on the casting drum was about 4 minutes.

(Comparative Example 1)
An electron beam with an irradiation dose of 200 kGy is applied to a single layer film obtained by extruding an ethylene-vinyl alcohol copolymer [manufactured by Kuraray; E105] using an electron beam irradiation apparatus [manufactured by Nissin High Voltage; Curetron EB200-100]. To obtain a crosslinked film.
The obtained film was affixed to a tire molded by a conventional method and vulcanized to produce a pneumatic tire (195 / 65R15) having the structure shown in FIG.

(Comparative Example 2)
A pneumatic tire was obtained by the same manufacturing method as in Comparative Example 1 except that a nylon [manufactured by Toray; CM1061] single layer film was used.

( Reference Example 1)
A pneumatic tire was obtained in the same manner as in Comparative Example 1 except that the film 1 was used.

( Reference Example 2)
A pneumatic tire was obtained in the same manner as in Comparative Example 1 except that the film 2 was used.

( Reference Example 3)
The tire molded by the usual method was vulcanized to produce a pneumatic tire (195 / 65R15) having the structure shown in FIG. On the inner surface of the pneumatic tire, the film 2 was affixed with an electron beam irradiation apparatus [manufactured by Nissin High Voltage; Curetron EV200-100] and irradiated with an electron beam with an irradiation dose of 200 kGy. . Furthermore, the film was bonded to the tire inner surface using an iron heated to 120 ° C.

(Comparative Example 3)
7 g of ethylene-vinyl alcohol copolymer (EVOH) [manufactured by Kuraray; E105] was placed in a 2 L 4-diameter eggplant flask, and a Dimroth condenser was attached. An EVOH solution was prepared by adding a mixed solvent in which 800 mL of isopropyl alcohol and 200 mL of distilled water were mixed and heating to reflux at 120 ° C. for 5 hours.
100 mL of the EVOH solution was sprayed onto the inner surface of the tire molded according to a conventional method, and the solvent was volatilized with hot air at 120 ° C.
The obtained tire was vulcanized to produce a pneumatic tire (195 / 65R15) having the structure shown in FIG.

( Reference Example 4 )
7 g of ethylene-vinyl alcohol copolymer (EVOH) [manufactured by Kuraray; E105] was placed in a 2 L 4-diameter eggplant flask, and a Dimroth condenser was attached. A mixed solvent in which 800 mL of isopropyl alcohol and 200 mL of distilled water were mixed was added, and the mixture was heated to reflux at 120 ° C. for 5 hours to prepare an EVOH solution.
21 g of polyurethane pellets (TPU) [manufactured by Kuraray; Clamiron 3190] was placed in a 2L 4-diameter eggplant flask, and a Dimroth condenser was attached. 1 L of 1,4-dioxane was added, and a TPU solution was prepared by heating to reflux at 100 ° C. for 5 hours.
100 mL of the TPU solution was sprayed onto the inner surface of the tire molded according to a conventional method, and the solvent was volatilized with hot air at 120 ° C. After volatilizing the solvent, 100 mL of EVOH solution was sprayed on, and the solvent was volatilized with hot air at 120 ° C. After volatilizing the solvent, the TPU solution, EVOH solution, and TPU solution were alternately sprayed in the same manner to volatilize the solvent.
The obtained tire was vulcanized to produce a pneumatic tire (195 / 65R15) having the structure shown in FIG.

(Example 5)
10 g of ethylene-vinyl alcohol copolymer (EVOH) [manufactured by Kuraray; E105] was placed in a 2 L 4-diameter eggplant flask, and a Dimroth condenser was attached. An EVOH solution was prepared by adding a mixed solvent in which 800 mL of isopropyl alcohol, 200 mL of distilled water, and 400 mL of benzyl alcohol were added and heated to reflux at 120 ° C. for 5 hours.
25 g of polyurethane pellets (TPU) [manufactured by Kuraray; Clamiron 3190] was placed in a 2 L 4-diameter eggplant flask, and a Dimroth condenser was attached. A mixed solvent prepared by mixing 1 L of 1,4-dioxane and 400 mL of benzyl alcohol was added, and the mixture was heated to reflux at 100 ° C. for 5 hours to prepare a TPU solution.
100 mL of the TPU solution was sprayed onto the inner surface of the tire molded according to a conventional method, and the solvent was volatilized with hot air at 120 ° C. After volatilizing the solvent, 100 mL of EVOH solution was sprayed on, and the solvent was volatilized with hot air at 120 ° C. After volatilizing the solvent, the TPU solution, EVOH solution, and TPU solution were alternately sprayed in the same manner to volatilize the solvent.
The obtained tire was vulcanized to produce a pneumatic tire (195 / 65R15) having the structure shown in FIG.

