JP2015203156A - Metal filament for rubber commodity reinforcing cord and rubber commodity reinforcing cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique which can effectively prevent formation of a gap between filaments comprising a cord and can prevent rusting in the cord for a long term.SOLUTION: At least one part of a surface of a metal filament for a rubber commodity reinforcing cord is coated with a coating material that a penetration measured by a penetration testing method following JIS K 2235-1991 at 25°C is more than 0. The rubber commodity reinforcing cord is made of twisted multiple filaments 1 and 2 including the metal filament for the rubber commodity reinforcing cord.

Description

  The present invention relates to a metal filament for rubber article reinforcement cord and a rubber article reinforcement cord (hereinafter also simply referred to as “filament” and “cord”), and more specifically, a rubber article reinforcement cord used for reinforcement of rubber articles such as tires, The present invention also relates to an improvement of a metal filament for a rubber article reinforcing cord used for the same.

  Conventionally, a cord including a plurality of metal filaments such as steel has been used as a reinforcing material in rubber articles such as tires. However, in a cord including such a metal filament, for example, when a tire having a belt layer reinforced with this cord is damaged and reaches the belt layer, moisture in the external environment causes the cord to be damaged. There was a problem that the cords rusted by entering the gaps between the constituting filaments.

  On the other hand, for example, a cord in which a plurality of strands in which a sheath formed by twisting a plurality of filaments is arranged around a core formed by twisting one or a plurality of filaments is further twisted at the time of manufacture. A technique is known in which the outer surface of the core is coated with unvulcanized rubber and then the sheath is further twisted to fill the gaps in the cord with rubber to prevent contact between water and the filament ( Patent Document 1).

International Publication No. 2009/011397

  However, even if the gaps between the filaments are filled with rubber, peeling of the rubber may occur due to repeated strain input during use of the tire, and there may be a gap again between the filaments and the rubber. If water, corrosive substances contained in water, sulfur compounds, etc. enter this gap and move by capillary action, rust is generated and progresses, which is undesirable for maintaining the strength of the cord and maintaining high cord strength. In order to continue this, it is important to prevent the occurrence of such a gap.

  Therefore, an object of the present invention is to provide a technique capable of effectively suppressing the occurrence of gaps between filaments constituting a cord and preventing the occurrence of rust in the cord for a long period of time.

  As a result of intensive studies, the present inventor has found that the above-described problem can be solved by adopting the following configuration, and has completed the present invention.

  That is, the metal filament for rubber article reinforcing cord of the present invention is a coating material in which at least a part of the surface has a penetration greater than 0 measured by a penetration test according to JIS K 2235-1991 at 25 ° C. It is characterized by being covered with.

  In the present invention, a wax can be suitably used as the coating material. Moreover, it is preferable that the said wax contains 5-50 mass parts thermoplastic resin with respect to 100 mass parts of wax components. Furthermore, in this invention, it is preferable that the penetration measured by the penetration test method according to JISK2235-1991 at 25 degreeC of the said coating material is 50 or less.

  The rubber article reinforcing cord of the present invention is characterized in that a plurality of filaments including the metal filament for rubber article reinforcing cord of the present invention are twisted together.

  According to the present invention, there is provided a filament for rubber article reinforcement cord and a rubber article reinforcement cord capable of effectively suppressing the occurrence of gaps between filaments constituting the cord and preventing the occurrence of rust in the cord for a long period of time. It became possible to realize.

It is sectional drawing of the direction orthogonal to the longitudinal direction of an example of the rubber article reinforcement cord of this invention. It is explanatory drawing which shows the definition of the clearance gap between the filaments in this invention. It is explanatory drawing which shows the state of the corrosion test in an Example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The metal filament for rubber article reinforcing cord of the present invention is characterized in that at least a part of the surface thereof is coated with a coating material having predetermined physical properties. Specifically, in the present invention, it is important to use a material whose penetration measured by a penetration test according to JIS K 2235-1991 at 25 ° C. is greater than 0.

  By using at least a part of the surface of the cord metal filament with a material having a penetration greater than 0, that is, a material softer than rubber or the like used in the prior art, deformation of the filament can be achieved. On the other hand, the coating material follows well. As a result, even when there is repeated strain input to the cord when using the tire, etc., the coating material becomes difficult to peel off from the filament, and even if damage (cut) that reaches the belt layer of the tire occurs. Since the effect of preventing contact between water and the cord can be obtained with certainty, it is possible to suppress the occurrence of rust in the cord over a long period of time.

