JPH0919987A - Laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate suitable for a pneumatic tire having, for example, an air permeation barrier layer such as an inner liner layer which keeps air pressure constant. SOLUTION: A laminate in which at least one kind gas barrier layer (A) selected from a group consisting of polyamide type resin, polyester type resin, polyarylate type resin, polyamide type alloy, and polyester type alloy and an adhesive layer (B) are laminated at least into two layers, a laminated film which is irradiated with electron beams at least from one surface is provided, and the adhesive layer (B) is a laminate consisting of a laminated film in which a rubber layer is heat-bonded and a rubber layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate suitable for a pneumatic tire having an air permeation preventive layer such as an inner liner layer for maintaining 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, a halogenated butyl rubber having a relatively low gas permeability is used as an inner liner layer on the inner surface of a pneumatic tire 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, the carcass layer inner surface rubber b and the inner liner layer c are wavy in the gap f between the carcass cords a and a. If it occurs, the rubber of the inner liner layer is also deformed along with the deformation of the carcass layer during rolling of the tire, 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 the thickness of the tie rubber in addition to the thickness of the inner liner layer of halogenated butyl rubber, and the total layer thickness is more than 1 mm (1000 μm). As a result, it has become one of the causes for 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 non-venting layer composed of a polyvinylidene chloride film, an ethylene-vinyl alcohol copolymer film or the like is used as a polyolefin film, an aliphatic polyamide film, or a polyurethane film. A pneumatic tire provided on the inner surface of the tire via an adhesive layer made of a film or the like has been proposed (Japanese Patent Laid-Open No. 6-40207).

However, the inner liner layer described in the above publication is, for example, a polyolefin film / non-venting layer / polyolefin film (an adhesive layer between layers is omitted).
In this case, if the tire is vulcanized at a normal temperature (the surface of the inner liner layer of a passenger car tire is about 180 ° C.), the film will be melted and the film will be destroyed. There wasn't. Further, a resin having a melting point of 180 ° C. or higher (for example, a polyamide resin,
When a film made of (polyester resin) is used,
When a large load is applied to the tire for a long time, there is a risk of peeling from the inside of the tire due to insufficient adhesive force.

Further, a tire molded with an ethylene-vinyl alcohol copolymer film or a polyvinylidene chloride film as a gas barrier layer (non-venting layer) has poor flexibility of the film, and the film deteriorates after vulcanization. Tends to be brittle. Also, due to the gas generated from rubber,
It is not preferable because there is a tendency for bubbles to be generated and foamed between the film and the rubber layer or in the film.

[0007]

In view of the above situation, an object of the present invention is, for example, excellent in heat resistance, durability and strength as well as air pressure retaining property for maintaining a constant tire air pressure.
By adhering a laminated film to a carcass layer rubber as an air permeation preventive layer, which can be suitably used as a component of a pneumatic tire capable of reducing the weight of a tire, a laminated body of a laminated film and a rubber layer is provided. is there.

[0008]

That is, the present invention provides at least one gas barrier layer selected from the group consisting of polyamide resins, polyester resins, polyarylate resins, polyamide alloys and polyester alloys ( A) and the adhesive layer (B) are laminated in at least two layers, and a laminated film irradiated with an electron beam from at least one surface is provided, and the adhesive layer (B) is a rubber layer (R). The present invention relates to a laminated body of a laminated film and a rubber layer, which are heat-bonded.

The laminate of the present invention is excellent in adhesive strength with rubber, mechanical strength (bending crack resistance), air pressure retention, heat resistance and the like.

Further, when the laminate of the present invention is placed inside a pneumatic tire and is heated and vulcanized at 180 ° C. to be molded into a tire, the laminate film in the laminate has excellent heat resistance. Therefore, the molding efficiency can be improved without melting and breaking the film surface.
Moreover, since the laminated film in the laminate of the present invention is tough even if it is a thin film, it is possible to reduce the weight of the tire,
It is possible to mold tires with excellent durability.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The resin forming the gas barrier layer (A) having air pressure retention according to the present invention is a polyamide resin, a polyester resin, a polyarylate resin,
It is at least one selected from the group consisting of polyamide alloys and polyester alloys.

