JPH09226056A - Laminated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated body being suitable for a pneumatic tire with a layer preventing air from permeating such as e.g. an inner liner layer for holding pneumatic pressure const. SOLUTION: A laminated body of a laminated film and a rubber layer prepd. by providing the laminated film prepd. by providing a crosslinked rubber adhesive layer B formed of a polyolefin resin contg. a heat crosslinking agent on at least one surface of at least one kind of a gas barrier layer A selected from a group consisting of polyamide resins, polyester resins, polyarylate resins, polyamide alloys and polyester alloys, and sticking a rubber layer on at least one surface of the rubber adhesive layer B by heating, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate, and more particularly, to a laminate suitable for a pneumatic tire having an air permeation preventive layer such as an inner liner layer of a pneumatic tire that maintains a constant air pressure. .

[0002]

2. Description of the Related Art In recent years, there has been a strong demand to reduce the weight of machines powered by various fossil fuels such as automobiles in order to improve energy-saving awareness, prevent global warming by releasing carbon dioxide, and protect the global environment. Has been done.

Conventionally, for example, on the inner surface of a pneumatic tire, a halogenated butyl rubber having a relatively low gas permeability is used as an inner liner layer in order to maintain a constant air pressure. However, since halogenated butyl rubber has a large hysteresis loss, for example, when a tire as shown in FIG. 1 is vulcanized, a carcass layer inner surface rubber b is formed in a gap f between the carcass cords a and a.
When the inner liner layer c is wavy, the rubber of the inner liner layer is also deformed along with the deformation of the carcass layer, which causes a problem of increased rolling resistance. Therefore, generally, the inner liner layer (halogenated butyl rubber) c and the inner surface rubber b of the carcass layer are joined together via a rubber sheet called tie rubber having a small hysteresis loss. Therefore, the thickness of the inner surface layer of the product tire is obtained by adding the thickness of the tie rubber in addition to the thickness of the inner liner layer of halogenated butyl rubber to obtain a total layer thickness of 1
The thickness exceeds mm (1,000 μm). As a result, it is one of the causes of increasing the weight of the product tire.

In recent years, as a technique for reducing the weight of the inner liner layer of a tire, a pneumatic tire in which various non-breathable films are provided on the inner surface of the tire via an adhesive layer has been proposed.

However, when the tire is vulcanized at a normal temperature (passenger car tire surface of the inner liner layer is about 180 ° C.), the film made of a resin having a low melting point is melted and destroyed, so that the inner liner layer is destroyed. The vulcanization temperature must be lowered to a temperature at which the film does not melt, and it is necessary to extend the vulcanization time by that amount, and as a result, production efficiency is unavoidably reduced. On the other hand, in the case of a film made of a resin having a melting point of 180 ° C. or higher (for example, a polyamide resin or a polyester resin), when a large load is applied to the tire for a long time, the adhesive strength is insufficient, and thus the film may be peeled from the inside of the tire. there were.

[0006]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is, for example, to maintain air pressure of a tire at a constant air pressure, and to adhere to rubber disposed on the inner surface of the tire, heat resistance, and durability. It is intended to provide a laminate which has excellent properties and strength and can be suitably used as an inner liner layer of a pneumatic tire that can be reduced in weight.

[0007]

That is, the present invention provides at least one gas barrier layer (A) selected from the group consisting of polyamide resins, polyester resins, polyarylate resins, polyamide alloys and polyester alloys. At least one of which is provided with a cross-linked rubber adhesive layer (B) formed of a polyolefin resin containing a thermal crosslinking agent via an adhesive, and the rubber adhesive The present invention relates to a laminate of a laminated film and a rubber layer in which a rubber layer (R) is heat-bonded to at least one of the layers (B).

In the present invention, at least one gas barrier layer (A) selected from the group consisting of polyamide resins, polyester resins, polyarylate resins, polyamide alloys and polyester alloys is thermally crosslinked. A laminated film provided with a crosslinked rubber adhesive layer (B) formed by extrusion laminating a polyolefin resin containing an agent, and at least one of the rubber adhesive layer (B). The present invention relates to a laminate of a rubber film and a laminated film in which the rubber layer (R) is heat-bonded.

In the present invention, the adhesive layer (at least one of the gas barrier layers (A) selected from the group consisting of polyamide resin, polyester resin, polyarylate resin, polyamide alloy and polyester alloy ( By irradiating an electron beam from at least one side of a film having at least a two-layer structure in which C) is laminated, and further, at least one adhesive layer (C) is extrusion laminated with a polyolefin resin containing a thermal crosslinking agent. A laminated film having at least a three-layer structure, which comprises a formed and crosslinked rubber adhesive layer (B), and a rubber layer (R) is heat-bonded to at least one of the rubber adhesive layers (B). And a rubber layer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The gas barrier resin forming the gas barrier layer (A) having air pressure retention property according to the present invention is a polyamide resin, a polyester resin, a polyarylate resin, a polyamide alloy or a polyester resin. It is an alloy. These gas barrier resins are used alone or in combination of two or more.

Examples of polyamide resins include aliphatic polyamide resins, aromatic polyamide resins, amorphous polyamide resins, and blends thereof.

The aliphatic polyamide resin may be one having a structure having no aromatic ring in the main chain and / or side chain. Specifically, nylon 6, nylon 66, nylon 610, polyamide such as nylon 12, nylon 6-
Examples include copolyamides such as 66 copolymers and nylon 6-610 copolymers, and polyamide elastomers such as nylon 66-polyethylene glycol block copolymers and nylon 6-polypropylene glycol block copolymers.

The aromatic polyamide resin may have a structure having an aromatic ring in its main chain and / or side chain. Specifically, a polyxylylene polymer obtained by polycondensation of meta or paraxylylenediamine and a dicarboxylic acid having about 4 to 12 carbon atoms can be exemplified. Such a polymer has characteristics such as gas barrier properties, low water absorption, and low moisture permeability.