(Example 6)
10 g of ethylene-vinyl alcohol copolymer (EVOH) [manufactured by Kuraray; E105] was placed in a 2 L 4-diameter eggplant flask, and a Dimroth condenser was attached. An EVOH solution was prepared by adding a mixed solvent in which 800 mL of isopropyl alcohol, 200 mL of distilled water, and 400 mL of benzyl alcohol were added and heated to reflux at 120 ° C. for 5 hours.
25 g of polyurethane pellets (TPU) [manufactured by Kuraray; Clamiron 3190] was placed in a 2 L 4-diameter eggplant flask, and a Dimroth condenser was attached. A mixed solvent prepared by mixing 1 L of 1,4-dioxane and 400 mL of benzyl alcohol was added, and the mixture was heated to reflux at 100 ° C. for 5 hours to prepare a TPU solution.
A tire (195 / 65R15) was produced by molding and vulcanizing according to a conventional method. 100 mL of the TPU solution was sprayed, and the solvent was volatilized with hot air at 120 ° C. After volatilizing the solvent, 100 mL of EVOH solution was sprayed on, and the solvent was volatilized with hot air at 120 ° C. After volatilizing the solvent, the TPU solution, EVOH solution, and TPU solution were alternately sprayed in the same manner to volatilize the solvent.

  The thickness of each barrier resin (composition) layer and each elastic body (TPU) layer is measured by SEM photographs of arbitrary five locations under the top tread of the barrier resin layer single layer and laminated body formed on the tire inner surface. did. The results are summarized in Tables 1 and 2.

<Internal pressure retention>
After the tires produced according to the comparative examples and examples were mounted on a 6JJ × 15 rim, the internal pressure was set to 240 kPa and left for 3 months. Measure the internal pressure after 3 months and use the following formula:
Internal pressure retention = ((240−b) / (240−a)) × 100
[Wherein, a is the internal pressure (kPa) after 3 months of the test tire, and b is the internal pressure (kPa) after 3 months of the test tire of the comparative example (Comparative Example 1 or 3)]. Evaluated.
Comparative Example 2 and Reference Examples 1 to 3 were indexed as Comparative Example 1, and Reference Example 4 and Examples 5 to 6 were Comparative Example 3 as 100, respectively. The larger the index value, the better the internal pressure retention.

<Internal pressure retention after running>
The tires produced according to the comparative examples and the examples were run at 10,000 km by pressing against a rotating drum corresponding to a speed of 80 km / h with a load of 6 kN at room temperature and an air pressure of 140 kPa. Then, after the tire (test tire) that was traveled was mounted on a 6JJ × 15 rim, the internal pressure was set to 240 kPa and left for 3 months. Measure the internal pressure after 3 months and use the following formula:
Internal pressure retention after measurement = ((240−b) / (240−a)) × 100
[Wherein, a is the internal pressure (kPa) after 3 months of the test tire, and b is the internal pressure (kPa) after 3 months of the test tire of the comparative example (Comparative Example 1 or 3)] The internal pressure retention was evaluated.
Other values were indexed with Comparative Example 2 and Reference Examples 1 to 3 as Reference Example 4 and Examples 5 to 6 as Comparative Example 3 as 100, respectively. The larger the index value, the better the internal pressure retention after running.

* 1 (Source) Made by Kuraray, (Product Name) E105
* 2 (Source) Made by Toray, (Product name) CM1061
* 3 (Source) Made by Mitsui Chemicals, (Product Name) Toughmer MH7010
* 4 (Source) Made by Kuraray, (Product name) Cramiron 3190

From the results of Table 1 and Table 2, the tires of Reference Examples 1 to 3 are in comparison with the tire of Comparative Example 1, and the tires of Reference Example 4 and Examples 5 to 6 are in tension compared to the tire of Comparative Example 3. It can be seen that even when a gas barrier resin having a large value is applied to the barrier layer, a tire excellent in maintaining the internal pressure can be produced, and the internal pressure retention after running can be improved.

  The tire manufactured by the tire manufacturing method of the present invention is suitably applicable to passenger car tires, large tires, off-the-road tires, motorcycle tires, aircraft tires, agricultural tires, and the like.

9 Bead part 10 Side wall part 11 Tread part 12 Carcass 13 Belt 14 Bead core 15 Bead filler 16 Inner liner 21 Laminate (inner liner)
DESCRIPTION OF SYMBOLS 22 Elastic body layer 23 Barrier layer 24 Elastic body layer 25 Barrier layer 26 Elastic body layer 27 Pneumatic tire

Claims (5)

After the molding process to mold the tire,
Including a laminate forming step of forming a laminate including at least two barrier layers containing a gas barrier resin on the inner surface of the molded tire, wherein the barrier layer is formed by coating in the laminate forming step, the solvent in the coating solution used for coating is azeotropically evaporated at once, a solvent which volatilizes at 120 ° C. the boiling point of 120 ° C. or higher alcohol as including a mixed solvent, the boiling point of 120 ° C. or higher alcohols benzyl alcohol And the content of the benzyl alcohol is 28.5% by volume to 35% by volume with respect to the solvent in the coating solution.   The tire manufacturing method according to claim 1, further comprising a vulcanizing step of vulcanizing the tire, wherein the laminate forming step is performed before the vulcanizing step.   The tire manufacturing method according to claim 1, wherein the laminate includes an elastic layer adjacent to the barrier layer.   The tire manufacturing method according to claim 3, wherein the laminated body includes the barrier layers and the elastic body layers alternately. The gas barrier resin contained in the barrier layer has an air permeability coefficient at 20 ° C. and 65% RH of 800 × 10 ⁻¹² cm ³ · cm ² · sec · cmHg or less. 5. The method for producing a tire according to any one of 4 above.

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