JP6924985B2

JP6924985B2 - Adhesion condition evaluation method of rubber wire composite, rubber wire composite and pneumatic tire

Info

Publication number: JP6924985B2
Application number: JP2017090970A
Authority: JP
Inventors: 鹿久保　隆志; 隆志鹿久保; 浩司陣内; 剛志樋口
Original assignee: Tohoku University NUC; Yokohama Rubber Co Ltd
Current assignee: Tohoku University NUC; Yokohama Rubber Co Ltd
Priority date: 2017-05-01
Filing date: 2017-05-01
Publication date: 2021-08-25
Anticipated expiration: 2037-05-01
Also published as: JP2018189455A

Description

本発明は、ゴムワイヤ複合体の接着状態評価方法、ゴムワイヤ複合体および空気入りタイヤに関する。 The present invention relates to a method for evaluating an adhesive state of a rubber wire composite, a rubber wire composite, and a pneumatic tire.

空気入りタイヤは、ゴム組成物中にワイヤ材が埋設されたゴムワイヤ複合体をゴム補強層として有することが多い。このようなゴムワイヤ複合体に使用されるワイヤ材としては、例えばスチールワイヤにブラスめっきが施されたものが用いられる。
ゴムワイヤ複合体においてゴムとスチールワイヤとが剥離すると、空気入りタイヤの故障の原因となり、空気入りタイヤの耐久性を悪化させることになる。このため、ゴムとブラスめっきとの接着強度を高めて、ゴムとスチールワイヤとを強固に接着させることが求められる（例えば、特許文献１を参照）。
また、ゴムワイヤ複合体は、走行時の振動や衝撃、熱、酸素、水分などに曝されるため、その影響によってゴムとスチールワイヤとの接着強度が弱まる可能性がある。そのため、様々な外的要因に起因する劣化によって接着強度が弱まることを防ぐことも求められる。 Pneumatic tires often have a rubber wire composite in which a wire material is embedded in a rubber composition as a rubber reinforcing layer. As the wire material used for such a rubber wire composite, for example, a steel wire plated with brass is used.
If the rubber and the steel wire are separated from each other in the rubber wire composite, it causes a failure of the pneumatic tire and deteriorates the durability of the pneumatic tire. Therefore, it is required to increase the adhesive strength between the rubber and the brass plating to firmly bond the rubber and the steel wire (see, for example, Patent Document 1).
Further, since the rubber wire composite is exposed to vibration, impact, heat, oxygen, moisture, etc. during traveling, the adhesive strength between the rubber and the steel wire may be weakened due to the influence. Therefore, it is also required to prevent the adhesive strength from being weakened due to deterioration caused by various external factors.

特開平１０‐２５０３１０号公報Japanese Unexamined Patent Publication No. 10-250310

上述のような強固な接着や、劣化による接着強度の低下の防止を可能にするためには、ゴムとスチールワイヤ（ブラスめっき）との間の接着の状態や、劣化の程度を評価することが求められる。
従来は、引張試験や剥離試験などを行い、接着の状態や劣化の程度を評価していた。しかしながら、このような評価方法では、例えばゴムとスチールワイヤとの界面における剥離やめっき変質の状態を直接観察することはできず、詳細な状態解析を行うことができなかった。 In order to enable the strong adhesion as described above and the prevention of deterioration of the adhesive strength due to deterioration, it is necessary to evaluate the state of adhesion between the rubber and the steel wire (brass plating) and the degree of deterioration. Desired.
Conventionally, a tensile test or a peeling test has been performed to evaluate the state of adhesion and the degree of deterioration. However, with such an evaluation method, for example, the state of peeling and plating deterioration at the interface between rubber and steel wire cannot be directly observed, and detailed state analysis cannot be performed.

本発明の目的は、ゴムワイヤ複合体におけるワイヤ材とゴム組成物との接着状態を精度よく評価するとともに、ワイヤ材とゴム組成物との接着状態を向上させたゴムワイヤ複合体およびこれを用いた空気入りタイヤを提供することにある。 An object of the present invention is to accurately evaluate the adhesive state between the wire material and the rubber composition in the rubber wire composite, and to improve the adhesive state between the wire material and the rubber composition, and the air using the rubber wire composite. The purpose is to provide rubberized tires.