  Here, the penetration is specifically measured by how many mm the specified needle enters the coating material kept at 25 ° C. from the vertical direction under the condition of a weight of 100 g for 5 seconds. The value is 10 times larger than this value. The larger the value, the softer. In the present invention, the penetration of the coating material needs to be greater than 0, preferably 50 or less, more preferably 1 to 35, and even more preferably 5 to 20. By making the penetration of the coating material 50 or less, the softness of the coating material is adjusted moderately to improve the ease of handling of the coating material at the time of manufacturing the filament of the present invention, and thus at the time of manufacturing the cord. can do. That is, by making the penetration of the coating material 50 or less, it is possible to effectively prevent the phenomenon that the coating material peels off from the wire surface when the wire coated with the coating material passes through a pulley or the like during production. it can. On the other hand, increasing the penetration of the coating material increases the corrosion resistance of the cord. However, if it is too high, the ease of handling is impaired, so there is an optimum range.

  In the present invention, if the coating material covers at least a part of the surface of the filament, the desired effect of the present invention can be obtained. For example, it is preferable from the viewpoint of preventing peeling of the coating material from the filament that the coating material covers an area of 30% or more, particularly 50% or more of the surface of the filament, and more preferably, It is assumed that the entire surface of the filament is covered with a coating material. The coverage of the coating material on the filament surface can be obtained, for example, by calculating the ratio of the covering portion in the total surface area of the arbitrary length portion of the filament for a plurality of locations in the filament length direction and obtaining the average value of the plurality of locations. Can do.

  The coating material used in the present invention may be any material as long as it satisfies the penetration conditions. Specifically, for example, wax can be suitably used. Since wax has adhesiveness and flexibility, it does not easily fall off from the filament surface and does not cause problems such as deterioration in workability due to adhesion to manufacturing equipment. Since it does not contain a substance that corrodes plating components such as brass plating, the life of the cord can be further extended.

  Here, the wax in the present invention is 50% by mass or more, preferably 70% by mass or more, made of an organic compound having 10 to 1000 carbon atoms, preferably 18 to 500 carbon atoms, and the carbon chain is linear. It may be either a shape or a branch. Specifically, synthetic wax or petroleum-derived wax can be used as such a wax. Examples of the synthetic wax include hydrocarbons such as Fischer-Tropsch wax and polyethylene wax, and those having polar groups such as fatty acids. Examples of the petroleum-derived wax include paraffin wax and microcrystalline wax. For example, the effect of inhibiting the corrosion of the cord can be further improved by mixing 5 to 50 parts by mass of a thermoplastic resin with 100 parts by mass of the wax component.

  Specific examples of the metal filament constituting the metal filament for rubber article reinforcing cord of the present invention include a steel filament.

  The cord of the present invention is formed by twisting a plurality of filaments including the metal filament of the present invention. In FIG. 1, sectional drawing of the direction orthogonal to the longitudinal direction of an example of the rubber article reinforcement cord of this invention is shown. The rubber article reinforcing cord shown in the figure has a layered twist structure in which a sheath 12 is formed by twisting nine filaments 2 around a core 11 in which three filaments 1 are twisted together.

  In the rubber article reinforcing cord of the present invention, at least a part of the gaps between the plurality of filaments 1 and 2, in the illustrated example, all are filled with the coating material 10 having the predetermined penetration. The soft coating material 10 follows the deformation of the cord better than in the past. Therefore, as described above, even when a strain is repeatedly input to the cord when using the tire, the coating material is difficult to peel off from the filament, and as a result, generation of rust that may occur in the metal filament is prolonged. The effect which suppresses over can be acquired.

  In the present invention, if the coating material fills at least part of the gaps between the plurality of filaments constituting the cord, the desired effect of the present invention can be obtained. Here, the gap between the plurality of filaments constituting the cord in the present invention is a single twist structure formed by simply twisting a plurality of filaments, or around a core formed by twisting a plurality of filaments. Further, in the case of a cord having a layer twist structure in which a plurality of filaments are twisted to form one or more sheaths, the center points of adjacent outermost layer filaments are connected in a cross section perpendicular to the longitudinal direction of the cord. This is a portion excluding the portion occupied by the filament from the space formed in this way (FIGS. 2A and 2B, hatched portions in the figure). In addition, in the case of a cord having a double twisted structure formed by twisting a plurality of strands obtained by twisting a plurality of filaments, in the cross section orthogonal to the longitudinal direction of the cord, From the space formed by connecting the center points of the outermost layer filaments, from the space formed by connecting the center points of the outer layer filaments, in addition to the portion excluding the portion occupied by the filaments, from the space formed by connecting the center points of the adjacent outermost layer strands, The portion excluding the portion occupied by the filament is also included (FIG. 2C, shaded portion in the figure). That is, in the present invention, in the case of layer twist cord, it is preferable not to use a filament coated with a coating material on the outermost layer filament. In the case of double twist cord, the outermost layer filament of the outermost layer strand is coated with a coating material. It is preferable not to use a filament.