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

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

The aromatic polyamide resin may be one having a structure having an aromatic ring in the 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 generically those having no crystallinity or 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. Specifically, the aliphatic glycol is ethylene glycol,
1,3-propanediol, 1,4-butanediol,
Examples are 1,6-hexanediol and 1,10-decanediol, and examples of the 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 of the present invention.

Examples of the polyarylate resin include polyesters composed of divalent phenol and aromatic dibasic acid. Specifically, a copolymer composed of bisphenol A and terephthalic acid / isophthalic acid is used. It can be illustrated.

As the polyamide-based alloy and the polyester-based alloy, at least one selected from the group consisting of the above-mentioned polyamide-based resin and polyester-based resin serves as a sea component, and an appropriate thermoplastic resin such as polyphenylene ether (PPE) or poly If necessary, at least one selected from the group consisting of arylate (PAR) and polycarbonate (PC) becomes an island component (where the sea component and the island component may be reversed), if necessary. Polymer alloys kneaded in the presence of a solubilizer can be mentioned, and specifically, polyphenylene ether / polyamide alloys, polyarylate / polyamide alloys, polycarbonate / polyamide alloys, and polyphenylene having a uniform sea-island structure. Ether / polyester alloy, polyaryle It can be mentioned DOO / polyester alloy and polycarbonate / polyester alloy as preferred. 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 the sea-island structure described above, it may be possible to use an alloy having a structure such as a polymer blend, and therefore, these are also included in the category of alloy in the present invention.

In the above, the 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 a styrene-maleic anhydride copolymer. Examples thereof include polyphenylene ether-maleic anhydride modified product, arylate-maleic anhydride copolymer, and epoxy group-containing styrene-based polymer. The amount of addition is not particularly limited, but at least one selected from the group consisting of polyamide resins and polyester resins, and an appropriate thermoplastic resin such as polyphenylene ether (PPE) or polyarylate (P
1 to 5% by weight based on the total amount of at least one selected from the group consisting of AR) and polycarbonate (PC).
The degree can be illustrated.

Further, in the above, nylon 6 and nylon 66 are used as the polyamide resin, and polybutylene terephthalate (PBT) is used as the polyester resin.
Polyethylene terephthalate (PET) is preferable, but not particularly limited. The polyphenylene ether is not particularly limited, but a polymer having an ether bond containing poly (2,6-dimethylphenylene oxide) as a main component is used as the polyarylate, and as the polyarylate, a divalent phenol and an aromatic diamine are used as described above. Polyester consisting of basic acid, eg bisphenol A
Polyesters composed of and terephthalic acid / isophthalic acid, polycarbonates include those obtained by the interfacial polycondensation reaction of sodium salt of bisphenol A and phosgene, and those obtained by the transesterification method of bisphenol A and diphenyl carbonate. , Respectively.

The resin forming the gas barrier layer (A) of the present invention may be a polyamide resin, a polyester resin, a polyarylate resin, a polyamide alloy or a polyester alloy, or a blend thereof. .

The adhesive layer (B) according to the present invention may be one that adheres to the gas barrier layer (A) and the rubber layer on the tire inner surface side. Examples of the adhesive resin that constitutes the adhesive layer (B) include homopolymers or copolymers of polyolefins such as olefins, unsaturated carboxylic acids such as maleic acid, fumaric acid, and acrylic acid, or acid anhydrides thereof. Copolymerization of derivatives such as ester or metal salt, for example, modified copolymer obtained by graft copolymerization and modification of ethylene-glycidyl methacrylate-methyl acrylate terpolymer or ethylene-ethyl acrylate-maleic anhydride terpolymer A polymer can be illustrated as a typical example. On this occasion,
A mixture of the above modified polymer and another component, for example, another polyolefin resin is also included in the category of the modified polymer. Further, these adhesive resins may be used as a mixture of two or more kinds. Incidentally, as the adhesive layer (B), it is possible to use an appropriate adhesive or the like.