上述の目的を達成するため、請求項１の発明にかかるゴムワイヤ複合体の接着状態評価方法は、めっきされたワイヤ材をゴム組成物で被覆したゴムワイヤ複合体における前記ワイヤ材と前記ゴム組成物との接着状態を評価する接着状態評価方法であって、走査型電子顕微鏡を用い、前記ゴムワイヤ複合体表面の組成分布を検出する検出工程と、集束イオンビームにより前記ゴムワイヤ複合体表面を所定厚さエッチングするエッチング工程と、をくり返し、前記ゴムワイヤ複合体の３次元組成分布を取得する組成分布取得工程と、前記３次元組成分布から、前記ワイヤ材と前記ゴム組成物との接着界面における前記組成分布を抽出し、当該接着界面において前記ワイヤ材の材料と前記ゴム組成物とが直接接する直接接触領域の割合に基づいて前記ワイヤ材と前記ゴム組成物との接着状態を評価する評価工程と、を含んだことを特徴とする。
請求項２の発明にかかるゴムワイヤ複合体の接着状態評価方法は、前記ゴム組成物は、ジエン系ゴムと、カーボンブラックと、硫黄とを含んでおり、前記ワイヤ材は鉄により形成されており、前記めっきはブラスめっきであり、前記評価工程では、前記接着界面において前記鉄と前記ゴム組成物または前記鉄と硫化銅とが直接接する直接接触領域の割合に基づいて接着状態を評価する、ことを特徴とする。
請求項３の発明にかかるゴムワイヤ複合体の接着状態評価方法は、前記評価工程では、前記３次元組成分布から前記接着界面を切断する任意の切断面を抽出し、前記切断面には前記ワイヤ材の外周長さの少なくとも１／２５０の長さを有する前記接着界面が含まれており、前記切断面中における前記直接接触領域の長さが前記切断面中における前記接着界面の長さ全体の５％以下である場合に、前記ワイヤ材と前記ゴム組成物との接着状態が良好と判断する、ことを特徴とする。
請求項４の発明にかかるゴムワイヤ複合体の接着状態評価方法は、前記評価工程では、前記３次元組成分布から前記ワイヤ材の外周長さの少なくとも１／２５０の長さを有する前記接着界面に沿った界面領域を抽出し、前記界面領域中における前記直接接触領域の面積が前記界面領域の面積全体の１０％以下である場合に、前記ワイヤ材と前記ゴム組成物との接着状態が良好と判断する、ことを特徴とする。
請求項５の発明にかかるゴムワイヤ複合体の接着状態評価方法は、前記エッチング工程により、前記集束イオンビームを前記ゴムワイヤ複合体の延在方向とほぼ直交する方向から照射することで前記ゴムワイヤ複合体の表面を所定厚さエッチングし前記ゴムワイヤ複合体の断面を形成し、前記検出工程により、前記走査型電子顕微鏡の電子ビームを前記ゴムワイヤ複合体の前記断面に対してほぼ垂直方向から入力させ、前記走査型電子顕微鏡で前記ゴムワイヤ複合体の前記断面を正面視した観察像を取得し前記ゴムワイヤ複合体の前記断面の組成分布を検出し、前記組成分取得工程により、前記エッチング工程および前記検出工程を繰り返して前記ゴムワイヤ複合体の３次元組成分布を取得する、ことを特徴とする。
請求項６の発明にかかるゴムワイヤ複合体の接着状態評価方法は、前記組成分布取得工程は、エネルギー分散型Ｘ線分析装置を用いて前記ゴムワイヤ複合体の断面に露出している元素の種類を測定し、前記走査型電子顕微鏡で得られたグレースケール画像と前記元素の種類とを対応させてセグメンテーション処理するセグメンテーション処理工程を更に含む、ことを特徴とする。 In order to achieve the above object, the method for evaluating the adhesive state of the rubber wire composite according to the invention of claim 1 is to use the wire material and the rubber composition in the rubber wire composite in which the plated wire material is coated with the rubber composition. This is an adhesive state evaluation method for evaluating the adhesive state of the rubber wire composite, which is a detection step of detecting the composition distribution on the surface of the rubber wire composite using a scanning electron microscope, and etching the surface of the rubber wire composite with a predetermined thickness by a focused ion beam. The composition distribution acquisition step of acquiring the three-dimensional composition distribution of the rubber wire composite and the composition distribution at the bonding interface between the wire material and the rubber composition are obtained from the three-dimensional composition distribution. An evaluation step of extracting and evaluating the bonding state between the wire material and the rubber composition based on the ratio of the direct contact region where the material of the wire material and the rubber composition are in direct contact at the bonding interface is included. It is characterized by that.
In the method for evaluating the adhesive state of the rubber wire composite according to the invention of claim 2, the rubber composition contains diene rubber, carbon black, and sulfur, and the wire material is formed of iron. The plating is brass plating, and in the evaluation step, the bonding state is evaluated based on the ratio of the direct contact region where the iron and the rubber composition or the iron and copper sulfide are in direct contact with each other at the bonding interface. It is a feature.
In the method for evaluating the adhesive state of a rubber wire composite according to the invention of claim 3, in the evaluation step, an arbitrary cut surface for cutting the adhesive interface is extracted from the three-dimensional composition distribution, and the wire material is used on the cut surface. The adhesive interface having a length of at least 1/250 of the outer peripheral length of the above is included, and the length of the direct contact region in the cut surface is 5 of the total length of the adhesive interface in the cut surface. When it is less than%, it is determined that the adhesive state between the wire material and the rubber composition is good.
The method for evaluating the adhesive state of the rubber wire composite according to the invention of claim 4 is, in the evaluation step, along the adhesive interface having a length of at least 1/250 of the outer peripheral length of the wire material from the three-dimensional composition distribution. When the area of the direct contact region in the interface region is 10% or less of the total area of the interface region, it is determined that the adhesive state between the wire material and the rubber composition is good. It is characterized by doing.
The method for evaluating the adhesion state of the rubber wire composite according to the invention of claim 5 is to irradiate the focused ion beam from a direction substantially orthogonal to the extending direction of the rubber wire composite by the etching step to obtain the rubber wire composite. The surface is etched to a predetermined thickness to form a cross section of the rubber wire composite, and the electron beam of the scanning electron microscope is input from a direction substantially perpendicular to the cross section of the rubber wire composite by the detection step, and the scanning is performed. An observation image of the cross section of the rubber wire composite viewed from the front is acquired with a scanning electron microscope, the composition distribution of the cross section of the rubber wire composite is detected, and the etching step and the detection step are repeated by the composition acquisition step. The three-dimensional composition distribution of the rubber wire composite is obtained .
In the method for evaluating the adhesion state of a rubber wire composite according to the invention of claim 6, in the composition distribution acquisition step, the type of element exposed on the cross section of the rubber wire composite is measured using an energy dispersive X-ray analyzer. It is characterized by further including a segmentation processing step of mapping the grayscale image obtained by the scanning electron microscope with the types of the elements .

請求項１の発明によれば、ワイヤ材とゴム組成物との接着界面を直接観察して評価するので、接着状態の評価精度を向上させることができる。また、ゴムワイヤ複合体の３次元組成分布を用いるので、任意の断面における接着界面を観察することができ、接着状態評価時の利便性を向上させることができる。
請求項２の発明によれば、鉄（ワイヤ材）とゴム組成物または鉄（ワイヤ材）と硫化銅との直接接触領域の割合に基づいて接着状態を評価するので、めっきの変質度合いを考慮して接着状態を評価することができる。
請求項３の発明によれば、接着界面を切断する切断面における直接接触領域の長さを用いて接着状態を評価するので、直接接触領域の長さを計測すればよく、比較的簡易に接着状態を評価することができる。
請求項４の発明によれば、接着界面に沿った界面領域における直接接触領域の面積を用いて接着状態を評価するので、より精度高く接着状態を評価することができる。
請求項５の発明によれば、走査型電子顕微鏡の電子ビーム照射軸と、集束イオンビームのイオンビーム照射軸とが互いに直交しているので、ゴムワイヤ複合体本来の構造に忠実な画像が安定して得られ、精度の高い３次元構造解析が実現可能となる。
請求項６の発明によれば、各元素の分布状態を画像上で判別しやすくする上で有利となる。 According to the invention of claim 1, since the bonding interface between the wire material and the rubber composition is directly observed and evaluated, the evaluation accuracy of the bonding state can be improved. Further, since the three-dimensional composition distribution of the rubber wire composite is used, the bonding interface in an arbitrary cross section can be observed, and the convenience at the time of evaluating the bonding state can be improved.
According to the invention of claim 2, since the adhesive state is evaluated based on the ratio of the direct contact region between the iron (wire material) and the rubber composition or the iron (wire material) and copper sulfide, the degree of deterioration of the plating is taken into consideration. The bonding state can be evaluated.
According to the invention of claim 3, since the bonding state is evaluated using the length of the direct contact region on the cut surface that cuts the bonding interface, the length of the direct contact region may be measured, and the bonding can be performed relatively easily. The condition can be evaluated.
According to the invention of claim 4, since the bonding state is evaluated using the area of the direct contact region in the interface region along the bonding interface, the bonding state can be evaluated with higher accuracy.
According to the invention of claim 5, since the electron beam irradiation axis of the scanning electron microscope and the ion beam irradiation axis of the focused ion beam are orthogonal to each other, an image faithful to the original structure of the rubber wire composite is stable. Therefore, highly accurate three-dimensional structural analysis can be realized.
According to the invention of claim 6, it is advantageous in making it easy to discriminate the distribution state of each element on an image .

ＦＩＢ−ＳＥＭ１０の概略を示す図である。It is a figure which shows the outline of FIB-SEM10. ゴムワイヤ複合体２０の拡大図である。It is an enlarged view of the rubber wire complex 20. ゴムワイヤ複合体２０表面の２次元組成分布である。It is a two-dimensional composition distribution of the surface of the rubber wire composite 20. ゴムワイヤ複合体２０の３次元組成分布である。It is a three-dimensional composition distribution of the rubber wire composite 20. ３次元組成分布を接着界面で切断した断面図である。It is sectional drawing which cut | cut the 3D composition distribution at an adhesive interface. ゴムワイヤ複合体の接着状態評価結果を示す表である。It is a table which shows the adhesive state evaluation result of the rubber wire composite. 実施の形態にかかるゴムワイヤ複合体の接着状態評価方法の処理を示すフローチャートである。It is a flowchart which shows the process of the adhesive state evaluation method of the rubber wire composite which concerns on embodiment.

