JP5649291B2 - Belt cord and vehicle tire - Google Patents

Description

  The present invention relates to a belt cord and a vehicle tire that are used for, for example, an element wire of a belt cord for tire reinforcement, and have improved adhesion between a brass-plated steel wire having a brass plating layer formed on the surface and rubber.

  For example, as shown in FIG. 6, the radial tire includes an inner liner 2 for maintaining airtightness in the tire, a carcass 3 that forms an aggregate of the tire on its outer periphery, and a bead wire 4 that holds a rim of the wheel. A bead filler 5 that reinforces retention of the rim, a plurality of belts 6a to 6d that are integrated into the crown portion of the tire, a cover rubber 7 that protects the belts 6a to 6d, a tread rubber 8, and a carcass 3 In order to protect the wheel rim from being directly touched, it is composed of a plurality of chafer cords 9 formed in an annular shape and disposed.

The plurality of belts 6a to 6d are formed by arranging a belt cord 20 twisted by bundling a plurality of brass-plated steel wires in a fence shape and coating the whole with rubber G, as will be described later.
As shown in FIG. 7, the belt cord 20 has, for example, a layer twist structure, and in the center side, three core filaments 51 are arranged so as to form a triangular shape, and the core filaments 51 are arranged. Nine inner sheath filaments 52s disposed on the outer periphery so as to surround, 15 outer sheath filaments 53s disposed on the outer periphery so as to surround the inner sheath filament 52s, and wrapping disposed on the outer periphery of the outer sheath filament 53s The filament 24 is configured such that the core filament 51, the inner sheath filament 52s, and the outer sheath filament 53s are twisted and the wrapping filament 24 is wound around the outer periphery thereof.
As shown in FIG. 8, the belt cord 25 has, for example, a double twist structure, and includes one core filament 56 and five sheath filaments 57 s arranged on the outer periphery so as to surround the core filament 56. A strand 58 is formed by layer twisting, and a double twisted structure in which four strands 58 are bundled and twisted is formed.

In this case, in the layer twist structure shown in FIG. 7, the core filament 51, the inner sheath filament 52s, the outer sheath filament 53s, and the wrapping filament 24 are, for example, a steel steel wire 50, The steel plate 50 is deposited around the steel wire 50, and the composition is composed of 55% to 66% by weight of copper Cu and a brass plating layer 50a made of zinc Zn.
Further, in the double twist structure shown in FIG. 8, the core filament 56 and the sheath filament 57s are, for example, attached to the steel steel wire 50 and the steel steel wire 50 as shown in FIG. The composition consists of copper Cu 55 wt% to 66 wt% and a brass plating layer 50 a made of zinc Zn.

In order to improve the elasticity and strength of the copper Cu in the brass plating forming the brass plating layer 50a of each filament 51, 52s, 53s, 24, 56, 57s constituting the belt cord 20, 25, and the rubber G. Bonded with sulfur S contained therein, an adhesive layer made of copper sulfide is formed at the interface between the belt cords 20 and 25 and the rubber G to provide initial adhesiveness, adhesiveness during overvulcanization, heat resistant adhesiveness, The belt end peel resistance and water resistance are obtained.
That is, by heating and vulcanizing in a vulcanization molding process at the time of manufacturing the tire, the belt cords 20 and 25 are caused to react with sulfur S contained in the rubber G and copper Cu in the brass plating of the brass plating layer 50a. By maintaining adhesion to the rubber G in the vicinity, the carcass 3, the shoulder portion, and the tread rubber 8 are reinforced.

  As a method for further improving the adhesion performance between the brass-plated steel wire of FIGS. 7 and 8 having the brass plating layer 50a and the rubber G, as shown in Patent Document 1 and Patent Document 2, the plating component of the brass plating layer 50a includes Fe. A method of alloying the surface layer by adding an alloy element such as Ni or Ni, a method of performing surface treatment by irradiating plasma to a steel wire subjected to brass plating as shown in Patent Document 3, as shown in Patent Document 4 In addition, a method for limiting the oxygen ratio of the outermost surface of the brass plating layer and a method for performing a blast treatment after wire drawing as shown in Patent Document 5 are known.