Examples of the polyolefin resin constituting the above-mentioned modified polymer include homopolymers of olefins, mutual copolymers, and other copolymerizable ones, for example,
Examples thereof include copolymers with other vinyl monomers and mixtures thereof. Specific examples of such a polyolefin resin include polyethylene of various densities ranging from low density to high density [linear low density polyethylene (LLDPE),
Includes very low density polyethylene (VLDPE). ], Polypropylene, polybutene and their mutual copolymers, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA), ethylene-acrylic Examples thereof include methyl acid copolymer (EMA), ethylene-methyl methacrylic acid copolymer (EMMA), and ethylene-methacrylic acid copolymer (EMAA). In the present invention, these polyolefin resins may be used alone or in combination of two or more. Further, a polyolefin resin and an appropriate elastomer, for example, an ethylene-propylene elastomer,
Mixtures with a small amount of styrene elastomer and the like are also included in the category of the polyolefin resin of the present invention.

The rubber layer (R) according to the present invention (corresponding to the carcass layer in FIG. 3) is not particularly limited, but a diene rubber and its hydrogenated product (for example, natural rubber, polyisoprene rubber, epoxidized natural rubber). Rubber, styrene-butadiene copolymer rubber, polybutadiene rubber (high cis BR and low cis BR), NBR, hydrogenated NBR, hydrogenated SB
R), various elastomers such as olefin rubber (eg ethylene propylene copolymer rubber (EPDM, EP
M), maleic acid modified ethylene propylene copolymer rubber (M-EPM), IIR, isobutylene and aromatic vinyl or diene monomer copolymer), halogen-containing rubber (eg brominated butyl rubber, chlorinated butyl rubber, isobutylene-p) Bromide of methylstyrene copolymer (Br
-IPMS), chlorosulfonated polyethylene (CS
M), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM), thermoplastic elastomer (for example, styrene-based elastomer, olefin-based elastomer, ester-based elastomer), carbon black, process oil, vulcanizing agent Examples of the rubber composition include a compounding agent such as It is sufficient for the rubber layer (R) to be composed of only the rubber layer, but it is also possible for the rubber layer to have a reinforcing agent such as a carcass cord appropriately embedded in the rubber layer. It is included in the category of the rubber layer of 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 bonded to the laminated film by heating. The carcass layer 2 includes a carcass coat rubber portion (b) and a carcass cord portion (a). However, in the description of the tire, the carcass layer 2 includes the carcass coat rubber portion (b) and the carcass cord portion (a) as described above. It shall be treated as equivalent to (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 of the pneumatic tire of 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 the X portion in FIG. The inner liner layer 3 is provided on at least one surface of a gas barrier layer (A) made of at least one resin selected from the group consisting of polyamide resins, polyester resins, polyarylate resins, polyamide alloys and polyester alloys. It is a laminated film in which an adhesive layer (B) made of a modified polyolefin resin is sequentially laminated.

Since the adhesive layer (B) of the laminate according to the present invention is made of, for example, a modified polyolefin resin, the modified polyolefin resin may melt under the temperature at which the rubber is vulcanized, depending on its type. The film may be destroyed. In order to prevent this, the adhesive layer (B) of the laminated film needs to be crosslinked and reinforced. As a method of crosslinking, it is preferable to adopt a method of subjecting at least one surface of the laminated film, preferably both surfaces, to electron beam irradiation.

The thickness of the laminated film according to the present invention is 10
The thickness can be, for example, not less than μm, preferably 25 to 200 μm, more preferably 50 to 150 μm. Below 10 μm,
When the air permeability becomes large, for example, when it is used for the inner liner layer of a pneumatic tire, etc., the air pressure retention tends to decrease and it is not possible to keep the tire air pressure constant, but the thickness of the laminated film Of course, there is no particular limitation, and it goes without saying that it may deviate from the above range if necessary.