Amorphous polyamide resins are collectively referred to as those having no crystallinity or those having poor crystallinity.
There is no particular limitation. Generally, a semi-aromatic polyamide resin having an aromatic ring in the main chain and / or side chain can be exemplified. Specific examples thereof include a polymer of a dicarboxylic acid such as terephthalic acid and isophthalic acid and a diamine such as hexamethylenediamine, and a terpolymer. Such an amorphous polyamide resin has an excellent gas barrier property at high humidity.

As the polyester resin, a polyester resin composed of a dicarboxylic acid component and a diol component can be used.

Here, examples of the dicarboxylic acid component include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic dicarboxylic acids and the like, and mixtures thereof. Specifically, as the aliphatic dicarboxylic acid, adipic acid having 2 to 20 carbon atoms, sebacic acid, dodecanecarboxylic acid and the like, and as the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid,
Examples thereof include naphthalene dicarboxylic acid, and examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid.

Examples of the diol component include aliphatic glycols, alicyclic glycols and the like, and mixtures thereof. Specific examples of the aliphatic glycols include ethylene glycol, 1,3-propanediol and 1,4- Examples are butanediol, 1,6-hexanediol, 1,10-decanediol, and the like, and examples of alicyclic glycol are 1,4-cyclohexanediol and the like.

Further, polyester-based elastomers such as polybutylene terephthalate-polytetramethylene oxide glycol block copolymer and polybutylene terephthalate-polycaprolactone block copolymer are also included in the polyester-based resin according to the present invention.

Examples of the polyarylate resin include polyesters composed of a divalent phenol and an aromatic dibasic acid, and specific examples thereof include a polymer composed of bisphenol A and terephthalic acid / isophthalic acid. .

As the above-mentioned polyamide-based alloy and polyester-based alloy, at least one selected from the group consisting of the above-mentioned polyamide-based resin and polyester-based resin becomes a sea component, and an appropriate thermoplastic resin such as polyphenylene is used. As one component selected from the group consisting of ether (PPE), polyarylate (PAR) and polycarbonate (PC) becomes the island component (the sea component and the island component described above may be reversed). If necessary, a polymer alloy obtained by kneading in the presence of a compatibilizer can be mentioned. Specifically, a polyphenylene ether / polyamide alloy having a uniform sea-island structure, a polyarylate / polyamide alloy, Polycarbonate / polyamide alloy, polyphenylene ether / polyester alloy It can be exemplified as preferred polyarylate / polyester type alloy and a polycarbonate / polyester alloy. At this time, if necessary, an appropriate third component may be added to each of the polyamide resin, polyester resin, polyarylate resin, and each alloy. Further, rather than the alloy having a sea-island structure described above, it is possible that a polymer blend having a structure such as a polymer blend may be used.
In the present invention, these are also included in the category of alloys.

The above-mentioned compatibilizer is not particularly limited, and a certain block or random copolymer having an affinity for the sea component and the island component, and further styrene-
Examples thereof include a maleic anhydride copolymer, a polyphenylene ether-maleic anhydride modified product, an arylate-maleic anhydride copolymer, and an epoxy group-containing styrene-based polymer. The addition amount thereof is not particularly limited, but for example, at least one selected from the group consisting of a polyamide resin and a polyester resin, and an appropriate thermoplastic resin such as polyphenylene ether (PPE) and polyarylate ( 1 to 5 relative to the total amount of at least one selected from the group consisting of PAR) and polycarbonate (PC).
For example, it can be about wt%. Here, nylon 6 and nylon 66 are preferable as the polyamide resin, and polybutylene terephthalate (PBT) and polyethylene terephthalate (PET) are preferable as the polyester resin, but they are not particularly limited. Examples of the polyphenylene ether (PPE) include polymers having an ether bond containing poly (2,6-dimethylphenylene oxide) as a main component. As mentioned above, examples of the polyarylate include polyesters composed of divalent phenol and aromatic dibasic acid, for example, polyesters composed of bisphenol A and terephthalic acid / isophthalic acid. Examples of the polycarbonate include those obtained by the interfacial polycondensation reaction of Na salt of bisphenol A and phosgene, those obtained by the transesterification method of bisphenol A and diphenyl carbonate, and the like.

The rubber adhesive layer (B) according to the present invention may be one that adheres to the rubber layer on the inner surface of the tire. Examples of the polyolefin resin constituting the rubber adhesive layer (B) include homopolymers of olefins, interpolymers, and other copolymerizable substances such as copolymers with other vinyl monomers and the like. These mixtures and homopolymers or copolymers of the above polyolefins are copolymerized with, for example, unsaturated carboxylic acids such as maleic acid, fumaric acid, acrylic acid or their acid anhydrides, derivatives such as esters or metal salts, for example, graft copolymers. Representative examples include modified polymers polymerized and modified polymers such as ethylene-glycidyl methacrylate-methyl acrylate terpolymer and ethylene-methyl acrylate-maleic anhydride terpolymer. In this case, a mixture of the modified polymer and other components such as an unmodified polyolefin resin is also within the range of the modified polymer as used herein. Further, these resins may be used as a mixture of two or more kinds.

The above-mentioned polyolefin resin, for example,
Specific examples of olefin homopolymers, interpolymers, other copolymerizable products, and copolymers with other vinyl monomers include polyethylenes of various densities ranging from low density to high density [wire Low density polyethylene (LLDP
E), including ultra low density polyethylene (VLDPE). ], Polypropylene, polybutene, polyoctene and their mutual copolymers, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EA)
A), ethylene-methyl acrylate copolymer (EM
A), ethylene-methyl methacrylate copolymer (EM
MA), ethylene-methacrylic acid copolymer (EMA
Examples include unmodified ones such as A). In the present invention, these polyolefin resins may be used alone or in combination of two or more.

