JPH0740702A - Pneumatic tire and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a pneumatic tire and a manufacture thereof, wherein reduction of the weight of a tire is attempted by thinning an inner liner layer, and performance for holding air pressure in the tire is improved. CONSTITUTION:A nylon film layer is bonded on the inside of a raw tire made of unvulcanized rubber, and then the raw tire is molded and vulcanized, thereby an inner liner layer formed by the nylon film layer is formed. It is desirable to use a nylon 6 type non-extending film as a nylon film layer, particularly, the nylon film layer formed by immersion-treating the nylon 6 type non- extending film front surface into resorcinol formaldehyde latex liquid, one formed by treating the nylon 6 type non-extending film front surface with silane coupling agent, or one formed by secondary-treating the nylon 6 type non- extending film front surface with silane coupling agent after primary-treating it by means of corona discharge can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire having an improved innerliner layer having a tubeless structure to prevent air from leaking and improve the performance of retaining the air pressure in the tire, and a method for producing the same.

[0002]

2. Description of the Related Art In a pneumatic tire having a tubeless structure, which is widely used because it is possible to reduce the weight of the tire as compared with a tire having a tube, the entire inner surface of the tire is made of a gas impermeable material. An inner liner layer is provided to maintain the internal pressure. Conventionally, halogenated butyl rubber has been generally used as a gas impermeable material for the inner liner layer.

[0003]

However, the halogenated butyl rubber used for the inner liner layer in the above conventional pneumatic tire is formed to have a thickness of a predetermined value or more in order to have a sufficiently low gas permeability. There was a problem that it was necessary.

An object of the present invention is to reduce the weight of a tire by thinning the inner liner layer, and
It is an object of the present invention to provide a pneumatic tire having improved performance of retaining air pressure in the tire and a method for manufacturing the pneumatic tire.

[0005]

In order to achieve the above object, the pneumatic tire of the present invention is a tubeless pneumatic tire having an inner liner layer made of a nylon film layer. As the nylon film layer, it is preferable to use a nylon 6 type unstretched film, particularly a nylon 6 type unstretched film surface dipped in a resorcinol formaldehyde latex solution, and a nylon 6 type unstretched film surface treated with a silane coupling agent. Or the nylon 6 type unstretched film surface after primary treatment by corona discharge,
It is possible to use a secondary treatment with a silane coupling agent. In the method for producing a pneumatic tire described above, an inner liner layer made of a nylon film layer is provided inside a raw tire formed of unvulcanized rubber, and then the raw tire is molded and vulcanized.

[0006]

[Function] Since the nylon film has a gas permeability much smaller than that of halogenated butyl rubber, the thickness of the inner liner layer can be reduced, the tire weight can be reduced, and the long-term The energy saving accumulated by use becomes large.

[0007]

Embodiments of the present invention will be described with reference to the drawings. The tire manufacturing process will be described with reference to the flowchart of FIG. 1. Natural rubber, synthetic rubber, chemicals such as compounding agents, oil, etc. are kneaded and mixed in a mixer, and the compounded rubber obtained is spread by rolling rollers and then cooled by a cooling device. Then, the vulcanizing agent is kneaded and mixed with the compounded rubber after cooling, and a strip of the compounded rubber having a predetermined cross-sectional shape is extruded with an extruder to form the obtained strip on the outer periphery of the tire to be manufactured. The tread is formed by cutting into a corresponding predetermined size.

