JP7446103B2 - Elastomer-metal cord composite and tires using the same - Google Patents

Description

The present invention relates to an elastomer-metal cord composite and a tire using the same, and more particularly, the present invention relates to an elastomer-metal cord composite and a tire using the same. The present invention relates to a cord composite and a tire using the same.

Generally, a carcass containing reinforcement cords buried along the meridian direction of the ring-shaped tire body is placed inside the tire where strength is required, and a belt layer is placed on the outside of the carcass in the tire radial direction. be done. This belt layer is usually formed using an elastomer-metal cord composite obtained by coating a metal cord such as steel with an elastomer, and provides the tire with load resistance, traction resistance, etc.

In recent years, there has been an increasing demand for lighter tires in order to improve the fuel efficiency of automobiles. Metal cords for reinforcing belts have attracted attention as a means of reducing the weight of tires, and many techniques have been published that use metal filaments as belt cords without twisting them. For example, Patent Document 1 discloses a steel cord for reinforcing tires in which a thermoplastic elastomer composition in which an elastomer is dispersed in a thermoplastic resin is coated around a steel cord body made of a single monofilament, and a steel cord using the same. Tires are disclosed. Furthermore, in Patent Document 2, two to six main filaments of the same diameter are arranged in parallel to form a single layer without being twisted to form a main filament bundle, and one straight filament with a smaller diameter than the main filaments is arranged in parallel to form a single layer without twisting. A pneumatic radial tire is disclosed in which a steel cord made of a steel filament wrapped around a main filament bundle as a wrapping filament is used as a tire belt layer.

Japanese Patent Application Publication No. 2010-053495 JP2012-106570A

As proposed in Patent Document 1 and Patent Document 2, by coating a metal monofilament with an elastomer to form a belt cord, it is possible to reduce the weight of the belt by making the belt thinner, and the monofilament can be bundled into a bundle. If used, it is also possible to improve belt edge separation (BES) resistance by ensuring a distance between monofilament bundles.

However, in Patent Document 1 and Patent Document 2, low loss properties, crack growth resistance, and separation resistance are not studied. Therefore, there has been a demand for a reinforcing material that can satisfy these performance requirements.

Therefore, an object of the present invention is to provide a reinforcing element consisting of a plurality of metal filaments aligned in a row without being twisted together and covered with an elastomer, which has excellent low loss properties, crack propagation resistance, and separation resistance. An object of the present invention is to provide an elastomer-metal cord composite and a tire using the same.

As a result of extensive studies, the present inventors have found that the above problem can be solved by having the reinforcing element made of metal filaments have the following configuration and using an elastomer that satisfies the following predetermined physical properties. The present invention has now been completed.

That is, in the elastomer-metal cord composite of the present invention, a reinforcing element made of a plurality of metal filaments aligned in a row without being twisted is coated with an elastomer.
The minimum gap distance between the metal filaments is 0.01 mm or more and less than 0.24 mm, the maximum gap distance between the metal filaments is 0.35 mm or more and 2.0 mm or less, and the metal filaments are The wire diameter is 0.15 mm or more and 0.35 mm or less, and the ratio M200/M50 of the 200% modulus value (M200) to the 50% modulus value (M50) of the elastomer is 5.0 or less. It is characterized by this.

Here, the above 50% modulus refers to the tensile stress when the elastomer elongates to 50%, and the above 200% modulus refers to the tensile stress when the elastomer elongates to 200%. When the elastomer is a rubber composition, these values can be measured in accordance with JIS K 6251 (2010) after vulcanizing the rubber composition to form a vulcanized rubber. The conditions for vulcanizing the rubber composition are not particularly limited, and known vulcanization conditions can be used as appropriate.

In the elastomer-metal cord composite of the present invention, it is preferable that the reinforcing element is a metal filament bundle consisting of 2 or more and 20 or less metal filaments.

Furthermore, in the elastomer-metal cord composite of the present invention, the elastomer preferably comprises a rubber composition containing a rubber component, carbon black, a phenol resin, and a methylene donor. In this case, the elastomer contains silica, and the content of the silica is preferably more than 0 parts by mass and 25 parts by mass or less based on 100 parts by mass of the rubber component, and the elastomer contains a cobalt compound, It is also preferable that the content of the compound is less than 0.01 parts by mass based on 100 parts by mass of the rubber component.

The tire of the present invention is characterized by using the elastomer-metal cord composite of the present invention.

According to the present invention, a reinforcing element made of a plurality of metal filaments aligned in a line without being twisted is coated with an elastomer, and the elastomer has excellent low loss properties, crack propagation resistance, and separation resistance. A metal cord composite and a tire using the same could be provided.

FIG. 1 is a partial cross-sectional view in the width direction of an elastomer-metal cord composite according to a preferred embodiment of the present invention. FIG. 2 is a schematic plan view of a metal cord of an elastomer-metal cord composite according to a preferred embodiment of the present invention. 1 is a schematic half-sectional view of a tire according to a preferred embodiment of the present invention.

Hereinafter, the elastomer-metal cord composite of the present invention and the tire of the present invention will be explained in detail using the drawings. FIG. 1 is a partial cross-sectional view in the width direction of an elastomer-metal cord composite according to a preferred embodiment of the present invention, and FIG. 2 is a partial cross-sectional view in the width direction of an elastomer-metal cord composite according to a preferred embodiment of the present invention. FIG. 2 is a schematic plan view of a composite metal cord.