However, since the methods shown in Patent Document 1 to Patent Document 5 are methods aimed at improving the initial adhesiveness and wet heat adhesiveness, the initial adhesiveness and wet heat adhesiveness between the brass-plated steel wire and the rubber G are improved. The main focus was placed. For this reason, in the above method, when the rubber thickness is thick, such as a heavy duty vehicle tire or a construction vehicle tire, the vulcanization time of the tire becomes long, and in the thin rubber portion etc. There was a risk of poor adhesion due to, and there was a problem in adhesion during vulcanization.
In recent years, heavy load vehicle tires and construction vehicle tires have been required to have a heavy load, a high traveling speed, and a long life. Thus, when the tire use conditions become heavy load and speed increase, the force acting on the tread rubber 8 portion increases, the distortion of the belts 6a to 6d increases, and the temperature rise of the belts 6a to 6d and the carcass 3 increases. Therefore, the adhesive force between the rubber G and the end portions of the belt cords 20 and 25 may be reduced, and the adhesive peeling may occur during traveling. In particular, the rubber G and the belt cord 20 at the shoulder portions that are the end portions of the belts 6a to 6d , There was a problem in the heat-resistant adhesiveness with the 25 end and the belt end peeling resistance.
In addition, in order to achieve a long life, the belt cords 20 and 25 are required to be water resistant so that the belt cords 20 and 25 are not easily rusted even if the tire is cut during traveling.
That is, in the adhesion of the belt cords 20 and 25 and the rubber G, the belt cord 20, the initial adhesion, the adhesion during overvulcanization, the heat resistant adhesion, the belt end peeling resistance, and the water resistance can all be improved. 25.

JP-A-8-209386 JP 2002-13081 A JP 2003-160895 A JP 2004-68102 A JP-A-5-278147

  In order to solve the above-mentioned problems, the present invention provides an initial adhesion between a belt cord and a rubber constituting a belt, an adhesion at the time of overvulcanization, a heat-resistant adhesion, a belt end during vulcanization or use of a tire. Provided are a belt cord and a vehicle tire for improving peeling resistance and water resistance.

As a first embodiment of the present invention, so as to surround the outer periphery of one core filament made of steel wire having a brass-plated layer on the surface, placing five sheath filaments made of steel wire having a brass-plated layer on the surface and, a belt cord of a tire multi-twisted structure in which twisted double bundled four strands were twisted layers, blanking lath plated layers of all of the sheath filament is made composition of copper and zinc, of which copper 55 weight An upper layer made of an amorphous part formed of crystal grains having a particle size of 20 nm or less and a lower layer made of a crystalline part made of crystal grains having a particle size exceeding 20 nm are laminated. formed as a laminated structure portion, the area ratio of the surface occupied noncrystalline portion of the laminated structure portion on the entire surface of the brass plating layer is 20% or more, the laminated structure The volume proportion of noncrystalline portion with respect to the total volume of formed 80% less than 20%, the brass plated layer of the core filament, the composition consists of copper and zinc, copper 55 wt% to 66 wt %, An upper layer composed of a crystalline part of a single layer or an amorphous part formed of 55% to 66% by weight of copper and having a grain size of 20 nm or less, and a grain size of 20 nm An area ratio of the surface of the non-crystalline portion of the laminated structure portion to the entire surface of the brass plating layer is 20 The copper supply rate is lower than the copper supply rate supplied from the brass plating layer of the sheath filament .
According to the present invention, the belt cord constituting the belt is composed of the brass-plated steel wire on which the brass plating layer composed of the upper layer portion and the lower layer portion having different crystal structures is formed, and this brass-plated steel wire constitutes the belt cord. Since it is contained as a sheath filament that is 50% or more of the sheath filament, when the tire is vulcanized, the brass plating layer in the upper layer reacts at the initial vulcanization stage, and subsequent vulcanization and use of the tire Sometimes the lower brass plating layer reacts, improving the initial adhesion performance of the belt, adhesion performance during over-vulcanization, and heat-resistant adhesion to heat generation when using the tire, and belt edge peeling resistance and water resistance. Can be improved.
In addition, since the surface of the belt cord is composed of brass plating layers having different properties, the upper brass plating layer and the exposed lower brass plating layer can react with the rubber during vulcanization of the tire, and the upper brass plating layer By combining the lower layer brass plating layer exposed on the surface at an appropriate ratio, the belt cord can be firmly adhered to the rubber, preventing the belt and rubber from peeling off at the belt end, and improving the water resistance. it can.
Also, Cu in the amorphous part of the brass plating layer first reacts with S in the rubber to secure the initial adhesion performance, and the Cu in the crystalline part and S in the rubber react slowly to overheat. Prevents adhesion failure due to vulcanization and ensures adhesion during overvulcanization, and the reaction continues even when the tire is used, so it acts on the belt due to heat-resistant adhesion due to heat generated during tire use and tire deflection The anti-separation performance between the rubber and the belt cord can be improved from the strain.