[0008] An organic fiber cord made of polyester, nylon or the like or a cord fabric in which steel cords are arranged in parallel is immersed and dried in a dipping device,
After applying tension with a heat stretcher and heating, a rubber sheet is coated with a calender to form a cord sheet, and as shown in FIG. The cut sheet 2 is formed by cutting (cutting line L) into a predetermined width at an angle. The obtained plural cut sheets 2
3 so that the cutting edges 2A and 2B are on both sides.
The belt-shaped carcass material is formed by joining the side edges 2C and 2D parallel to each other (see FIG. 3). The nylon film sheet is subjected to a bonding pretreatment described below and then wound up (batch-up) together with the carcass material to bond the nylon film to one side surface of the carcass material to form a nylon film layer. As a means for forming the nylon film layer, a nylon film sheet which has been subjected to a pre-bonding treatment after forming the carcass may be attached to the inner surface. Further, a nylon film sheet having a rubber film attached thereto may be used as the nylon film layer, and an example of the nylon film layer provided with the rubber film will be described with reference to FIG. In FIG. 4A, the rubber film 5 is attached to the nylon film sheet 6, and the rubber film 5 is interposed between the inner surface of the carcass 4 and the nylon film sheet 6. As shown in FIG. 4B, the inner surface of the carcass 4 and the nylon film sheet 6 are directly adhered to each other, and the rubber film 5 is attached to the inner surface of the nylon film sheet 6 (the side surface opposite to the carcass 4). As shown in FIG. 4C, the outer surface of the nylon film sheet 6 (carcass 4
A rubber film 51 is attached to the side surface, and a rubber film 52 is attached to the inner surface (side surface opposite to the carcass 4).

A plurality of cords (generally steel cords) are twisted together, coated with rubber, wound on a roll, cut into a predetermined length to form a bead, and a lapping process is performed. The carcass material after molding is cut into a predetermined size corresponding to the outer circumference of the tire to be manufactured, a tread is overlaid on the side opposite to the side of the carcass material on which the nylon film layer is provided, and beads are arranged on both ends of the carcass material. The green tire is formed by forming the tire into an annular shape. After vulcanizing the raw tire,
Finishing of tires is performed, tire balance and uniformity are measured, and product inspection is performed to obtain product tires. With the above configuration, the nylon film layer can be easily provided on the inner surface of the tire.

As the nylon film, nylon 66 type, nylon 610 type, nylon 3 type and the like may be used, but those having a low elastic modulus and a large elongation are preferable for ensuring good adhesiveness, and the elastic modulus is Is 20 to 80 kg / m
Suitable for those with m ² and elongation of 200-500%, nylon 6 type unstretched film is particularly suitable.
It is desirable to set it to 15μ to 100μ. If the thickness of the nylon 6 type unstretched film layer is less than 15 μm, the gas permeability thereof is larger than that of the halogenated butyl rubber layer having a thickness of 1.5 mm, and the tire air pressure retention capability is reduced. Also, 1
If it exceeds 00μ, the flexibility of the film layer is lowered, the deformation of the tire during use cannot be completely followed, and peeling or damage of the film layer may occur, which is unsuitable as an inner liner layer of the tire.

The following method is suitable as a pretreatment for adhesion to a nylon 6 type unstretched film. A method of dipping the film in a resorcinol-formaldehyde latex solution (RFL processing). Initial condensate (RF resin) obtained by reacting resorcin and formalin in an aqueous solution using an alkaline catalyst or an acidic catalyst.
Then, add latex and ripen, then add latex,
Further, a nylon 6 type unstretched film is dipped in a resorcinol formaldehyde latex solution obtained by adding a necessary amount of formalin and then heated and dried to form an adhesive layer for carcass rubber on at least one surface of the nylon 6 type unstretched film. To do. A method of treating the film surface with a silane coupling agent. A silane coupling agent is applied to the surface of the nylon 6 type unstretched film by a spraying device and the like, and heated at 150 ° C. for 30 seconds or more to form an adhesive layer for the carcass rubber on the surface of the nylon 6 type unstretched film. A method in which the film surface is first treated by corona discharge and then secondarily treated with a silane coupling agent. Adhesion of the surface facing the corona electrode by passing the nylon 6 type unstretched film toward the corona electrode in the corona electric field formed by discharging from the corona electrode After the primary treatment for improving the heat resistance, a surface of the nylon 6 type unstretched film facing the corona electrode is coated with a silane coupling agent by a spraying device or the like.
An adhesive layer for the carcass rubber is formed by heating at 0 ° C. for 30 seconds or more. With the above configuration, the surface of the nylon 6 type unstretched film having the adhesive layer is brought into close contact with the carcass material and wound up, whereby the nylon 6 type unstretched film can be reliably bonded to the carcass material. In addition, the durability of the inner liner layer can be improved by performing these pre-bonding treatments.