The elastomer-metal cord composite 10 of the present invention is formed by covering with an elastomer 3 a reinforcing element 2 consisting of a plurality of metal filaments 1 arranged in a line without being twisted together. With such a configuration, the thickness of the elastomer-metal cord composite 10 of the present invention can be reduced, and when the elastomer-metal cord composite 10 of the present invention is used in the belt layer of a tire, the thickness of the elastomer-metal cord composite 10 of the present invention can be reduced. The weight can be reduced. Note that the metal filament according to the present invention is a substantially straight metal filament. Here, a straight metal filament refers to a metal filament that is not intentionally shaped and is substantially unshaped.

In the illustrated example, the reinforcing element 2 is a metal cord 2 made of a bundle of a plurality of metal filaments 1 aligned in a row without being twisted together, but the present invention is not limited to this. The reinforcing element 2 according to the present invention may include a plurality of metal filaments 1 that are not twisted together but are aligned in a row and are evenly arranged. In particular, it is preferable that the reinforcing element 2 is a metal cord 2 made of a bundle of a plurality of metal filaments 1 that are not twisted together but are aligned in a row.

When the reinforcing element 2 is a metal cord 2 consisting of a bundle as shown, the number of metal filaments 1 is preferably 2 or more, more preferably 5 or more, and preferably 20 or less, more preferably The metal cord 2 is preferably composed of a metal filament bundle of 12 or less, more preferably 10 or less, particularly preferably 9 or less. In the illustrated example, five metal filaments 1 are aligned without being twisted together to form a metal cord 2.

In the present invention, the minimum gap distance between the metal filaments 1 constituting the reinforcing element 2 is 0.01 mm or more and less than 0.24 mm. By setting the minimum gap distance between adjacent metal filaments 1 to 0.01 mm or more, it becomes possible for the elastomer 3 to sufficiently penetrate between the metal filaments 1. On the other hand, by setting the minimum gap distance to less than 0.24 mm, the occurrence of separation between the metal filaments 1 can be suppressed. The minimum gap distance between the metal filaments 1 constituting the reinforcing element 2 is preferably 0.03 mm or more and 0.20 mm or less, more preferably 0.03 mm or more and 0.18 mm or less.

In addition, when the reinforcing element 2 is a metal cord 2 consisting of a bundle as shown in the figure, the interval w1 between the metal filaments 1 constituting the metal cord 2 corresponds to the above-mentioned minimum gap distance.

In addition, as a result of intensive studies on achieving both low loss property and crack propagation resistance, the present inventors also found that the 200% modulus value (M50) of the elastomer 3 covering the metal cord 2 is We focused on the fact that the ratio M200/M50 of M200) is highly related to crack growth resistance. As a result of further studies, the present inventors found that by setting the ratio M200/M50 to a specific value or less, it is possible to achieve both low loss property and crack growth resistance at a higher level than the conventional technology. I discovered that. That is, in the elastomer-metal cord composite 10 of the present invention, the ratio M200/M50 of the 200% modulus value to the 50% modulus value of the elastomer 3 covering the metal cord 2 is 5.0 or less.

Therefore, in the elastomer-metal cord composite 10 of the present invention, by using the reinforcing element 2 including the pair of the predetermined metal filaments 1 in combination with the elastomer 3 having the predetermined physical property values, low loss can be achieved. It is possible to improve all of the properties, crack propagation resistance, and separation resistance.

In the elastomer-metal cord composite 10 of the present invention, the maximum gap distance between the metal filaments 1 constituting the reinforcing element 2 is preferably 0.25 mm or more and 2.0 mm or less, more preferably 0.3 mm or more. , 1.8 mm or less, more preferably 0.35 mm or more and 1.5 mm or less. By setting the maximum gap distance between metal filaments 1 to 0.25 mm or more, when the elastomer-metal cord composite 10 of the present invention is used in a tire belt layer, the cord end at the end in the belt width direction is the starting point. It is possible to suppress the occurrence of belt edge separation, where the rubber peeling propagates between adjacent metal cords. Furthermore, by setting the maximum gap distance between the metal filaments 1 to 2.0 mm or less, the rigidity of the belt can be maintained when the elastomer-metal cord composite 10 of the present invention is used in the belt layer of a tire. can.

In addition, when the reinforcing element 2 is a metal cord 2 consisting of a bundle as shown in the drawing, the interval w2 between the metal cords 2 corresponds to the above-mentioned maximum gap distance.

Further, in the elastomer-metal cord composite 10 of the present invention, the wire diameter of the metal filament 1 is preferably 0.15 mm or more and 0.40 mm or less. It is more preferably 0.18 mm or more, still more preferably 0.20 mm or more, and preferably 0.35 mm or less. By setting the wire diameter of the metal filament 1 to 0.40 mm or less, when the elastomer-metal cord composite 10 of the present invention is used in the belt layer of a tire, a sufficient weight reduction effect of the tire can be obtained. On the other hand, by setting the wire diameter of the metal filament 1 to 0.15 mm or more, sufficient belt strength can be exhibited when the elastomer-metal cord composite 10 of the present invention is used in the belt layer of a tire.

In the elastomer-metal cord composite 10 of the present invention, the elastomer 3 can be sufficiently penetrated between the adjacent metal filaments 1, but there is a non-elastomer coating that is not covered with an elastomer between the adjacent metal filaments. From the viewpoint of preventing regions from continuously existing, it is preferable to satisfy the following conditions. That is, when the reinforcing element 2 is a metal cord 2 consisting of a bundle as shown in the figure, the elastomer coverage of the adjacent metal filaments 1 in the widthwise side surface of the metal cord 2 is equal to the unit length. It is preferably 10% or more, more preferably 20% or more. More preferably, the coating is 50% or more, and particularly preferably 80% or more. Most preferably, it is covered by 90% or more. As a result, when the elastomer-metal cord composite 10 of the present invention is used in the belt layer of a tire, it not only ensures corrosion resistance in the belt layer, but also improves the in-plane rigidity of the belt and improves handling stability. Good effects can be obtained.

