JP2002172721A - Rubber composite material and rubber article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composite material capable of enhancing adhesive properties of a nonwoven fabric and a rubber, enhancing durability of the rubber article when the material is used as a reinforcing material of the rubber article such as a tire, a belt or the like, and lightening and the rubber article using the same. SOLUTION: The rubber composite material comprises the nonwoven fabric, a film formed with a metal or a metal compound capable of being reactive with a sulfur on surfaces of filaments for constituting the fabric by a physical vapor deposition method(PVD) or a chemical vapor deposition method(CVD), and the rubber adhered to the film and coating the fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber-based composite material and a rubber article using the same, and more specifically, to enhance the durability of the rubber article when used as a reinforcing material for a rubber article such as a tire or a belt. The present invention relates to a rubber-based composite material capable of reducing weight and a rubber article using the same, and particularly to a tire.

[0002]

2. Description of the Related Art Organic fiber cords and steel cords have been widely used as reinforcing materials for rubber-based composite materials applied to tires and belts. In this case, it is important that the rubber and the reinforcing material are firmly bonded from the viewpoint of the durability of the product. Therefore, conventionally, in a composite material of an organic fiber cord and a rubber, the organic fiber cord is dipped in a resorcinol-formaldehyde condensate / latex (RFL) adhesive in order to enhance the adhesion between the two. Was. Also, in the case of a composite material of steel cord and rubber, in order to enhance the adhesion between them,
It has been common practice to apply various plating treatments to steel cords.

It is also known to use a nonwoven fabric as a reinforcing material for a rubber-based composite material applied to tires, belts and the like, in addition to organic fiber cords and steel cords. For example, in Japanese Patent Application Laid-Open No. Hei 10-53010, the rigidity of the tire sidewall portion is increased without impairing the inherent performance of the radial tire such as ride comfort and durability, and without complicating the manufacturing method, and controlling the tire. In order to improve stability, it has been proposed to apply a rubber-filament fiber composite using a nonwoven fabric between a carcass layer and a sidewall.

[0004]

As a reinforcing material for a rubber-based composite material, nonwoven fabrics have attracted attention because of their performance-improving ability. In addition to further improving the performance of tires, rubber articles other than tires have a high rigidity and durability. Application to materials requiring high performance, such as belt rubber, has also been studied. In addition, a rubber-based composite material having a structure that does not include a conventional reinforcing material can also be designed with a reinforcing material that includes a nonwoven fabric.

[0005] However, in the case of a nonwoven fabric, the adhesiveness is improved by applying a dipping treatment of the organic fiber cord into the RFL adhesive applied in the conventional organic fiber cord or a plating treatment applied in the steel cord. I couldn't do that. Because, when these treatments are applied to the nonwoven fabric, the nonwoven fabric becomes clogged and becomes a film, and the contact area between the nonwoven fabric and the rubber when combined with the rubber is reduced, and the desired effect can be obtained. Because there was no.

Accordingly, an object of the present invention is to solve the above-mentioned problems, to enhance the adhesion between the nonwoven fabric and rubber, and to improve the durability of the rubber article when used as a reinforcing material for rubber articles such as tires and belts. It is an object of the present invention to provide a rubber-based composite material which can be increased and can be reduced in weight, and a rubber article using the same.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have achieved the above object by performing a specific coating treatment by a vapor phase growth method on a filament surface constituting a nonwoven fabric. The inventors have found that the present invention can be performed, and have completed the present invention.

That is, the rubber-based composite material of the present invention comprises a non-woven fabric and a metal or a metal compound capable of reacting with sulfur on the surface of a filament constituting the non-woven fabric by physical vapor deposition (PV).
D) or a film formed by chemical vapor deposition (CVD), and a rubber which adheres to the film and coats the nonwoven fabric.

[0009] The present invention also provides a rubber article, particularly a tire, wherein the rubber-based composite material is used as a reinforcing material.

The rubber-based composite material of the present invention can increase the rigidity of a rubber article using the same as a reinforcing material without impairing the durability of the rubber article. In particular, in the case of a pneumatic radial tire, when such a rubber-based composite material is applied to a tire sidewall portion, the rigidity of the sidewall portion can be increased, and the steering stability of the tire can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below. First, the nonwoven fabric applicable in the present invention is a web produced by a carding method, a papermaking method, an air lay method, a melt blowing, a spunbonding method, or the like without twisting or weaving a large number of fiber bundles. As a method for bonding the fibers in the web other than the melt blowing and the spun bond method, a heat fusion method, a method using a binder, a water entanglement method in which the fibers are entangled by a water flow or the force of a needle, and a needle punch method can be suitably used.
Water entanglement, in which the fibers are entangled with water or needles,
A nonwoven fabric obtained by a needle punch method, a melt blow, or a spun bond method is preferable.