Further, a mixture of a polyolefin resin and an elastomer, for example, an ethylene-propylene elastomer, a styrene elastomer, etc. is also included in the category of the polyolefin resin of the present invention. In addition, as such a rubber adhesive layer, the above-mentioned unmodified polyolefin-based resin can be used if necessary.

As the thermal crosslinking agent contained in advance in the polyolefin resin forming the rubber adhesive layer (B), any conventionally known one can be used as long as it is a compound capable of crosslinking by heat. Examples of such thermal crosslinking agents include dicumyl peroxide, t-butylperoxybenzoate, t-butylcumyl peroxide, 2,5
-Dimethyl 2,5-di (t-butylperoxy) hexane, 2,5-dimethyl 2,5-di (t-butylperoxy) hexyne-3, α, α-bis (t-butylperoxy)- Di-isopropylbenzene etc. can be illustrated. Among these, dicumyl peroxide is preferable. The content of the thermal cross-linking agent is not particularly limited, but may be about 1 to 10% by weight, preferably about 1 to 5% by weight, based on the total amount including the resin. At this time, if the content of the thermal crosslinking agent is less than 1% by weight, the crosslinking tends to be insufficient. On the contrary, if it exceeds 10% by weight, the viscosity of the molten resin is increased due to the crosslinking reaction occurring inside the molding machine during film formation. It tends to rise and become difficult to mold.

The crosslinking efficiency can be increased by using a thermal crosslinking agent together with a crosslinking aid, if necessary. The cross-linking aid is not particularly limited, but specific examples thereof include ethylene glycol dimethacrylate, trimethylolpropane trimetallate, triallyl cyanurate, and triallyl isocyanurate. The amount of the crosslinking aid used is not particularly limited, but is usually about 1 to 5% by weight, preferably 1 to 3% by weight, based on the total amount including the resin and the crosslinking agent.
The degree can be illustrated.

The resin forming the adhesive layer (C) for adhering the rubber adhesive layer (B) and the gas barrier layer (A) according to one embodiment of the present invention is not particularly limited, but, for example, an adhesive resin may be used. This can be exemplified by, for example, a polyolefin resin of a homopolymer or a copolymer of the above olefins, for example, an unsaturated carboxylic acid such as maleic acid, fumaric acid or acrylic acid, or an acid anhydride thereof, a derivative such as an ester or a metal salt thereof. Copolymerization, for example, graft copolymerized modified polymers and modified polymers such as ethylene-glycidyl methacrylate-methyl acrylate terpolymers and ethylene-ethyl acrylate-maleic anhydride terpolymers are exemplified as typical ones. it can. At this time, the modified polymer and other components,
For example, a mixture with another polyolefin resin is also within the range of the modified polymer as referred to herein. In addition, an unmodified polyolefin resin or the like can be used as the adhesive layer. Further, these adhesive layers may be used as a mixture of two or more kinds of resins, or may be divided into two layers to have a structure such as (C ₁ ) and (C ₂ ) layers. As the adhesive layer (C), it is possible to use an appropriate adhesive or the like.

Further, at this time, as an example of dividing the adhesive layer (C) into two layers, the modified polymer is used as the adhesive layer (C ₁ ) and the unmodified polyolefin resin is used as the adhesive layer (C ₂ ). At least one of the gas barrier layers (A) (C ₁ )
It is also possible to successively stack layers, followed by (C ₂ ) layers.

The adhesive used for adhering the rubber adhesive layer (B) and the gas barrier layer (A) according to one embodiment of the present invention is not particularly limited, but is generally a dry laminating method or the like. Examples of the adhesive to be used include polyol / polyisocyanate-based, polyol / NCO-terminated prepolymer-based or OH-terminated prepolymer / NCO-terminated prepolymer-based polyurethane two-component adhesives.

The thickness of the adhesive may be such that the rubber adhesive layer (B) and the gas barrier layer (A) can be adhered, and is preferably 3 μm (solid content) or less. If it exceeds 10 μm, the possibility that defects will be formed in the applied adhesive layer increases, and cohesive failure of the adhesive tends to occur.

The rubber layer (R) according to the present invention (corresponding to the carcass layer (2) in FIG. 3) is not particularly limited, but a diene rubber and its hydrogenated product (for example, natural rubber, polyisoprene rubber, Epoxidized natural rubber, styrene-butadiene copolymer rubber, polybutadiene rubber (high cis B
R and low cis BR), NBR, hydrogenated NBR, hydrogenated S
BR), various elastomers such as olefin rubber (eg ethylene propylene rubber (EPRM, EP
M), maleic acid-modified ethylene propylene rubber (ME
PM), IIR, isobutylene and aromatic vinyl or diene monomer copolymer), halogen-containing rubber (eg brominated butyl rubber, chlorinated butyl rubber, isobutylene paramethylstyrene bromide (Br-IPM)
S), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM), thermoplastic elastomer (for example, styrene elastomer, olefin elastomer, ester elastomer), etc. An example is a rubber composition containing a compounding agent such as black, process oil or a vulcanizing agent. It is sufficient for the rubber layer (R) to be composed of only the rubber layer, but it is also possible to embed a reinforcing material such as a carcass cord in the rubber layer. Is a category of the rubber layer according to the present invention. Further, it goes without saying that an appropriate material may be provided on the surface of the rubber layer opposite to the surface that is heat-bonded to the laminated film. The carcass layer 2 includes a carcass cord rubber portion (b) and a carcass cord portion (a). However, in the description of the tire, the carcass layer (2) includes the carcass cord rubber portion (b) and the carcass cord rubber portion (a). It shall be treated as equivalent to the layer (R).

The structure of the pneumatic tire according to the present invention will be described in detail with reference to FIG.

FIG. 2 is a meridional direction sectional view illustrating a pneumatic tire according to the present invention.

