JP2018193490A - Rubber composition, rubber using the same, inner liner, and pneumatic tire - Google Patents

Abstract

To provide a rubber composition capable of giving a rubber excellent in air permeation resistance and crack resistance, and to provide a rubber excellent in air permeation resistance and crack resistance, an inner liner, and a tire.SOLUTION: The rubber composition contains a continuous phase being a rubber component containing a butyl rubber, and a dispersed phase being fragments of a multilayer structure irradiated with an active energy ray. The content of the butyl rubber in the rubber component is 50 mass% or more. The multilayer structure has a layer A comprising a resin composition containing a gas barrier resin, and a layer B adjacent to the layer A and comprising an elastomer composition containing an elastomer.SELECTED DRAWING: None

Description

  The present invention relates to a rubber composition, a rubber using the same, an inner liner, and a pneumatic tire.

  In order to maintain the tire air pressure for a long period of time, the inner liner of the tire is required to have air permeation resistance, and crack resistance that does not cause cracks even when subjected to repeated bending deformation is required. Conventionally, among the various rubbers, butyl rubber having excellent air permeation resistance has been used for the inner liner. On the other hand, in recent years, functional resin films have been developed, and many resin films have better gas barrier properties than butyl rubber.

  For example, Patent Document 1 discloses a multilayer used for an inner liner in order to provide an inner liner for a pneumatic tire that has high bending resistance and can be thinned while maintaining excellent gas barrier properties. The structure has an A layer made of a resin composition containing a gas barrier resin, and a B layer made of a resin composition containing an elastomer adjacent to the A layer, and the A layer and the B layer are a predetermined total layer. It is disclosed that the structure has a number and a layer thickness and is irradiated with active energy rays.

Attempts have also been made to obtain the advantages of both by multiplying a resin film and butyl rubber.
For example, Patent Document 2 provides an inner liner for a pneumatic tire that has excellent gas barrier properties and bending resistance, and can reduce the weight of the tire while improving the internal pressure retention of the tire when new and after running. Therefore, a resin composition in which a flexible resin having a Young's modulus at 23 ° C. smaller than that of a modified ethylene-vinyl alcohol copolymer is dispersed in a matrix made of a modified ethylene-vinyl alcohol copolymer as an inner liner for a pneumatic tire. It is disclosed that the structure includes at least a layer made of

  Further, for example, Patent Document 3 discloses a rubber composition for an inner liner of a pneumatic tire in order to provide a rubber composition for an inner liner that achieves both low air permeability and good flexibility and low temperature. Is composed of 100 parts by weight of a rubber component made of butyl rubber, 10 to 50 parts by weight of clay having an average aspect ratio of 3 or more and less than 30, and 10 to 60 parts by weight of carbon black. ing.

  Further, for example, in Patent Document 4, in order to provide an inner liner for a pneumatic tire that is less likely to be deteriorated in air barrier property due to fatigue and that is easy to manufacture, a thermoplastic resin or a heat It is disclosed that a film piece having a predetermined shape made of a thermoplastic elastomer composition in which an elastomer component is dispersed in a plastic resin component is blended with rubber.

International Publication No. 2012/042679 JP 2008-24217 A JP 2002-88206 A JP 2012-76679 A

  An object of the present invention is to provide a rubber composition from which a rubber excellent in air permeation resistance and crack resistance is obtained, a rubber excellent in air permeation resistance and crack resistance, an inner liner, and a tire.

<1> A continuous phase that is a rubber component containing butyl rubber and a dispersed phase that is a fragment of a multilayer structure irradiated with active energy rays, and the content of the butyl rubber in the rubber component is 50% by mass or more, and the multilayer structure includes a layer A made of a resin composition containing a gas barrier resin and a layer B made of an elastomer composition containing an elastomer adjacent to the layer A. It is.

<2> The A layer and the B layer each have one or more layers, and the total of the A layer and the B layer is three or more, and the average layer thickness of the A layer per layer is 0.00. The rubber composition according to <1>, in which the average layer thickness per layer of the B layer is 0.001 μm or more and 40 μm or less.

<3> The rubber composition according to <1> or <2>, wherein an adhesive layer containing an adhesive is laminated on at least one of the outermost layers of the multilayer structure.

<4> The rubber composition according to <3>, wherein the adhesive is chlorosulfonated polyethylene, epoxidized natural rubber, or a styrene-based thermoplastic elastomer.

<5> The rubber composition according to <3> or <4>, wherein the adhesive is chlorosulfonated polyethylene.

<6> The rubber composition according to <3> or <4>, wherein the adhesive is a styrene-based thermoplastic elastomer.

<7> The rubber composition according to any one of <1> to <6>, wherein at least one selected from the group consisting of the resin composition and the elastomer composition contains a crosslinking agent.

<8> The rubber composition according to any one of <1> to <7>, wherein a content of the fragments of the multilayer structure is 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the butyl rubber. It is a thing.

<9> The rubber composition according to any one of <1> to <8>, wherein an average thickness of the fragments of the multilayer structure is 10 μm or more and 200 μm or less.

<10> The rubber composition according to any one of <1> to <9>, wherein an average maximum length of the fragments of the multilayer structure is 2 μm or more and 2000 μm or less.

<11> The rubber composition according to any one of <1> to <10>, wherein an average aspect ratio of the fragments of the multilayer structure is 1 or more and 100 or less.

<12> The gas barrier resin is made of ethylene-vinyl alcohol copolymer (EVOH), polyamide resin, polyester resin, polyvinylidene chloride, acrylonitrile copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, and polyvinyl alcohol. The rubber composition according to any one of <1> to <11>, which is at least one selected from the group.

<13> The group in which the elastomer is composed of polystyrene elastomer, polyolefin elastomer, polydiene elastomer, polyvinyl chloride elastomer, chlorinated polyethylene elastomer, polyurethane elastomer, polyester elastomer, polyamide elastomer, and fluororesin elastomer. The rubber composition according to any one of <1> to <12>, which is at least one selected from more.

<14> The rubber composition according to any one of <1> to <13>, further including a vulcanizing agent.

<15> A rubber obtained by vulcanizing the rubber composition according to <14>.

<16> An inner liner using the rubber according to <15>.

<17> A pneumatic tire using the rubber according to <15>.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition from which the rubber excellent in air permeation resistance and crack resistance is obtained, the rubber excellent in air permeation resistance and crack resistance, an inner liner, and a tire are obtained.

It is a figure which shows the screw structure of the extruder used in the Example.

The present invention is described in detail below.
<Rubber composition>
The rubber composition of the present invention includes a rubber component containing a butyl rubber and a fragment of a multilayer structure irradiated with active energy rays.
Here, the rubber component containing butyl rubber is a continuous phase of the rubber composition, and the content in the rubber composition is 50% by mass or more.
The fragments of the multilayer structure irradiated with active energy rays are dispersed phases dispersed in the rubber component. The multilayer structure has an A layer made of a resin composition containing a gas barrier resin and a B layer made of an elastomer composition containing an elastomer, and the B layer is adjacent to the A layer.

The reason why the rubber composition of the present invention has the above-described configuration can provide a rubber excellent in both air permeation resistance and crack resistance is not clear, but is thought to be as follows.
As described above, butyl rubber is superior in air permeability among various rubbers, but gas barrier resin specialized in gas barrier property tends to have better air permeability than butyl rubber. is there. Further, since the gas barrier resin is superior in air permeation resistance than the clay used in Patent Document 3, excellent air permeation resistance can be expected by using the gas barrier resin. If the gas barrier resin is a multilayer structure as disclosed in Patent Document 1, a product with better air permeation resistance can be obtained, but since the resin has less rubber elasticity than rubber, Regarding crack resistance, butyl rubber is superior to gas barrier resin. In particular, the resin tends to break easily in a low temperature environment. Therefore, it is considered that the advantages of both can be obtained by mixing the gas barrier resin and the butyl rubber.
However, when the rubber composition is vulcanized and used as a vulcanized rubber, the resin film is easily melted by heating during vulcanization. When the gas barrier resin is melted by the heat of vulcanization, the gas barrier property due to the resin is lowered. Therefore, in the configuration in which the resin film is dispersed in the rubber as in Patent Document 4, the resin film is melted when the rubber composition is vulcanized. However, it is considered that sufficient air permeation resistance cannot be exhibited.

On the other hand, the rubber composition of the present invention uses not only a resin having a multilayer structure as a gas barrier resin but also a resin in a state where the multilayer structure is irradiated with active energy rays. The multilayer structure irradiated with active energy rays is considered to be a structure in which the resin contained in the multilayer structure forms a crosslinked structure and is not easily melted by heat of vulcanization.
On the other hand, it has been found that if the resin forms a crosslinked structure and the hardness is simply increased, the fragments are easily damaged when the rubber component and the fragments of the multilayer structure are mixed, resulting in a decrease in air permeation resistance. did. Therefore, in the present invention, the multilayer structure is not a multilayer structure having only a gas barrier resin layer, but a multilayer structure having a resin layer containing a more elastic elastomer in addition to a resin layer containing a gas barrier resin; did. Thereby, the multilayer structure can have elasticity, and when the rubber component and the fragments of the multilayer structure are mixed, the fragments can be prevented from being further crushed.

Therefore, the rubber composition of the present invention is unlikely to impair the properties of the gas barrier resin, and can be considered to have excellent crack resistance due to the elasticity of the rubber component and the elasticity of the multilayer structure including the elastomer.
Further, in the present invention, since the resin fragments dispersed in the rubber component are fragments of a multilayer structure, the resin fragments are less likely to melt than the rubber of Patent Document 2 in which the film piece is not a multilayer structure. It is thought that it is excellent in air permeability and crack resistance.

[Rubber component]
The rubber component is contained in the rubber composition as a continuous phase.
The rubber component used in the rubber composition of the present invention is not particularly limited as long as it includes butyl rubber, and may include diene rubber other than butyl rubber. By including a butyl rubber in the rubber component, the air permeation resistance of the vulcanized rubber obtained from the rubber composition of the present invention can be greatly improved, and a rubber composition suitable for producing a tire inner liner, Become.

Examples of diene rubber other than butyl rubber include natural rubber (NR) and diene synthetic rubber. Here, examples of the diene-based synthetic rubber include polyisoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), and the like. Can be mentioned.
These rubber components may be used alone, or a combination of butyl rubber and one or more other rubbers may be used.

The content of the butyl rubber in the rubber component of the present invention is 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more from the viewpoint of air permeability resistance of the vulcanized rubber. More preferably it is. That is,
The butyl rubber includes not only butyl rubber (IIR) but also halogenated butyl rubber, and examples of the halogenated butyl rubber include chlorinated butyl rubber and brominated butyl rubber. Among these butyl rubbers, it is preferable to use halogenated butyl rubber because air permeation resistance can be improved.

  Since the rubber component is a continuous phase of the rubber composition, the content of the rubber component in the rubber composition exceeds 50% by mass, and is preferably 60% by mass or more, more preferably from the viewpoint of crack resistance. It is 70 mass% or more, More preferably, it is 80 mass% or more. From the viewpoint of air permeation resistance, the content of the rubber component in the rubber composition is preferably less than 100% by mass, more preferably 95% by mass or less, and still more preferably 90% by mass or less. .

[Debris of multilayer structure irradiated with active energy rays]
The rubber composition of the present invention contains, as a dispersed phase, fragments of a multilayer structure irradiated with active energy rays. The multilayer structure has an A layer made of a resin composition containing a gas barrier resin and a B layer made of an elastomer composition containing an elastomer adjacent to the A layer.
Since the debris is not a single-layer structure but a multilayer structure, the impact resistance of the debris can be improved, and the debris can be prevented from being crushed when the debris is stirred and mixed with the rubber component. Therefore, it is possible to suppress a decrease in gas barrier properties due to miniaturization of the gas barrier resin contained in the crushing.
In the present invention, an elastomer refers to a resin having elasticity at around room temperature. Specifically, the elastomer is doubled under conditions of room temperature (20 ° C.) and held in that state for 1 minute. A resin having the property of shrinking to less than 1.5 times the original length within minutes. The elastomer is structurally a polymer having a hard segment and a soft segment in the polymer chain.