Here, in the present invention, the elastomer coverage ratio means, for example, when rubber is used as the elastomer and steel cord is used as the metal cord, the rubber-steel cord obtained after coating the steel cord with rubber and vulcanizing it. Pull out the steel cord from the composite, measure the length of the side surface of the steel filament in the width direction of the metal cord, which is covered with rubber that has penetrated into the gaps between the steel filaments that make up the steel cord, and calculate based on the formula below. It is the average of the values.
Elastomer coverage = (rubber coverage length/sample length) x 100 (%)
Note that calculations can be made in the same way when an elastomer other than rubber is used as the elastomer, and when a metal cord other than steel cord is used as the metal cord.

In the present invention, the metal filament 1 generally refers to steel, that is, a linear metal whose main component is iron (the mass of iron is more than 50% by mass relative to the total mass of the metal filament), and is composed only of iron. It may also contain metals other than iron, such as zinc, copper, aluminum, and tin.

Further, in the present invention, the surface state of the metal filament 1 is not particularly limited, but may take the following form, for example. That is, the metal filament 1 may have N atoms on the surface of 2 at % or more and 60 at % or less, and a Cu/Zn ratio of 1 or more and 4 or less. In addition, in the metal filament 1, the amount of phosphorus contained as an oxide in the outermost layer of the filament from the filament surface to 5 nm inward in the radial direction of the filament is 7.0 at % in proportion to the total amount excluding the amount of C. Examples include the following cases.

Furthermore, in the present invention, the surface of the metal filament 1 may be plated. The type of plating is not particularly limited, and examples include zinc (Zn) plating, copper (Cu) plating, tin (Sn) plating, brass (copper-zinc (Cu-Zn)) plating, and bronze (copper-tin (Cu-Zn)) plating. In addition to Cu--Sn) plating, ternary alloy plating such as copper-zinc-tin (Cu-Zn-Sn) plating and copper-zinc-cobalt (Cu-Zn-Co) plating can be mentioned. Among these, brass plating and copper-zinc-cobalt plating are preferred. This is because metal filaments with brass plating have excellent adhesion to rubber. In addition, in brass plating, the ratio of copper to zinc (copper:zinc) is usually 60 to 70:30 to 40 on a mass basis, and in copper-zinc-cobalt plating, the ratio of copper to zinc is usually 60 to 75% by weight, Cobalt is 0.5-10% by weight. Further, the thickness of the plating layer is generally 100 nm or more and 300 nm or less.

Furthermore, in the present invention, there are no particular limitations on the wire diameter, tensile strength, or cross-sectional shape of the metal filament 1. For example, as the metal filament 1, a filament with a tensile strength of 2500 MPa (250 kg/mm ² ) or more can be used, thereby reducing the amount of metal used in the belt while maintaining the durability of the tire. It is possible to improve the noise level. Further, the cross-sectional shape of the metal filament 1 in the width direction is not particularly limited, and may be a perfect circle, an ellipse, a rectangle, a triangle, a polygon, etc., but a perfect circle is preferable. In addition, in the present invention, when the reinforcing element 2 is a metal cord 2 consisting of a bundle as shown in the figure, if it is necessary to restrain the bundle of metal filaments 1 constituting the metal cord 2, a metal filament bundle is used. A wrapping filament (spiral filament) may be wound around.

In the present invention, the elastomer 3 is not particularly limited as long as the ratio M200/M50 of the 200% modulus value (M200) to the 50% modulus value (M50) is 5.0 or less; A rubber composition or the like used for coating a metal cord can be used.

The above M50 is a parameter related to the elasticity of the elastomer in a low strain range. Therefore, M50 needs to be set as high as possible in order to suppress deformation of the belt portion of the tire. To this end, for example, in the rubber composition, it is possible to incorporate a phenol resin or a methylene donor, which will be described later, while adjusting the type and content of carbon black, which will be described later. On the other hand, the above M200 is a parameter related to the elasticity of the elastomer in a high strain range. Therefore, from the viewpoint of suppressing crack propagation, M200 needs to be set to a low value in order to alleviate stress concentration at the crack tip. For this purpose, for example, in the rubber composition, it is possible to adjust the type and content of carbon black, which will be described later. By setting the ratio of the size of M200 to the size of M50 to 5.0 or less (M200/M50≦5.0), an elastomer that can exhibit excellent low loss properties and crack growth resistance. can be realized. Further, from the same viewpoint, the ratio M200/M50 is preferably 4.8 or less, more preferably 4.5 or less.

The 50% modulus value and the 200% modulus value of the coated rubber are calculated according to JIS K 6251 (2010), for example, after vulcanizing a sample of each rubber composition at 145°C for 40 minutes to form a vulcanized rubber. Values measured in accordance with the above can be used. In addition, the above modulus value is calculated by vulcanizing a tire with two belt layers using each rubber composition as a belt coating rubber at a predetermined temperature and vulcanization time, and After taking out the belt coating rubber located between the steel cords and polishing the surface smooth, a dumbbell-shaped test piece was punched out so that the longitudinal direction was along the tire circumferential direction, and this was used to test according to JIS K 6251 (2010). It is also possible to use values measured by

The specific numerical ranges of M50 and M200 of Elastomer 3 are not particularly limited; is preferably 10.5 MPa or less, more preferably M50 is 1.8 MPa or more, and M200 is 9.0 MPa or less.