Examples of the material of the nonwoven fabric include natural polymer fibers such as cotton, rayon, and cellulose; synthetic polymer fibers such as aliphatic polyamide, polyester, polyvinyl alcohol, polyimide, and aromatic polyamide; carbon fiber, glass fiber, and steel. One or more kinds of fibers selected from wires can be mixed. Also,
A filament fiber having a multilayer structure in which the material is different from that of the adjacent layer may be used. Further, a core-sheath structure in which different materials are arranged in an inner layer and an outer layer, or a composite fiber such as a U-shaped, petal-shaped, or layered-type can also be used.

In the present invention, such a nonwoven fabric has a structure in which rubber is impregnated between the fiber filaments, and the filament fiber and the rubber can form a continuous layer mutually over a relatively long distance over a wide range. Having a structure is an important basic requirement. For this reason, the diameter or the maximum diameter of the filament fiber is preferably 0.1 to 1
It is within the range of 00 μm, more preferably 0.1 to 50 μm. However, the cross-sectional shape may be a circular shape, a cross-sectional shape different from a circle, a shape having a hollow portion, or the like.

[0014] The length of the filament fiber is preferably at least 8 mm, more preferably at least 10 mm.
When the length of the filament fiber is less than 8 mm, the entanglement between the fiber filaments is not sufficient, and the strength as the reinforcing layer cannot be maintained.

Weight per unit area of non-woven fabric (mass per 1 m ² )
Is preferably from 10 to 300 g, more preferably from 10 to 300 g.
It is in the range of 100 g. If the basis weight of the nonwoven fabric is less than 10 g, it is difficult to maintain the uniformity of the nonwoven fabric itself, resulting in a nonwoven fabric having many irregularities, and variations in the strength, rigidity, and elongation at break when the vulcanized nonwoven fabric / rubber composite is obtained. Is undesirably large. On the other hand, if it exceeds 300 g, although it depends on the fluidity of the rubber, the rubber does not penetrate into the voids inside the nonwoven fabric. For example, when considered as a tire member, it is not preferable from the viewpoint of the peeling resistance of the rubber-nonwoven fabric composite.

In the present invention, a metal or a metal compound capable of reacting with sulfur is formed on the surface of the filament constituting the nonwoven fabric by physical vapor deposition (PVD) or chemical vapor deposition (CVD). I do. Forming a coating by PVD or CVD has the advantage of less pollution to the environment because it is solventless. In addition, since the film is formed in the gas phase, there is an advantage that the nonwoven fabric is not clogged unlike the conventional dip treatment or plating treatment.

As the PVD method applicable to the present invention, a vacuum evaporation method, for example, resistance heating evaporation, electron beam heating evaporation, molecular beam epitaxy method, laser ablation method, sputtering method, for example, DC sputtering, high frequency sputtering, magnetron Sputtering, ECR sputtering, ion beam, ion plating method, for example, high frequency ion plating, ionized cluster beam film forming method, ion beam method, and the like can be mentioned. As the CVD method, thermal CVD method, for example, Pressure CVD, reduced pressure CVD, metal organic CVD, optical CVD, or plasma CVD,
For example, DC plasma CVD, high frequency plasma CVD,
Microwave plasma CVD or ECR plasma CV
D and the like. Of these, a sputtering method is preferably used, and a magnetron sputtering method is particularly preferred.

The first reason that the sputtering method is preferable is that film formation can be performed at a low temperature on the surface of the nonwoven fabric as the base material. Second, the operating pressure during film formation is usually relatively high, 5 × 10 ⁻² Pa to ¹ × 10 ¹ Pa, and the influence of outgas from the nonwoven fabric is small. Third, particles sputtered from the target are likely to be scattered by an atmospheric gas such as argon (Ar) before going straight and reaching the surface of the nonwoven fabric as a base material, and "wraparound" is likely to occur. No. In other words, because of this "wraparound", the nonwoven fabric has an extremely complicated shape, but it is possible to suitably form a film on a portion of the nonwoven fabric that does not face the target or a shaded portion. .

As sputtering conditions, particularly magnetron sputtering conditions, for example, an atmosphere gas is an inert gas,
For example, Ar, He, Ne, Kr, particularly Ar, may be added with a reactive gas, if necessary, for example, O ₂ , H ₂ O in the case of an oxidation system.
For example, N ₂ and NH ₃ may be mixed in the case of nitriding, and CH ₄ may be mixed in the case of carbonizing. The mixing ratio of the reaction gas and the inert gas (volume ratio of the supply gas) is 100/0 to 0/100.
(Inert gas / reaction gas), preferably 100/0
20/80.