When the multilayer structure includes a gas barrier resin and an elastomer, the multilayer structure has elasticity. Furthermore, by irradiating the multilayer structure with active energy rays, the gas barrier resins and elastomers form a crosslinked structure, and the multilayer structure is not easily melted by the heat of vulcanization when the rubber composition is vulcanized. Become. Furthermore, by dividing the gas barrier resin and the elastomer into the A layer and the B layer, respectively, the layer thickness, layer configuration, etc. of each layer can be adjusted, so that the degree of air permeation resistance and crack resistance is finely adjusted. be able to.
First, a multilayer structure before irradiation with active energy rays will be described.

(Multilayer structure)
The multilayer structure before irradiation with active energy rays in the present invention has an A layer made of a resin composition containing a gas barrier resin and a B layer made of an elastomer composition containing an elastomer adjacent to the A layer.
In the multilayer structure, from the viewpoint of preventing melting of debris due to heat of vulcanization of the rubber composition, there are one or more layers A and B, respectively, and there are three or more layers in total of the layers A and B. The average layer thickness per layer of the A layer is preferably 0.001 μm or more and 30 μm or less, and the average layer thickness per layer of the B layer is preferably 0.001 μm or more and 40 μm or less. By making the multilayer structure fragments difficult to melt even with heat of vulcanization, the gas barrier function of the gas barrier resin can be maintained and the elasticity of the elastomer can be maintained. It is easy to obtain a vulcanized rubber having crack resistance.
The resin composition and the elastomer composition preferably contain additives such as metal salts and radical crosslinking agents.
Hereinafter, the layer structure of the multilayer structure, the A layer, the B layer, the additive to each composition, the relationship between the A layer and the B layer, and the manufacturing method will be described in this order.

[Layer structure]
The multilayer structure preferably includes a total of three or more layers of the A layer and the B layer. As a result of suppressing the continuous occurrence of defects such as pinholes and cracks by the structure in which a total of 7 or more layers A and B are laminated in this way, it is possible to prevent the breakage of all layers of the multilayer structure. It has high air permeation resistance, crack resistance and other characteristics.

  From this viewpoint and the manufacturing viewpoint, the total number of layers A and B is preferably 17 or more, and more preferably 25 or more. The multilayer structure may be a multilayer structure, and the total number of layers A and B may be 128 or more, 256 or more, 512 or more, or 1,024 or more. The upper limit of the total number of layers is appropriately selected depending on the use of the multilayer structure.

The multilayer structure can also have a C layer other than the A layer and the B layer. In addition, as the stacking order of the A layer and the B layer, for example,
(1-1) A, B, A, B... A, B (that is, (AB) _n )
(1-2) A, B, A, B... A (that is, (AB) _n A)
(1-3) B, A, B, A... B (that is, (BA) _n B)
(1-4) A, A, B, B... B, B (that is, (AABB) _n )
A stacking order such as can be adopted. Moreover, when it has other C layers, for example,
(1-5) A, B, C... A, B, C (that is, (ABC) _n )
A stacking order such as can be adopted.

  In particular, as the stacking order of the A layer and the B layer, the A layer and the B layer are alternately stacked one by one as in (1-1), (1-2), or (1-3) above. It is preferable. By irradiating active energy rays to the laminate in which the A layers and the B layers are alternately laminated in this manner, the connectivity between the laminated layers can be improved and high adhesiveness can be expressed. As a result, the interlayer adhesion of the multilayer structure, as well as air permeation resistance, crack resistance, and the like can be significantly improved. Moreover, since A layer is pinched | interposed into B layer from both surfaces by laminating | stacking A layer and B layer alternately, the ductility of A layer is improved more.

  In the multilayer structure, support layers may be laminated on both sides or one side of a laminate comprising such an A layer, a B layer, and other C layers. 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 multilayer structure, the average layer thickness of the A layer and the B layer is preferably 0.001 μm to 10 μm and 0.001 μm to 40 μm, respectively. By setting the average layer thickness of one layer of the A layer and the B layer in the above range, the number can be increased even when the overall thickness of the multilayer structure is the same, and as a result, the air permeation resistance of the multilayer structure can be increased. Property, crack resistance and the like can be further improved.

  In addition, since the multilayer structure is formed of a resin composition containing a gas barrier resin and a B layer made of an elastomer composition containing an elastomer together with an A layer having a thickness in the above range, the ductility of the gas barrier resin itself. Even when is low, the ductility of A layer which consists of a resin composition with low ductility can be improved. This is presumably because the resin layer having low ductility is transferred to a highly ductile state by thinly laminating the layer A made of the resin composition having low ductility on the layer B having excellent ductility. The present invention pays attention to the above fact, and the layer A is generally made of a material having low ductility. Thus, by making the thickness of each layer very thin, air permeation resistance required for an inner liner for tires and the like is required. High compatibility with crack resistance. Therefore, even when the multilayer structure is used after being deformed such as bending, characteristics such as high air permeation resistance can be maintained.

  The lower limit of the average layer thickness of the A layer is more preferably 0.005 μm, and still more preferably 0.01 μm. On the other hand, the upper limit of the average layer thickness of the A layer is more preferably 7 μm, further preferably 5 μm, still more preferably 3 μm, still more preferably 1 μm, and still more preferably 0.5 μm.

  When the average layer thickness of the A layer is equal to or more than the above lower limit, the multilayer structure can be easily formed with a uniform thickness, and the air permeability and crack resistance of the multilayer structure are hardly impaired. In addition, when the average layer thickness of one layer A is equal to or less than the above upper limit, even when the thickness of the entire multilayer structure is the same, the durability and crack resistance of the multilayer structure are unlikely to decrease. In addition, when the average layer thickness of one A layer is not more than the above upper limit, the improvement in ductility of the A layer is easily exhibited sufficiently. In addition, the average layer thickness of one layer of A layer means the value which remove | divided the sum total of the layer thickness of all the A layers contained in a multilayer structure by the number of layers of A layer.

  The lower limit of the average layer thickness of one B layer is more preferably 0.005 μm and even more preferably 0.01 μm for the same reason as that for the A layer. On the other hand, the upper limit of the average layer thickness of one B layer is more preferably 30 μm and even more preferably 20 μm. When the average layer thickness of one layer B is equal to or less than the above upper limit, even when the thickness of the entire multilayer structure is the same, the durability and crack resistance of the multilayer structure are unlikely to decrease. In addition, the average layer thickness of one layer of B layer means the value which remove | divided the sum total of the layer thickness of all the B layers contained in a multilayer structure by the number of layers of B layer.

  Regarding the average layer thickness of the B layer, the ratio of the average layer thickness of the B layer to the average layer thickness of the A layer (B layer / A layer) is preferably 1/3 or more. This is more desirable. Further, the above ratio is preferably 1 or more, that is, the average layer thickness of one B layer is more than or equal to the average layer thickness of one A layer, more preferably 2 or more. By setting the ratio of the layer thicknesses of the A layer and the B layer in this manner, the bending fatigue characteristics until the multilayer structure reaches the entire layer breakage is improved.

[A layer]
The A layer is a layer made of a resin composition containing a gas barrier resin. When the resin composition constituting the A layer contains a gas barrier resin, a multilayer structure having excellent air permeation resistance can be obtained.

The gas barrier resin is a resin having a function of preventing the permeation of gas. Specifically, measurement is performed according to the method described in JIS-K7126: 2006 (isobaric method) under the condition of 20 ° C.-65% RH. This refers to a resin having an oxygen transmission rate of 100 mL · 20 μm / (m ² · day · atm) or less. The oxygen permeation rate of the gas barrier resin used in the present invention is preferably 50 mL · 20 μm / (m ² · day · atm) or less, more preferably 10 mL · 20 μm / (m ² · day · atm) or less.

  Examples of such a gas barrier resin include ethylene-vinyl alcohol copolymer (EVOH), polyamide resin, polyester resin, polyvinylidene chloride, acrylonitrile copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, polyvinyl alcohol, and the like. be able to.

  Among these air permeable resins, EVOH, polyamide resin, and polyester resin are preferable from the viewpoint of air permeability resistance. In addition to air permeability, EVOH from the viewpoint of melt moldability and adhesion to the B layer. Is particularly preferred.

[Polyamide resin]
The polyamide resin is a polymer having an amide bond, and can be obtained by ring-opening polymerization of lactam or polycondensation of aminocarboxylic acid or diamine with dicarboxylic acid.

  Examples of the lactam include ε-caprolactam and ω-laurolactam.

  Examples of the aminocarboxylic acid include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and paraaminomethylbenzoic acid.

  Examples of the diamine include tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,4-trimethylhexamethylene diamine, 2,4,4-trimethylhexamethylene diamine, and 5-methylnonamethylene. Diamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-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. It can be.

  Examples of the dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecane dicarboxylic acid, cyclohexane dicarboxylic acid, decalin dicarboxylic acid, norbornane dicarboxylic acid, tricyclodecane dicarboxylic acid, penta Cyclododecane dicarboxylic acid, isophorone dicarboxylic acid, 3,9-bis (2-carboxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, trimellitic acid, trimesic acid, pyromellitic acid, Examples include tricarballylic acid, terephthalic acid, isophthalic acid, phthalic acid, 2-methylterephthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and tetralindicarboxylic acid.

  As a polycondensation method when synthesizing a polyamide resin, for example, a method of polycondensation in a molten state, and a method of heat-treating in a solid phase after polycondensation in a molten state to obtain a low viscosity polyamide (So-called solid phase polymerization). As a polycondensation method in a molten state, for example, an aqueous solution of a nylon salt of a diamine and a dicarboxylic acid is heated under pressure and polycondensed in a molten state while removing water and condensed water, and the diamine is converted into a dicarboxylic acid in a molten state. In addition to the direct addition, there can be mentioned a method of polycondensation under normal pressure.

  Specific polyamide resins that are polycondensates of the above compounds include, 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, aliphatic polyamide resin such as 11-aminoundecanoic acid condensation product (nylon 11), Examples thereof include aromatic polyamide resins such as polyhexamethylene isophthalamide (nylon 6IP), metaxylenediamine / adipic acid copolymer (nylon MXD6), and metaxylenediamine / adipic acid / isophthalic acid copolymer. . These can be used alone or in combination of two or more.

  Among these polyamide resins, nylon MXD6 having excellent air permeation resistance is preferable. As the diamine component of this nylon MXD6, metaxylylenediamine is preferably contained in an amount of 70 mol% or more, and as the dicarboxylic acid component, adipic acid is preferably contained in an amount of 70 mol% or more. By obtaining nylon MXD6 from a monomer having the above blending range, it is possible to exhibit better air permeation resistance and mechanical performance.

[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. Examples of the polyester resin used as the air-permeable resin of the multilayer structure include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyglycolic acid (PGA), and aromatic liquid crystal polyester. . These may be used alone or in combination of two or more. Among these polyester resins, PGA and wholly aromatic liquid crystal polyester are preferable from the viewpoint of high air permeation resistance.

[PGA]
PGA is a homopolymer or copolymer having a structural unit (GA) represented by —O—CH ₂ —CO—. 60 mass% or more is preferable, as for the content rate of the said structural unit (GA) in PGA, 70 mass% or more is more preferable, and 80 mass% or more is still more preferable. Moreover, as this upper limit, 100 mass% is preferable. When the content ratio of the structural unit (GA) is equal to or more than the above lower limit, the air permeation resistance is easily exhibited sufficiently.