As a second embodiment of the present invention, the sheath filament is made of a brass-plated steel wire having a volume ratio of 50% or more of the laminated structure portion with respect to the entire volume of the brass-plated layer of the sheath filament .
According to the present invention, the volume ratio occupied by the laminated structure part composed of the amorphous part and the crystalline part is 50% or more, so that Cu in the amorphous part and S in the rubber are vulcanized. In some cases, the reaction can be performed for a longer period of time, so that the belt cord end and rubber, belt and tread rubber, and overvulcanization in each belt can be prevented.

As a third aspect of the present invention, the sheath filament is made of a brass-plated steel wire in which the area ratio occupied by the surface of the amorphous portion with respect to the entire surface of the brass-plated layer of the sheath filament is 80% or more. Configured.
According to the present invention, since the area ratio occupied by the surface of the amorphous portion is 80% or more, the area that reacts at the initial stage during vulcanization is widened, so the initial adhesion performance can be improved over a wide area. . In addition, the crystalline part located inside the non-crystalline part can react with rubber over a wide area when overvulcanized or when using a tire. Peel resistance and water resistance can be further improved.

As a fourth aspect of the present invention, a vehicle tire is configured by applying the belt cord according to any one of claims 1 to 3 to at least a belt located in the outermost layer.
According to the present invention, the adhesion of the outermost belt is secured while preventing over-vulcanization of the belt located on the inner side, and the vulcanization time is reduced. It is possible to prevent the failure of the tire at the time.

Sectional drawing of the belt cord of the layer twist structure which concerns on this invention. Sectional drawing of the brass plating steel wire which concerns on this invention. The cross-sectional enlarged view of the brass plating steel wire which concerns on this invention. Sectional drawing of the belt cord of the double twist structure which concerns on this invention. The table which evaluated the effect of the belt cord concerning the present invention. The schematic structure sectional drawing of a tire. The illustration figure of the layer twist structure of the conventional belt cord. The illustration figure of the double twist structure of the conventional belt cord. Sectional drawing of a conventional steel belted steel cord of belt cord.

Embodiment FIG. 1 is a cross-sectional view showing an example of a belt cord 20 having a layer twist structure according to the present invention.
When the belt cord 20 has a layered twist structure, the three core filaments 21 that are located in a triangle on the center side, the nine inner sheath filaments 22 that are arranged around the core filament 21, and the inner sheath filaments 22 that are arranged around the core filament 21 are arranged. 15 outer sheath filaments 23s, 23t, and a twisted cord structure in which the whole is twisted and wrapped with a wrapping filament 24 (3 core filaments + 9 inner sheath filaments + 15 outer sheath filaments + 15 wrapping filaments) 1).
The core filament 21, the inner sheath filament 22, and the outer sheath filaments 23s and 23t have a wire diameter of 0.23 mm, and the wrapping filament 24 has a wire diameter of 0.15 mm.

In the present embodiment, as shown by hatching in FIG. 1, 50% or more of outer sheath filaments 23s out of the total number of all outer sheath filaments F (in this example, eight outer sheaths out of 15 outer sheath filaments F). Filament) is a composition in which Cu and Zn are combined so that the composition is 55% to 66% by weight of copper Cu, 34% to 45% by weight of zinc Zn, and 100% by weight, and the grain size is 20 nm or less. Formed by a laminated brass-plated steel wire 12 formed by laminating an upper layer made of a noncrystalline part 11m formed of grains and a lower layer made of a crystalline part 11n made of crystal grains having a grain size exceeding 20 nm. (See FIG. 2).
In the present example, the remaining outer sheath filament 23t of all outer sheath filaments F is composed of, for example, a composition ratio of the brass plating layer made of Cu and Zn of 55 wt% to 66 wt% and the remaining ratio of Zn. Single layer brass-plated steel wire consisting only of crystalline parts, crystalline layer consisting of crystallized grains with grain size exceeding 20 nm and upper layer consisting of non-crystalline parts formed by crystal grains with grain size of 20 nm or less Formed of a brass plating layer in which the surface ratio of the amorphous part of the laminated structure portion occupies less than 20% of the entire surface of the brass plating layer. Made of steel steel wire.