Specifically, as the elastomer 3, a rubber composition or the like that has been conventionally used for coating a metal cord can be used. The main components of the elastomer 3 include, for example, natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene butadiene rubber (SBR), butadiene rubber (BR, high cis BR and low cis BR), nitrile rubber (NBR), hydrogenated NBR, hydrogenated SBR and other diene rubbers and their hydrogenated products, ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber (M-EPM), butyl rubber (IIR), isobutylene Aromatic vinyl or diene monomer copolymers, acrylic rubber (ACM), olefin rubbers such as ionomers, Br-IIR, CI-IIR, brominated isobutylene-paramethylstyrene copolymers (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHR), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), halogen-containing rubber such as maleic acid-modified chlorinated polyethylene rubber (M-CM), methyl vinyl silicone rubber, dimethyl Silicone rubber, silicone rubber such as methylphenyl vinyl silicone rubber, sulfur-containing rubber such as polysulfide rubber, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicone rubber, fluorine-containing phosphazene rubber Thermoplastic elastomers such as fluororubbers such as rubber, styrene elastomers, olefin elastomers, ester elastomers, urethane elastomers, and polyamide elastomers can be preferably used. These may be used alone or in combination of two or more.

In addition to the above main components, Elastomer 3 also contains sulfur, vulcanization accelerators, carbon black, anti-aging agents commonly used in rubber products such as tires and conveyor belts, zinc oxide, stearic acid, etc. can be appropriately blended.

As the elastomer 3 used in the elastomer-metal cord composite 10 of the present invention, it is particularly preferable to use a rubber composition containing a rubber component, carbon black, a phenol resin, and a methylene donor. With such a composition, it becomes easy to achieve the above-mentioned predetermined modulus ratio M200/M50. Such a rubber composition will be explained below.

(rubber component)
Regarding the rubber component, from the viewpoint of obtaining excellent crack growth resistance and abrasion resistance, natural rubber or diene-based synthetic rubber alone, or a combination of natural rubber and diene-based synthetic rubber, It can contain. Further, the rubber component can be composed only of the above-mentioned diene-based rubber, but it can also contain rubbers other than diene-based rubbers as long as the object of the present invention is not impaired. In addition, from the viewpoint of being able to obtain excellent crack growth resistance, the content of diene rubber in the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, and 50% by mass. % or more is more preferable.

Here, among the above diene-based synthetic rubbers, polybutadiene rubber (BR), isoprene rubber (IR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber ( NBR), etc. Furthermore, examples of non-diene rubber include ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM), butyl rubber (IIR), and the like. Note that these rubber components may be used alone or as a blend of two or more. Further, these rubbers may be modified with a modifying group.

(Carbon black)
There are no particular limitations on carbon black, but one having a DBP (dibutyl phthalate) absorption of 50 cm ³ /100 g or more and 100 cm ³ /100 g or less can be suitably used. By using carbon black with a DBP absorption amount within the above range and a low structure, it is possible to achieve both reinforcing properties and appropriate flexibility of the rubber composition, and to obtain excellent crack growth resistance. can. By setting the DBP absorption amount to 100 cm ³ /100 g or less, the structure can be lowered, the reinforcing properties of the rubber composition can be moderately suppressed, flexibility can be ensured, and sufficient crack growth resistance can be obtained. can. The DBP absorption amount of carbon black is preferably 90 cm ³ /100g or less, more preferably 80 cm ³ /100g or less.

Note that the carbon black structure refers to the size of a structure (agglomerate of carbon black particles) formed as a result of spherical carbon black particles being fused and connected. Further, the DBP absorption amount of carbon black refers to the amount of DBP (dibutyl phthalate) absorbed by 100 g of carbon black, and can be measured in accordance with JIS K 6217-4 (2008).

Further, regarding the carbon black, the nitrogen adsorption specific surface area (N ₂ SA) is preferably 70 m ² /g or more and 90 m ² /g or less, and more preferably 75 m ² /g or more and 85 m ² /g or less. . This makes it possible to further optimize the structure of carbon black, thereby making it possible to further improve low loss properties and crack growth resistance. The above nitrogen adsorption specific surface area can be measured by a single point method in accordance with ISO 4652-1. For example, after immersing degassed carbon black in liquid nitrogen, the carbon black surface area at equilibrium The amount of nitrogen adsorbed on the substrate can be measured, and the specific surface area (m ² /g) can be calculated from the measured value.

Furthermore, regarding the type of carbon black, for example, any hard carbon produced by an oil furnace method can be used. Among these, it is preferable to use HAF grade carbon black from the viewpoint of achieving better low loss properties and crack growth resistance.

The content of carbon black is preferably 35 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the rubber component. By setting the content of carbon black to 35 parts by mass or more with respect to 100 parts by mass of the above rubber component, high reinforcing properties and crack growth resistance can be obtained, and by setting the content to 50 parts by mass or less, low Further improvement in loss resistance can be achieved.

(phenolic resin)
In the rubber composition suitable as the elastomer 3 used in the elastomer-metal cord composite 10 of the present invention, the 50% modulus value (M50) can be improved by including a phenol resin together with the methylene donor described below. , it is possible to improve the reinforcing properties of the rubber composition while maintaining excellent low loss properties, and to achieve excellent crack growth resistance.