In FIG. 2, a pair of left and right bead cores 1,
The carcass layer 2 is mounted between the two. An inner liner layer 3 is provided on the inner surface of the tire inside the carcass layer 2. On the other hand, a sidewall 4 is provided outside the carcass layer 2.

FIG. 3 is an enlarged view of portion X in FIG. The inner liner layer 3 is formed by coating an adhesive agent on both sides of an appropriate gas barrier resin gas barrier layer (A), and further by forming a thermal crosslinking agent-containing polyolefin resin on the outside thereof.
It has a laminated structure in which a crosslinked rubber adhesive layer (B) is provided and is bonded to the carcass layer 2 via the rubber adhesive layer (B).

Rubber adhesive layer (B) of the laminate according to the present invention
Since it is made of a polyolefin resin, depending on the type thereof, the polyolefin resin may melt and the film may be broken at the temperature at which the rubber is vulcanized. In order to prevent this, the rubber adhesive layer (B) of the laminated film according to the present invention needs to be crosslinked and reinforced. As a method of cross-linking, a method of forming a surface layer on at least one side of the laminate, adding a thermal cross-linking agent to the polyolefin resin, and simultaneously performing thermal cross-linking during rubber vulcanization may be adopted.

The thickness of the laminated film according to the present invention is 10
˜300 μm, preferably 25 to 200 μm, and more preferably 50 to 150 μm. When it is less than 10 μm, the air permeability becomes large, and when it is used for an inner liner layer of a pneumatic tire, for example, the air pressure retention property tends to be low and the tire air pressure cannot be kept constant. If it exceeds, there is a tendency that good flexibility cannot be maintained, but there is no particular limitation, and it goes without saying that the above range may be exceeded if necessary.

At this time, the thickness of the rubber adhesive layer (B) adhered to the rubber is 5 to 200 μm, preferably 10
˜100 μm, more preferably 15 to 80 μm. If it is less than 5 μm, the adhesive force with rubber will be reduced to 200
If it exceeds μm, it tends to be hard, which is not preferable. In the case of laminating with an adhesive, the coating thickness is sufficient as long as the rubber adhesive layer (B) and the gas barrier layer (A) can be adhered to each other, and can be typically 3 μm (solid content) or less. The thickness of the layer (C) can be usually about 3 μm or less. Further, the thickness of the gas barrier layer (A) may be, for example, a thickness capable of keeping the tire air pressure constant,
It is preferably 3 μm or more, and more preferably 3 to 50 μm. If it is less than 3 μm, the air pressure retention will be reduced,
There is a tendency that the tire pressure cannot be kept constant, but the thickness of each of these layers (A), (B) and (C) and the adhesive coating thickness may deviate from the above range depending on the application. Of course.

The thickness of the rubber layer (R) bonded to the rubber adhesive layer (B) depends on the application and is not particularly limited. For example, when used as a carcass layer of a tire,
An example is 0.5 to 2.0 mm.

In a preferred embodiment of the laminate according to the present invention, a rubber adhesive layer (B) made of a polyolefin resin containing a thermal crosslinking agent is bonded to at least one surface of the gas barrier layer (A) via an adhesive. (A) // (B), which comprises a laminated film having at least a two-layer structure in which at least one surface of the rubber adhesive layer (B) is heat-bonded to the rubber layer (R). / (R), (B) /
/ (A) // (B) / (R), (R) / (B) //
An aspect having a configuration such as (A) // (B) / (R) can be exemplified as a preferable one. Here, // means that the layers are laminated via an adhesive.

In another preferred embodiment, at least one of the gas barrier layers (A) is provided with a crosslinked rubber adhesive layer (B) formed by extrusion laminating a polyolefin resin containing a thermal crosslinking agent. A laminated film, and a rubber layer (R) heat-bonded to at least one of the rubber adhesive layers (B) (A) //
(B) / (R), (B) // (A) // (B) /
(R), (R) / (B) // (A) // (B) / (R)
An embodiment having such a constitution can be exemplified as a preferable one. Here, // represents lamination by the extrusion laminating method. At this time, when the lamination strength is insufficient only by the extrusion laminating method, an anchor coat or the like may be previously applied to the film forming the gas barrier layer.

In another preferable embodiment, an electron beam is irradiated from at least one surface of a film having at least two layers having an adhesive layer (C) on at least one of the gas barrier layers (A), and further, the above-mentioned. A crosslinked rubber adhesive layer (B) formed by extrusion laminating a polyolefin resin containing a thermal crosslinking agent onto at least one adhesive layer (C) of the gas barrier layer (A) having an adhesive layer (C) on at least one side. ) Is provided, and the rubber layer (R) is heat-bonded to at least one of the rubber adhesive layers (B) [(A) / (C)]. ] ← // (B) / (R),
(R) / (B) // → [(C) / (A) / (C)] ← /
/ (B) / (R), [(A) / (C ₁ ) / (C ₂ )] ← /
/ (B) / (R), (R) / (B) // → [(C ₂ ) /
(C ₁ ) / (A) / (C ₁ ) / (C ₂ )] ← // (B) /
A preferred embodiment is one having a configuration such as (R). Here, // represents lamination by the extrusion laminating method, and [] represents electron beam irradiation. Further, → or ← indicates the direction of electron beam irradiation. The reason why the electron beam irradiation is performed here is (C), (C ₁ ) and (C ₂ )
This is to improve heat resistance, since a material containing a thermal crosslinking agent is not used.

When a tire is manufactured using the above-mentioned laminated body, the laminated body of the present invention is placed on the inner surface of the tire by, for example, the method described below, and vulcanized and molded by an appropriate method.

Next, a method for producing a laminated film constituting the laminated body of the present invention will be described.