  As a method for producing PGA, (2-1) a synthesis method by dehydration polycondensation of glycolic acid, (2-2) a synthesis method by dealcoholization polycondensation of glycolic acid alkyl ester, (2-3) glycolide (1 , 4-dioxane-2,5-dione) and the like.

  As a method for synthesizing PGA as a copolymer, in each of the above synthesis methods, as a comonomer, for example, ethylene oxalate (1,4-dioxane-2,3-dione), lactide, lactones (for example, β Cyclic monomers such as propiolactone, β-butyrolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, trimethylene carbonate, 1,3-dioxane; Hydroxycarboxylic acids such as 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid and 6-hydroxycaproic acid or alkyl esters thereof; aliphatic diols such as ethylene glycol and 1,4-butanediol; Aliphatic dicarboxylic acids such as succinic acid and adipic acid A substantially equimolar mixture of such a kill esters, glycolide, may be mentioned a method of copolymerizing appropriately combined with glycolic acid or glycolic acid alkyl ester.

  As a specific method for the ring-opening polymerization of (2-3) above, 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.) The method of heating to about 250 degreeC and performing is 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.

  As the solution phase depolymerization method, for example, a mixture containing (3-1) glycolic acid oligomer and at least one high-boiling polar organic solvent having a boiling point in the range of 230 to 450 ° C. is used under normal pressure or reduced pressure. (3-2) The oligomer is dissolved in a solvent until the residual ratio (volume ratio) of the melt phase of the oligomer is 0.5 or less. (3-3) Further heating is continued at the same temperature to depolymerize the oligomer, and (3-4) the produced dimer cyclic ester (glycolide) is distilled together with a high-boiling polar organic solvent, (3- 5) A method for recovering glycolide from the distillate can be mentioned.

  Examples of the high-boiling polar organic solvent include bis (alkoxyalkyl esters) phthalates such as di (2-methoxyethyl) phthalate, alkylene glycol dibenzoates such as diethylene glycol dibenzoate, and aromatic carboxyls such as benzylbutyl phthalate and dibutyl phthalate. Examples thereof include aromatic phosphates such as acid esters and 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.

[Totally aromatic liquid crystalline 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.

  Examples of aromatic polycarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 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 can be mentioned. These can be used alone or in combination of two or more.

  Examples of aromatic polyols include hydroquinone, methylhydroquinone, 4,4'-dihydroxydiphenyl, resorcinol, phenylhydroquinone, 3,4'-bisphenol A, and the like. These can be used alone or in combination of two or more.

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

[EVOH]
Hereinafter, EVOH suitably used as the gas barrier resin will be described in detail.

  This EVOH has an ethylene unit and a vinyl alcohol unit as structural units, and is usually obtained by polymerizing ethylene and a vinyl ester and saponifying the resulting ethylene-vinyl ester copolymer.

  The lower limit of the ethylene unit content of EVOH (that is, the ratio of the number of ethylene units to the total number of monomer units in EVOH) is preferably 3 mol%, more preferably 10 mol%, still more preferably 20 mol%. 25 mol% is particularly preferable. On the other hand, the upper limit of the ethylene unit content of EVOH is preferably 70 mol%, more preferably 60 mol%, still more preferably 55 mol%, and particularly preferably 50 mol%.

  By making the ethylene unit content in the range of 3 to 70 mol%, the air permeation resistance of the multilayer structure can be improved, and in addition, the melt moldability can be improved. Can be improved. When the ethylene unit content of EVOH is not less than the above lower limit, the water resistance of the multilayer structure, the hot water resistance, and the air permeation resistance under high humidity are unlikely to deteriorate, and the melt moldability of the multilayer structure is unlikely to be impaired. . When the ethylene unit content of EVOH is not more than the above, it is possible to prevent a decrease in air permeability of the multilayer structure.

  The lower limit of the saponification degree of EVOH (that is, the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH) is preferably 80 mol%, more preferably 95 mol%, 99 mol% Is particularly preferred. By making EVOH saponification degree 80 mol% or more, the air permeation resistance of the multilayer structure can be further improved, the moisture resistance can be improved, and in addition, interlayer adhesion with the elastomer layer Can be improved. When the saponification degree of EVOH is not less than the above lower limit, it is difficult to impair the melt moldability, and the deterioration of the air permeation resistance, coloring resistance and moisture resistance of the multilayer structure can be prevented.

  On the other hand, the upper limit of the saponification degree of EVOH is preferably 99.99 mol%. When the saponification degree of EVOH is equal to or less than the above upper limit, it is possible to expect an increase in air permeation resistance and the like with respect to an increase in EVOH production cost. In addition, although EVOH can also be used independently, several EVOH from which saponification degree differs can also be mixed and used.

The EVOH 1,2-glycol bond structural unit content G (mol%) preferably satisfies the following formula (4-1) and the intrinsic viscosity is 0.05 L / g or more and 0.2 L / g or less. . In following formula (4-1), E is ethylene unit content (mol%) in EVOH (however, E <= 64 (mol%)).
G ≦ 1.58−0.0244 × E (4-1)

  When the resin composition of the layer A contains EVOH having such a content G of 1,2-glycol bond structural units and an intrinsic viscosity, the humidity dependency of air resistance of the resulting multilayer structure is reduced. In addition to exhibiting such properties, it has good transparency and gloss, and can be easily laminated with other thermoplastic resins. The content G of the 1,2-glycol bond structural unit was determined according to the method described in S. Aniya et al. (Analytical Science Vol. 1,91 (1985)), using an EVOH sample as a dimethyl sulfoxide solution and a temperature of 90 It can be measured by a nuclear magnetic resonance method at ° C.

  EVOH preferably has at least one selected from the group consisting of the following structural units (I) and (II).

(In 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, or carbon. the number represents the 6-10 aromatic hydrocarbon group or a hydroxyl group. ^Further, R 1, which may be a pair is bound of ^{R 2} and ^{R 3 (where,} of R 1, ^{R 2} and ^{R 3} Except when the pair is a hydrogen atom.) In addition, 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. May have a hydroxyl group, a carboxy group or a halogen atom.

In formula (II), R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an alicyclic hydrocarbon group having 3 to 10 carbon atoms. Represents an aromatic hydrocarbon group or a hydroxyl group having 6 to 10 carbon atoms. R ⁴ and R ⁵ or R ⁶ and R ⁷ may be bonded (except when R ⁴ and R ⁵ or R ⁶ and R ⁷ 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 is a hydroxyl group, an alkoxy group, a carboxy group, or a halogen atom. You may have an atom. )

  When the EVOH of the A layer has the structural unit (I) or (II) in the above content range, the flexibility and processing characteristics of the resin composition constituting the A layer are improved, and the interlayer adhesion of the multilayer structure is improved. , Flexibility, thermoformability and the like can be improved.

  As a minimum of content with respect to all the structural units of the said structural unit (I) or (II), 0.5 mol% is preferable, 1 mol% is more preferable, 1.5 mol% is still more preferable. On the other hand, the upper limit of the content of the structural unit (I) or (II) is preferably 30 mol%, more preferably 15 mol%, still more preferably 10 mol%. When the resin composition of the A layer has the structural units (I) and / or (II) in the above range, the flexibility and processing characteristics of the resin composition constituting the A layer are improved, resulting in a multilayer structure. The stretchability and thermoformability of the body 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 A cycloalkyl 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 hydroxyl group, a hydroxymethyl group or a hydroxyethyl group. Among these, More preferably, they are each independently a hydrogen atom, a methyl group, a hydroxyl group or a hydroxymethyl group. By being such R ¹ , R ² and R ³ , the stretchability and thermoformability of the multilayer structure can be further improved.

  The method of incorporating the structural unit (I) in EVOH is not particularly limited. For example, in the polymerization of ethylene and vinyl ester, a method of copolymerizing a monomer derived from the structural unit (I) and the like. Can be mentioned. Monomers derived from this structural unit (I) include alkenes 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, 4 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 hydroxyl group such as 1-hexene and 5,6-diacyloxy-1-hexene, and an ester group may be mentioned. Among them, from the viewpoint of copolymerization reactivity and air permeation resistance of the resulting multilayer structure, propylene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1-butene 3,4-diacetoxy-1-butene is preferred. Specifically, among them, propylene, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene, and 3,4-diacetoxy-1-butene are preferable. 1,4-diacetoxy-1-butene is particularly preferred. In the case of an alkene having an ester, it is derived into the structural unit (I) during the 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 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 is preferably an alkyl group or an alkenyl group. From the viewpoint of particularly focusing on the air permeation resistance of the multilayer structure, it is particularly preferable that one of R ⁶ and R ⁷ is a methyl group or an ethyl group, and the other is a hydrogen atom. It is also particularly preferred 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.

  The method for containing the structural unit (II) in EVOH is not particularly limited, and a method for containing EVOH obtained by a saponification reaction by reacting it with a monovalent epoxy compound is used. As the monovalent epoxy compound, compounds represented by the following formulas (III) to (IX) are preferably used.

In the above formulas (III) to (IX), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms (an alkyl group or an alkenyl group). Etc.), 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). Moreover, i, j, k, p, and q represent the integer of 1-8.

  Examples of the monovalent epoxy compound represented by the above formula (III) include epoxy ethane (ethylene oxide), epoxy propane, 1,2-epoxybutane, 2,3-epoxybutane, and 3-methyl-1,2-epoxy. Butane, 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- Epoxy hexane, 5-methyl-1,2-epoxy hexane, 3-ethyl-1,2-epoxy hexane, 3-propyl-1,2-epoxy hexa 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-epoxy Heptane, 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-epoxyheptane, 4-methyl-2,3-epoxyheptane, 4-ethane 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-epoxy Heptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 3,4-epoxyoctane, 4,5-epoxyoctane, 1,2-epoxynonane, 2,3-epoxynonane, 3,4-epoxynonane 4,5-epoxynonane, 1,2-epoxydecane, 2,3-epoxydecane, 3,4-epoxydecane, 4,5-epoxydecane, 5,6-epoxy Sidecan, 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-1,2-epoxyhexane, 4-phenyl-1,2-epoxy Shihekisan, 5-phenyl-1,2-epoxy hexane, 6-phenyl-1,2-epoxy hexane, and the like.

  Examples of the monovalent epoxy compound represented by the above formula (IV) include 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-ethoxy Hexane, 1,2-epoxy-6-propoxyhexane, 1,2-epoxy-6-butoxyhexane, 1,2-epoxy-6-heptyloxyhexane, 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-ethoxy Octane, 1,2-epoxy-8-butoxyoctane, glycidol, 3,4-epoxy-1-butanol, 4,5- Poxy-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, etc. are mentioned.

  Examples of the monovalent epoxy compound represented by the formula (V) include ethylene glycol monoglycidyl ether, propanediol monoglycidyl ether, butanediol monoglycidyl ether, pentanediol monoglycidyl ether, hexanediol monoglycidyl ether, heptanediol mono Examples thereof include glycidyl ether and octanediol monoglycidyl ether.

  Examples of the monovalent epoxy compound represented by the formula (VI) include 3- (2,3-epoxy) propoxy-1-propene, 4- (2,3-epoxy) propoxy-1-butene, and 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.

  Examples of the monovalent epoxy compound represented by the formula (VII) include 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-pentanol, 2,3-epoxy-4,4-dimethyl-1-pen Tanol, 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-methyl-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-nonanol, 3,4-epoxy-5-nonanol, 2,3-epoxy- 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-decanol, 1,2-epoxy-3-decanol and the like.

  Examples of the monovalent epoxy compound represented by the above formula (VIII) include 1,2-epoxycyclopentane, 1,2-epoxycyclohexane, 1,2-epoxycycloheptane, 1,2-epoxycyclooctane, 1, Examples include 2-epoxycyclononane, 1,2-epoxycyclodecane, 1,2-epoxycycloundecane, 1,2-epoxycyclododecane and the like.