  In the present invention, the entire gap between the filaments can be filled with a coating material. For example, in the case of a cord having a double twist structure, adjacent to each strand in a cross section perpendicular to the longitudinal direction of the cord. Rust generation can be effectively suppressed by filling the coating material in the space formed by connecting the center points of the matching outermost layer filaments except for the portion occupied by the filament. In particular, it is most effective to fill the coating material at least in the space formed by connecting the center points of the adjacent outermost layer filaments of the core strand except for the portion occupied by the filament. The generation of rust can be suppressed, which is preferable.

  Further, in the present invention, it is preferable that the portion where the coating material is not filled in the gap between the filaments does not exist continuously from the start point to the end point of the length of 2 cm at any part of the cord. . In the longitudinal direction of the cord, the rust preventive effect can be ensured satisfactorily by avoiding the formation of a portion where the coating material does not exist continuously over 2 cm. In particular, in the case of a cord having a double twist structure, it is preferable that the gap between the filaments in the core strand does not have a portion where there is no continuous coating material over a length of 2 cm. In the case of a cord with a double twist structure, the core strand is the part that is most difficult for rubber penetration (rubber penetration), so by properly defining the gap amount filled with the coating material, the rust prevention effect can be obtained more reliably. it can.

  The rubber article reinforcing cord of the present invention can be manufactured by, for example, extruding a coating material in a gap between filaments by a technique applied to electric wire coating. The rubber article reinforcing cord of the present invention is produced by coating at least a part of the surface of the metal filament with the coating material according to a conventional method to produce the rubber article reinforcing cord filament of the present invention. It is also possible to produce using a rubber article reinforcing cord filament. Note that a cord in which a plurality of filaments including a filament coated with a coating material are twisted may be filled with a gap between the filaments with wax, resin, rubber, or the like, or may not be filled.

Hereinafter, the present invention will be described in more detail with reference to examples.
According to the conditions shown in the following table, the entire surface of a steel filament (SHT, n = 3) of φ0.30 mm was measured at 25 ° C. according to the penetration test method according to JIS K 2235-1991. Samples for evaluation of the examples and comparative examples were prepared by coating with different coating materials.

<Corrosion test>
As shown in FIG. 3, each evaluation sample 100 bent with a radius of curvature R (corresponding to a curvature strain of 30 kgf / mm ² ) is immersed in a corrosive solution L containing Cl ⁻ , NO ₃ ⁻ , SO ₄ ^−. In the immersed state, each evaluation sample was twisted. Durability was evaluated by measuring the number of twists to break. The greater the number of twists, the better the durability performance.

<Productivity>
The handleability of the coating material when producing each evaluation sample was evaluated by an index value with the coating material of Comparative Example 4 being 100. The larger the value, the better the handleability.

＊１）２５℃において、ＪＩＳ Ｋ ２２３５−１９９１に準ずる針入度試験法により測定された、各被覆材料の針入度である。
＊２）三井化学（株）製のエチレン結合化合物ワックス（三井ハイワックス４０５ＭＰ）
＊３）日本精蝋（株）製のマイクロクリスタリンワックス（Ｈｉ−Ｍｉｃ−２０４５）
＊４）８０質量％の日本精蝋（株）製のマイクロクリスタリンワックス（Ｈｉ−Ｍｉｃ−２０９５）と２０質量％のポリマー成分（三井・デュポン・ポリケミカル（株）製のエチレン−酢酸ビニル共重合樹脂，エバフレックスＶ５２７４）との混合物。
＊５）９０質量％の日本精蝋（株）製のマイクロクリスタリンワックス（Ｈｉ−Ｍｉｃ−１０４５）と１０質量％のポリマー成分（三井・デュポン・ポリケミカル（株）製のエチレン−酢酸ビニル共重合樹脂，エバフレックスＰ１００７）との混合物。
＊６）三井化学（株）製のポリプロピレン分解型ワックス（三井ハイワックスＮＰ０５５）
＊７）９５質量％の三井化学（株）製の低密度ポリエチレン分解ワックス（ＮＬ５００）と５質量％のポリマー成分（三菱化学（株）製のポリエチレン樹脂，モディック Ｌ５０４）との混合物。
＊８）９５質量％の三井化学（株）製のポリプロピレン分解ワックス（ＮＰ０５５）と５質量％のポリマー成分（三菱化学（株）製のポリプロピレン樹脂，モディック Ｐ５６５）との混合物。