For laminating by a dry laminating method, for example, the rubber adhesive layer (B) is adhered to a film made of a polyolefin resin containing a heat-crosslinking agent by an appropriate known method (gravure printing machine etc.). An appropriate publicly known method (gravure printing machine) is applied to a film forming the gas barrier layer (A) formed in a separate step while applying the agent, or conversely to a film including the gas barrier layer (A). etc)
A dry laminating method is preferred in which a film made of a polyolefin resin containing a thermal cross-linking agent that forms the rubber adhesive layer (B) is adhered by applying heat and pressure while applying the adhesive.

At this time, each film is separately
For example, the film may be formed as a tubular film by the inflation method or a flat film by the T-die method without any particular limitation. Further, these films may be stretched if necessary. Examples of the stretching method include a method of performing film formation-cooling and then reheating, and sequential biaxial stretching, simultaneous biaxial stretching, a tubular stretching method, and longitudinal and transverse methods in which film formation is followed by continuous stretching. Examples of the method include a method in which the stretching is performed in a separate step, a melt stretching method, and the like, and the stretching may be performed at an appropriate stretching temperature and stretching ratio. Furthermore, you may heat-fix by a well-known appropriate method as needed.

For lamination by the extrusion laminating method, a film forming the gas barrier layer (A) may be extrusion laminated with a polyolefin resin containing a thermal crosslinking agent to form a rubber adhesive layer (B) before crosslinking. In this case, it is desirable to use, for example, a modified polymer as the polyolefin resin. In order to further improve the adhesiveness, it is perfectly acceptable to preliminarily apply an anchor coat or the like to the film surface forming the gas barrier layer (A). At this time, the material used for the anchor coat or the like is not particularly limited.

Further, a laminated film having an adhesive layer (C) on at least one of the films forming the gas barrier layer (A) is prepared, and electron beam irradiation or the like is performed from at least one surface of the laminated film to prepare the laminated film in advance. After improving the heat resistance of such a laminated film, a polyolefin resin containing a thermal crosslinking agent may be extrusion laminated to be laminated.

At this time, the gas barrier resin and the resin forming the adhesive layer are coextruded to prepare a laminated film having the gas barrier layer (A) and the adhesive layer (C), and the (C) layer surface is formed. By extrusion laminating a polyolefin resin containing a thermal crosslinking agent, (A) / (C) / (B) before crosslinking,
It is also possible to prepare a laminated film comprising (B) / (C) / (A) / (C) / (B) before crosslinking, and various modes are adopted for extrusion lamination. You can also Here, the coextruded (A) /
In the laminated film of (C), it is difficult to add a thermal crosslinking agent to the (C) layer because the extrusion temperature of the (A) layer is high. It is desirable that the rubber be imparted to the rubber layer so that it can withstand the vulcanization of the rubber layer in the subsequent step.

Further, a laminated film is formed by forming two layers of an adhesive layer (C ₁ ) and an adhesive layer (C ₂ ) as an adhesive layer (C) on at least one of the films constituting the gas barrier layer (A). It is also possible to form a laminated film by subjecting it to electron beam irradiation or the like from at least one surface of the laminated film to improve the heat resistance of the laminated film in advance, and then laminate the polyolefin resin containing a thermal crosslinking agent by extrusion lamination. .
At this time, the (C ₁ ) layer is a modified polymer, and the (C ₂ ) layer is
It is preferably composed of an unmodified polyolefin resin, but there is no particular limitation.

Such a laminated film formed by the extrusion laminating method may be stretched or heat-fixed at any stage, if necessary, in the same manner as described above, and the method is the same as that described above. It can be illustrated.

Here, as the above-mentioned method of crosslinking, a method of irradiating with an electron beam from at least one surface of the laminated film, preferably from both surfaces, is desirable. At this time, it is particularly preferable to irradiate from both sides in the above-mentioned laminated film having a structure having (C) layers on both surfaces.

Further, it is possible to use together with a technique of adding an electron beam cross-linking agent such as triallyl isocyanurate, triallyl cyanurate, trimethylolpropane trimethacrylate to an appropriate layer of the laminated film. There is no limitation, but it is preferable to use 100 materials for each layer.
An amount of 1 to 5 parts by weight can be given as an example. When the electron beam cross-linking agent is also used in this way, it is possible to reduce the electron beam irradiation amount and the like.

The electron beam irradiation has an acceleration voltage of, for example, 50 kV or more, preferably 150 to 250 kV, more preferably 200 to 200, from at least one surface of the laminated film.
Irradiation at 250 kV, the irradiation dose is 80 Mrad or less, preferably 0.1 to 50 Mrad, more preferably 1 to 20.
Irradiation is preferably performed within the range of Mrad.

Here, when the accelerating voltage is low, there is a tendency that a uniform dose is not obtained from the front surface to the back surface, but the above values are not particularly limited.
It may be appropriately selected in consideration of the thickness of the film, the resin used, and the like so as to obtain a preferable irradiation intensity. If the irradiation amount is too large, the adhesiveness with the rubber layer tends to decrease.

The adhesive film (C), the adhesive layer (C ₁ ), the adhesive layer (C ₂ ) and the like of the laminated film irradiated with an electron beam are crosslinked as necessary to improve the strength and heat resistance of the film. To do.

Next, the laminated films need to be crosslinked by heat in order to improve heat resistance and strength and adhesiveness.

As a method of crosslinking, when a pneumatic tire is manufactured, the heat-crosslinking agent-containing rubber adhesive layer (B) of the laminated film is laminated so as to be in contact with unvulcanized green rubber, and thus prepared. A method of inserting the green tire into a mold and heating and vulcanizing it can be exemplified.

The above-mentioned cross-linked laminated film is, in particular,
A layer made of a polyolefin resin containing a thermal crosslinking agent is crosslinked, and the crosslinked rubber adhesive layer (B) has improved strength, heat resistance, adhesion to the rubber layer (R), impact resistance and the like.