Here, the phenol resin is not particularly limited and can be appropriately selected depending on the required performance. Examples include those produced by condensing phenols such as phenol, cresol, resorcinol, tert-butylphenol, or mixtures thereof with formaldehyde in the presence of an acid catalyst such as hydrochloric acid or oxalic acid. Furthermore, the phenol resin may be modified, for example, with oil such as rosin oil, tall oil, cashew oil, linoleic acid, oleic acid, or linoleic acid. In addition, regarding the above-mentioned phenol resin, one type can be used alone, or a plurality of types can be used in combination.

Further, the content of the phenol resin is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. The amount is preferably 7 parts by mass or less, and more preferably 7 parts by mass or less. By setting the content of phenolic resin to 2 parts by mass or more based on 100 parts by mass of the above rubber component, crack propagation resistance can be further improved, and by setting it to 10 parts by mass or less, deterioration of low loss properties can be suppressed. can.

(methylene donor)
In the rubber composition suitable as the elastomer 3 used in the elastomer-metal cord composite 10 of the present invention, the 50% modulus value (M50) can be improved by including a methylene donor as a curing agent for the phenolic resin. This makes it possible to improve the reinforcing properties of the rubber composition while maintaining excellent low loss properties.

The methylene donor is not particularly limited and can be appropriately selected depending on the required performance. For example, hexamethylenetetramine, hexamethoxymethylolmelamine, pentamethoxymethylolmelamine, hexamethoxymethylmelamine, pentamethoxymethylmelamine, hexaethoxymethylmelamine, hexakis-(methoxymethyl)melamine, N,N',N''-trimethyl-N ,N',N"-trimethylolmelamine, N,N',N"-trimethylolmelamine, N-methylolmelamine, N,N'-(methoxymethyl)melamine, N,N',N"-tributyl-N , N',N"-trimethylolmelamine, paraformaldehyde, etc. Among these methylene donors, methylene donors selected from the group consisting of hexamethylenetetramine, hexamethoxymethylmelamine, hexamethoxymethylolmelamine and paraformaldehyde, Preferably, at least one type of methylene donor is used.These methylene donors may be used alone or in combination.

Further, the ratio of the content of the phenolic resin to the content of the methylene donor is preferably 0.6 or more and 7 or less, from the viewpoint of achieving both low loss property and a higher level of crack growth resistance, and 1 More preferably, the number is 5 or less. By setting the ratio of the phenolic resin content to the methylene donor content to be 0.6 or more, M50 can be sufficiently improved and crack growth resistance can be sufficiently improved. By setting it to 7 or less, low loss property can be satisfactorily maintained.

(Other ingredients)
The rubber composition suitable as the elastomer 3 used in the elastomer-metal cord composite 10 of the present invention contains, in addition to the above-mentioned rubber component, carbon black, phenol resin, and methylene donor, other components to achieve the effects of the invention. It can be included to the extent that it does not cause any damage. Other ingredients include fillers other than the above carbon black, anti-aging agents, crosslinking accelerators, crosslinking agents, crosslinking accelerators, silane coupling agents, stearic acid, antiozonants, surfactants, etc. Mention may be made of the additives commonly used in the rubber industry.

Examples of the filler include silica and other inorganic fillers, among which it is preferable to include silica because it provides better low loss properties and crack growth resistance.

Examples of the silica include wet silica, colloidal silica, calcium silicate, and aluminum silicate. Among these, it is preferable to use wet silica, and it is more preferable to use precipitated silica. This is because these silicas have high dispersibility and can further improve the low loss properties and abrasion resistance of the rubber composition. In addition, precipitated silica is produced by growing primary particles of silica by using a reaction solution at a relatively high temperature in the neutral to alkaline pH range in the early stage of production, and then controlling the pH to the acidic side to grow the primary particles. This refers to silica obtained as a result of agglomeration.

The content of silica is not particularly limited, but from the viewpoint of achieving excellent low loss properties, it is preferably greater than 0 parts by mass, and 1 part by mass or more, based on 100 parts by mass of the rubber component. The amount is preferably 3 parts by mass or more, more preferably 25 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less.

Moreover, as the above-mentioned inorganic filler, it is also possible to use, for example, an inorganic compound represented by the following formula (I).
nM・xSiO _y・zH ₂ O...(I)
(wherein M is a metal selected from the group consisting of aluminum, magnesium, titanium, calcium and zirconium, oxides or hydroxides of these metals, hydrates thereof, and carbonates of these metals) (n, x, y and z are each an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5, and an integer of 0 to 10.)

Examples of the inorganic compound represented by the above formula (I) include alumina (Al ₂ O ₃ ) such as γ-alumina and α-alumina; alumina monohydrate (Al ₂ O ₃ ·H ₂ O) such as boehmite and diaspore; ; Aluminum hydroxide [Al(OH) ₃ ] such as gibbsite and bayerite; Aluminum carbonate [Al ₂ (CO ₃ ) ₃ ], magnesium hydroxide [Mg(OH) ₂ ], magnesium oxide (MgO), magnesium carbonate ( MgCO ₃ ), talc (3MgO.4SiO _{2.H 2} O), attapulgite (5MgO.8SiO _{2.9H 2} O), titanium white (TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO), Calcium hydroxide [Ca(OH) ₂ ], magnesium aluminum oxide (MgO・Al ₂ O ₃ ), clay (Al ₂ O ₃・2SiO ₂ ), kaolin (Al ₂ O ₃・2SiO ₂・2H ₂ O), pyro Phyllite ( _{Al2O3.4SiO2.H2O )} , bentonite _{( Al2O3.4SiO2.2H2O} ), magnesium _silicate ( _{Mg2SiO4 , MgSiO3 , etc.} ) _, calcium aluminum silicate ( _{Al2O3 ・}CaO・2SiO2 _etc. ), magnesium calcium silicate ( _CaMgSiO4 ), calcium carbonate ( _CaCO3 ), zirconium oxide ( _ZrO2 ), zirconium hydroxide [ZrO(OH) ₂・_nH2O ], Examples include zirconium carbonate [Zr(CO ₃ ) ₂ ], hydrogen that corrects charge like various zeolites, and crystalline aluminosilicates containing alkali metals or alkaline earth metals.