  Examples of the monovalent epoxy compound represented by the formula (IX) include 3,4-epoxycyclopentene, 3,4-epoxycyclohexene, 3,4-epoxycycloheptene, 3,4-epoxycyclooctene, 3, 4-epoxycyclononene, 1,2-epoxycyclodecene, 1,2-epoxycycloundecene, 1,2-epoxycyclododecene and the like can be 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 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 above formulas. Specifically, from the viewpoint of reactivity with EVOH and air permeation resistance of the resulting multilayer structure, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, epoxyethane, and glycidol are preferable. Of these, epoxypropane and glycidol are particularly preferred.

  Next, a method for producing EVOH will be specifically described. The copolymerization method of ethylene and vinyl ester 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.

  As vinyl ester used for polymerization, fatty acid vinyl such as vinyl acetate, vinyl propionate and vinyl pivalate can be used.

  In the above polymerization, as a copolymerization component, a monomer that can be copolymerized in addition to the above components, for example, alkenes other than the above: unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, or anhydrides thereof Products, salts, mono- or dialkyl esters, etc .: nitriles such as acrylonitrile and methacrylonitrile, amides such as acrylamide and methacrylamide: olefin sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, or salts thereof: alkyl Vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride and the like can be copolymerized in a small amount.

  Moreover, a vinyl silane compound can be contained as 0.0002 mol% or more and 0.2 mol% or less as a copolymerization component. Here, examples of the vinylsilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, and γ-methacryloyloxypropylmethoxysilane. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferably used.

  The solvent 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. Examples of such a solvent include alcohols such as methanol, ethanol, propanol, n-butanol, and tert-butanol: dimethyl sulfoxide. Among them, methanol is particularly preferable in that removal and separation after the reaction is easy.

  Examples of the catalyst used for the polymerization include 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobis- (4-methoxy-). 2,4-dimethylvaleronitrile), 2,2′-azobis- (2-cyclopropylpropionitrile) and other azonitrile initiators: isobutyryl peroxide, cumylperoxyneodecanoate, diisopropylperoxycarbonate, Organic peroxide initiators such as di-n-propyl peroxydicarbonate, t-butylperoxyneodenoate, lauroyl peroxide, benzoyl peroxide, and t-butyl hydroperoxide can be used.

  As superposition | polymerization temperature, it is about 20-90 degreeC, Preferably it is 40-70 degreeC. The polymerization time is about 2 to 15 hours, preferably 3 to 11 hours. The polymerization rate is 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 as necessary, and after removing unreacted ethylene gas, unreacted vinyl ester is removed. As a method for removing the unreacted vinyl ester, for example, the above 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 mixed vapor 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. The saponification method can be either a continuous type or a batch type. As this alkali catalyst, for example, sodium hydroxide, potassium hydroxide, alkali metal alcoholate and the like are used.

  As saponification conditions, for example, in the case of a batch system, the copolymer solution concentration is about 10 to 50% by mass, the reaction temperature is about 30 to 65 ° C., and the amount of catalyst used is 0.02 to 1 mol of vinyl ester structural unit. About 1.0 mol and saponification time is about 1 to 6 hours.

  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. .

[Additives in resin composition forming layer A]
The resin composition forming the A layer may contain an additive such as one or more compounds selected from a phosphoric acid compound, a carboxylic acid, and a boron compound depending on the embodiment. By containing such a phosphoric acid compound, carboxylic acid or boron compound in the resin composition of the A layer, various performances of the multilayer structure can be improved.

  Specifically, the thermal stability at the time of melt molding of the multilayer structure can be improved by including a phosphoric acid compound in the resin composition of the A layer containing EVOH and the like. 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 compound conversion content of a phosphoric acid compound in a dry resin composition of A layer), 1 mass ppm is preferred, 10 mass ppm is more preferred, and 30 mass ppm is still more preferred. . On the other hand, as an upper limit of content of a phosphoric acid compound, 10,000 mass ppm is preferable, 1,000 mass ppm is more preferable, and 300 mass ppm is still more preferable. 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 histories are 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 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, 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 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. On the contrary, 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 A 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 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 the resin composition containing EVOH or the like is not particularly limited. For example, when preparing pellets of the resin composition containing EVOH or the like, the resin composition 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 metal salt described later, a resin other than EVOH, 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 A 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 A 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 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 here. 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. More preferred is 5 mass ppm 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 the compound after polymerization as described above and before the saponification from the viewpoint of improving surface smoothness and 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 A layer is a range that does not impair the object of the present invention, in addition to the above additives, various resins such as EVOH and other resins, heat stabilizers, ultraviolet absorbers, antioxidants, colorants, fillers, and the like. An additive may be included. When the resin composition of layer A 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 A layer has a viscosity behavior stability (M ₁₀₀ / M ₂₀ , where M ₂₀ is 20 minutes from the start of kneading) in relation to torque and melt kneading time 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.

[B layer]
B layer is a layer which consists of an elastomer composition containing an elastomer. When the elastomer composition which comprises B layer contains an elastomer, the ductility of a multilayer structure can be improved and crack resistance can be improved.
As described above, the elastomer means a resin having elasticity at around room temperature. Specifically, the elastomer is doubled under the condition of room temperature (20 ° C.), held in that state for 1 minute, 1 A resin having the property of shrinking to less than 1.5 times the original length within minutes. The elastomer is structurally a polymer having a hard segment and a soft segment in the polymer chain.

  Examples of such elastomers include polystyrene elastomers, polyolefin elastomers, polydiene elastomers, polyvinyl chloride elastomers, chlorinated polyethylene elastomers, polyurethane elastomers, polyester elastomers, polyamide elastomers, and fluororesin elastomers. At least one selected from the group consisting of: Among these, from the viewpoint of ease of molding, at least one selected from the group consisting of polystyrene elastomers, polyolefin elastomers, polydiene elastomers, polyurethane elastomers, polyester elastomers and polyamide elastomers is preferably used. An elastomer is more preferably used.

  Such an elastomer is not particularly limited and can be appropriately selected from known thermoplastic elastomers and non-thermoplastic elastomers. For the purpose of melt molding, thermoplastic elastomers may be used. preferable.

  Examples of the thermoplastic elastomer include polystyrene-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, polydiene-based thermoplastic elastomers, polyvinyl chloride-based thermoplastic elastomers, chlorinated polyethylene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, and polyesters. And at least one selected from the group consisting of thermoplastic thermoplastic elastomers, polyamide thermoplastic elastomers, and fluororesin thermoplastic elastomers. Among these, from the viewpoint of ease of molding, from the group consisting of polystyrene-based thermoplastic elastomers, polyolefin-based thermoplastic elastomers, polydiene-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers and polyamide-based thermoplastic elastomers. At least one selected from the above is preferably used, and a polyurethane-based thermoplastic elastomer is more preferably used.

[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.

  This polystyrene-based thermoplastic elastomer is, for example, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-isobutylene-styrene, depending on the arrangement pattern of the soft segments therein. Block copolymer (SIBS), styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), and polybutadiene and butadiene-styrene random copolymer A block copolymer of crystalline polyethylene and ethylene / butylene-styrene random copolymer obtained by hydrogenation of the block copolymer, a block of polybutadiene or ethylene-butadiene random copolymer and polystyrene. The copolymer obtained by hydrogenating, for example, there is such 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), in terms of the balance of mechanical strength, heat stability, weather resistance, chemical resistance, air permeation resistance, flexibility, workability, etc. Styrene-ethylene / butylene-styrene block copolymers (SEBS) and styrene-ethylene / propylene-styrene block copolymers (SEPS) are preferred.

[Polyolefin thermoplastic elastomer]
Examples of the polyolefin-based thermoplastic elastomer include a thermoplastic elastomer using a polyolefin such as polypropylene and polyethylene as a hard segment and an ethylene-propylene-diene copolymer rubber as a soft segment. There are blended and implantable types. Mention may also be made of maleic anhydride-modified ethylene-butene-1 copolymer, maleic anhydride-modified ethylene-propylene copolymer, halogenated butyl rubber, modified polypropylene, modified polyethylene and the like.

[Polydiene thermoplastic elastomer]
Examples of the polydiene-based thermoplastic elastomer include 1,2-polybutadiene-based TPE and trans 1,4-polyisoprene-based TPE, hydrogenated conjugated diene-based TPE, epoxidized natural rubber, and maleic anhydride-modified products thereof. it can.

  1,2-polybutadiene-based TPE is a polybutadiene containing 90% or more of 1,2-bonds in the molecule, and includes crystalline syndiotactic 1,2-polybutadiene as a hard segment and amorphous 1 as a soft segment. , 2-Polybutadiene.

  On the other hand, trans 1,4-polyisoprene-based TPE has a trans 1,4-structure of 98% or more, and includes crystalline trans 1,4-segment as a hard segment and amorphous trans 1 as a soft segment. , 4-segment.

[Polyvinyl chloride (PVC) thermoplastic elastomer]
Generally, the following three types of polyvinyl chloride-based thermoplastic elastomers (TPVC) are listed. Note that this TPVC may also be a modified product such as maleic anhydride-modified PVC.

(5-1) High molecular weight PVC / plasticized PVC blend type TPVC
This type of TPVC uses PVC having a high molecular weight as a hard segment and having a function of a crosslinking point at a microcrystalline portion, and PVC softened with a plasticizer as a soft segment.

(5-2) Partially cross-linked PVC / plasticized PVC blend type TPVC
This type of TPVC uses 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.

(5-3) PVC / elastomer alloy type TPVC
This type of TPVC uses PVC for the hard segment, rubber such as partially crosslinked NBR, polyurethane TPE, polyester TPE, and TPE for the soft segment.

[Chlorinated polyethylene (CPE) thermoplastic elastomer]
The chlorinated polyethylene thermoplastic elastomer is a soft resin obtained by reacting polyethylene with an aqueous suspension or with chlorine gas in a solvent such as carbon tetrachloride. CPE uses a crystalline polyethylene part for the hard segment and a chlorinated polyethylene part for the soft segment. In CPE, both parts are mixed as a multi-block or random structure.

  CPE has different molecular properties such as chlorine content, blockiness, and residual crystallinity depending on the type of raw polyethylene, chlorination degree, and production conditions. As a result, CPE has a wide range of hardness from resin to rubber. A wide range of properties has been obtained. CPE can also have the same properties as vulcanized rubber by crosslinking, and can also be modified by modification with maleic anhydride.

[Polyester thermoplastic elastomer]
The polyester-based thermoplastic elastomer (TPEE) is a multi-block copolymer using a polyester as a hard segment in a molecule and a polyether or polyester having a low glass transition temperature (Tg) as a soft segment. TPEE has the following types depending on the molecular structure. Among them, (6-1) polyester / polyether type and (6-2) polyester / polyester type are common.

(6-1) Polyester / polyether type TPEE
In general, this type of TPEE uses an aromatic crystalline polyester as a hard segment and a polyether as a soft segment.

(6-2) Polyester / Polyester type TPEE
This type of TPEE uses an aromatic crystalline polyester as a hard segment and an aliphatic polyester as a soft segment.

(6-3) Liquid crystalline TPEE
This type of TPEE uses, as a special one, a rigid liquid crystal molecule as a hard segment and an aliphatic polyester as a soft segment.

[Polyamide thermoplastic elastomer]
The polyamide-based thermoplastic elastomer (TPA) is a multi-block copolymer using polyamide as a hard segment and polyether and polyester having a low Tg as a soft segment. The polyamide component is selected from nylon 6, 66, 610, 11, 12, and the like, and nylon 6 or nylon 12 is common.