In the case of producing the pneumatic tire according to the present invention as described above, the laminated film is wound around a tire building drum, and then a carcass layer, a sidewall, a bead core and a bead filler, a steel belt layer, a tread are prepared in a conventional manner. Rubber is laminated to form a green tire made of unvulcanized rubber. Then, the green tire is inserted into a mold and vulcanized and molded by an ordinary method to form an inner liner layer 3 on the tire inner surface of the carcass layer 2.
Can be provided.

At this time, in the present invention, a new rubber layer (R) using tie rubber or the like is provided between the carcass layer and the adhesive layer (C).
It is also possible to add, and in the case of such a structure, "carcass layer (2) / rubber layer (R) / adhesive layer (B) ...", and in some cases the rubber layer (R) has a double structure. is there.

In particular, a rubber adhesive layer (B) made of a polyolefin resin containing a crosslinking agent on both outer sides of the laminated film.
In the case of providing, for example, as shown in FIG.
In the overlapping portion 5 of the inner liner layer 3, the rubber adhesive layers (B) made of a polyolefin resin containing a thermal cross-linking agent come into contact with each other and are firmly adhered by heating, further improving air pressure retention. be able to. In addition, since the bladder inserted inside the tire does not come into direct contact with the gas barrier layer (A) during vulcanization molding, the gas barrier layer (A) can be protected thermally and mechanically. .

As another tire molding method, the laminated film used as the inner liner layer is laminated with the carcass layer 2 in advance, and the film / carcass layer in the pre-laminated state is wound around the tire molding drum, and then according to a conventional method. , A carcass layer, a sidewall, a bead core and a bead filler, a steel belt layer, and a tread rubber are laminated to form a green tire made of unvulcanized rubber. Next, the green tie is inserted into a mold, vulcanized and molded by a usual method, and heat-bonded.

In this case, by providing the rubber adhesive layers (B) on both outer sides of the laminated body, as shown in FIG. 5, the gas barrier layer (A) is replaced by the carcass in the superposed portion 5 of the inner liner layer 3. Since it is possible to avoid direct adhesion with the layer 2, good adhesion can be obtained.

The drawings of FIGS. 3 to 5 shown in the present invention are examples showing a preferable tire structure. For example, a layer (C) is interposed between a layer (A) and a layer (B). Needless to say, the layer structure is not particularly limited to the above drawings.

The inner liner layer described above is the air permeation preventive layer as described above, and may be provided in the middle portion of the pneumatic tire without being restricted by the word "inner".

The laminate of the present invention is excellent in strength, adhesive strength of rubber layer, air permeability (gas barrier property), heat resistance, impact resistance and the like. For example, an inner layer of a pneumatic tire (eg inner liner layer). + When used as a carcass layer), the pneumatic tire can be reduced in weight.

The preferred embodiments of the present invention have been illustrated above, and it goes without saying that the present invention can take any embodiment without being limited to the description.

[0069]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

Example 1 A thermal cross-linking agent (Mitsui Petrochemical Industry Co., Ltd.) was applied to both surfaces of the film constituting the gas barrier layer (A) made of nylon 66.
Manufactured by dicumyl peroxide "Mitsui DCP") 100 parts by weight of ethylene-ethyl acrylate-maleic anhydride terpolymer containing 3 parts by weight of polyurethane is used as the film constituting the rubber adhesive layer (B) before crosslinking. The film was laminated by a dry laminating method using a system adhesive to obtain a film having a three-layer structure. The thickness of the laminate film is (B) before crosslinking / (A) / (B) before crosslinking = 20/40 / 20μ
It was m = 80 μm.

The obtained laminated film was used as an inner liner layer, and an unvulcanized tire laminated with the carcass layer (2) in the tire was vulcanized at 180 ° C. for 10 minutes to vulcanize the rubber adhesive layer (B) and the carcass layer. (2) and (2) were heated and bonded, and at the same time, the rubber adhesive layer was crosslinked to obtain a finished tire. The tire size was 185 / 65R14. The results of the visual observation of the tire thus obtained, the visual observation after the indoor endurance test, the air leakage test and the tire weight are shown in Table 1 below.

The rubber composition used for the carcass layer is
The carcass layer has the composition shown in Table 2 below. The carcass layer was produced by coating both surfaces of the aligned polyester cord with the rubber composition.

In the examples of the present invention, each test item was measured and evaluated by the following methods.

[Observation after vulcanization]: The inner surface of the tire after vulcanization was visually confirmed, and those with no abnormalities were marked with ◯, those with abnormalities were marked with x, and abnormalities were found. For, the state was also shown.

[Observations after Indoor Durability Test]: A tire indoor durability test was conducted under the following conditions and methods, and the inner surface of the tire after the test was visually inspected. What was observed was marked with x, and when a failure was seen, its state was also shown.

The conditions, methods and criteria for the durability test are shown below.

Rim: 14 × 5 1 / 2-J Air pressure: 140 kPa Load 6 kN Room temperature: 38 ° C. Diameter 1707 mm Running on drum at speed 80 km / h After running 10,000 km, visually inspect tire inner surface for cracks, cracks, peeling, The one in which the float was found was rejected.

[Air leak test]: A tire (stationary state) was mounted on a rim of size 14 × 5 1 / 2-J at room temperature of 21 ° C., and then left at an internal pressure of 200 kPa for 48 hours to give an internal pressure of 20.
Readjusted to 0 kPa. Immediately after readjustment, the internal pressure was measured every 4 days for 3 months, starting from the start of measurement.

Measurement pressure Pt, initial pressure P0, elapsed days t
As the air leakage coefficient α
I asked.

[0080]

[Equation 1]

Then, by substituting t = 30 days, the internal pressure decrease rate (% / month) β per month was calculated according to the following mathematical formula 2.

[0082]

[Equation 2]

Comparative Example 1 A tire was prepared in the same manner as in Example 1 except that the rubber adhesive layer (B) did not contain a thermal crosslinking agent, and the tire was visually inspected. The tire after the indoor durability test was visually inspected. Table 1 shows the results of the findings, air leakage test, and tire weight.