Known anti-aging agents can be used and are not particularly limited. For example, phenol-based anti-aging agents, imidazole-based anti-aging agents, amine-based anti-aging agents, etc. can be mentioned. These anti-aging agents can be used alone or in combination of two or more.

As the crosslinking accelerator, known ones can be used and there are no particular limitations. For example, thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide; Sulfenamide vulcanization accelerators; Guanidine vulcanization accelerators such as diphenylguanidine; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetradodecylthiuram disulfide, tetraoctylthiuram disulfide, tetrabenzylthiuram disulfide, di Examples include thiuram-based vulcanization accelerators such as pentamethylenethiuram tetrasulfide; dithiocarbamate-based vulcanization accelerators such as zinc dimethyldithiocarbamate; and zinc dialkyldithiophosphate.

There are no particular restrictions on the crosslinking agent, and examples thereof include sulfur, bismaleimide compounds, and the like. Examples of bismaleimide compounds include N,N'-o-phenylenebismaleimide, N,N'-m-phenylenebismaleimide, N,N'-p-phenylenebismaleimide, N,N'-(4,4 Examples include '-diphenylmethane)bismaleimide, 2,2-bis-[4-(4-maleimidophenoxy)phenyl]propane, and bis(3-ethyl-5-methyl-4-maleimidophenyl)methane. In the present invention, N,N'-m-phenylenebismaleimide, N,N'-(4,4'-diphenylmethane)bismaleimide, and the like can be suitably used.

Examples of the crosslinking accelerator include zinc white (ZnO) and fatty acids. The fatty acid may be any saturated or unsaturated, linear or branched fatty acid, and the number of carbon atoms in the fatty acid is not particularly limited. For example, a fatty acid having 1 to 30 carbon atoms, preferably 15 to 30 carbon atoms. More specifically, cyclohexanoic acid (cyclohexanecarboxylic acid), naphthenic acid such as alkylcyclopentane having a side chain; hexanoic acid, octanoic acid, decanoic acid (including branched carboxylic acids such as neodecanoic acid), dodecanoic acid, Examples include saturated fatty acids such as tetradecanoic acid, hexadecanoic acid, and octadecanoic acid (stearic acid); unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid, and linolenic acid; resin acids such as rosin, tall oil acid, and abietic acid. . These may be used alone or in combination of two or more. In the present invention, zinc white and stearic acid can be suitably used.

Further, in the present invention, the elastomer 3 may or may not contain a cobalt compound. The content of the cobalt compound in the elastomer 3 can be preferably less than 0.01 parts by mass, and more preferably not contained, based on 100 parts by mass of the rubber component. By suppressing the content of the cobalt compound, and especially by not containing the cobalt compound, it becomes possible to suppress the deterioration of the elastomer 3, particularly the deterioration of the unvulcanized rubber.

Note that when the rubber composition suitable as the elastomer 3 used in the elastomer-metal cord composite 10 of the present invention contains silica as the filler, it is preferable to further contain a silane coupling agent. This is because the effects of reinforcing properties and low loss properties due to silica can be further improved. Note that any known silane coupling agent can be used as appropriate. The preferred content of the silane coupling agent varies depending on the type of silane coupling agent, but it is preferably 2% by mass or more, particularly preferably 5% by mass or more, based on the silica. It is preferably 25% by mass or less, more preferably 20% by mass or less, particularly preferably 18% by mass or less. By setting the content of the silane coupling agent to 2% by mass or more, the effect as a coupling agent can be fully exhibited, and by setting the content to 25% by mass or less, gelation of the rubber component can be prevented. can.

The rubber composition suitable as the elastomer 3 used in the elastomer-metal cord composite 10 of the present invention is not particularly limited, and the rubber composition as each component constituting the rubber composition, carbon black, phenol resin, methylene donor and It can be prepared by blending and kneading other ingredients. At this time, each of the above components can be kneaded at the same time, or it is also possible to knead any one of the components in advance and then knead the remaining components. These conditions can be changed as appropriate depending on the performance required of the rubber composition.

For example, from the viewpoint of realizing better low loss properties and crack growth resistance, it is preferable to mix and knead the rubber component and carbon black prior to kneading with the phenol resin. Phenol resin has a strong interaction with carbon black, so if it is added at the same time, there is a risk that the reaction between the rubber component and carbon black will be reduced. Therefore, by blending and kneading the rubber component and carbon black prior to kneading with the phenolic resin, the dispersibility and reinforcing properties of carbon black can be improved, and further improvements in low loss properties and crack growth resistance can be achieved. becomes.

The elastomer-metal cord composite 10 of the present invention can be manufactured by known methods. For example, a reinforcing element 2 made of a plurality of metal filaments 1 arranged in parallel at a predetermined interval may be covered with an elastomer 3, or a reinforcing element 2 made of a metal filament bundle made of a plurality of metal filaments 1 aligned without being twisted together. The metal cord 2 can be made by covering it with the elastomer 3.