At this time, the thickness of the adhesive layer (B) adhered to the rubber layer (R) is 5 to 200 μm, preferably 10
˜100 μm, more preferably 15 to 80 μm. If it is less than 5 μm, the adhesive strength with the rubber layer (R) will be reduced, and if it exceeds 200 μm, it will tend to be hard. Further, the thickness of the gas barrier layer (A) may be, for example, a thickness such that the tire pressure can be kept constant.
It is preferably at least μm, more preferably 3 to 50 μm. If the thickness is less than 3 μm, the air pressure retention tends to be low, and the tire air pressure tends to be unable to be kept constant, but the thickness of each of these layers (A) and (B) may deviate from the above range depending on the application. Of course.

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

A preferred embodiment of the laminate according to the present invention is at least 2 in which an adhesive layer (B) made of a modified polyolefin resin is provided on the surface of the gas barrier layer (A).
(A) / (B) / (R) or (B) /, which comprises a laminated film having a layered structure, and a rubber layer (R) is laminated on the adhesive layer (B) surface of the laminated film. (A) /
(B) / (R) is preferred. Further, the laminate of the present invention,
An appropriate layer may be provided between each layer of (A) / (B), and at least any one of these layers may be provided in two or more layers. Specifically, (B ₁ ) / (B ₂ )
The constitutions such as / (A) / (B ₂ ) / (B ₁ ) / (R) can be exemplified, where (B ₁ ) and (B ₂ ) are the same in the adhesive resin constituting the adhesive layer, for example. Of course, different types of resins or different types of resins may be 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, for example, as described later, and vulcanized and molded by an appropriate method. At this time, the adhesive layer (B) and the rubber layer (R) are heated and adhered during the vulcanization step. in this way,
The heat bonding in the present invention is usually performed simultaneously with the vulcanization step, but of course, a step for heat bonding may be provided separately from the vulcanization step. Here, the heat bonding is preferably performed at about 130 to 200 ° C., but there is no particular limitation.

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

The laminated film of the present invention may be formed into a tubular film by the inflation method or a flat film by the coextrusion T-die method using an appropriate apparatus such as coextrusion, and there is no particular limitation. . If necessary, it may be stretched. Examples of the stretching method include a method in which film formation-cooling and reheating are performed. Sequential biaxial stretching, simultaneous biaxial stretching, tubular simultaneous biaxial stretching method in which film formation is followed by continuous stretching. Examples include a method of stretching in a separate step, a melt stretching method, and the like.

At this time, the stretching ratio is not particularly limited, and for example, it is desirable that it is more than 1 time to 4 times, preferably more than 1 time to 2 times in each of length and width. The stretching temperature is also not particularly limited,
Generally, 100 to 200 ° C, preferably 120 to 1
About 80 ° C is good.

Further, if necessary, heat fixing may be carried out by an appropriate known method. In general, there can be exemplified a method of heat-setting subsequent to the drawing while being relaxed by several% in the width direction at a temperature higher than the above-mentioned drawing temperature, but there is no particular limitation.

The method for laminating is not particularly limited,
In addition to the co-extrusion method described above, a film made of a polyolefin resin and at least one resin selected from the group consisting of a polyamide resin, a polyester resin, a polyarylate resin, a polyamide alloy and a polyester alloy Film by separately forming a film, and a pressure-and-heat adhesion method in which an adhesive layer is interposed, a polyamide-based film, a polyester-based film, a polyarylate-based film, and a polyolefin through the adhesive layer on the surface of the film made of the alloy. An extrusion laminating method in which a system resin is melt extruded and laminated can be exemplified.