The brass plating layer is composed of Cu and Zn, of which Cu is 55 wt% to 66 wt%, and an upper layer is formed of an amorphous portion formed of crystal grains having a grain size of 20 nm or less, and a grain size of 20 nm. An area ratio of the surface of the non-crystalline portion of the laminated structure portion to the entire surface of the brass plating layer is 20 %, The two brass plating layers 11 on the surface of the laminated brass-plated steel wire 12 whose non-crystalline portion accounts for 20% to 80% of the entire volume of the laminated structure portion 2, a laminated structure portion 13 in which an amorphous portion 11m as an upper layer portion located on the surface side and a crystalline portion 11n as a lower layer portion located on the steel steel wire side are laminated, as shown in FIG. Have and also Amorphous-crystalline portion 11n only may have a non-laminated structure portion 14 made of (single layer). In this case, the non-laminate structure portion 14 is a portion (non-laminate portion) where the crystalline part 11n is exposed on the surface side and is not laminated with the non-crystalline part 11m. Accordingly, the laminated brass-plated steel wire 12 having the two-layered brass-plated steel wire is covered with the laminated structure portion 13 and the non-laminated structure portion 14.
In this example, the amorphous part 11m as the upper layer part is composed of Cu and Zn so that the composition is in the range of 55 wt% to 66 wt% of Cu and 34 wt% to 45 wt% of Zn, and the wt% is 100%. It consists of a combination of brass plating, and the crystalline part 11n as the lower layer part has a composition of Cu 55 wt% to 66 wt%, Zn 34 wt% to 45 wt%, and Cu and Cu so that the wt% is 100%. It consists of brass plating combined with Zn.

The amorphous part 11m is formed of crystal grains having a grain size of 20 nm or less. Specifically, it is composed of a part formed by fine crystal grains of 20 nm or less and a part formed by amorphous material in which the crystal grains cannot be distinguished. The crystalline part 11n is a part formed by crystal grains having a grain size exceeding 20 nm. The non-crystalline portion 11m has an area ratio of 20% or more of the surface of the non-crystalline portion of the laminated structure portion with respect to the entire surface of the brass plating layer, and is non-existent with respect to the entire volume of the laminated structure portion. It is formed so that the volume ratio occupied by the crystalline part is 20% or more and 80% or less.
The amorphous part 11m and the crystalline part 11n are discriminated by the backscattered electron beam pattern of the filament cross section observed by crystal orientation analysis (EBSP). A Kikuchi pattern corresponding to the crystal orientation of Cu can be obtained in the crystalline part 11n of the non-laminated structure part 14, but a clear Kikuchi pattern cannot be obtained in the noncrystalline part 11m of the laminated structure part 13.

Thus, in this embodiment, as shown in FIGS. 1-3, some outer sheath filaments 23s are formed among all the outer sheath filaments F, and the composition of the brass plating layer of the outer sheath filament 23t is 55% by weight of Cu. A single-layer brass-plated steel wire comprising only 66% by weight of the remaining part of Zn and having a crystalline part, and an upper layer comprising an amorphous part formed of crystal grains having a grain size of 20 nm or less; It is formed as a laminated structure part in which a lower layer made of a crystalline part composed of crystal grains having a grain size of more than 20 nm is laminated, and the surface of the amorphous part of the laminated structure part with respect to the entire surface of the brass plating layer It is formed of a filament on which brass plating having a plating composition with an area ratio of less than 20% is applied.
The outer sheath filament 23s is configured to be 50% or more of all the outer sheath filaments F. In this embodiment, eight of the 15 outer sheath filaments are made of laminated brass-plated steel wire 12.