The thickness of the elastomer-metal cord composite 10 of the present invention is preferably greater than 0.30 mm and less than 1.00 mm. By setting the weight within this range, when the elastomer-metal cord composite 10 of the present invention is used in a belt layer, it is possible to sufficiently reduce the weight of the belt.

Next, the tire of the present invention will be explained.
FIG. 3 shows a schematic half-sectional view of a tire according to a preferred embodiment of the present invention. The tire 100 of the present invention is made using the elastomer-metal cord composite 10 of the present invention, and thereby can improve low loss properties, separation resistance, and crack growth resistance. The illustrated tire 100 includes a tread portion 101 that forms a ground contact portion, a pair of sidewall portions 102 that extend inward in the tire radial direction continuously from both sides of the tread portion 101, and an inner periphery of each sidewall portion 102. This is a pneumatic tire equipped with a bead portion 103 that is continuous on the side. Examples of the tire 100 of the present invention include tires for passenger cars and tires for trucks and buses.

In the illustrated tire 100, a tread portion 101, a sidewall portion 102, and a bead portion 103 are reinforced by a carcass 104 made of a single carcass layer extending in a toroidal shape from one bead portion 103 to the other bead portion 103. . Further, the tread portion 101 is reinforced by a belt 105 made of at least two layers (in the illustrated example, two layers, a first belt layer 105a and a second belt layer 105b) disposed outside the crown region of the carcass 104 in the tire radial direction. has been done. Here, the carcass 104 may have a plurality of carcass layers, and organic fiber cords extending in a direction substantially orthogonal to the tire circumferential direction, for example, at an angle of 70° or more and 90° or less, can be suitably used.

In the tire 100 of the present invention, the elastomer-metal cord composite 10 of the present invention can be used for the first belt layer 105a and the second belt layer 105b. By using the elastomer-metal cord composite 10 of the present invention, the thickness of the first belt layer 105a and the second belt layer 105b can be reduced, and the weight of the tire can be reduced. Further, by using the elastomer-metal cord composite 10 of the present invention for a belt cord, the low loss properties, separation resistance, and crack growth resistance of the belt can be improved at the same time. The cord angle in the belt 105 can be 30° or less with respect to the tire circumferential direction.

The tire 100 of the present invention may be one that uses the elastomer-metal cord composite 10 of the present invention, and there are no particular limitations on the specific tire structure other than that. Furthermore, the application of the elastomer-metal cord composite 10 of the present invention is not limited to the belt 105. For example, in the tire of the present invention, a belt reinforcing layer may be arranged on the outside of the belt 105 in the tire radial direction, or other reinforcing members may be used, and the elastomer-metal cord composite 10 of the present invention It may also be used as a belt reinforcing layer or other reinforcing members.

Further, in the tire 100 of the present invention, a bead core 106 can be placed in each of the pair of bead portions 103, and the carcass 104 is normally rolled up and locked around the bead core 106 from the inside to the outside. Further, although not shown, a bead filler having a tapered cross section may be disposed on the outer side of the bead core 106 in the tire radial direction. Note that as the gas to be filled in the tire 100, in addition to normal air or air with adjusted oxygen partial pressure, inert gas such as nitrogen, argon, helium, etc. can be used.

Hereinafter, the present invention will be explained in more detail using examples.

(Preparation of rubber composition)
Rubber compositions A and B were prepared by blending and kneading according to a conventional method according to the formulations shown in the table below. Each component was kneaded using a Banbury mixer with a capacity of 3.0 L. In addition, regarding rubber composition B, the rubber component and carbon black were kneaded prior to kneading with the phenol resin. In addition, the 50% modulus value (M50) and 200% modulus value (M200) of each rubber composition are determined when a tire with two belt layers using each rubber composition as a belt coating rubber is vulcanized at a predetermined temperature. After taking out the belt coating rubber located between each steel cord of the two belt layers and polishing the surface smooth, test it in a dumbbell shape so that the longitudinal direction is along the tire circumferential direction. A piece was punched out and subjected to a tensile test according to JIS K 6251 (2010), and the tensile stress was measured when 50% elongation and 200% elongation were applied.

*1) HAF grade carbon black, “Asahi #70L” manufactured by Asahi Carbon Co., Ltd., DBP absorption: 75 cm ³ /100g, nitrogen adsorption specific surface area: 81 m ² /g
*2) “Sumilight Resin PR-50235” manufactured by Sumitomo Bakelite Co., Ltd.
*3) “CYREZ 964” manufactured by ALLNEX
*4) “Nip Seal AQ” manufactured by Tosoh Silica Co., Ltd., nitrogen adsorption specific surface area = 210 m ² /g
*5) "Nocrac NS-6" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., 2,2'-methylenebis(4-methyl-6-tert-butylphenol)
*6) "Nocrac 6C" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine *7) Insoluble sulfur (product name: Christex HS OT) -20, manufactured by Flexis)
*8) "Noxela DZ" manufactured by Ouchi Shinko Chemical Industry Co., Ltd., N,N-dicyclohexyl-2-benzothiazolylsulfenamide *9) "Manobond C" manufactured by OMG, organic acid in cobalt salt of organic acid Composite salt in which part of is replaced with boric acid, cobalt content: 22.0% by mass
*10) “BMI-RB” manufactured by Daiwa Chemical Industries, Ltd.

A steel cord as a reinforcing element according to the conditions shown in the table below was covered from both upper and lower sides with a sheet approximately 0.5 mm thick made of a rubber composition shown in the table below, and the elastomer of each example and conventional example was - A metal cord composite was produced.