以下に添付図面を参照して、本発明にかかるゴムワイヤ複合体の接着状態評価方法、ゴムワイヤ複合体および空気入りタイヤの好適な実施の形態を詳細に説明する。
図７は、実施の形態にかかるゴムワイヤ複合体の接着状態評価方法の処理を示すフローチャートである。
図７に示す処理は、めっきされたワイヤ材をゴム組成物で被覆したゴムワイヤ複合体におけるワイヤ材とゴム組成物との接着状態を評価するものである。
まず、走査型電子顕微鏡を用い、ゴムワイヤ複合体表面の組成分布を検出する（ステップＳ７００：検出工程）。検出工程では、ゴムワイヤ複合体表面の組成分布が２次元の画像として得られる。
後述する評価工程を行うために十分な数（規定数）の組成分布が得られるまでは（ステップＳ７０１：Ｎｏ）、集束イオンビームによりゴムワイヤ複合体表面を所定厚さエッチングする（ステップＳ７０２：エッチング工程）。エッチング工程により、ゴムワイヤ複合体表面が削られ、ステップＳ７００で組成分布を得た位置よりも所定厚さ下層の断面が露出する。その後、ステップＳ７００に戻り、以降の処理をくり返す。
そして、十分な数の組成分布が得られると（ステップＳ７０１：Ｙｅｓ）、ステップＳ７００で得られた２次元の組成分布を重ねて、ゴムワイヤ複合体の３次元組成分布を生成する（ステップＳ７０３）。ステップＳ７００〜Ｓ７０３の処理が、請求項における組成分布取得工程に対応する。
その後、ステップＳ７０３で生成したゴムワイヤ複合体の３次元組成分布から、ワイヤ材とゴム組成物との接着界面における組成分布を抽出し（ステップＳ７０４）、抽出した接着界面における組成分布に基づいてワイヤ材とゴム組成物との接着状態を評価する（ステップＳ７０５：評価工程）。 Hereinafter, with reference to the accompanying drawings, a method for evaluating the adhesive state of the rubber wire composite according to the present invention, and preferred embodiments of the rubber wire composite and the pneumatic tire will be described in detail.
FIG. 7 is a flowchart showing the process of the method for evaluating the adhesive state of the rubber wire composite according to the embodiment.
The process shown in FIG. 7 evaluates the adhesive state between the wire material and the rubber composition in the rubber wire composite in which the plated wire material is coated with the rubber composition.
First, a scanning electron microscope is used to detect the composition distribution on the surface of the rubber wire complex (step S700: detection step). In the detection step, the composition distribution on the surface of the rubber wire complex is obtained as a two-dimensional image.
Until a sufficient number (specified number) of composition distributions are obtained for performing the evaluation step described later (step S701: No), the surface of the rubber wire composite is etched to a predetermined thickness by the focused ion beam (step S702: etching step). ). By the etching step, the surface of the rubber wire composite is scraped, and the cross section of the lower layer having a predetermined thickness is exposed from the position where the composition distribution is obtained in step S700. After that, the process returns to step S700, and the subsequent processing is repeated.
Then, when a sufficient number of composition distributions are obtained (step S701: Yes), the two-dimensional composition distributions obtained in step S700 are superimposed to generate a three-dimensional composition distribution of the rubber wire composite (step S703). The processing of steps S700 to S703 corresponds to the composition distribution acquisition step in the claim.
Then, the composition distribution at the bonding interface between the wire material and the rubber composition is extracted from the three-dimensional composition distribution of the rubber wire composite generated in step S703 (step S704), and the wire material is based on the composition distribution at the extracted bonding interface. The state of adhesion between the wire and the rubber composition is evaluated (step S705: evaluation step).

つぎに、上述した各ステップの詳細について説明する。
図１は、組成分布取得工程に用いるＦＩＢ（ＦｏｃｕｓｅｄＩｏｎＢｅａｍ：集束イオンビーム）−ＳＥＭ（ＳｃａｎｎｉｎｇＥｌｅｃｔｒｏｎＭｉｃｒｏｓｃｏｐｅ：走査型電子顕微鏡）１０の概略を示す図である。
ＦＩＢ−ＳＥＭ１０は、試料表面の組成分布を観察する電子顕微鏡であるＳＥＭと、集束イオンビームの照射により試料表面をエッチングするＦＩＢ装置を１つの装置内に備える。
ＦＩＢ−ＳＥＭ１０を用いることによって、断続的にＦＩＢによる断面加工とＳＥＭ観察とを繰り返し、すなわち図７のフローチャートにおける検出工程とエッチング工程とをくり返し、得られた複数のＳＥＭ像を画像ソフトウェアで立体的に再構築し、３次元的な構造解析を行うことができる。このような断層的な観察を行うことで、折り重なって影で見えない部分の構造や、界面の状態など明瞭に観察することができ、また３次元の数値情報を得られることから、表面からの観察では得ることのできない表面積なども算出することができる。 Next, the details of each step described above will be described.
FIG. 1 is a diagram showing an outline of FIB (Focused Ion Beam) -SEM (Scanning Electron Microscope) 10 used in the composition distribution acquisition step.
The FIB-SEM 10 includes an SEM, which is an electron microscope for observing the composition distribution of the sample surface, and a FIB device, which etches the sample surface by irradiation with a focused ion beam, in one device.
By using the FIB-SEM10, the cross-section processing and the SEM observation by the FIB are intermittently repeated, that is, the detection step and the etching step in the flowchart of FIG. 7 are repeated, and the obtained plurality of SEM images are three-dimensionally displayed by the image software. It can be reconstructed into a three-dimensional structural analysis. By performing such tomographic observation, it is possible to clearly observe the structure of the part that is folded and invisible in the shadow, the state of the interface, etc., and since three-dimensional numerical information can be obtained, it is possible to obtain three-dimensional numerical information from the surface. It is also possible to calculate the surface area that cannot be obtained by observation.

なお、上記図７のステップＳ７００〜Ｓ７０２の工程、すなわちＦＩＢ加工とＳＥＭ観察とを繰り返す過程において、途中でエネルギー分散型Ｘ線分析（ＥＤＸ：ＥｎｅｒｇｙＤｉｓｐｅｒｓｉｖｅＸ−ｒａｙｓｐｅｃｔｒｏｍｅｔｒｙ）装置を用いて試料表面に露出している元素の種類を測定する。そして、ＳＥＭ観察により得られたグレースケールの画像と元素の種類とを対応させてセグメンテーション処理（色分け処理）する。
すなわち、組成分布取得工程は、エネルギー分散型Ｘ線分析装置を用いてゴムワイヤ複合体表面に露出している元素の種類を測定し、走査型電子顕微鏡で得られたグレースケール画像と元素の種類とを対応させてセグメンテーション処理するセグメンテーション処理工程を更に含んでいる。
このようなセグメンテーション処理を行うのは、グレースケール画像のままでは、各元素の分布状態を直接判別しにくいためである。本実施の形態では、概ねＦＩＢ観察５０回につき１回ＥＤＸを実施したが、ＥＤＸの実施頻度については任意である。 In the steps S700 to S702 of FIG. 7, that is, in the process of repeating FIB processing and SEM observation, an energy dispersive X-ray analysis (EDX: Energy Dispersive X-ray spectroscopy) device was used on the sample surface during the process. Measure the type of exposed element. Then, the grayscale image obtained by SEM observation is associated with the type of element to perform a segmentation process (color-coded process).
That is, in the composition distribution acquisition step, the types of elements exposed on the surface of the rubber wire composite are measured using an energy dispersive X-ray analyzer, and the grayscale image obtained by the scanning electron microscope and the types of elements are used. Further includes a segmentation processing step of performing segmentation processing in correspondence with the above.
The reason why such a segmentation process is performed is that it is difficult to directly determine the distribution state of each element with the grayscale image as it is. In the present embodiment, EDX is performed approximately once for every 50 FIB observations, but the frequency of EDX implementation is arbitrary.