  In the outer sheath filament 23s, the area ratio A occupied by the surface area of the laminated structure portion 13 with respect to the entire surface area of the brass plating layer 11 of the laminated brass-plated steel wire 12 is 20% or more. On the other hand, the steel steel wire is brass-plated so that the volume ratio B occupied by the amorphous part 11m is 20% or more and 80% or less.

According to the belt cord 20 having the above-described structure, the laminated brass-plated steel wire 12 of a part of the outer sheath filaments 23s (50% or more of all outer sheath filaments F in the outermost layer in the case of the layer twist structure as in this example) Since the non-crystalline portion 11m located on the surface side has a very high lattice defect concentration and high activity in that portion, the diffusion rate of Cu atoms is high.
As a result, in the amorphous part 11m of the laminated brass-plated steel wire 12 that comes into contact with the rubber G when the tire is vulcanized, Cu diffused from the amorphous part 11m and S in the rubber G quickly By reacting, an adhesive layer is formed at the interface between the laminated brass-plated steel wire 12 and the rubber G, so that the initial adhesive performance between the rubber G and the belt cord 20 is obtained.

Further, if the area ratio A of the surface area of the amorphous part 11m to the entire surface area of the brass plating layer 11 is 80% or more, the contact area between the amorphous part 11m and the rubber G increases. In the early stage of vulcanization, an adhesive layer between the laminated brass-plated steel wire 12 and the rubber G can be formed and bonded in a wide range, and the initial adhesive performance between the belt cord 20 and the rubber G is surely improved. be able to.
Further, a crystalline part 11n having a lower activity and a slower diffusion rate of Cu is provided inside the amorphous part 11m of the laminated brass-plated steel wire 12 constituting the belt cord 20. Therefore, even if vulcanization is performed for a long time, the adhesive layer is not enlarged due to excessive supply of Cu in the shoulder portion of the tire, and deterioration of the adhesiveness of overvulcanization can be prevented.
That is, the laminated brass-plated steel wire 12 constituting the belt cord 20 is included in the rubber G after the amorphous part 11m that reacts with S contained in the rubber G in the initial stage of vulcanization. Since it has a crystalline part 11n that reacts with S, Cu that precipitates from the belt cord 20 constituting the belts 6a to 6d even if a reaction due to moisture or heat proceeds in the shoulder part during use of the tire. There is no early depletion. Accordingly, the belt cord 20 is improved in both the initial adhesion performance and the adhesion durability performance, and the belts 6a to 6d and the rubber G are firmly adhered to each other, thereby peeling off the end portions of the belts 6a to 6d made of the belt cord 20. It is possible to improve water resistance to prevent rust caused by contact of moisture entering from the scratches and cracks generated in the tread with the belt cord 20.

For example, in the case where the brass plating layer of the laminated brass-plated steel wire 12 constituting the belt cord 20 is composed only of the non-crystalline part 11m having high activity, the brass plating layer can be used in a severe wet heat deterioration environment. Cu reacts excessively with S in the rubber G, the composition balance of the brass plating layer is lost, and the interface between the brass plating layer and the steel wire becomes weak, and the belt cord 20 itself, that is, the belts 6a to 6d is destroyed. There is a risk of starting.
In this example, the laminated brass-plated steel wire 12 constituting the belt cord 20 is formed with an amorphous part 11m on the surface side as an upper layer part, and with a crystalline part 11n on the inner side as a lower layer part thereof. Therefore, the durability adhesion performance is improved.

  If the volume ratio B occupying the entire brass plating layer 11 of the laminated structure portion 13 is 45% or more, the enlargement of the adhesive layer due to excessive supply of Cu can be prevented and the belt cord constituting the belts 6a to 6d Since early depletion of Cu deposited from 20 can be prevented, adhesion durability performance can be ensured. As a result, the belt cord 20 and the rubber G are more closely adhered to each other, so that peeling at the end portions of the belts 6 a to 6 d is prevented, and rust caused by contact of moisture entering from the cracks generated in the rubber G with the belt cord 20 is prevented. The water resistance to prevent can be improved more.