The reinforcing element of Comparative Example 1 is a twisted cord made of steel filaments twisted together in a structure of 2 x 0.225 mm + 3 x 0.18 mm. The reinforcing element of Comparative Example 2 is a cord made of a steel filament bundle made up of seven steel filaments each having a wire diameter of 0.24 mm and aligned in a line without being twisted. The reinforcing element of Comparative Example 3 is a cord in which steel filaments with a diameter of 0.3 mm are evenly arranged in a line without being twisted. The reinforcing element of Example 1 is a cord made of a steel filament bundle consisting of five steel filaments each having a wire diameter of 0.26 mm, which are aligned in a row without being twisted. The reinforcing element of Example 2 is a cord made of a steel filament bundle made up of three steel filaments each having a wire diameter of 0.3 mm that are aligned in a row without being twisted.

Each of the obtained elastomer-metal cord composites was evaluated in terms of elastomer coverage, low loss properties, crack growth resistance, and separation resistance according to the following.

<Elastomer coverage (%)>
The elastomer coverage was determined by coating the cords of each example and comparative example with rubber, vulcanizing them at 160°C for 10 to 15 minutes, and then pulling out the steel cord from the resulting rubber-steel cord composite. The length of the side surface of the steel filament in the width direction of the metal cord, which is covered with rubber that has penetrated into the gaps between the steel filaments that make up the steel cord, was measured, and the length was calculated as the average of the values calculated based on the following formula. . The formula for calculating the elastomer coverage is as follows.
Elastomer coverage = (rubber coverage length/sample length) x 100 (%)
The rubber covering length is the length of the area where the surface of the steel filament is completely covered with rubber when the pulled steel cord is observed from a direction perpendicular to the longitudinal direction of the cord. The larger the number, the higher the adhesive strength and the better the performance.

<Low loss>
Each of the rubber compositions A and B was vulcanized at 145° C. for 40 minutes to obtain a vulcanized rubber. The loss tangent (tan δ) of the obtained vulcanized rubber was measured using a spectrometer (manufactured by Ueshima Seisakusho Co., Ltd.) under conditions of a temperature of 24° C., a strain of 1%, and a frequency of 52 Hz. The evaluation is expressed as an index when the tan δ of the sample of rubber composition A is set to 100, and the smaller the index value, the better the low heat generation property is.

<Crack growth resistance>
Each of the rubber compositions A and B was vulcanized at 145° C. for 40 minutes to obtain a vulcanized rubber. A sheet of 2 mm x 50 mm x 6 mm was prepared from the obtained vulcanized rubber, and a small hole was made in the center to form an initial crack. Thereafter, stress was repeatedly applied to this sheet in the long side direction under conditions of 2.0 MPa, a frequency of 6 Hz, and an ambient temperature of 80°C. Then, for each sample, the number of repetitions from application of repeated stress until the test piece broke was measured, and then the common logarithm of the number of repetitions was calculated. The measurement test up to breakage was performed four times for each sample to calculate the common logarithm, and the average of these was taken as the average common logarithm. Regarding the evaluation, the average common logarithm of the rubber composition A was rated as ○, the case where the average common logarithm of the sample was larger than this was rated as ◎, and the case where it was smaller was rated as ×.

<Separation resistance>
The separation length of the tires in which the elastomer-metal cord composites of each Example and Comparative Example were applied to the belt layer was evaluated using a drum tester, and then the separation length was determined. When the separation length was smaller than that of Comparative Example 1, it was rated as ○, when it was the same as △, and when it was larger, it was rated as ×.

The obtained results are also listed in the table below.

From the results in the table above, it was found that in an elastomer-metal cord composite in which a reinforcing element consisting of a plurality of metal filaments aligned in a row without being twisted is covered with an elastomer, the minimum gap distance between the metal filaments and It can be seen that in each example in which the modulus ratio M200/M50 of the elastomer was set within a predetermined range, good results were obtained in terms of low loss properties, crack growth resistance, and separation resistance.

1 Metal filament 2 Reinforcement element (metal cord)
3 Elastomer 10 Elastomer-metal cord composite 100 Tire 101 Tread portion 102 Sidewall portion 103 Bead portion 104 Carcass 105 Belt 105a, 105b Belt layer 106 Bead core

Claims (6)

In an elastomer-metal cord composite in which a reinforcing element consisting of a plurality of metal filaments arranged in a line without being twisted is coated with an elastomer,
The minimum gap distance between the metal filaments is 0.01 mm or more and less than 0.24 mm, the maximum gap distance between the metal filaments is 0.35 mm or more and 2.0 mm or less, and the metal filaments are The wire diameter is 0.15 mm or more and 0.35 mm or less, and the ratio M200/M50 of the 200% modulus value (M200) to the 50% modulus value (M50) of the elastomer is 5.0 or less. An elastomer-metal cord composite characterized by: The elastomer-metal cord composite according to claim 1 , wherein the reinforcing element is a metal filament bundle consisting of 2 or more and 20 or less metal filaments. The elastomer-metal cord composite according to claim 1 or 2, wherein the elastomer comprises a rubber composition containing a rubber component, carbon black, a phenol resin, and a methylene donor. The elastomer-metal cord composite according to claim 3 , wherein the elastomer contains silica, and the content of the silica is more than 0 parts by mass and 25 parts by mass or less based on 100 parts by mass of the rubber component. The elastomer-metal cord composite according to claim 3 or 4 , wherein the elastomer contains a cobalt compound, and the content of the cobalt compound is less than 0.01 parts by mass based on 100 parts by mass of the rubber component. A tire comprising the elastomer-metal cord composite according to any one of claims 1 to 5 .

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