ＦＩＢ−ＳＥＭ１０は、電子ビーム鏡筒１２、イオンビーム鏡筒１４、試料台１６、処理装置１８等を備える。
本実施の形態では、電子ビーム鏡筒１２（走査型電子顕微鏡）からの電子ビーム照射軸Ｂ１と、イオンビーム鏡筒１４からのイオンビーム照射軸Ｂ２とが互いに直交している。電子ビーム照射軸Ｂ１は、試料台１６に載置されたゴムワイヤ複合体２０の表面（断面）Ｆに垂直に入力し、ゴムワイヤ複合体２０の表面Ｆを正面視した観察像を撮影する。イオンビーム照射軸Ｂ２は、ゴムワイヤ複合体２０の表面Ｆの延在方向に沿って入力し、ゴムワイヤ複合体２０の表面Ｆをその延在方向に沿ってエッチングする。
このように電子ビーム鏡筒１２とイオンビーム鏡筒１４とを直角に配置することで、ＦＩＢ加工断面の垂直入射ＳＥＭ観察を実施することができる。従来のＦＩＢ−ＳＥＭでは、電子ビーム鏡筒１２とイオンビーム鏡筒１４とが斜め方向に配置されていたため、断面ＳＥＭ像の歪みや連続画像収集時の視野逃げなどが生じる可能性があったが、本実施の形態のような直交配置により、本来の構造に忠実な画像が安定して得られ、精度の高い３次元構造解析が実現可能となる。 The FIB-SEM 10 includes an electron beam lens barrel 12, an ion beam lens barrel 14, a sample table 16, a processing device 18, and the like.
In the present embodiment, the electron beam irradiation axis B1 from the electron beam lens barrel 12 (scanning electron microscope) and the ion beam irradiation axis B2 from the ion beam lens barrel 14 are orthogonal to each other. The electron beam irradiation axis B1 is vertically input to the surface (cross section) F of the rubber wire complex 20 placed on the sample table 16, and an observation image of the surface F of the rubber wire complex 20 viewed from the front is taken. The ion beam irradiation shaft B2 inputs along the extending direction of the surface F of the rubber wire composite 20, and etches the surface F of the rubber wire composite 20 along the extending direction.
By arranging the electron beam lens barrel 12 and the ion beam lens barrel 14 at right angles in this way, it is possible to carry out vertical incident SEM observation of the FIB processed cross section. In the conventional FIB-SEM, since the electron beam lens barrel 12 and the ion beam lens barrel 14 are arranged in an oblique direction, there is a possibility that the cross-sectional SEM image is distorted and the visual field escapes during continuous image collection. By the orthogonal arrangement as in the present embodiment, an image faithful to the original structure can be stably obtained, and highly accurate three-dimensional structural analysis can be realized.

図２は、ゴムワイヤ複合体２０の拡大図である。
ゴムワイヤ複合体２０は、めっきされたワイヤ材２２をゴム組成物２６で被覆して加硫処理することにより形成される。
ゴム組成物２６は、ジエン系ゴムと、カーボンブラックと、硫黄とを含んでいる。より詳細には、本実施の形態ではゴム組成物２６はタイヤ内部の接着用ゴムであり、ジエン系ゴム１００重量部に対し、カーボンブラックを３０〜８０重量部、硫黄を３〜１０重量部含んでいる。
ワイヤ材２２は、鉄（スチール）により形成されており、その表面は、ブラス（Ｃｕ−Ｚｎ（真鍮））によりめっきされている（めっき層２４）。 FIG. 2 is an enlarged view of the rubber wire composite 20.
The rubber wire composite 20 is formed by coating the plated wire material 22 with the rubber composition 26 and vulcanizing it.
The rubber composition 26 contains a diene-based rubber, carbon black, and sulfur. More specifically, in the present embodiment, the rubber composition 26 is an adhesive rubber inside a tire, and contains 30 to 80 parts by weight of carbon black and 3 to 10 parts by weight of sulfur with respect to 100 parts by weight of diene rubber. I'm out.
The wire material 22 is made of iron (steel), and its surface is plated with brass (Cu—Zn (brass)) (plating layer 24).