Further, the gas barrier layer (A) according to the present invention
The laminated film having the adhesive layer (B) provided on one side or both sides thereof needs to be crosslinked in order to improve heat resistance and adhesiveness between the gas barrier layer (A) and the adhesive layer (B).

As a method of crosslinking, a method of crosslinking by irradiating an electron beam from at least one surface of the laminated film, particularly from both surfaces, is preferable. At this time, it is particularly preferable to irradiate from both sides in the above-mentioned laminated film having the (B) layer on both surfaces. Further, in an appropriate layer of the laminated film, triallyl isocyanurate, triallyl cyanurate,
A technique for adding an electron beam cross-linking agent such as trimethylolpropane trimetalylate can also be used in combination, and the addition amount thereof is not particularly limited, but preferably, the material forming each layer is 10
When the amount is 0 part by weight, the amount may be about 1 to 5 parts by weight.
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 is performed by accelerating voltage of, for example, 50 kV or more from at least one surface of the laminated film in which the gas barrier layer (A) is provided with the adhesive layer (B).
Preferably 150-250 kV, more preferably 200
The irradiation amount is 80 Mrad or less, preferably 0.1 to 50 Mrad, more preferably 1 to 2
It is preferable to irradiate in the range of 0 Mrad.

Here, when the accelerating voltage is small, 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 between the adhesive layer (B) and the rubber layer (R) tends to decrease.

In the laminated film irradiated with the electron beam as described above, the adhesive layer (B) is cross-linked and the strength and heat resistance of the film are improved.

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 rubber are prepared according to a conventional method. Are laminated to form a green tire made of unvulcanized rubber. Then, the green tire is inserted into a mold, vulcanized and molded by an ordinary method, and heat-bonded to provide the inner liner layer 3 made of the laminated film according to the present invention on the tire inner surface of the carcass layer 2. . At this time, in the present invention, it is also possible to add a new rubber layer (R ') using tie rubber or the like between the carcass layer and the adhesive layer (B). In such a configuration, the "carcass layer (2)" / Rubber layer (R ') / Adhesive layer (B) ... ", and the rubber layer (R) has a double structure in some cases.

In particular, when the inner liner layer 3 is provided with the adhesive layers (B) on both outer sides thereof, FIG.
As shown in FIG.
Since the adhesive layers (B) come into contact with each other and are firmly adhered by heating, the air pressure retention can be further improved, and the bladder inserted inside the tire at the time of vulcanization molding is made of gas. Barrier layer (A)
Since it does not come into direct contact with the gas barrier layer (A)
Can be protected thermally and mechanically.

As another tire molding method, a laminated film is laminated with the carcass layer 2 in advance, the film / carcass layer in the pre-laminated state is wound around a tire molding drum, and then a sidewall, a conventional method is used. A method in which a bead core and a bead filler, a steel belt layer, and a tread rubber are laminated, a green tire made of unvulcanized rubber is molded, and then the green tire is inserted into a mold, vulcanized and molded by a conventional method, and heat-bonded. Can be illustrated. In this case, by providing the adhesive layers (B) on both outer sides of the laminate, the gas barrier layer (A) and the carcass layer 2 are directly connected to each other in the overlapping portion 5 of the inner liner layer 3 as shown in FIG. Since it is possible to avoid heat-bonding, good adhesiveness can be obtained.

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

The above is an example of the preferred embodiment of the present invention, and it goes without saying that the present invention can take any embodiment without being limited to the description.

According to the present invention, at least one surface of at least one gas barrier layer (A) selected from the group consisting of polyamide resins, polyester resins, polyarylate resins, polyamide alloys and polyester alloys, For example, an adhesive layer (B) made of a modified polyolefin resin is laminated, and a laminated film irradiated with an electron beam from at least one surface is provided, and the adhesive layer (B) is heated with a rubber layer (R). The present invention relates to a laminated body of a laminated film and a rubber layer that are bonded together. The electron beam irradiation conditions are preferably such that the irradiation amount is in the range of 80 Mrad or less. The laminate is excellent in strength, adhesive strength of rubber layer, non-permeability (gas barrier property), heat resistance and the like, and is used for, for example, an inner layer of a pneumatic tire (for example, inner liner layer + carcass layer) and the like. It is possible to reduce the weight of the filled tire.