Further, if necessary, a bias voltage may be applied to the nonwoven fabric as the base material. In that case, either DC or AC bias is possible. In the case of an alternating current, a pulse or a high frequency (rf) is preferable. In the case of direct current, the voltage range is preferably -1 kV to +1 kV.

The gas pressure may be any value as long as the gas can be sputtered, but is preferably 1 × 10 ⁻² Pa to 5 ×.
10 ² Pa, more preferably 5 × 10 ⁻² Pa to ¹ × 10 ¹
Pa. Further, the power supply frequency (supplied to the target) may be any of known DC and AC. Generally, a DC power supply, a high-frequency (rf) power supply, or the like is used, but a pulse power supply may be used. Activate the particles during sputtering by generating inductive plasma between the target and the substrate,
So-called ionized magnetron sputtering
Etron sputtering is also possible.

The average thickness of the film formed by such a vapor phase growth is usually 1 × 10 ⁻¹⁰ m to 1 × 10 ⁻⁵ m, preferably 1 × 10 ⁻⁹ m to 1 × 10 ⁻⁶ m. And more preferably 5 × 10 ⁻⁹ m to 5 × 10 ⁻⁷ m. Here, the average thickness is the average thickness of the film attached to the fiber surface of the nonwoven fabric. If the film thickness is too small, the adhesion becomes insufficient, while if it is too large, the film tends to peel off from the substrate due to the internal stress of the film. Such a coating may be formed on the fiber surface of the nonwoven fabric as long as necessary for the sulfurization reaction, and does not necessarily need to be formed uniformly. During or after deposition
When exposed to the atmosphere, it reacts with oxygen and water vapor in the air, and impurities such as oxygen and hydrogen may be mixed into the film. If necessary, plasma treatment, ion implantation, ion irradiation, heat treatment, or the like may be performed after the film formation to improve the surface state, reactivity, internal stress, and the like of the film. In addition, it is desirable to sufficiently clean the surface of the nonwoven fabric before film formation, if necessary. As a cleaning method, discharge treatment can be suitably used in addition to or in addition to solvent cleaning. Moreover,
Several cleaning methods can be combined to enhance the cleaning effect.

The metal or metal compound capable of reacting with sulfur that can be used in the present invention includes alloys, oxides and nitrides, and any material capable of sulfurating with sulfur in rubber during rubber vulcanization. May be. For example, Co, Cu,
Zn, Cr, Al, Ag, Ni, Pb, Ti, W, and alloys composed of two or more of these, and further, compounds such as oxides, nitrides, carbides, sulfides, and sulfates thereof are used. be able to. In particular, Co, Co
Metals such as / Cr alloy, Cu / Zn alloy and Cu / Al alloy, alloys thereof, and oxides thereof can be suitably used. More preferably, it is Co or an oxide of Co (JP-A-62-87311, 62-246278).
No., JP-A-1-290342). Here, compounds such as oxides, nitrides, and carbides may or may not be obtained by stoichiometric values. Preferably, the ratio of the metal element is higher than the stoichiometric value.

When a non-vulcanized rubber is coated and heated and pressed after forming a film on the surface of the non-woven fabric, it is considered that adhesion occurs due to a sulfurization reaction between the above-mentioned coating and the rubber at the time of rubber vulcanization. Here, vulcanization and sulfurization are competing reactions, and in order for both to be suitably performed, matching of reactivity is necessary. In sputter film formation, it is easy to form a compound thin film having an appropriate sulfurization reactivity by adding an appropriate amount of a reaction gas such as oxygen or nitrogen in addition to an inert gas such as Ar at the time of film formation.

The compounding of the nonwoven fabric and the rubber used in the present invention is performed by pressing a sheet-like unvulcanized rubber composition from both upper and lower surfaces or one surface with a press or a roll to replace the air inside the nonwoven fabric with rubber. It is performed by

The rubber composition that can be used in the present invention is not particularly limited. For example, a rubber composition commonly used in tires and belts can be used. Therefore, any of natural rubber and synthetic rubber may be used as the rubber component, and a vulcanizing agent, a vulcanization accelerator, a reinforcing material, an antioxidant, a softener and the like can be appropriately compounded.

FIG. 1 shows a cross section of a pneumatic radial tire according to an embodiment to which the rubber composite material of the present invention is applied. In this tire, both ends of one layer of the carcass layer 2 whose cord direction is oriented in the radial direction of the tire 1 are wound around a pair of left and right bead wires 3a and 3b and turned back, and the upper portion of the carcass layer 2 in the tire radial direction is folded. A two-layer steel belt 4 is arranged in a ring shape, and a tread rubber 6 is arranged on a tire tread portion 5 above the steel belt 4.
Also, on the carcass layers on both sides of the tread rubber 6,
Sidewall rubbers 7a, 7b are adhered via rubber-based composite materials 8a, 8b. In this example, the rubber-based composite materials 8a and 8b are provided between the carcass layer 2 and the side wall rubbers 7a and 7b, respectively, in the form of bead fillers 9a and 9b.
From the upper end to the vicinity of the maximum width end of the belt portion.