Next, a test tire to which the present invention is applied,
The results of the air leak test conducted using the comparative tire having the conventional structure will be described. Tire size: P165 / 70R13 Test tire: An inner liner layer composed of a nylon 6 type unstretched film layer having a thickness of 15μ. Comparative tire: 1.5 mm thick inner liner layer made of 100% bromobutyl rubber. Test method: Attached to standard rim at room temperature, internal pressure 2.3kgf / cm ²
After 48 hours, the tires whose internal pressure was readjusted to 1.9 kgf / cm ² were run for 30,000 km on an indoor drum running tester at a speed of 80 km / h and a load of 545 kg, and then cooled to room temperature. Measure the internal pressure. The test results are shown in Table 1. [Table 1] Test tires Comparative tire Inner lining Nylon 6 type 100% Brommer layer Unstretched film (15μ thickness) Butyl rubber (1.5 mm thickness) Internal pressure after 30,000km running 1.7 kgf / cm ² 1.6 kgf / cm ² (Maintaining internal pressure (89.5%) (84.2%) Inner liner No treatment No treatment Treatment-Peeling with adhesive pretreatment method and durability of 3,000 km Complete run Complete run Complete run Tire weight 7.52kg 8.01kg (94) (100) Indicates that the treatment was RFL treatment, the treatment was a silane coupling agent treatment, the treatment was a primary treatment by corona discharge, and the secondary treatment was a silane coupling agent.

From Table 1, the inner liner layer composed of the nylon 6 type unstretched film layer of the present invention is 10
The inner liner layer of 0% bromobutyl rubber can be formed to be extremely thin and has a high internal pressure holding ability, and the tire weight can be reduced.

[0014]

Since the present invention is constructed as described above, it has the following effects. Nylon film has a much smaller gas permeability than halogenated butyl rubber, so the inner liner layer can be made thinner, which can reduce the weight of the tire and allow it to be used for a long time. The accumulated energy savings will be significant.

[Brief description of drawings]

FIG. 1 is a flowchart of a pneumatic tire manufacturing method of the present invention.

FIG. 2 is an explanatory diagram showing a carcass material cutting step.

FIG. 3 is an explanatory diagram showing a carcass material bonding step.

4 (a), (b), and (c) are configuration explanatory views of a nylon film layer.

[Explanation of symbols]

1 code sheet, 2 cut sheet, 3 code, L
Cutting line

[Procedure amendment]

[Submission date] October 22, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (6)

[Claims] 1. A pneumatic tire having a tubeless structure, wherein an inner liner layer made of a nylon film layer is provided. 2. A method for producing a pneumatic tire, which comprises providing an inner liner layer made of a nylon film layer on the inner side of a green tire formed of unvulcanized rubber, and then molding and vulcanizing the green tire. 3. A nylon 6 type unstretched film is used as the nylon film layer.
The pneumatic tire described in. 4. Nylon 6 as the nylon film layer
A pneumatic tire characterized in that the surface of an unstretched film of the type is immersed in a resorcinol formaldehyde latex solution. 5. Nylon 6 as the nylon film layer
A pneumatic tire comprising a type unstretched film whose surface is treated with a silane coupling agent. 6. Nylon 6 as the nylon film layer
A pneumatic tire characterized in that the surface of a non-stretched type film is first treated by corona discharge and then secondarily treated with a silane coupling agent.