ＦＩＢ−ＳＥＭ１０は、ゴムワイヤ複合体２０の断面、すなわちワイヤ材２２の延在方向Ｅとの直交方向に沿った断面ＦをＳＥＭ観察する。ＳＥＭ観察では、試料を構成している原子に当たって跳ね返された反射電子の数に基づいて試料の組成分布を反映した画像が得られる。
なお、本実施の形態で用いたＦＩＢ−ＳＥＭ１０におけるＳＥＭ観察の範囲は４μｍ四方〜２５μｍ四方の範囲で倍率を設定可能である。また、本実施の形態におけるワイヤ材２２の直径は２００μｍなので、ワイヤ材２２の外周長さは約６３０μｍとなる。よって、４μｍ四方で観察を行った場合にはワイヤ材２２の外周の１／１５７、２５μｍ四方で観察を行った場合にはワイヤ材２２の外周の１／２５の範囲を観察可能となる。
一般的にタイヤで用いられるワイヤ材２２の直径は、概ね１００μｍ〜３００μｍ程度の太さであり、直径１００μｍの場合にはワイヤ材２２の外周の１／７９（４μｍ四方）〜１／１３（２５μｍ四方）の範囲を観察可能となる。また、直径３００μｍの場合にはワイヤ材２２の外周の１／２３５（４μｍ四方）〜１／３８（２５μｍ）の範囲を観察可能となる。
これらの範囲は、ＦＩＢ−ＳＥＭ１０の解像度（設定可能倍率）やワイヤ材２２の直径などによっても異なるが、概ねワイヤ材２２の外周全体の少なくとも１／２５０を含んで測定することが好ましい。
４μｍ四方での観察はより微細な状態を観察可能であり、２５μｍ四方での観察はワイヤ材２２の外周のより広い範囲での観察が可能であるが、本発明の適用においては、より広い範囲での観察が可能な２５μｍ四方での観察が好ましい。
例えばワイヤ材２２の直径が上記範囲より太い４００μｍの場合、観察可能範囲は４μｍ四方で１／３１４、２５μｍ四方で１／５０となる。ワイヤ材２２の直径が４００μｍの場合には４μｍ四方より大きい倍率での観察が好ましい。また、ワイヤ材２２の直径が上記範囲より細くなる場合は、観察範囲内に入る外周の割合が高くなるので、接着状態の評価精度への影響は少ない。
また、ＦＩＢ−ＳＥＭ１０の観察範囲の縦横比率が１：１でない場合は、当然にワイヤ材２２の外周をより広範囲に観察できるように撮影方向を決定することが好ましい。
その後、断面ＦをＦＩＢにより切削し、露出した新たな断面ＦをＳＥＭ観察する。このように得られた複数の２次元画像を重ねることにより、ゴムワイヤ複合体２０の３次元組成分布を得られる。１回のＦＩＢ切削深さは１ｎｍ〜２０ｎｍが可能であり、今回は８ｎｍごとにＦＩＢ切削した。
すなわち、走査型電子顕微鏡を用い、ゴムワイヤ複合体２０表面の組成分布を検出する検出工程と、集束イオンビームによりゴムワイヤ複合体２０表面を所定厚さエッチングするエッチング工程と、をくり返し、ゴムワイヤ複合体２０の３次元組成分布を取得する計測工程と、を、ＦＩＢ−ＳＥＭ１０により実施する。 The FIB-SEM 10 SEM observes the cross section of the rubber wire composite 20, that is, the cross section F along the direction orthogonal to the extending direction E of the wire material 22. In SEM observation, an image reflecting the composition distribution of the sample is obtained based on the number of reflected electrons that hit the atoms constituting the sample and bounced off.
The range of SEM observation in the FIB-SEM10 used in this embodiment can be set in the range of 4 μm square to 25 μm square. Further, since the diameter of the wire material 22 in the present embodiment is 200 μm, the outer peripheral length of the wire material 22 is about 630 μm. Therefore, when observing in 4 μm square, it is possible to observe the range of 1/157 of the outer circumference of the wire material 22, and when observing in 25 μm square, it is possible to observe the range of 1/25 of the outer circumference of the wire material 22.
The diameter of the wire material 22 generally used in a tire is about 100 μm to 300 μm, and when the diameter is 100 μm, the outer circumference of the wire material 22 is 1/79 (4 μm square) to 1/13 (25 μm). The range on all sides) can be observed. Further, when the diameter is 300 μm, the range of 1/235 (4 μm square) to 1/38 (25 μm) of the outer circumference of the wire material 22 can be observed.
These ranges vary depending on the resolution (settable magnification) of the FIB-SEM10, the diameter of the wire material 22, and the like, but it is preferable to measure at least 1/250 of the entire outer circumference of the wire material 22.
Observation in 4 μm square allows observation of a finer state, and observation in 25 μm square allows observation in a wider range of the outer circumference of the wire material 22, but in the application of the present invention, a wider range can be observed. It is preferable to observe in a 25 μm square, which can be observed in.
For example, when the diameter of the wire material 22 is 400 μm, which is thicker than the above range, the observable range is 1/314 in 4 μm square and 1/50 in 25 μm square. When the diameter of the wire material 22 is 400 μm, observation at a magnification larger than 4 μm square is preferable. Further, when the diameter of the wire material 22 is smaller than the above range, the ratio of the outer periphery within the observation range is high, so that the influence on the evaluation accuracy of the bonded state is small.
When the aspect ratio of the observation range of the FIB-SEM 10 is not 1: 1, it is naturally preferable to determine the photographing direction so that the outer circumference of the wire material 22 can be observed in a wider range.
Then, the cross section F is cut by FIB, and the exposed new cross section F is observed by SEM. By superimposing the plurality of two-dimensional images thus obtained, the three-dimensional composition distribution of the rubber wire composite 20 can be obtained. The depth of FIB cutting at one time can be 1 nm to 20 nm, and this time, FIB cutting was performed every 8 nm.
That is, the detection step of detecting the composition distribution on the surface of the rubber wire composite 20 using a scanning electron microscope and the etching step of etching the surface of the rubber wire composite 20 to a predetermined thickness with a focused ion beam are repeated to repeat the rubber wire composite 20. The measurement step of acquiring the three-dimensional composition distribution of the above is carried out by FIB-SEM10.

図３は、ゴムワイヤ複合体２０表面の２次元組成分布であり、図４は、図３の２次元組成分布を用いて作成した３次元組成分布である。図３の２次元組成分布は、図４の３次元組成分布を矢印Ａ方向から見た像に対応する。ＳＥＭ測定ではグレー表示で結果が得られるため各組成分布を把握しにくい。そのためＥＤＸ測定（エネルギー分散型Ｘ線分析（ＥｎｅｒｇｙｄｉｓｐｅｒｓｉｖｅＸ−ｒａｙｓｐｅｃｔｒｏｍｅｔｒｙ、ＥＤＸ、ＥＤＳ）を併用して、各グレースケールと組成をセグメンテーション解析により区分けした。
図３および図４に示すように、ワイヤ材２２を構成する鉄（スチール）Ｆｅとゴム組成物２６との間には、めっき層２４を構成するブラス（Ｃｕ−Ｚｎ）の他、硫化銅（ＣｕＳ、Ｃｕ_２Ｓ）、酸化亜鉛（ＺｎＯ）が存在する。硫化銅（ＣｕＳ、Ｃｕ_２Ｓ）は、ブラス（Ｃｕ−Ｚｎ）内の銅が加硫に伴って硫化することにより形成される。また、酸化亜鉛（ＺｎＯ）は元のブラス（Ｃｕ−Ｚｎ）表面にＺｎＯが形成しており、亜鉛の酸化によって形成される。ゴム中にも酸化亜鉛が配合してある。
ここで、図３では鉄（スチール）Ｆｅとゴム組成物２６との接着界面の全域に渡ってブラス（Ｃｕ−Ｚｎ）が存在しているが、図４では符号Ｎで示す枠内で鉄（Ｆｅ）と硫化銅（ＣｕＳ、Ｃｕ_２Ｓ）が直接接している。このように、ワイヤ材２２とゴム組成物２６との接着界面において、鉄（Ｆｅ）と硫化銅（ＣｕＳ、Ｃｕ_２Ｓ）とが直接接する、または更に劣化が進み鉄（Ｆｅ）とゴム組成物２６とが直接接する領域（以下、「直接接触領域」という）では、接着界面の接着不良が生じる。 FIG. 3 is a two-dimensional composition distribution on the surface of the rubber wire composite 20, and FIG. 4 is a three-dimensional composition distribution created by using the two-dimensional composition distribution of FIG. The two-dimensional composition distribution of FIG. 3 corresponds to an image of the three-dimensional composition distribution of FIG. 4 viewed from the direction of arrow A. In SEM measurement, it is difficult to grasp each composition distribution because the result is obtained in grayed out. Therefore, EDX measurement (Energy Dispersive X-ray Spectrometry, EDX, EDS) was used in combination, and each gray scale and composition were classified by segmentation analysis.
As shown in FIGS. 3 and 4, between the iron (steel) Fe constituting the wire material 22 and the rubber composition 26, in addition to the brass (Cu—Zn) constituting the plating layer 24, copper sulfide ( CuS, _Cu 2 S), zinc oxide (ZnO) is present. Copper sulfide (CuS, _Cu 2 S) is formed by copper in the brass (Cu-Zn) is sulfurized in accordance with the vulcanization. Further, zinc oxide (ZnO) is formed by the oxidation of zinc, which is formed on the surface of the original brass (Cu-Zn). Zinc oxide is also contained in the rubber.
Here, in FIG. 3, brass (Cu—Zn) is present over the entire area of the bonding interface between the iron (steel) Fe and the rubber composition 26, but in FIG. 4, iron (Cu-Zn) is present within the frame indicated by reference numeral N. Fe) and copper sulfide (CuS, in contact _Cu 2 S) directly. Thus, in the bonding interface between the wire member 22 and the rubber composition 26, iron (Fe) and copper sulfide (CuS, _Cu 2 S) and is in direct contact, or even degradation proceeds rubber composition iron (Fe) In the region in direct contact with 26 (hereinafter, referred to as “direct contact region”), poor adhesion at the adhesive interface occurs.