In the present invention, such a rubber-based composite material is provided between the carcass layer and the side wall or between the carcass layer and the inner liner layer from the lower end of the bead portion to the maximum width end of the belt portion. At least 10
mm or more. If it is less than 10 mm, the effect of improving the steering stability is not sufficient, which is not preferable.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Non-woven fabric (fiber type: polyester, fiber diameter: 25μ)
m, the basis weight: 40 g / m ² , the thickness: 5 mm), and the surface (both sides) was cleaned by a low pressure plasma method under the conditions shown in Table 1 below. 3N) was sputtered to form Co and its oxide film on both surfaces. The power density in the cleaning was the power supplied per 1 m ² of the nonwoven fabric. As a comparative example, a nonwoven fabric which was not subjected to cleaning and Co film formation was prepared.

[0030]

[Table 1]

A rubber-based composite material obtained by sandwiching the above nonwoven fabric with unvulcanized rubber from both sides and integrating the same is used as a reinforcing member layer.
As shown in FIG. 1, each of the bead fillers was stuck 50 mm from the upper end of the bead filler between the carcass layer and the sidewall. A green tire obtained by applying the unvulcanized rubber composite material obtained as described above as a fiber reinforcing member layer is molded, and then vulcanized to a tire size of 195/60.
Radial tires of R15 and carcass ply PET1670dtex / 2 were each prototyped. In addition, a radial tire was prototyped in the same manner except that no reinforcing member layer was applied as a conventional example. For these tires, a steering stability test and a high load drum durability test were performed as follows.

<Steering stability> A prototype tire was mounted on a vehicle (Domestic F
F2000cc), speed 40-120km / h
The vehicle was run straight under the conditions of a lane change, and the driving stability was evaluated based on the driver's feeling.
The evaluation was in comparison with the control, and was classified into 0: unchanged +2: somewhat good +4: somewhat good +8: good and the total score was indicated by an index with the control being 100.

<Durability of High Load Drum>
After adjusting to the maximum air pressure of JATMA standard in a room at ℃ ± 2 ℃, let it stand for 24 hours and readjust the air pressure.
A load twice as large as the maximum load of the MA standard is applied to the tire, and the tire is driven at a speed of 60 km / h on a 1.7-m diameter drum. The index was displayed with the running distance of 100 as an index. The higher the value, the better the result. The results obtained are shown in Table 2 below.

[0034]

[Table 2]

[0035]

As described above, according to the present invention, the adhesiveness between a nonwoven fabric and rubber is enhanced, and when used as a reinforcing material for rubber articles such as tires and belt conveyors,
The durability and the weight of the rubber article can be reduced. In particular, when this is used as a reinforcing material for the side portion of the radial tire, the driving stability and the driving stability are greatly improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example pneumatic radial tire of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pneumatic radial tire 2 Carcass layer 3a, 3b Bead wire 4 Belt 5 Tire tread 6 Tread rubber 7a, 7b Sidewall rubber 8a, 8b Rubber-based composite material 9a, 9b Bead filler

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 14/20 C23C 14/20 A 16/06 16/06 16/40 16/40 D06M 11/83 B60C 13 / 00 G // B60C 13/00 D06M 11/00 FF term (reference) 4F100 AK42 AN00B BA02 BA07 DG15A EH66A GB90 JL03 JL11 4K029 AA11 AA21 BA06 BA43 CA05 GA03 4K030 BA05 BA42 CA07 CA08 CA11 DA08 4L031 AB05 DA05

Claims (6)

[Claims] 1. A non-woven fabric and a metal or a metal compound capable of reacting with sulfur on the surface of a filament constituting the non-woven fabric by physical vapor deposition (PVD) or chemical vapor deposition (C).
A rubber-based composite material comprising: a film formed by VD); and a rubber that adheres to the film and covers the nonwoven fabric. 2. The rubber-based composite material according to claim 1, wherein the metal or metal compound capable of reacting with sulfur is cobalt or cobalt oxide. 3. The rubber-based composite material according to claim 1, wherein a sputtering method is used as the physical vapor deposition (PVD). 4. The rubber-based composite material according to claim 3, wherein the sputtering method is a magnetron sputtering method. 5. A rubber article using the rubber-based composite material according to claim 1 as a reinforcing material. 6. A tire using the rubber-based composite material according to claim 1 as a reinforcing material.