Comparative Example 2 An inner liner layer (thickness: 500 μm) made of unvulcanized butyl rubber having the composition shown in Table 3 below was provided on the inner surface of a green tire through a tie rubber having a thickness of about 700 μm. Table 1 shows the results of vulcanization and production under the same conditions as in Example 1, visual observation of the tire after completion of vulcanization, visual observation of the tire after an indoor endurance test, air leakage test, and tire weight. .

[0085]

[Table 1]

[0086]

[Table 2]

[0087]

[Table 3]

As is apparent from Table 1, in the tire of Example 1, no failure was found in the inner liner layer even after the vulcanization failure and the indoor durability test, and the air leakage performance was the same as the inner liner layer made of butyl rubber. Equal or better. Also, the thickness of the inner liner layer could be reduced to 1/5, and as a result, the weight of the tire was 7.
It was possible to reduce the weight by 6%.

Comparative Example 1 in which the rubber adhesive layer did not contain a thermal crosslinking agent was unsuitable because the B layer melts and fractures after vulcanization.

Example 2 Anchor coat (Dainippon Ink and Chemicals LX90)
Ethylene containing the same amount of the same thermal crosslinking agent as in Example 1 on both sides of the film constituting the gas barrier layer (A) made of nylon 66 having both sides coated with 1 / KW75 = 6/1).
Rubber adhesive layer (B) made of vinyl acetate copolymer before crosslinking
The resin constituting the above was laminated by an extrusion laminating method to obtain a film having a three-layer structure. The thickness of the laminate film is (B) before crosslinking / (A) / (B) before crosslinking = 20/40 /
20 μm = 80 μm.

The obtained laminated film was used as an inner liner layer, and an unvulcanized tire laminated with the carcass layer (2) was vulcanized at 180 ° C. for 10 minutes to vulcanize the rubber adhesive layer (B) and the carcass layer (2). ) And heat-bonding
A completed tire was obtained by crosslinking the rubber adhesive layer (B). The results of the visual observation of the tire thus obtained, the visual observation after the indoor endurance test, the air leakage test, and the tire weight are shown in Table 4.

Comparative Example 3 Except that the rubber adhesive layer (B) did not contain a thermal crosslinking agent,
A tire was prepared in the same manner as in Example 2, and the results of the visual observation of the tire, the visual observation of the tire after the indoor endurance test, the air leakage test, and the tire weight are shown in Table 4.
It was shown to.

[0093]

[Table 4]

As is clear from Table 4, in the tire of Example 2, no failure was found in the inner liner layer even after the vulcanization failure and the indoor durability test, and the air leakage performance was the same as the inner liner layer made of butyl rubber. Equal or better. Also, the thickness of the inner liner layer could be reduced to 1/5, and as a result, the weight of the tire was 7.
It was possible to reduce the weight by 6%.

Comparative Example 2 in which the rubber adhesive layer did not contain a thermal crosslinking agent was unsuitable because the layer (B) was melted and destroyed after vulcanization.

Example 3 The combination of the film constituting the gas barrier layer (A) and the adhesive layer (C) is shown in Table 5, and the layer (C) is coextruded on both sides of the layer (A) to form a three-layer structure. A laminated film of was obtained. Then, from both sides of the film, accelerating voltage 200 k
An electron beam with V and a dose of 5 Mrad was irradiated. Furthermore, an ethylene-vinyl acetate copolymer containing the same amount of the same thermal crosslinking agent as in Example 1 was laminated on both sides of the laminated film by an extrusion laminating method to obtain a film having a five-layer structure. The thickness of the laminated film is (B) / (C) / (A) / (C) before crosslinking.
/ (B) before crosslinking = 20/5/40/5/20 = 90μ
m.

The obtained laminated film was used as an inner liner layer, and the unvulcanized tire laminated with the carcass layer (2) was vulcanized at 180 ° C. for 10 minutes to be vulcanized to the rubber adhesive layer (B) and the carcass layer (2). (1) and (2) are heat-bonded to each other, and at the same time, the rubber adhesive layer (B) is crosslinked to obtain a finished tire. The results of the visual observation of the tire thus obtained, the visual observation after the indoor endurance test, the air leakage test and the tire weight are shown in Table 5.

Comparative Example 4 A tire was prepared in the same manner as in Example 3 except that the rubber adhesive layer (B) did not contain a thermal crosslinking agent, and the tire was visually inspected. The tire after the indoor durability test was visually inspected. Table 5 shows the results according to the findings, air leakage test, and tire weight.

Comparative Example 5 A tire was manufactured in the same manner as in Example 3 except that no electron beam irradiation was applied, and the visual observation of the tire, the visual observation of the tire after the indoor endurance test, the air leakage test and the The results of tire weight are shown in Table 5.

[0100]

[Table 5]

As is clear from Table 5, in the tire of Example 3, no failure was found in the inner liner layer even after the vulcanization failure and the indoor durability test, and the air leakage performance was the same as the inner liner layer made of butyl rubber. Equal or better. Also, the thickness of the inner liner layer could be reduced to 1/5, and as a result, the weight of the tire was 7.
It was possible to reduce the weight by 6%.

Comparative Example 4, in which the rubber adhesive layer did not contain a thermal crosslinking agent, was unsuitable because the B layer melts and fractures after vulcanization.

Comparative Example 5 in which the adhesive layer (C) was not irradiated with an electron beam was unsuitable because the adhesive layer (C) was melted and destroyed.