  As a constituent material of the soft segment, a long-chain polyol of polyether diol or polyester diol is used. Typical examples of the polyether include poly (oxytetramethylene) glycol (PTMG), poly (oxypropylene) glycol and the like. Representative examples of polyester diols 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 block copolymer composed of a fluororesin as a hard segment and a fluororubber as a soft segment. Tetrafluoroethylene-ethylene copolymer or polyvinylidene fluoride (PVDF) is used for the hard segment fluororesin, and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer for the soft segment fluororubber. Etc. are used. More specifically, vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, tetrafluoroethylene-perfluoromethyl vinyl ether rubber, phosphazene fluororubber, fluoropolyether, fluoronitroso rubber, perfluorotriazine Is mentioned.

  As with other TPEs, fluororesin-based TPE is microphase-separated and hard segments form cross-linking points.

[Polyurethane thermoplastic elastomer]
Polyurethane-based thermoplastic elastomers (TPU) are (7-1) polyurethane obtained by the reaction of short chain glycol (low molecular polyol) and isocyanate as a hard segment, and (7-2) long chain glycol (polymer) as a soft segment. Polyol) and a polyurethane obtained by the reaction of an isocyanate, such as a linear multi-block copolymer. Here, polyurethane is a general term for compounds having a urethane bond (—NHCOO—) obtained by a polyaddition reaction (urethanization reaction) of isocyanate (—NCO) and alcohol (—OH).

  The multilayer structure is preferable because the stretchability and the thermoformability can be improved by laminating the B layer made of an elastomer composition containing TPU as an elastomer. In addition, in the multilayer structure, since the interlayer adhesion between the B layer and the A layer can be strengthened, the durability is high, and the air permeation resistance and the stretchability are maintained even when deformed. This is preferable.

  TPU is composed of polymer polyol, organic polyisocyanate, chain extender and the like. This polymer polyol is a substance having a plurality of hydroxyl groups, and can be 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). These polymer polyols may be used alone or in combination of two or more. Among these, a polyester polyol or a polycarbonate polyol is preferable, and a polyester polyol is particularly preferable.

  For example, the polyester polyol can be obtained by condensing an ester-forming derivative such as dicarboxylic acid, its ester or its anhydride and a low molecular weight polyol by direct esterification or transesterification, or by opening a lactone according to a conventional method. It can be produced by polymerization.

  It does not specifically limit as dicarboxylic acid which comprises polyester polyol, What is generally used in manufacture of polyester can be used. 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- Aliphatic dicarboxylic acids having 4 to 12 carbon atoms such as methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid: cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid: terephthalic acid, isophthalate Examples thereof include aromatic dicarboxylic acids such as acids, orthophthalic acid, and naphthalenedicarboxylic acid. These dicarboxylic acids may be used alone or in combination of two or more. Among these, an aliphatic dicarboxylic acid having 6 to 12 carbon atoms is preferable in that it has a carbonyl group that is more easily reacted with a hydroxyl group such as EVOH in the A layer, and the interlayer adhesion of the multilayer structure becomes higher. Adipic acid, azelaic acid or sebacic acid are particularly preferred.

  It does not specifically limit as a low molecular polyol, What is generally used can be used. 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, B hexane dimethanol, cyclooctane dimethanol, an alicyclic diol such as dimethyl cyclooctane dimethanol; and 1,4-bis (beta-hydroxyethoxy) aromatic dihydric alcohol and benzene. These low molecular polyols may be used alone or in 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-dimethyl The aliphatic diol having 5 to 12 carbon atoms having a methyl group in the side chain such as -1,9-nonanediol easily reacts with an ester group in the polyester polyol and a hydroxyl group such as EVOH in the A layer. It is preferable in that the interlayer adhesion of the resulting multilayer structure is higher. Moreover, when mixing and using 2 or more types as a low molecular polyol, the C5-C12 aliphatic diol which has a methyl group in this side chain is a ratio of 50 mol% or more with respect to the whole quantity of a low molecular polyol. More preferably, it is used. Further, 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 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 alone or in combination of two or more. Among these, polytetramethylene glycol is preferable.

  Examples of the polycarbonate polyol include aliphatic groups having 2 to 12 carbon atoms such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol. A diol or a mixture thereof obtained by subjecting diphenyl carbonate or phosgene or the like to condensation polymerization is preferably used.

  As a minimum of the number average molecular weight of the above-mentioned polymer polyol, 500 is preferred, 600 is more preferred, and 700 is still more preferred. 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. Since the number average molecular weight of the polymer polyol is not less than the above lower limit, the compatibility with the organic polyisocyanate is not excessively increased, and the decrease in elasticity of the obtained TPU can be suppressed. It is difficult to impair mechanical properties such as properties and thermoformability. When the number average molecular weight of the polymer polyol is not more than the above upper limit, a decrease in compatibility with the organic polyisocyanate is suppressed, and the mixing in the polymerization process is facilitated. As a result, it is possible to prevent the formation of a lump of gel-like material, and it is easy to obtain a stable TPU. The number average molecular weight of the polymer polyol is a number average molecular weight measured based on JIS-K1557: 2007 and calculated based on the hydroxyl value.

  The organic polyisocyanate is not particularly limited, and a known organic diisocyanate generally used for production of TPU is 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 thereof include aromatic diisocyanates such as diisocyanate; 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 in that the strength and crack resistance of the resulting multilayer structure can be improved. These organic diisocyanates may be used alone or in combination of two or more.

  As the chain extender, a chain extender generally used in the production of TPU is used, and a low molecular weight compound having a molecular weight of 300 or less having two or more active hydrogen atoms capable of reacting with an isocyanate group in the molecule is preferably used. 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, an aliphatic diol having 2 to 10 carbon atoms is preferable, and 1,4-butanediol is particularly preferable in that the stretchability and thermoformability of the obtained multilayer structure are further improved. These chain extenders may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  As a method for producing TPU, the above-mentioned polymer polyol, organic polyisocyanate and chain extender are used and produced using a known urethanization reaction technique, and any of the prepolymer method and the one-shot method is used. can do. Among these, it is preferable to perform melt polymerization in the substantial absence of a solvent, and it is particularly preferable to perform continuous melt polymerization using a multi-screw extruder.

  In 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 is 1.02 or less, it is easy to perform long-term operation stably during molding.

  Although the nitrogen content of TPU is determined by appropriately selecting the use ratio of the polymer polyol and the organic diisocyanate, a practical range of 1 to 7% by mass is preferable.

  In addition, the B layer elastomer composition may use an appropriate catalyst or the like that accelerates the reaction between the organic polyisocyanate and the polymer polyol, if necessary. Further, the elastomer composition of the B layer contains various additives such as a resin other than the 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. Also good. When the elastomer composition of the B 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 or less with respect to the total amount of the elastomer composition. It is particularly preferred that

  The hardness of the elastomer in the elastomer composition of the B layer such as TPU is preferably from 50 to 95 as Shore A hardness, more preferably from 55 to 90, and still more preferably from 60 to 85. Use of a material having a hardness in the above range is preferable because a laminated structure having excellent mechanical strength and durability and excellent flexibility can be obtained.

[Metal salt]
In the multilayer structure, it is preferable that a metal salt is contained in at least one of the resin composition and the elastomer composition. Thus, by including a metal salt in at least one of the A layer and the B layer, very good interlayer adhesion between the A layer and the B layer is exhibited. Due to such excellent interlayer adhesion, the multilayer structure has high durability. The reason why such a metal salt improves interlaminar adhesion is not necessarily clear. For example, bond formation occurs between EVOH or the like in the resin composition of the A layer and TPU or the like in the elastomer composition of the B layer. It is conceivable that the reaction is accelerated by the presence of a metal salt. Examples of such a bond formation reaction include a hydroxyl group exchange reaction that occurs between the carbamate group of TPU and the hydroxyl group of EVOH, and an addition reaction of the hydroxyl group of EVOH to the remaining isocyanate group in TPU. The metal salt may be contained in both the A-layer resin composition and the B-layer elastomer composition, and may be contained in either the A-layer resin composition or the B-layer elastomer composition. Also good.

  Although it does not specifically limit as a metal salt, Alkali metal salt, alkaline-earth metal salt, or d block metal salt described in the 4th period of a periodic table is preferable at the point which raises interlayer adhesiveness more. Among these, alkali metal salts or alkaline earth metal salts are more preferable, and alkali metal salts are particularly preferable.

  The alkali metal salt is not particularly limited, and examples thereof include aliphatic carboxylates such as lithium, sodium, and potassium, aromatic carboxylates, phosphates, and metal complexes. Specific examples of the alkali metal salt include sodium acetate, potassium acetate, sodium phosphate, lithium phosphate, sodium stearate, potassium stearate, sodium salt of ethylenediaminetetraacetic acid, and the like. Among these, sodium acetate, potassium acetate, and sodium phosphate are particularly preferable because they are easily available.

  The alkaline earth metal salt is not particularly limited, and examples thereof include acetates or phosphates such as magnesium, calcium, barium, and beryllium. Among these, magnesium or calcium acetate or phosphate is particularly preferable because it is easily available. When such an alkaline earth metal salt is contained, there is also an advantage that the die adhesion amount of the molding machine of the resin that has deteriorated at the time of melt molding can be reduced.

  Although it does not specifically limit as a metal salt of d block metal described in the 4th period of a periodic table, For example, carboxylate, phosphorus, such as titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc And acid salts and acetylacetonate salts.

  The lower limit of the metal salt content (content in terms of metal element based on the entire multilayer structure) is preferably 1 mass ppm, more preferably 5 mass ppm, further preferably 10 mass ppm, and 20 mass ppm. Particularly preferred. On the other hand, the upper limit of the content of the metal salt is preferably 10,000 ppm by mass, more preferably 5,000 ppm by mass, still more preferably 1,000 ppm by mass, and particularly preferably 500 ppm by mass. When the content of the metal salt is not less than the above lower limit, the interlayer adhesion is hardly lowered and the durability of the multilayer structure can be prevented from being lowered. When the content of the metal salt is less than or equal to the above upper limit, coloring of the resin composition and the elastomer composition can be suppressed, and the appearance of the multilayer structure is hardly damaged.

  As a minimum of content of metal salt to each composition of a resin composition containing a metal salt and an elastomer composition, 5 mass ppm is preferred, 10 mass ppm is more preferred, 20 mass ppm is still more preferred, and 50 mass ppm. Is particularly preferred. On the other hand, the upper limit of the content of the metal salt is preferably 5,000 mass ppm, more preferably 1,000 mass ppm, still more preferably 500 mass ppm, and particularly preferably 300 mass ppm. When the content of the metal salt is smaller than the above lower limit, the adhesion to the adjacent other layer is lowered, and the durability of the multilayer structure may be lowered. On the other hand, when the content of the metal salt is not more than the above upper limit, each composition of the resin composition and the elastomer composition becomes difficult to be colored, and the appearance of the multilayer structure is hardly impaired.

  The method of containing this metal salt in the resin composition of the A layer and the elastomer composition of the B layer is not particularly limited, and a phosphoric acid compound or the like is contained in the resin composition of the A layer as described above. A method similar to the method is adopted.

[Crosslinking agent]
In the multilayer structure, it is preferable that at least one of the compositions constituting the A-layer resin composition and the B-layer elastomer composition contains a crosslinking agent.
The crosslinking agent is not particularly limited as long as it is a component that undergoes a crosslinking reaction with the gas barrier resin and the elastomer, but a radical crosslinking agent is preferably used.
By irradiating active energy rays to a multilayer structure having an A layer made of a resin composition containing a radical crosslinking agent and / or a B layer made of an elastomer composition containing a radical crosslinking agent, The cross-linking effect is promoted, the interlayer adhesion between the A layer and the B layer is further improved, and the air permeation resistance is further increased. Moreover, it becomes possible to reduce the irradiation amount of an active energy ray compared with the case where a radical crosslinking agent does not exist.