  In the laminated brass-plated steel wire 12 of this example, the area of the surface of the amorphous portion 11m of the laminated structure portion 13 is set to 20% or more of the area ratio A occupying the entire surface area of the brass-plated layer 11. This is because when the area ratio A is less than 20%, the amount of Cu supplied from the amorphous part 11m is small and Cu atoms do not sufficiently diffuse into the rubber G, so that the initial adhesion performance cannot be obtained. .

In the laminated brass-plated steel wire 12 of this example, the volume ratio B of the amorphous portion 11m of the laminated structure portion 13 occupying the entire laminated structure portion 13 is set to 20% or more and 80% or less.
When the volume ratio B is less than 20%, the effect of laminating the amorphous part 11m and the crystalline part 11n cannot be obtained, so not only the initial adhesion performance but also the adhesion performance during overvulcanization. And heat-resistant adhesion performance cannot be obtained.
Further, if the volume ratio B exceeds 80%, Cu atoms diffuse too much during vulcanization, and Cu is depleted when heat is generated at the shoulder portions where the ends of the belts 6a to 6d are located. Performance cannot be obtained.
On the other hand, when the volume ratio B is 20% or more and 80% or less, the diffusion of Cu from the amorphous part 11m at the time of initial bonding, the crystalline part 11n and the amorphous part at the time of overvulcanization The supply of Cu from 11 m and the supply of Cu from the amorphous part 11 m and the crystalline part 11 n during wet heat deterioration during traveling function in a well-balanced manner. This is because the Cu component of the crystalline part 11n remains sufficiently even after vulcanization for a long time, so that Cu can be sufficiently supplied even if heat is generated during tire use.

  As described above, according to the present embodiment, for example, the brass plating layer 11 of the laminated brass-plated steel wire 12 is formed on the belt cord 20 that constitutes the belts 6a to 6d of heavy-duty vehicle tires and construction vehicle tires. The composition is 55 wt% to 66 wt% Cu, 34 wt% to 45 wt% Zn, and an amorphous portion 11 m composed of crystal grains having a particle size of 20 nm or less on the surface side as the upper layer portion of the brass plating layer 11. And a layered structure portion 13 in which a crystalline portion 11n made of crystal grains having a grain size exceeding 20 nm is laminated on the inner side as a lower layer portion, and the non-crystalline property of the layered structure portion 13 The area ratio A that the surface of the portion 11m occupies in the entire surface of the brass plating layer 11 is 20% or more, and the entire laminated structure portion 13 of the amorphous portion 11m of the laminated structure portion 13 is formed. Since the belt cord with a volume ratio B of 20% or more and 80% or less is used, the initial adhesion performance, the adhesion performance during overvulcanization, the heat resistance adhesion performance, the belt edge peeling resistance performance, and the water resistance performance should be improved. Can do.

Further, as described above, outer sheath filaments 23s made of laminated brass-plated steel wire 12 are applied to all outer sheath filaments F of the outermost layer of belt cord 20 produced by twisting a plurality of brass-plated steel wires in a layer twist structure. By using 50% or more, belt cord 20 excellent in all of initial adhesion performance, adhesion performance during overvulcanization, heat resistance adhesion performance, belt end peeling resistance performance, and water resistance performance can be obtained. The durability of the shoulder portion and tread portion of the tire for construction vehicles can be improved.
In addition, the core filament and the sheath filament that are not in contact with the rubber outside the belt cord are made of a conventional brass plating layer composed of Cu and Zn, of which Cu is 55 wt% to 66 wt%, and crystalline. A brass-plated steel wire having a single brass-plated layer composed of a crystalline portion, an upper layer composed of an amorphous portion formed by crystal grains having a grain size of 20 nm or less, and crystal grains having a grain size exceeding 20 nm Brass plating formed as a laminated structure portion in which a lower layer made of a crystalline portion is laminated, and the area ratio of the amorphous portion of the laminated structure portion to the entire surface of the brass plating layer is less than 20% By using the filament formed by the layer for the belt cord 20, disconnection when the belt cord 20 composed entirely of the filaments to which the present invention is applied is manufactured. It is possible to reduce the number, adhesion performance can be secured.