そこで、本実施の形態では、ＦＩＢ−ＳＥＭ１０を用いて得た３次元組成分布から、ワイヤ材２２とゴム組成物２６との接着界面における組成分布を抽出し、当該接着界面における組成分布に基づいてワイヤ材２２とゴム組成物２６との接着状態を評価する。
すなわち、ワイヤ材２２とゴム組成物２６との接着界面において、鉄（Ｆｅ）と硫化銅（ＣｕＳ、Ｃｕ_２Ｓ）とが直接接する、または更に劣化が進み鉄（Ｆｅ）とゴム組成物２６とが直接接する直接接触領域が少ないほどワイヤ材２２とゴム組成物２６との接着状態が良好（劣化が少ない）であり、直接接触領域が多いほどワイヤ材２２とゴム組成物２６との接着状態が不良（劣化が進んでいる）と判断することができる。 Therefore, in the present embodiment, the composition distribution at the bonding interface between the wire material 22 and the rubber composition 26 is extracted from the three-dimensional composition distribution obtained by using FIB-SEM10, and based on the composition distribution at the bonding interface. The adhesive state between the wire material 22 and the rubber composition 26 is evaluated.
That is, in the bonding interface between the wire member 22 and the rubber composition 26, iron (Fe) and copper sulfide (CuS, _Cu 2 S) and is in direct contact, or even degradation proceeds with iron (Fe) and the rubber composition 26 The smaller the direct contact area with which is in direct contact, the better the adhesive state between the wire material 22 and the rubber composition 26 (less deterioration), and the larger the direct contact area, the better the adhesive state between the wire material 22 and the rubber composition 26. It can be judged as defective (deterioration is progressing).

例えば、図４に示すような３次元組成分布から接着界面を切断する任意の切断面、すなわち、図３に示すようなゴムワイヤ複合体２０の断面（ワイヤ材２２の延在方向Ｅとの直交方向に沿った断面）の画像を抽出する。この画像中の切断面には、ワイヤ材２２の外周長さの少なくとも１／２５０の長さを有する接着界面が含まれるようにする。そして、当該切断面中における直接接触領域の長さが、切断面中における接着界面の長さ全体の例えば５％以下である場合に、ワイヤ材２２とゴム組成物２６との接着状態が良好と判断する。 For example, an arbitrary cut surface that cuts the adhesive interface from the three-dimensional composition distribution as shown in FIG. 4, that is, a cross section of the rubber wire composite 20 as shown in FIG. 3 (direction orthogonal to the extending direction E of the wire material 22). (Cross section along) is extracted. The cut surface in this image is intended to include an adhesive interface having a length of at least 1/250 of the outer peripheral length of the wire material 22. When the length of the direct contact region in the cut surface is, for example, 5% or less of the total length of the adhesive interface in the cut surface, the adhesive state between the wire material 22 and the rubber composition 26 is good. to decide.

また、例えば図４に示すような３次元組成分布から接着界面に沿った界面領域、すなわち図４中のＢ−Ｂ断面に沿った切断面の画像を抽出する。このとき、ワイヤ材の外周長さの少なくとも１／２５０の長さを有する接着界面に沿った界面領域を抽出する。そして、界面領域中における直接接触領域の面積が、界面領域の面積全体の１０％以下である場合に、ワイヤ材２２とゴム組成物２６との接着状態が良好と判断する。
図５に、図４の３次元組成分布をＢ−Ｂ断面で切断した断面図を示す。なお、図５の画像は横２０μｍ、縦７．５μｍの範囲を示す。実線枠内が鉄（Ｆｅ）とゴム組成物２６とが直接接している領域であり、点線枠内が鉄（Ｆｅ）と硫化銅（ＣｕＳ、Ｃｕ_２Ｓ）とが直接接している領域である。図５の面積全体に対する実線枠内および点線枠内の面積の比率を求めることによって、ワイヤ材２２とゴム組成物２６との接着状態を評価することができる。 Further, for example, from the three-dimensional composition distribution as shown in FIG. 4, an image of the interface region along the adhesive interface, that is, the cut surface along the BB cross section in FIG. 4 is extracted. At this time, an interface region along the adhesive interface having a length of at least 1/250 of the outer peripheral length of the wire material is extracted. Then, when the area of the direct contact region in the interface region is 10% or less of the total area of the interface region, it is determined that the adhesive state between the wire material 22 and the rubber composition 26 is good.
FIG. 5 shows a cross-sectional view of the three-dimensional composition distribution of FIG. 4 cut along a BB cross section. The image of FIG. 5 shows a range of 20 μm in width and 7.5 μm in length. An area solid frame in contact iron (Fe) and the rubber composition 26 and directly, is a region where the dotted line frame iron (Fe) and copper sulfide (CuS, Cu 2 _S) and is in direct contact .. By obtaining the ratio of the area in the solid line frame and the area in the dotted line frame to the entire area in FIG. 5, the adhesive state between the wire material 22 and the rubber composition 26 can be evaluated.

このように、ワイヤ材２２とゴム組成物２６との接着界面の組成分布を直接観察して接着状態を評価することにより、接着状態の評価精度を向上させることができる。
また、ゴムワイヤ複合体２０の３次元組成分布を用いることにより、任意の断面における接着界面を観察することができ、接着状態評価時の利便性を向上させることができる。
また、鉄（ワイヤ材２２）とゴム組成物２６または鉄（ワイヤ材２２）と硫化銅との直接接触領域の割合に基づいて接着状態を評価することにより、めっきの変質度合いを考慮して接着状態を評価することができる。
また、接着界面を切断する切断面における直接接触領域の長さを用いて接着状態を評価すれば、直接接触領域の長さを計測すればよく、比較的簡易に接着状態を評価することができる。
また、接着界面に沿った界面領域における直接接触領域の面積を用いて接着状態を評価すれば、より精度高く接着状態を評価することができる。
また、走査型電子顕微鏡の電子ビーム照射軸と、集束イオンビームのイオンビーム照射軸とが互いに直交する直交型のＦＩＢ−ＳＥＭ１０を用いることによって、ゴムワイヤ複合体本来の構造に忠実な画像が安定して得られ、精度の高い３次元構造解析が実現可能となる。 In this way, by directly observing the composition distribution of the bonding interface between the wire material 22 and the rubber composition 26 and evaluating the bonding state, the evaluation accuracy of the bonding state can be improved.
Further, by using the three-dimensional composition distribution of the rubber wire composite 20, it is possible to observe the adhesive interface in an arbitrary cross section, and it is possible to improve the convenience at the time of evaluating the adhesive state.
Further, by evaluating the bonding state based on the ratio of the direct contact region between the iron (wire material 22) and the rubber composition 26 or the iron (wire material 22) and copper sulfide, the bonding is performed in consideration of the degree of deterioration of the plating. The condition can be evaluated.
Further, if the adhesive state is evaluated using the length of the direct contact region on the cut surface for cutting the adhesive interface, the length of the direct contact region may be measured, and the adhesive state can be evaluated relatively easily. ..
Further, if the bonding state is evaluated using the area of the direct contact region in the interface region along the bonding interface, the bonding state can be evaluated with higher accuracy.
Further, by using the orthogonal FIB-SEM10 in which the electron beam irradiation axis of the scanning electron microscope and the ion beam irradiation axis of the focused ion beam are orthogonal to each other, an image faithful to the original structure of the rubber wire composite is stabilized. Therefore, highly accurate three-dimensional structural analysis can be realized.