Example 4 Film constituting the gas barrier layer (A), adhesive layer (C
₁ ) and the raw material components of the polyolefin layer (C ₂ ) are combined as shown in Table 6, and (C ₂ ) / (C ₁ ) / (A) /
A (C ₁ ) / (C ₂ ) structure was coextruded to obtain a laminated film having a five-layer structure. Then, an electron beam having an accelerating voltage of 200 kV and an irradiation amount of 15 Mrad was irradiated from both sides of the film. Furthermore, a resin constituting the rubber adhesive layer (B) before crosslinking, which is composed of an ethylene-vinyl acetate copolymer containing the same thermal crosslinking agent as in Example 3, is laminated on both surfaces of the laminated film by an extrusion laminating method, A 7-layer film was obtained. The thickness of the laminate film is (B) before crosslinking /
(C ₂ ) / (C ₁ ) / (A) / (C ₁ ) / (C ₂ ) / (B) before crosslinking = 20/10/3/40/3/3/20/20 = 1
It was 06 μm.

The obtained laminated film was used as an inner liner layer, and the unvulcanized tire laminated with the carcass layer (2) was vulcanized at 180 ° C. for 10 minutes to vulcanize the rubber adhesive layer (B) and the carcass layer (2). (1) and (2) were heat-bonded to each other, and at the same time, the rubber adhesive layer was crosslinked to obtain a finished tire.
The results of the visual observation of the tire thus obtained, the visual observation after the indoor endurance test, the air leakage test, and the tire weight are shown in Table 6.

Comparative Example 6 A tire was prepared in the same manner as in Example 4 except that the rubber adhesive layer (B) did not contain a thermal crosslinking agent, and the tire was visually inspected and the tire after the indoor durability test was visually inspected. Table 6 shows the results according to the findings, air leakage test, and tire weight.

Comparative Example 7 A tire was prepared in the same manner as in Example 4 except that no electron beam irradiation was applied, and the visual observation of the tire, the visual observation of the tire after the indoor endurance test, the air leak test and the The results of tire weight are shown in Table 6.

[0108]

[Table 6]

As is clear from Table 6, in the tire of Example 4, no failure was found in the inner liner layer even after the vulcanization failure and the indoor durability test, and the air leakage performance was the same as the inner liner layer made of butyl rubber. Equal or better. Also, the thickness of the inner liner layer could be reduced to 1/5, and as a result, the weight of the tire was 7.
It was possible to reduce the weight by 6%.

Comparative Example 6 in which the rubber adhesive layer did not contain a heat-crosslinking agent was unsuitable because the B layer melts and fractures after vulcanization.

Comparative Example 7 in which the adhesive layer was not subjected to electron beam irradiation
Was unsuitable because the adhesive layers (C ₁ ) and (C ₂ ) melt-fractured.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating generation of undulations of a carcass layer inner surface rubber and an inner liner layer in an interval between cords after vulcanization of a conventional tire.

FIG. 2 is a meridional direction half cross-sectional view showing a main part of a pneumatic tire according to the present invention.

FIG. 3 is an enlarged cross-sectional view showing an example of an X portion of FIG.

FIG. 4 is an enlarged cross-sectional view showing an example of the splice portion of the inner liner layer in the tire according to the present invention.

FIG. 5 is an enlarged cross-sectional view illustrating another aspect of the splice portion of the inner liner layer in the tire according to the present invention.

[Explanation of symbols]

 a carcass cord b carcass layer inner surface rubber c inner liner layer 1 bead core 2 carcass layer 3 inner liner layer 4 sidewall 5 overlapping part 6 belt layer A gas barrier layer B rubber adhesive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 25/16 B32B 25/16 25/18 25/18 27/00 27/00 D 27/16 101 27/16 101 27/34 27/34 C08J 7/04 C08J 7/04 P C08L 71/12 LQP C08L 71/12 LQP // B29K 105: 24 B29L 30:00

Claims (7)

[Claims] 1. An adhesive is applied to at least one of at least one gas barrier layer (A) selected from the group consisting of a polyamide resin, a polyester resin, a polyarylate resin, a polyamide alloy and a polyester alloy. A laminated film provided with a crosslinked rubber adhesive layer (B) formed from a polyolefin resin containing a thermal crosslinking agent, and a rubber layer on at least one of the rubber adhesive layers (B). A laminated body of a laminated film and a rubber layer, wherein (R) is heat-bonded. 2. A thermal crosslinking agent is contained in at least one of at least one gas barrier layer (A) selected from the group consisting of a polyamide resin, a polyester resin, a polyarylate resin, a polyamide alloy and a polyester alloy. A laminated film provided with a crosslinked rubber adhesive layer (B) formed by extrusion-laminating a polyolefin resin as described above, and a rubber layer (at least one of the rubber adhesive layers (B)). A laminated body of a laminated film and a rubber layer, wherein R) is heat-bonded. 3. An adhesive layer (C) is provided on at least one of at least one gas barrier layer (A) selected from the group consisting of a polyamide resin, a polyester resin, a polyarylate resin, a polyamide alloy and a polyester alloy. An electron beam is irradiated from at least one surface of the laminated film having at least two layers, and further, the at least one adhesive layer (C) is formed by extrusion laminating a polyolefin resin containing a thermal crosslinking agent,
A laminated film having at least a three-layer structure provided with a crosslinked rubber adhesive layer (B), and a rubber layer (R) heat-bonded to at least one of the rubber adhesive layers (B). A laminated body of a laminated film and a rubber layer. 4. The laminate according to claim 3, wherein the resin forming the adhesive layer (C) is a modified polymer. 5. At least one of the adhesive layers (C) comprises a modified polymer layer (C ₁ ) and an unmodified polyolefin resin layer (C ₂ ), and the modified polymer layer (C ₁ ) comprises
4. A structure which is in contact with the gas barrier layer (A).
Or the laminate according to 4. 6. The rubber layer (R) comprises at least one selected from the group consisting of a diene rubber, a diene rubber hydrogenated product, an olefin rubber, a halogen-containing rubber and a thermoplastic elastomer. The laminated body according to any one of to 5. 7. A pneumatic tire comprising the laminated film according to claim 1 as an air permeation preventive layer.