[0051]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples.

Adhesion Test A confirmation test of the adhesion between the laminated film and the rubber was conducted.

(1) Content and Preparation of Test Rubber The content of the test rubber is shown in Table 1 below.

Formulations 1 to 6: A masterbatch was prepared by mixing a vulcanization accelerator and raw materials other than sulfur in an internal mixer. The standard mixing time was 3.5 minutes and the release temperature was 150 ° C. An unvulcanized test rubber was prepared by adding the remaining compounding ingredients to the masterbatch with an open roll.

Formulations 7 and 8: A masterbatch was prepared by mixing zinc white, a vulcanization accelerator and raw materials other than sulfur in an internal mixer. The standard mixing time is 3.5 minutes and the release temperature is 1
It was 50 ° C. An unvulcanized test rubber was prepared by adding the remaining compounding ingredients to the masterbatch with an open roll.

[0056]

[Table 1]

The components in Table 1 are as follows.

NR; Product name: RSS # 1 SBR; Product name: Nipol 1502, ZEON CORPORATION
BR; Trade name: Nipol BR1220, Nippon Zeon Co., Ltd. EPT; Esplen 505A, Sumitomo Chemical Co., Ltd. Br-IIR; Trade name: Exon Bromobutyl 224
4, carbon black FEF manufactured by Exxon Chemical Co., Ltd .; trade name: HTC100, aroma oil manufactured by Chubu Carbon Co., Ltd .; trade name: Komorex 300, ZnO manufactured by Nippon Oil Co., Ltd .; trade name: Zinling Zinhua, Toho Zinc Stearic acid manufactured by Co., Ltd .; trade name: LUNAC YA, RD manufactured by Kao Co., Ltd .; trade name: Nocrac 224 (anti-aging agent), DM manufactured by Ouchi Shinko Chemical Co., Ltd. DM; trade name: Nocceller DM (acceleration of vulcanization) Agent), sulfur produced by Ouchi Shinko Chemical Co., Ltd .; trade name: powdered sulfur, manufactured by Karuizawa Smelting Co., Ltd.

(2) Test Film The gas barrier layer (A) and the adhesive layer (B) were combined as shown in Table 2 below, and the (B) layer was coextruded on both sides of the (A) layer to form a three-layer structure. A laminated film of was obtained. Then, from both sides of the film, an acceleration voltage of 200 kV and an irradiation dose of 15 Mrad
Was irradiated. The thickness of the laminate film is (B) / (A) / (B) = 30/36/30 μm = 96
μm. Since the laminated film of Comparative Example 1 has heat resistance, it is not subjected to electron beam irradiation.

(3) Preparation of Adhesion Test Sample and Adhesion Test Method The preparation and adhesion test method of the sample are JIS K6256.
Followed. Sample is cloth reinforced rubber / unvulcanized test rubber /
The test film / unvulcanized test rubber / fabric reinforced rubber laminated in this order was vulcanized at 180 ° C. for 10 minutes, and the vulcanized laminated sheet was cut into strips having a width of 25 mm. The strip-shaped sample was attached to the peel tester, and the peeling strength between the test film and the test rubber was measured with the gripping speed of the tester set to 50.0 ± 5.0 mm / min. JI for other tests
According to SK6256.

The results of the adhesion test are also shown in Table 2.

[0062]

[Table 2]

Assuming that the desirable adhesive strength between the test film and the test rubber is 0.5 N / mm or more, it is clear from Table 2 that the films of Examples 1 to 4 have desired adhesive strengths with any of the test rubbers. However, Comparative Example 1 using a film having a constitution different from that of the laminated film of the present invention was below the above-mentioned desired adhesive strength with any of the test rubbers.