また、実施の形態にかかるゴムワイヤ複合体の接着状態評価方法を用いて材料設計および／または加硫条件が決められたゴムワイヤ複合体は、適正な加硫条件で加硫することができるので、接着強度を高めると共に、劣化を抑制することができる。また、このゴムワイヤ複合体で構成されたことを特徴とする空気入りタイヤは、ゴム補強層においてゴムとスチールコードとを強固に接着することができるので、ゴムとスチールコードとの間の剥離が生じ難く、耐久性を向上することができる。この評価方法により得られた結果を、加硫後の接着性を改良するゴム組成物および／または劣化を抑制するゴム組成物の設計に反映し、ワイヤ材との接着性に優れたゴム組成物を得ることができる。 Further, the rubber wire composite whose material design and / or vulcanization conditions have been determined by using the method for evaluating the adhesion state of the rubber wire composite according to the embodiment can be vulcanized under appropriate vulcanization conditions, and thus adheres. It is possible to increase the strength and suppress deterioration. Further, in the pneumatic tire made of this rubber wire composite, the rubber and the steel cord can be firmly adhered to each other in the rubber reinforcing layer, so that the rubber and the steel cord are separated from each other. It is difficult and durability can be improved. The results obtained by this evaluation method are reflected in the design of the rubber composition that improves the adhesiveness after vulcanization and / or the rubber composition that suppresses deterioration, and the rubber composition has excellent adhesiveness to the wire material. Can be obtained.

＜実施例＞
図６に、同一の材料で形成したゴムワイヤ複合体を老化処理した上で、本発明にかかる接着状態評価方法により評価を行った結果を示す。
実験例で用いたゴムワイヤ複合体の成分を図７に示す。図７に示す各成分の含有量は質量部である。また、図７に記載の原材料の種類を下記に示す。
・ＮＲ：天然ゴム（ＲＳＳ＃３）
・カーボンブラック（ＣＢ）：シースト３００（東海カーボン株式会社製）
・亜鉛華（ＺｎＯ）：酸化亜鉛３種（正同化学工業株式会社製）
・老化防止剤：ＶＵＬＫＡＮＯＸ４０２０（ランクセス社製）
・ステアリン酸コバルト：ＤＩＣ社製
・硫黄：クリステックスＨＳＯＴ２０（アクゾノーベル株式会社製）
・加硫促進剤：ノクセラーＤＺ（大内新興化学工業株式会社製） <Example>
FIG. 6 shows the results of aging treatment of a rubber wire composite formed of the same material and then evaluating it by the adhesive state evaluation method according to the present invention.
The components of the rubber wire complex used in the experimental example are shown in FIG. The content of each component shown in FIG. 7 is a part by mass. The types of raw materials shown in FIG. 7 are shown below.
・ NR: Natural rubber (RSS # 3)
-Carbon black (CB): Seest 300 (manufactured by Tokai Carbon Co., Ltd.)
・ Zinc oxide (ZnO): 3 types of zinc oxide (manufactured by Shodo Chemical Industry Co., Ltd.)
-Anti-aging agent: VULKANOX 4020 (manufactured by LANXESS)
-Cobalt stearate: manufactured by DIC Corporation-Sulfur: Chris Tex HS OT 20 (manufactured by AkzoNobel Co., Ltd.)
・ Vulcanization accelerator: Noxeller DZ (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.)

実験例１〜５では、めっきされたワイヤ材をゴム組成物で被覆して１０分間加硫処理してゴムワイヤ複合体を形成し、このゴムワイヤ複合体に所定期間温度と湿度を与えて老化処理を行った。
実験例１は老化処理なし、実験例２は温度７０℃：期間２週間（湿度条件なし）、実験例３は温度７０℃：湿度９６％：期間１週間、実験例４は温度７０℃：湿度９６％：期間２週間、実験例５は温度７０℃：湿度９６％：期間４週間とした。すなわち、実験例１〜５の順に老化条件を厳しくした。 In Experimental Examples 1 to 5, the plated wire material is coated with a rubber composition and vulcanized for 10 minutes to form a rubber wire complex, and the rubber wire complex is subjected to an aging treatment by applying temperature and humidity for a predetermined period of time. went.
Experimental Example 1 has no aging treatment, Experimental Example 2 has a temperature of 70 ° C.: a period of 2 weeks (no humidity condition), Experimental Example 3 has a temperature of 70 ° C.: humidity of 96%: a period of 1 week, and Experimental Example 4 has a temperature of 70 ° C.: humidity. 96%: period 2 weeks, in Experimental Example 5, temperature 70 ° C.: humidity 96%: period 4 weeks. That is, the aging conditions were stricter in the order of Experimental Examples 1 to 5.

接着状態の評価は、本発明にかかる方法の他、従来から実施されている引張引抜力測定およびゴム付着率測定を行った。
引張引抜力測定では、ワイヤ材を引っ張り、ゴム組成物から引き抜かれた際の引張力（引張引抜力）を測定する。引張引抜力が大きいほど接着状態が良好と評価できる。
ゴム付着率測定は、ゴム組成物から引き抜かれたワイヤ材表面におけるゴム組成物の付着面積の比率を測定する。ゴム付着率が高いほど接着状態が良好と評価できる。
引張引抜力測定の結果は、実験例１〜５の順に、５５０Ｎ、５１０Ｎ、５３０Ｎ、５１０Ｎ、３８０Ｎであった。また、ゴム付着率測定の結果は、実験例１〜５の順に、１００％、１００％、８５％、７０％、３５％であった。 In addition to the method according to the present invention, the tensile pull-out force measurement and the rubber adhesion rate measurement, which have been conventionally performed, were carried out for the evaluation of the adhesive state.
In the tensile pull-out force measurement, the tensile force (tensile pull-out force) when the wire material is pulled and pulled out from the rubber composition is measured. It can be evaluated that the larger the tensile pull-out force, the better the adhesive state.
The rubber adhesion rate measurement measures the ratio of the adhesion area of the rubber composition on the surface of the wire material drawn from the rubber composition. It can be evaluated that the higher the rubber adhesion rate, the better the adhesion state.
The results of the tensile pull-out force measurement were 550N, 510N, 530N, 510N, and 380N in the order of Experimental Examples 1 to 5. The results of rubber adhesion measurement were 100%, 100%, 85%, 70%, and 35% in the order of Experimental Examples 1 to 5.