  The radical crosslinking agent is not particularly limited, and examples thereof include poly (meth) acrylates of polyhydric alcohols such as trimethylolpropane trimethacrylate, diethylene glycol diacrylate, neophenylene glycol diacrylate, triallyl isocyanurate, triallyl cyanurate. And so on. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The content of the radical crosslinking agent relative to the resin composition containing the radical crosslinking agent and the elastomer composition containing the radical crosslinking agent before irradiation with the active energy ray is preferably 0.01% by mass or more and 10% by mass or less. 0.05 mass% or more and 9 mass% or less is still more preferable, and 0.1 mass% or more and 8 mass% or less is preferable from a viewpoint of the balance of a crosslinking effect and economical efficiency.

  The method for containing the radical crosslinking agent in the resin composition or the elastomer composition is not particularly limited, and for example, a method of melt kneading each composition using a twin screw extruder or the like can be used.

[Relationship between layer A and layer B]
As the peeling resistance between the A layer and the B layer in the multilayer structure, after heating at 180 ° C. for 15 minutes, in accordance with JIS-K6854: 1999, at 23 ° C. and 50% RH atmosphere, at a pulling speed of 50 mm / min. In the measurement, it is preferably 25 N / 25 mm or more, more preferably 27 N / 25 mm or more, still more preferably 30 N / 25 mm or more, and particularly preferably 50 N / 25 mm or more. Thus, the A layer and the B layer have very good interlayer adhesion.

  Regarding the interlayer relationship of the multilayer structure, it is considered that the cross-linking reaction between molecules occurs at the interface between the A layer and the B layer due to the irradiation of active energy rays, and it is considered that the layers are firmly bonded, and high interlayer adhesion is expressed. The In addition, for example, as described above, a bond formation reaction between EVOH or the like in the resin composition of the A layer and TPU or the like in the elastomer composition of the B layer due to the inclusion of the metal salt (for example, the carbamate group of TPU and EVOH) A hydroxyl group exchange reaction with the hydroxyl group of the epoxy group, an addition reaction of the hydroxyl group of EVOH to the remaining isocyanate group in TPU, etc.), thereby exhibiting higher interlayer adhesion and air permeability of the multilayer structure Further, durability and the like can be improved. Furthermore, as mentioned above, a radical crosslinking agent is contained in the A layer and / or the B layer and irradiated with active energy rays, the crosslinking reaction is further promoted, and the interlayer adhesion can be further improved.

(Manufacturing method of multilayer structure)
The production method of the multilayer structure is not particularly limited as long as the A layer and the B layer are laminated and bonded well, and known methods such as co-extrusion, lamination, coating, bonding, and adhesion are known. This method can be adopted. As a method for producing a multilayer structure, specifically, (8-1) A layer forming resin composition and B layer forming elastomer composition are used, and A layer and B layer are formed by multilayer coextrusion method. (8-2) using a resin composition for forming an A layer and an elastomer composition for forming a B layer, and laminating and stretching a plurality of laminates via an adhesive Examples thereof include a method for producing a multilayer structure having an A layer and a B layer. Among these, from the viewpoint of high productivity and excellent interlayer adhesion, molding is performed by a multilayer coextrusion method using the resin composition for forming the A layer and the elastomer composition for forming the B layer of (8-1). The method is preferred.

  In the multilayer coextrusion method, the resin composition for forming the A layer and the elastomer composition for forming the B layer are heated and melted, supplied from different extruders and pumps to the extrusion dies through the respective flow paths, and extruded. A multilayer structure is formed by laminating and bonding after being extruded into multiple layers from the die. As this extrusion die, for example, a multi-manifold die, a field block, a static mixer, or the like can be used.

(Active energy ray irradiation)
In the multilayer structure contained in the rubber composition of the present invention, the multilayer laminate obtained as described above is irradiated with active energy rays to promote the crosslinking reaction, and the interlayer adhesion between the A layer and the B layer To further improve the performance. Since the multilayer structure is thus irradiated with the active energy rays, the adhesion between the layers is enhanced, and as a result, the air permeation resistance and the crack resistance can be improved.

  Active energy rays refer to those having energy quanta among electromagnetic waves or charged particle beams, specifically, ultraviolet rays, γ rays, electron beams and the like. Among these active energy rays, an electron beam is preferable from the viewpoint of improving the interlayer adhesion. By using an electron beam as the active energy ray, the cross-linking reaction between layers is further promoted, and the interlayer adhesion of the multilayer structure can be further improved.

  When irradiating an electron beam, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type are used as an electron beam source. It is preferable to irradiate within an irradiation dose range of 5 to 600 kGy with a normal acceleration voltage of 100 to 500 kV.

  Moreover, when using an ultraviolet-ray as an active energy ray, it is good to irradiate what contains the ultraviolet-ray with a wavelength of 190-380 nm. The ultraviolet light source is not particularly limited, and for example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, or the like is used.

  In the multilayer structure irradiated with active energy rays, the gas barrier resin and the elastomer each form a crosslinked structure. Further, the multilayer structure has a crosslinked structure derived from the crosslinking agent by irradiating the resin composition constituting the A layer and the elastomer layer constituting the B layer with active energy irradiation in a state where the crosslinking agent is contained. Therefore, the strength is higher than that of the multilayer structure.

  The multilayer structure is not limited to the above embodiment. For example, other layers besides the A layer and the B layer may be included. Although the kind of resin composition which comprises this other layer is not specifically limited, A thing with high adhesiveness between A layer and / or B layer is preferable. The other layer has a molecular chain having a functional group that reacts with a hydroxyl group of EVOH in the A layer and a carbamate group or an isocyanate group in the molecular chain of TPU in the B layer to form a bond. Those that are particularly preferred.

(Crushing method of multilayer structure)
The multilayer structure irradiated with active energy rays is pulverized into pieces, and then mixed with the rubber component. The method for pulverizing the multilayer structure is not particularly limited. For example, the multilayer structure may be crushed with a hammer or administered to a mixer for pulverization. Moreover, you may use airflow-type grinders (for example, Nisshin Engineering, SUPER JET M-LL etc.).
It is preferable to classify after pulverizing the multilayer structure.

The shape of the fragments is not particularly limited, but from the viewpoint of recycling the vulcanized rubber obtained from the rubber composition of the present invention as a used rubber component, and from the viewpoint of dispersibility to be uniformly dispersed in the rubber component as a continuous phase. The average thickness of the fragments is preferably 10 μm or more and 200 μm or less, and the average maximum length of the fragments is preferably 2 μm or more and 2000 μm or less.
The average thickness of the fragments is more preferably 20 μm or more and 180 μm or less. The average maximum length of the fragments is more preferably 5 μm or more and 1800 μm or less.
Further, from the viewpoint of the air permeability of the vulcanized rubber and the dispersibility of the fragments in the rubber component, the average aspect ratio of the fragments is preferably 1 or more and 100 or less, and more preferably 2 or more and 90 or less. More preferably, it is 3 or more and 80 or less. The average aspect ratio is obtained as x / y from the average maximum length x and the average thickness y of the fragments.
In addition, the average thickness and the average maximum length of the fragments are calculated as average values of 10 randomly selected fragments.

The fragments of the multilayer structure irradiated with active energy rays improve the air permeation resistance and crack resistance of the vulcanized rubber obtained from the rubber composition of the present invention, and the multilayer structure during kneading and mixing with the rubber component From the viewpoint of suppressing defects in the rubber component, it is preferably 1 part by mass or more and 30 parts by mass or less, and more preferably 1.5 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the butyl rubber in the rubber component. Preferably, it is 2 parts by mass or more and 20 parts by mass or less.
Further, from the viewpoint of improving the air permeation resistance and crack resistance of the vulcanized rubber obtained from the rubber composition of the present invention, the fragments of the multilayer structure irradiated with active energy rays are contained in the rubber composition. Is preferably 0.5% by mass or more and 30% by mass or less. The vulcanized rubber obtained when the content of crushed pieces in the rubber composition is 0.5% by mass or more is more excellent in air permeation resistance, and when it is 30% by mass or less, it is more excellent in crack resistance.
As for content of the crushed piece in a rubber composition, it is more preferable that it is 1 mass% or more. Further, the content of the fragments in the rubber composition is more preferably 25% by mass or less, and further preferably 20% by mass or less.

[Adhesive layer]
In the multilayer structure irradiated with active energy rays, an adhesive layer containing an adhesive is preferably laminated on at least one outermost layer of the multilayer structure. By laminating an adhesive layer on one or both of the outermost layers of the multilayer structure, the fragments of the multilayer structure irradiated with active energy rays serving as the dispersed phase can easily adhere to the rubber component serving as the continuous phase. Become.
Examples of the adhesive used for the adhesive layer include chlorosulfonated polyethylene, epoxidized natural rubber, and styrenic thermoplastic elastomer.
Examples of the styrene-based thermoplastic elastomer include epoxidized products of styrene-butadiene block copolymers.
As the adhesive, commercially available products can be used. For example, as chlorosulfonated polyethylene, Chemlock (registered trademark) of Road Japan Co., Ltd., and the like, as styrenic thermoplastic elastomer, manufactured by Daicel Corporation, Epofriend (Registered trademark) and the like.
The adhesive may be used alone or in combination of two or more.
Among these, when recycling the vulcanized rubber obtained from the rubber composition of the present invention, from the viewpoint of facilitating peeling of the debris of the multilayer structure irradiated with active energy rays from the rubber component, chlorosulfonated polyethylene or It is preferable to use a styrenic thermoplastic elastomer.
The layer thickness of the adhesive layer is not particularly limited, but is usually 1 μm or more and 100 μm or less.
The method of laminating the adhesive layer on the outermost layer of the multilayer structure is not particularly limited, and may be laminated by applying an adhesive before spraying the multilayer structure, spraying, etc. It may be laminated by a method in which it is administered and taken out from the solution.

[Various additive components of rubber composition]
The rubber composition of the present invention includes a vulcanizing agent, a vulcanization accelerator, a zinc oxide, an anti-aging agent, a fatty acid, and a scorch inhibiting agent that are usually included in the rubber composition, in addition to the components described as a continuous phase and a dispersed phase. , Fillers, peptizers, organic modifiers, softeners, plasticizers, tackifiers, and the like.
Examples of the vulcanizing agent include sulfur or a compound containing a sulfur atom.
In addition to fatty acids, fatty acid derivatives such as fatty acid esters can be used as the fatty acid. Examples of fatty acids and fatty acid derivatives include palm oil, palm kernel oil, camellia oil, olive oil, almond oil, canola oil, peanut oil, rice sugar oil, cocoa butter, palm oil, soybean oil, cottonseed oil, sesame oil, linseed oil , Aliphatic carboxylic acids derived from vegetable oils such as castor oil and rapeseed oil, aliphatic carboxylic acids derived from animal oils such as beef tallow, aliphatic carboxylic acids chemically synthesized from petroleum, stearic acid, palmitic acid, myristic acid, lauric acid, capryl Examples include acids, oleic acid, linoleic acid and the like. These fatty acids and fatty acid derivatives may be used alone or in combination of two or more. Of these fatty acids and fatty acid derivatives, stearic acid is particularly preferable.