Example 5 The tire size was 185 / 65R14, and in the structure of FIG. 2, an adhesive composed of ethylene-ethyl acrylate-maleic anhydride terpolymer was attached to both sides of the gas barrier layer (A) composed of nylon 66. The layer (B) was coextruded to obtain a laminated film having a three-layer structure. Then from both sides of the film,
An electron beam having an acceleration voltage of 200 kV and a dose of 15 Mrad was irradiated. The thickness of the laminated film is (B) / (A)
/ (B) = 30/36/30 μm = 96 μm.

The resulting 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 be vulcanized to obtain an adhesive layer (B) and a carcass layer (2). A finished tire was obtained by heat-bonding and. Visual observation of the tire thus obtained,
Table 3 shows the results of the visual observation of the tire after the indoor durability test, the air leak test, and the tire weight.

[0066]

[Table 3]

The rubber composition used for the carcass layer is
The carcass layer has the formulation contents shown in Table 4, and the carcass layer was produced by coating both sides of the polyester cord with the rubber composition.

[0068]

[Table 4]

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

[Observation after vulcanization]: Visual inspection of the inner surface of the tire after vulcanization was completed, in which no abnormalities were found, ◯, abnormal ones were marked 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. The inner surface of the tire after the test was visually confirmed. What was seen was marked with x, and when something was found to be defective, 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 at a speed of 80 km / h After running 10,000 km, the tire inner surface was visually inspected to find cracks, cracks, and peeling. The one in which rising 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., then left at an internal pressure of 200 kPa for 48 hours, and an internal pressure of 20.
Readjust to 0 kPa. Immediately after readjustment, the internal pressure was measured every 4 days for 3 months, starting from the start of measurement.

The air leak coefficient α was obtained by regressing the function of the following formula 1 as the measured pressure P _t , the initial pressure P _o , and the elapsed time t.

[0076]

[Equation 1]

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

[0078]

[Equation 2]

Examples 6 to 8 Tires were prepared in the same manner as in Example 5 except that the structure of the inner liner layer was shown in Table 3, and the visual observation of the tires and the visual observation of the tires after the indoor durability test were conducted. Findings,
The results of the air leak test and the tire weight are shown in Table 3.

Comparative Example 2 A tire was prepared in the same manner as in Example 5 except that the inner liner layer had the structure shown in Table 3 and was not irradiated with an electron beam. The results of the visual observation of the tire after the test, the air leakage test, and the tire weight are shown in Table 3.

Comparative Example 3 The composition of the inner liner layer is as shown in Table 3 and in the same manner as in Example 5 except that the electron beam was not irradiated.
Table 3 shows the results of the tire visual observation, the visual observation of the tire after the indoor durability test, the air leakage test, and the tire weight.

Comparative Example 4 An inner liner layer (thickness: 500 μm) made of unvulcanized butyl rubber having the composition shown in Table 5 was provided on the inner surface of a green tire through a tie rubber having a thickness of about 700 μm. Table 3 shows the results of vulcanization and production under the same conditions as in Example 5, visual observation after completion of vulcanization, visual observation of tire after indoor durability test, air leakage test, and tire weight.

[0083]

[Table 5]

As is clear from Table 3, in the tires of Examples 5 to 8, no failure was found in the inner liner layer after the vulcanization failure and the indoor durability test, and the air leak performance was an inner liner made of butyl rubber. It was equal to or higher than the layer. Also, make the thickness of the inner liner layer 1 /
As a result, the weight of the tire was
It was possible to reduce the weight by 7.6%.

Further, in Comparative Example 2 in which electron beam irradiation is not applied,
The findings after the indoor durability test tended to be unacceptable and were unsuitable.

Even if the inner liner layer has a constitution according to the present invention, Comparative Example 3 in which the electron beam irradiation is not carried out is not suitable because bubbles are generated and the post-vulcanization findings are unacceptable. Met.