また、ゴムワイヤ複合体の組成分布から、接着界面を切断する切断面中における直接接触領域の長さの比率（２次元画像接触長さ比率）を計測した結果は、実験例１〜５の順に、０％、０％、２％、１１％、２１％であった。なお、ＦＩＢ−ＳＥＭにおける観察範囲は２５μｍ四方とした。
また、ゴムワイヤ複合体の組成分布から、接着界面に沿った界面領域中における直接接触領域の面積の比率（３次元画像接触面積比率）を計測した結果は、実験例１〜５の順に、０％、１％、６％、２１％、３４％であった。 Further, the results of measuring the ratio of the length of the direct contact region (two-dimensional image contact length ratio) in the cut surface for cutting the adhesive interface from the composition distribution of the rubber wire composite are shown in the order of Experimental Examples 1 to 5. It was 0%, 0%, 2%, 11%, and 21%. The observation range in the FIB-SEM was 25 μm square.
Further, from the composition distribution of the rubber wire composite, the result of measuring the ratio of the area of the direct contact region in the interface region along the adhesive interface (three-dimensional image contact area ratio) is 0% in the order of Experimental Examples 1 to 5. It was 1%, 6%, 21%, and 34%.

実験例１〜３では、ゴム組成物とワイヤ材の接着状態が良好であった。このことから、ゴム組成物とワイヤ材の接着界面を切断する切断面中における直接接触領域の長さの比率が５％以下、または接着界面に沿った界面領域中における直接接触領域の面積の比率が１０％以下である場合に、ゴム組成物とワイヤ材の接着状態が良好である（使用前の接着状態をほぼ保っている）と判断することができる。
また、実験例４では、ゴム組成物とワイヤ材の接着状態がやや悪化しており、実験例５では、ゴム組成物とワイヤ材の接着状態が悪化していた。このことから、ゴム組成物とワイヤ材の接着界面を切断する切断面中における直接接触領域の長さの比率が１０％を超える場合、または接着界面に沿った界面領域中における直接接触領域の面積の比率が２０％を超える場合に、ゴム組成物とワイヤ材の接着状態の悪化が顕著になることがわかった。よって、このようなゴムワイヤ複合体、およびこれを用いたタイヤにおいては、上記直接接触領域の長さの比率が１０％以下、または上記直接接触領域の面積の比率が２０％以下のものの使用が推奨されると考えられる。すなわち、直接接触領域の割合が長さ１０％以下、または面積２０％以下であれば、使用に耐えうる接着状態を保っていると判断することができる。 In Experimental Examples 1 to 3, the adhesive state between the rubber composition and the wire material was good. From this, the ratio of the length of the direct contact region in the cut surface for cutting the adhesive interface between the rubber composition and the wire material is 5% or less, or the ratio of the area of the direct contact region in the interface region along the adhesive interface. When is 10% or less, it can be determined that the adhesive state between the rubber composition and the wire material is good (the adhesive state before use is almost maintained).
Further, in Experimental Example 4, the adhesive state between the rubber composition and the wire material was slightly deteriorated, and in Experimental Example 5, the adhesive state between the rubber composition and the wire material was deteriorated. From this, when the ratio of the length of the direct contact region in the cut surface for cutting the adhesive interface between the rubber composition and the wire material exceeds 10%, or the area of the direct contact region in the interface region along the adhesive interface. It was found that when the ratio of the above was more than 20%, the deterioration of the adhesive state between the rubber composition and the wire material became remarkable. Therefore, in such a rubber wire composite and a tire using the same, it is recommended to use one having a ratio of the length of the direct contact region of 10% or less or a ratio of the area of the direct contact region of 20% or less. It is thought that it will be done. That is, if the proportion of the direct contact region is 10% or less in length or 20% or less in area, it can be determined that the adhesive state that can withstand use is maintained.

１０ＦＩＢ−ＳＥＭ
１２電子ビーム鏡筒
１４イオンビーム鏡筒
１６試料台
１８処理装置
２０ゴムワイヤ複合体
２２ワイヤ材
２４めっき層
２６ゴム組成物
Ｂ１電子ビーム照射軸
Ｂ２イオンビーム照射軸 10 FIB-SEM
12 Electron beam lens barrel 14 Ion beam lens barrel 16 Sample stand 18 Processing device 20 Rubber wire composite 22 Wire material 24 Plating layer 26 Rubber composition B1 Electron beam irradiation axis B2 Ion beam irradiation axis

Claims

It is an adhesion state evaluation method for evaluating the adhesion state between the wire material and the rubber composition in a rubber wire composite in which a plated wire material is coated with a rubber composition.
Using a scanning electron microscope, the detection step of detecting the composition distribution on the surface of the rubber wire composite and the etching step of etching the surface of the rubber wire composite to a predetermined thickness with a focused ion beam are repeated, and the rubber wire composite 3 The composition distribution acquisition process for acquiring the dimensional composition distribution and
From the three-dimensional composition distribution, the composition distribution at the bonding interface between the wire material and the rubber composition is extracted, and the ratio of the direct contact region where the material of the wire material and the rubber composition are in direct contact at the bonding interface. An evaluation step for evaluating the adhesive state between the wire material and the rubber composition based on
A method for evaluating the adhesive state of a rubber wire complex, which comprises.

The rubber composition contains a diene-based rubber, carbon black, and sulfur.
The wire material is made of iron, and the plating is brass plating.
In the evaluation step, the bonding state is evaluated based on the ratio of the direct contact region where the iron and the rubber composition or the iron and copper sulfide are in direct contact with each other at the bonding interface.
The method for evaluating an adhesive state of a rubber wire complex according to claim 1.

In the evaluation step, an arbitrary cut surface for cutting the adhesive interface is extracted from the three-dimensional composition distribution, and the adhesive interface has a length of at least 1/250 of the outer peripheral length of the wire material on the cut surface. When the length of the direct contact region in the cut surface is 5% or less of the total length of the adhesive interface in the cut surface, the wire material and the rubber composition Judging that the adhesive condition is good,
The method for evaluating an adhesive state of a rubber wire composite according to claim 1 or 2.

In the evaluation step, an interface region along the adhesive interface having a length of at least 1/250 of the outer peripheral length of the wire material is extracted from the three-dimensional composition distribution, and the direct contact region in the interface region is extracted. When the area is 10% or less of the total area of the interface region, it is determined that the adhesive state between the wire material and the rubber composition is good.
The method for evaluating an adhesive state of a rubber wire complex according to claim 1 or 2.

In the etching step, the surface of the rubber wire composite is etched to a predetermined thickness by irradiating the focused ion beam from a direction substantially orthogonal to the extending direction of the rubber wire composite to form a cross section of the rubber wire composite.
By the detection step, an electron beam of the scanning electron microscope is input from a direction substantially perpendicular to the cross section of the rubber wire composite, and an observation image of the cross section of the rubber wire composite viewed from the front with the scanning electron microscope. To detect the composition distribution of the cross section of the rubber wire composite,
In the composition acquisition step, the etching step and the detection step are repeated to acquire the three-dimensional composition distribution of the rubber wire complex.
The method for evaluating an adhesive state of a rubber wire composite according to any one of claims 1 to 4, wherein the rubber wire composite is characterized by this.

In the composition distribution acquisition step, the types of elements exposed on the cross section of the rubber wire composite are measured using an energy dispersive X-ray analyzer, and the grayscale image obtained by the scanning electron microscope and the elements Further includes a segmentation processing step of performing segmentation processing in correspondence with the type of
The method for evaluating an adhesive state of a rubber wire composite according to any one of claims 1 to 5, wherein the rubber wire composite is characterized by this.