Examples of the filler include carbon black and inorganic filler.
For carbon black, in order for the vulcanized rubber properties of the rubber composition to be obtained to satisfy the above vulcanized rubber properties, among the FEF grade, FF grade, HAF grade, ISAF grade and SAF grade, It is preferable to use at least one selected from
Examples of the inorganic filler include alumina (Al ₂ O ₃ ) such as γ-alumina and α-alumina, alumina monohydrate (Al ₂ O ₃ .H ₂ O) such as boehmite and diaspore, gibbsite, and bayerite. Aluminum hydroxide [Al (OH) ₃ ], aluminum carbonate [Al ₂ (CO ₃ ) ₂ ], magnesium hydroxide [Mg (OH) ₂ ], magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ), talc _{(3MgO · 4SiO 2 · H 2} O), attapulgite _{(5MgO · 8SiO 2 · 9H 2} O), titanium white _(TiO 2), titanium black _{(TiO 2n-1),} calcium oxide (CaO), calcium hydroxide [Ca (OH) ₂ ], aluminum magnesium oxide (MgO.Al ₂ O ₃ ), clay (Al ₂ O ₃ .2SiO ₂₎ ), Kaolin (Al ₂ O ₃ .2SiO ₂ .2H ₂ O), pyrophyllite (Al ₂ O ₃ .4SiO ₂ .H ₂ O), bentonite (Al ₂ O ₃ .4SiO ₂ .2H ₂ O), silicic acid Aluminum silicate (Al ₂ SiO ₅ , Al ₄ · 3SiO ₄ · 5H ₂ O, etc.), Magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), Calcium silicate (Ca ₂ · SiO ₄ etc.), Aluminum calcium silicate (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ · nH ₂ O] , zirconium carbonate _{[Zr (CO 3) 2]} , hydrogen to correct electric charge as various zeolites, alkali metal Or such crystalline aluminosilicate containing an alkaline earth metal can be used.
Among these, carbon black and silica are preferable as the filler, and carbon black is particularly preferable.

  As a softener, what contains at least 1 sort (s) selected from naphthenic oil, paraffinic oil, and aromatic oil can be used. Among these, paraffinic oil and naphthenic oil are preferable. A softener may be used individually by 1 type and may use 2 or more types together.

The rubber composition of the present invention can be produced by kneading, for example, a rubber component, a fragment of a multilayer structure irradiated with active energy rays, a vulcanizing agent, etc. with a Banbury mixer.
The debris that becomes the dispersed phase is composed of a multilayer structure and is irradiated with active energy rays to form a crosslinked structure. Therefore, even when kneaded with a Banbury mixer, it is difficult to break and is obtained by vulcanizing the rubber composition. The resulting vulcanized rubber has excellent air permeation resistance and crack resistance.

<Rubber, inner liner, pneumatic tire>
The pneumatic tire of the present invention is produced by an ordinary method using the rubber composition of the present invention as an inner liner. That is, if necessary, the rubber composition of the present invention obtained by blending various chemicals as described above is processed as an inner liner member in an unvulcanized state, and molded as a tire inner liner by a conventional manufacturing process. To process. The inner liner can be configured as a laminate (a laminate for an inner liner) of an inner liner layer and a carcass adjacent layer, and the rubber composition of the present invention is suitable for the inner liner layer. The inner liner layer is vulcanized at a vulcanization temperature of 130 ° C. or higher after being molded as a tire.
The method for manufacturing a pneumatic tire according to the present invention includes a step of laminating another tire member on a laminate for an inner liner of a pneumatic tire and molding a raw tire, and a step of vulcanizing the raw tire. It is preferable to contain.
According to the method for manufacturing a pneumatic tire of the present invention, the other tire member is laminated on the laminated body for the inner liner of the pneumatic tire having high adhesiveness with the rubber member. The adhesive strength between the inner liner laminate and the inner liner laminate is high, and the peeling of the inner liner laminate from the other tire member can be suppressed even when the green tire is molded or after running the tire. The raw tire molding step is not particularly limited except that other tire members are laminated on the inner liner laminate of the pneumatic tire, and can be performed in the same manner as normal green tire molding. . The shape of the green tire can be appropriately selected according to the shape of the pneumatic tire that is the product.

  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.

<Manufacture of fragments of multilayer structure irradiated with active energy rays>
The fragments 1 to 3 of the multilayer structure used in Examples 1 to 4 and 8 to 13 were formed into a film of the resins 1 to 3 produced as follows, irradiated with an electron beam, and then pulverized with a pulverizer. It was manufactured by doing.
Moreover, the fragments 4-6 of the multilayer structure with an adhesive layer used in Examples 5-7 co-extruded the resin 3 and the adhesive by a combination of the resin 3 and the adhesive shown in Tables 1 and 2. Thereafter, a film was formed, irradiated with an electron beam, and then pulverized with a pulverizer.
First, the details of the resins 1 to 3 will be described.

(Resin 1)
First, the manufacturing method of the EVOH pellet (A-1a) used as the raw material of the resin 1 and the TPU pellet (B-1a) is shown.

1) Production of A-layer pellet (A-1a) Modified EVOH produced based on Synthesis Example 3 of JP-A-2006-233222 was used as Resin 1 in Table 1.
Specifically, it was produced as follows.
100 parts by mass of water-containing pellets (water content: 130% (dry base)) made of an ethylene-vinyl alcohol copolymer having an ethylene content of 32 mol%, a saponification degree of 99.6%, and an intrinsic viscosity of 0.0882 L / g, It was immersed in 370 parts by mass of an aqueous solution containing 0.1 g / L of acetic acid and 0.044 g / L of potassium dihydrogen phosphate at 25 ° C. for 6 hours and stirred. The obtained pellets were dried at 105 ° C. for 20 hours, the potassium content was 8 ppm (in terms of metal element), the acetic acid content was 53 ppm, the phosphate compound content was 20 ppm (phosphate group equivalent), and the alkaline earth metal salt was contained. Dry EVOH pellets having an amount of 0 ppm and MFR of 8 g / 10 min (190 ° C., under 2160 g load) were obtained.

  A TEM-35BS extruder (37 mmφ, L / D = 52.5) manufactured by Shiba Machine Co., Ltd. was used, and a screw configuration and a vent and a pressure inlet were installed as shown in FIG. The barrel C1 was water-cooled, the barrels C2 to C3 were set to 200 ° C., the barrels C4 to C15 were set to 240 ° C., and the operation was performed at a screw speed of 400 rpm. The dry EVOH pellets obtained above were fed from the C1 resin feed port at a rate of 16 kg / hr and melted. Then, water and oxygen were removed from the vent 1, and epoxypropane was supplied from the C9 hydraulic inlet to 2.4 kg / hr. It was fed at a rate of hr (pressure during feeding: 6 MPa). Thereafter, unreacted epoxypropane was removed from the vent 2, and MFR = 2.8 g / 10 minutes (under a load of 190 ° C. and 2160 g), and the content of the structural unit (II) [specifically, the following structural unit] was 5 Resin A-1 which was mol% modified EVOH was obtained. The content of the structural unit (II) of the resin A-1 was calculated by the method described in JP-A-2006-233222. The obtained resin A-1 was rapidly solidified on a casting drum and formed into a film. Subsequently, it pelletized and the pellet for A layer (A-1a) was obtained.

2) Production of B-layer TPU pellets (B-1a) The number of hydroxyl groups per molecule obtained by reacting 1,4-butanediol and adipic acid is 2.0, and the number average molecular weight is 1. A mixture of 68.8% by weight of polyester diol, 27.5% by weight of 4,4-diphenylmethane diisocyanate, and 3.7% by weight of 1,4-butanediol was added to a multi-screw extruder (die temperature 260). Thermoplastic polyurethane resin TPU (B-1) (Shore A hardness: 85) was produced by melt-kneading at 20 ° C. for 20 minutes. Subsequently, it pelletized and the TPU pellet (B-1a) was obtained.

3) Production of resin 1 Using EVOH pellets (A-1a) and TPU pellets (B-1a), a multilayer structure having one A layer and two B layers alternately according to the resin composition constituting each pellet. In a three-layer feed block, a co-extruder is supplied in a molten state at 210 ° C., and is co-extruded and joined to form a multilayer laminate. The melted pellets (A-1a) and pellets (B-1a) to be joined are extruded by changing each layer flow path so that it gradually becomes thicker from the surface side toward the center side in the feed block. The multilayer structure was extruded so that the thickness of each layer was uniform. In addition, the slit shape was designed so that the layer thicknesses of the adjacent A layer and B layer were substantially the same. The thus obtained laminate composed of a total of 3 layers was rapidly cooled and solidified on a casting drum which was kept at a surface temperature of 25 ° C. and applied with static electricity. 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 are set so that the time from when the melted pellets (A-1a) and pellets (B-1a) join together to be rapidly cooled and solidified on the casting drum is about 4 minutes. did.

(Resin 2)
1) Manufacture of pellet for A layer (A-2a) Nylon 6 resin of "Ube nylon 1022B" manufactured by Ube Industries, Ltd. was used, and a film was formed after melt kneading. Subsequently, it pelletized and the pellet for A layer (A-2a) was obtained.

2) Production of Resin 2 Using EVOH pellets (A-2a) and TPU pellets (B-1a) used for the production of Resin 1, each of the A layers is alternately formed by the resin composition constituting the pellets. In a three-layer feed block, a molten state at 210 ° C. is supplied in a three-layer feed block so that a two-layer multilayer structure is formed. The melt of pellets (A-2a) and pellets (B-1a) to be merged is extruded by changing each layer flow path so that it gradually becomes thicker from the surface side toward the center side in the feed block. The multilayer structure was extruded so that the thickness of each layer was uniform. In addition, the slit shape was designed so that the layer thicknesses of the adjacent A layer and B layer were substantially the same. The thus obtained laminate composed of a total of 3 layers was rapidly cooled and solidified on a casting drum which was kept at a surface temperature of 25 ° C. and applied with static electricity. 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 are set so that the time from when the melted pellets (A-2a) and pellets (B-1a) join together to be rapidly cooled and solidified on the casting drum is about 4 minutes. did.

(Resin 3)
1) Production of EVOH pellets for layer A (A-3a) In a polymerization tank having a cooling device and a stirrer, 20,000 parts by mass of vinyl acetate, 1,020 parts by mass of methanol, and 2,2′-azobis- ( 4-Methoxy-2,4-dimethylvaleronitrile) was charged with 3.5 parts by mass, and after nitrogen substitution with stirring, ethylene was introduced, the internal temperature was adjusted to 60 ° C., the ethylene pressure was adjusted to 5.9 MPa, and the temperature was increased for 4 hours. Then, the pressure was maintained and stirred for polymerization. Next, 10 parts by mass of sorbic acid (SA) (0.05% by mass with respect to the charged vinyl acetate) was dissolved in methanol and added as a 1.5% by mass solution. The polymerization rate was 30% based on the charged vinyl acetate. This copolymerization reaction liquid was supplied to the purge and unreacted vinyl acetate was removed from the top of the tower by introducing methanol vapor from the bottom of the tower, and a 40 mass% methanol solution of this copolymer was obtained. This copolymer had an ethylene unit content of 44.5 mol% and a vinyl acetate unit content of 55.5 mol%.

  This methanol solution of the copolymer was introduced into a saponification reactor, and then a sodium hydroxide / methanol solution (85 g / L) was added so as to be 0.5 equivalent to the vinyl acetate component in the copolymer. Further, methanol was added to adjust the copolymer concentration to 15% by mass. The temperature inside the reactor was raised to 60 ° C., and the reaction was carried out for 5 hours while blowing nitrogen gas into the reactor. Thereafter, the reaction was stopped by neutralization with acetic acid, and the contents were taken out from the reactor and left at room temperature to precipitate in the form of particles. The operation of draining the precipitated particles with a centrifuge and adding a large amount of water to remove the liquid was repeated to obtain EVOH (A-3) having a saponification degree of 99.5%. Subsequently, it pelletized and the pellet for A layer (A-3a) was obtained.

3) Production of Resin 3 Using EVOH pellets (A-3a) and TPU pellets (B-1a) used for the production of Resin 1, each of the A layers was alternately 16 layers and B layers depending on the resin composition constituting the pellets. Was supplied in a molten state at 210 ° C. to a co-extruder in a 33-layer feed block so that a 17-layer multi-layer structure was formed, and co-extrusion was performed to join them to form a multi-layer laminate. The melt of pellets (A-3a) and pellets (B-1a) to be merged is extruded by changing each layer flow path so that it gradually becomes thicker from the surface side toward the center side in the feed block. The multilayer structure was extruded so that the thickness of each layer was uniform. In addition, the slit shape was designed so that the layer thicknesses of the adjacent A layer and B layer were substantially the same. The thus obtained laminate composed of a total of 33 layers was rapidly cooled and solidified on a casting drum which was kept at a surface temperature of 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 are set so that the time from when the melt of the pellet (A-3a) and the pellet (B-1a) merges to when rapidly solidified on the casting drum is about 4 minutes. did.