Examples 9 to 10 Example 5 was repeated except that the gas barrier layer (A) of the laminated film constituting the inner liner layer had the thickness shown in Table 6.
A tire was prepared in the same manner as in 1. 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 6.

[0088]

[Table 6]

Examples 11 to 13 Tires were prepared in the same manner as in Example 5 except that the structure of the inner liner layer was shown in Table 7, and the visual observation of the tire and the visual observation of the tire after the indoor durability test were performed. Findings,
The results of the air leak test and the tire weight are shown in Table 7.

[0090]

[Table 7]

Examples 14 to 16 and Comparative Example 5 In the tires of Example 5, three kinds of films which were irradiated with electron beams under the conditions of accelerating voltage and irradiation amount of 150 kV, 5 Mrad, 200 kV, 20 Mrad and 250 kV, 40 Mrad, respectively, and Table 8 shows the results of visual observations of these tires, visual observations of the tires after the indoor endurance test, air leakage tests, and tire weights when tires were produced using a film that was not irradiated with electron beams.

[0092]

[Table 8]

As is clear from Table 8, the inner liner layer according to the present invention was not destroyed by electron beam irradiation, and a tire having excellent adhesion to the carcass layer could be obtained.

Examples 17 to 18 Tire size was 185 / 65R14, and in the configuration of FIG. 2, 3% triallyl isocyanurate (TAIC) was formed on both sides of the gas barrier layer (A) made of nylon 66.
Adhesive layer (B) comprising ethylene-ethyl acrylate copolymer (100 parts by weight of the copolymer) contained by weight.
Was coextruded to obtain a laminated film having a three-layer structure. Then, electron beams were irradiated from both sides of the film as shown in Table 9. The thickness of the laminated film is (B) / (A) /
(B) = 30/36/30 μm = 96 μm.

An unvulcanized tire obtained by stacking the obtained laminated film as an inner liner layer and a carcass layer (2) was vulcanized at 180 ° C. for 10 minutes to be vulcanized to obtain an adhesive layer (B) and a carcass layer (2). A finished tire was obtained by heat-bonding and. Visual observation of the tire thus obtained,
Table 9 shows the results of the visual observation of the tire after the indoor durability test, the air leak test, and the tire weight.

The rubber composition used for the carcass layer is
The carcass layer has the formulation contents shown in Table 4, and the carcass layer was produced by coating both sides of the polyester cord with the rubber composition.

[0097]

[Table 9]

As is clear from Table 9, by including TAIC in the adhesive layer (B), the inner liner layer according to the present invention is not destroyed even with a small electron beam irradiation amount of 0.5 Mrad, and the carcass layer It was possible to obtain a tire having excellent adhesiveness with.

[Brief description of the 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 a portion X in FIG.

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

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

[Description of sign]

 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 Overlap part 6 Belt layer A Rubber adhesive layer B Adhesive layer C Gas barrier layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Jiro Watanabe No. 2 Oiwake, Hiratsuka City, Kanagawa Prefecture Yokohama Rubber Co., Ltd. Hiratsuka Factory (72) Inventor Hiroyuki Kaito No. 2 Oiwake, Hiratsuka City, Kanagawa Prefecture Yokohama Rubber Co., Ltd. Ceremony Company Hiratsuka Factory

Claims (5)

[Claims] 1. At least one gas barrier layer (A) and an adhesive layer (B) 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 and a rubber layer which are laminated in at least two layers and which are provided with a laminated film irradiated with an electron beam from at least one surface and in which the adhesive layer (B) is heat-adhered to the rubber layer (R). And a laminate. 2. The laminate according to claim 1, wherein the adhesive layer (B) is a layer made of an adhesive resin. 3. The laminate according to claim 2, wherein the adhesive resin is a modified polymer. 4. The rubber layer (R) is 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 1 to 3. 5. A pneumatic tire comprising the laminated film of the laminate according to claim 1 as an air permeation preventive layer.