* 1) The penetration of each coating material measured at 25 ° C. by a penetration test method according to JIS K 2235-1991.
* 2) Ethylene bond compound wax (Mitsui High Wax 405MP) manufactured by Mitsui Chemicals, Inc.
* 3) Microcrystalline wax (Hi-Mic-2045) manufactured by Nippon Seiwa Co., Ltd.
* 4) 80% by mass of Nippon Seiwa Co., Ltd. microcrystalline wax (Hi-Mic-2095) and 20% by mass of polymer component (Mitsui-DuPont Polychemical Co., Ltd. ethylene-vinyl acetate copolymer) Resin, Evaflex V5274).
* 5) 90% by mass of Nippon Seiwa Co., Ltd. microcrystalline wax (Hi-Mic-1045) and 10% by mass of polymer component (Mitsui-DuPont Polychemical Co., Ltd. ethylene-vinyl acetate copolymer) Resin, Evaflex P1007).
* 6) Polypropylene degradable wax (Mitsui High Wax NP055) manufactured by Mitsui Chemicals, Inc.
* 7) A mixture of 95% by mass of a low-density polyethylene decomposition wax (NL500) manufactured by Mitsui Chemicals, Ltd. and 5% by mass of a polymer component (polyethylene resin manufactured by Mitsubishi Chemical Co., Ltd., Modic L504).
* 8) A mixture of 95% by mass of a polypropylene decomposition wax (NP055) manufactured by Mitsui Chemicals, Ltd. and 5% by mass of a polymer component (polypropylene resin manufactured by Mitsubishi Chemical Co., Ltd., Modic P565).

＊９）住友スリーエム（株）製のエポキシ樹脂（３Ｍスコッチ・ウェルドＥＷ０５０）
＊１０）天然ゴム１００質量部と、カーボンブラック（ＨＡＦ）６０質量部と、亜鉛華６質量部と、老化防止剤ノクラック６Ｃ（Ｎ−フェニル−Ｎ’−（１，３−ジメチルブチル）−ｐ−フェニレンジアミン，大内新興化学工業（株）製）１質量部と、加硫促進剤ノクセラーＤＺ（Ｎ，Ｎ’−ジシクロヘキシル−２−ベンゾチアジルスルフェンアミド，大内新興化学工業（株）製）１質量部と、マノボンドＣ２２．５（コバルト脂肪酸塩，コバルト含有量２２．５質量％，ＯＭＧ社製）１質量部との混合物
＊１１）三井・デュポン・ポリケミカル（株）製のエチレン−酢酸ビニル共重合樹脂（エバフレックスＶ５２７４）

* 9) Epoxy resin manufactured by Sumitomo 3M Limited (3M Scotch Weld EW050)
* 10) 100 parts by mass of natural rubber, 60 parts by mass of carbon black (HAF), 6 parts by mass of zinc oxide, and anti-aging agent NOCRACK 6C (N-phenyl-N ′-(1,3-dimethylbutyl) -p -Phenylenediamine, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) and 1 part by weight of a vulcanization accelerator Noxeller DZ (N, N'-dicyclohexyl-2-benzothiazylsulfenamide, Ouchi Shinsei Chemical Industry Co. 1 part by mass and Manobond C22.5 (cobalt fatty acid salt, cobalt content 22.5% by mass, manufactured by OMG) 1 part by mass * 11) Ethylene manufactured by Mitsui DuPont Polychemical Co., Ltd. -Vinyl acetate copolymer resin (Evaflex V5274)

  As shown in the above table, in the steel filament in which the surface is coated with a coating material having a predetermined penetration, it is not coated with a coating material or is coated with a coating material with a penetration of 0 It was confirmed that the number of twists to break can be significantly increased compared to steel filaments. In particular, in Examples 3, 4, 6, and 7 in which a mixture in which a thermoplastic resin as a polymer component was mixed with wax as a coating material was used, the number of twists until breakage increased.

1, 2 Filament 10 Coating material 11 Core 12 Sheath 100 Evaluation sample L Corrosion solution

Claims (5)

  A rubber article reinforcing cord characterized in that at least a part of the surface is coated with a coating material having a penetration measured by a penetration test according to JIS K 2235-1991 at 25 ° C. of greater than 0. Metal filament for use.   The metal filament for a rubber article reinforcing cord according to claim 1, wherein the coating material is a wax.   The metal filament for rubber article reinforcement cords according to claim 1 or 2, wherein the wax contains 5 to 50 parts by mass of a thermoplastic resin with respect to 100 parts by mass of the wax component.   The rubber article reinforcing cord according to any one of claims 1 to 3, wherein a penetration of the coating material measured at 25 ° C by a penetration test according to JIS K 2235-1991 is 50 or less. Metal filament for use. A rubber article reinforcement cord comprising a plurality of filaments including the metal filament for a rubber article reinforcement cord according to any one of claims 1 to 4.

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