(Active energy ray irradiation)
An active energy ray (electron beam) having an acceleration voltage of 200 kV and an irradiation dose of 200 kGy was applied to each film formed as described above by an electron beam accelerator [manufactured by Nisshin High Voltage, model name “Curetron EB200-100”]. Line) was irradiated to obtain a multilayer structure.

(Manufacture of fragments 1-6)
The film formed with active energy ray irradiation was pulverized with a pulverizer to obtain pieces 1-6.
Ten pieces were randomly selected for each of the pieces 1 to 6, and cross-sectional observation was performed with DIGITAL MICROSCOPE VHX-900 (manufactured by KEYENCE) and electron microscope VE-8800 (manufactured by KEYENCE). The average layer thickness, average maximum length and average aspect ratio of each piece were measured, and the average value was calculated. The results are shown in Tables 1 and 2.

[Example 1]
An unvulcanized rubber composition for an inner liner was obtained by using a crushed piece 1 as a crushed piece of a multilayer structure irradiated with active energy rays and kneading with a Banbury mixer with the composition shown in Table 1.

[Example 2]
An unvulcanized rubber composition for an inner liner was obtained by using the crushed pieces 2 as the crushed pieces of the multilayer structure irradiated with active energy rays and kneading with a Banbury mixer with the composition shown in Table 1.

[Example 3 and Example 4]
The unvulcanized rubber composition for each inner liner is obtained by kneading with a Banbury mixer with the composition shown in Table 1, using the fragments 3 as fragments of the multilayer structure irradiated with active energy rays. Obtained.

Example 5
An unvulcanized rubber composition for an inner liner was obtained by using the crushed pieces 4 as the crushed pieces of the multilayer structure irradiated with active energy rays and kneading them with a Banbury mixer with the composition shown in Table 1.

Example 6
An unvulcanized rubber composition for an inner liner was obtained by using the crushed pieces 5 as the crushed pieces of the multilayer structure irradiated with active energy rays, and kneading with a Banbury mixer with the composition shown in Table 2.

Example 7
An unvulcanized rubber composition for an inner liner was obtained by using the crushed pieces 6 as the crushed pieces of the multilayer structure irradiated with active energy rays, and kneading with a Banbury mixer with the composition shown in Table 2.

[Examples 8 to 13]
The unvulcanized rubber composition for each inner liner is obtained by kneading with a Banbury mixer with the composition shown in Table 2, using the fragments 3 as fragments of the multilayer structure irradiated with active energy rays. Obtained.

[Comparative Example 1]
By kneading with a Banbury mixer with the composition shown in Table 1, an unvulcanized rubber composition for an inner liner was obtained.

[Comparative Example 3]
A rubber component having the composition shown in Table 1 and EVOH pellets were kneaded with a Banbury mixer to obtain an unvulcanized rubber composition for an inner liner.

[Comparative Example 4]
By kneading with a Banbury mixer with the composition shown in Table 1, an unvulcanized rubber composition for an inner liner was obtained.

<Evaluation>
An unvulcanized test piece obtained by calendering the obtained unvulcanized rubber composition was vulcanized at 160 ° C. for 50 minutes to obtain a vulcanized test piece. The obtained vulcanized test piece was measured for air permeation resistance.
Moreover, the inner liner was produced using the unvulcanized rubber composition for each inner liner of an Example and a comparative example. An inner liner produced as described above is wound on a molding drum, a carcass is pasted thereon, another tire member is further pasted to form a raw tire, and the raw tire is vulcanized. Then, a pneumatic tire having a size of 195 / 65R15 was produced by a conventional method. Using the obtained tire, appearance evaluation after a drum running test was performed, and crack resistance was evaluated from the evaluation result.
In Comparative Example 2, the air permeation resistance was measured using a modified EVOH (resin 1) produced based on Synthesis Example 3 of JP-A-2006-233222 instead of the vulcanized test piece. Using the plate-like body obtained by injection molding the modified EVOH (resin 1) as an inner liner, the appearance evaluation after the drum running test was performed in the same manner as in Example 1.
The results are shown in Tables 1 and 2.

(1) Air permeation resistance evaluation The vulcanized rubber obtained in Examples 1 to 13 and Comparative Examples 1 to 4 was air permeated at 60 ° C using an air permeation tester M-C1 (manufactured by Toyo Seiki Co., Ltd.) The contribution was measured. The air permeability of Comparative Example 1 was taken as 100, and the air permeability (JIS K 6275-1: 2009) was shown as an index. The smaller the index, the smaller the air permeability and the better the air permeation resistance.

(2) Evaluation of crack resistance The evaluation of crack resistance of the vulcanized rubber obtained in Examples 1 to 13 and Comparative Examples 1 to 4 was evaluated by appearance evaluation after a drum running test. Using the tires of Examples 1 to 13 and Comparative Examples 1 to 4, a CBU drum running test and a low temperature drum running test were performed, and the tires after each test were observed and checked to see if the tire was cracked.

(2-1) CBU Drum Running Test The CBU drum test is a drum test that is performed under conditions that can reproduce the failure of the cord breakage of the carcass ply at the upper part of the tire bead. Specifically, the tire was pressed with a load of 6 kN onto a drum having an air pressure of 140 kPa and a rotational speed corresponding to a speed of 80 km / h, and traveled 1,000 km at 23 ° C.

(2-2) Low temperature drum running test The tire was pressed at a load of 6 km on a drum having a pneumatic pressure of 140 kPa and a rotational speed corresponding to a speed of 80 km / h, and running at 1,000 km at 0 ° C.

The unit of the amount of each component of the rubber composition, the filler, the multilayer structure, the adhesive, and the various additive components shown in Tables 1 and 2 is “part by mass” unless otherwise specified. The unit of the content of the rubber component and crushed pieces in the rubber composition is “% by mass”.
The details of * 1 to * 13 shown in Tables 1 and 2 are as follows.
* 1: Modified EVOH produced according to Synthesis Example 3 of JP-A-2006-233222 was used.
* 2: Made by JSR, trademark: “JSR BROMOBUTYL 2255”
* 3: Flat clay [manufactured by J, M, Huber, registered trademark: “POLYFIL DL” (aspect ratio: 10)] (flat clay has a large aspect ratio of kaolin clay)
* 4: EF-F manufactured by Kuraray Co., Ltd.
* 5: Chlorosulfonated polyethylene (DuPont Dow Elastomer, Hypalon)
* 6: Made by Mu-ang Mai Guthrie Pubulic Company Limited, EPOXYPRENE 25
* 7: Epofriend (registered trademark), manufactured by Daicel
* 8: Asahi Carbon Co., Ltd., N660, trade name “Asahi # 55”
* 9: Softener (paraffinic oil, Idemitsu Kosan Paraffinic oil, trade name “Diana Process Oil PW-90”)
* 10: ESCOREZ 1102 manufactured by Exxon mobil chemical
* 11: Vulcanization accelerator [Noxeller DM-P, manufactured by Ouchi Shinsei Chemical Co., Ltd., registered trademark (di-2-benzothiazolyl disulfide)]

〔Evaluation results〕
As is clear from Tables 1 and 2, in Comparative Examples 1 and 4 in which the crushed pieces irradiated with active energy rays were not used together with the rubber component, the air permeation resistance was worse than that in the Examples. However, even if only the resin irradiated with active energy rays was used, although it was excellent in air permeation resistance, crack resistance was not obtained, and it was not possible to achieve both air permeation resistance and crack resistance ( Comparative Example 2). In addition, when a resin not irradiated with active energy rays was added to the rubber component, the air permeation resistance equivalent to that of Example 2 was obtained, but the crack resistance at low temperatures was not obtained (Comparative Example 3).

  On the other hand, in Example 2, since the fragment which irradiated the active energy ray to the rubber component is irradiated, the air permeation resistance is obtained and the crack resistance at low temperature is also obtained. As debris to be dispersed in the rubber composition, modified EVOH was used, or debris having a laminated structure having a total of 33 layers of the A layer and the B layer was used, whereby air permeation resistance superior to that of Example 2 was obtained. (Examples 1, 3 etc.). By providing an adhesive layer on the fragments 1 and 2 of Examples 1 and 2, the air permeation resistance is improved (Examples 5 and 6). In particular, in Example 6, the change is more than double that of Example 2. It was seen. Furthermore, by incorporating clay into the rubber composition, even better air permeation resistance was obtained even if the fragments did not have an adhesive layer (Example 4).

  The rubber composition of the present invention is useful for rubber products that require both air permeation resistance and crack resistance. For example, it is useful as a rubber composition for inner liners of various tires, and various pneumatic products for passenger cars, light trucks, light passenger cars, light trucks and large vehicles (trucks, buses, construction vehicles, etc.) It is suitably used as an inner liner for tires.

C1-C15 barrel

Claims (17)

A continuous phase that is a rubber component containing butyl rubber;
A dispersed phase that is a fragment of a multilayer structure irradiated with active energy rays,
The content of the butyl rubber in the rubber component is 50% by mass or more, and the multilayer structure is adjacent to the A layer made of a resin composition containing a gas barrier resin, and contains an elastomer. A rubber composition having a B layer made of an elastomer composition.   The A layer and the B layer are each one or more layers, and the total of the A layer and the B layer is three or more layers, and the average layer thickness per layer of the A layer is 0.001 μm or more and 30 μm. The rubber composition according to claim 1, wherein an average layer thickness per layer of the B layer is 0.001 μm or more and 40 μm or less.   The rubber composition according to claim 1 or 2, wherein an adhesive layer containing an adhesive is laminated on at least one of the outermost layers of the multilayer structure.   The rubber composition according to claim 3, wherein the adhesive is chlorosulfonated polyethylene, epoxidized natural rubber, or styrenic thermoplastic elastomer.   The rubber composition according to claim 3 or 4, wherein the adhesive is chlorosulfonated polyethylene.   The rubber composition according to claim 3 or 4, wherein the adhesive is a styrene-based thermoplastic elastomer.   The rubber composition according to any one of claims 1 to 6, wherein at least one selected from the group consisting of the resin composition and the elastomer composition contains a crosslinking agent.   The rubber composition according to any one of claims 1 to 7, wherein a content of the fragments of the multilayer structure is 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the butyl rubber.   The rubber composition according to claim 1, wherein an average thickness of the fragments of the multilayer structure is 10 μm or more and 200 μm or less.   The rubber composition according to any one of claims 1 to 9, wherein an average maximum length of the fragments of the multilayer structure is 2 µm or more and 2000 µm or less.   The rubber composition according to any one of claims 1 to 10, wherein an average aspect ratio of the fragments of the multilayer structure is 1 or more and 100 or less.   The gas barrier resin is at least selected from the group consisting of ethylene-vinyl alcohol copolymer, polyamide resin, polyester resin, polyvinylidene chloride, acrylonitrile copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, and polyvinyl alcohol. It is 1 type, The rubber composition of any one of Claims 1-11.   The elastomer is selected from the group consisting of polystyrene elastomers, polyolefin elastomers, polydiene elastomers, polyvinyl chloride elastomers, chlorinated polyethylene elastomers, polyurethane elastomers, polyester elastomers, polyamide elastomers, and fluororesin elastomers. The rubber composition according to claim 1, wherein the rubber composition is at least one kind.   The rubber composition according to any one of claims 1 to 13, further comprising a vulcanizing agent.   A rubber obtained by vulcanizing the rubber composition according to claim 14.   An inner liner using the rubber according to claim 15.   A pneumatic tire using the rubber according to claim 15.