In the above embodiment, as an example of the belt cord 20, the core filament 21, the inner sheath filament 22, the outer sheath filaments 23s and 23t, and the wrapping filament 24 have a cord structure of 3 + 9 + 15 ++ 1 layers. However, the present invention is not limited to this, and may be a belt cord 25 having a double twist structure described later (shown in FIG. 4).
Further, among the 15 outer sheath filaments F located in the outermost layer constituting the belt cord 20, the laminated brass-plated steel wire 12 having the above laminated structure is used for the eight outer sheath filaments 23s. The sheath filament F may be the laminated brass-plated steel wire 12 described above. In short, the belt cords 20 and 25 are composed of 50% or more of the outermost outer sheath filament of the outermost layer in the layer twist structure, and 50% or more of the outermost sheath filament of the outermost strand in the double twisted structure. And Zn, of which Cu is 55 wt% to 66 wt%, and the upper layer is made of an amorphous part formed by crystal grains having a grain size of 20 nm or less, and the crystallinity made of crystal grains having a grain size of more than 20 nm. Is formed as a laminated structure portion laminated with a lower layer composed of a portion, and the ratio of the area of the amorphous portion of the laminated structure portion to the entire surface of the brass plating layer is 20% or more, It is composed of a brass-plated steel wire 12 having a desired non-crystalline part ratio such that the non-crystalline part accounts for 20% to 80% of the entire volume. , It is possible to sufficiently exhibit the effect of the present invention.
In addition, when the ratio of the said laminated brass plating steel wire 12 in all the outer sheath filaments F is less than 50%, the supply amount of Cu at the time of overvulcanization and wet heat deterioration decreases, and the effect of this invention Is not sufficiently exhibited, the adhesiveness with the rubber G is lowered. Therefore, it is preferable that 50% or more of the total outer sheath filament F is the laminated brass-plated steel wire 12.

As an example of the belt cord 25 having a double twist structure, as shown in FIG. 4, one core filament 26 and five sheath filaments 27 s and 27 t arranged on the outer periphery so as to surround the core filament 26 are layered. A strand 28 is formed by twisting, and a four-strand cord structure in which four strands 28 are bundled and twisted (four strands × (one core filament + one sheath filament)) is formed. For example, the core filament 26 and the sheath filaments 27s and 27t have the same wire diameter of 0.25 mm.
In the belt cord 25, as shown by hatching in FIG. 4, a part of the total number of the sheath filaments E (50% or more; in this example, 3 out of 5) sheath filaments 27s (excluding the sheath filament 27t) ) Is formed of crystal grains having a composition of 55% to 66% by weight of Cu and 34% to 45% by weight of Zn, and Cu and Zn are combined so that the weight% becomes 100%. The laminated brass-plated steel wire 12 is formed by laminating an upper layer made of the noncrystalline part 11m and a lower layer made of the crystalline part 11n made of crystal grains having a grain size of more than 20 nm ( (See FIG. 3).
In this example, the remaining sheath filaments 27t of all the sheath filaments are composed of, for example, a composition ratio of a brass plating layer made of Cu and Zn of 55 wt% to 66 wt%, and the remaining ratio is made of Zn. A single-layer brass-plated steel wire comprising only a part, an upper layer comprising an amorphous part formed by crystal grains having a grain size of 20 nm or less, and a crystalline part comprising crystal grains having a grain size exceeding 20 nm A steel steel wire formed as a laminated structure portion in which a lower layer is laminated, and comprising a brass plating layer in which the surface ratio of the amorphous portion of the laminated structure portion is less than 20% with respect to the entire surface of the brass plating layer Consists of.
The belt cord 25 having the double twist structure may be used for the sheath filament 27s of 50% or more with respect to all the sheath filaments E in which the laminated brass-plated steel wire 12 forms the strand 28. The same effect as when the belts 6a to 6d are configured by the cord 20 can be obtained.

In this example, the brass-plated steel wire of the present invention is 50% or more for the outermost sheath filament in the case of layer twist, and 50% or more for the outermost sheath filament of the outermost strand in the case of double twist structure. .
Furthermore, as a preferable form, in the case of layer twist, 100% is applied to the outermost layer sheath filament, and in the case of double twist, 100% is applied to the outermost layer sheath filament of the outermost layer strand. A conventional filament may be applied.

Examples Hereinafter, in order to investigate the effect of the present invention, a belt cord 20 having a layer twist structure and a belt cord 25 having a double twist structure were prepared. As shown in Tables 1 and 2 of FIG. The wire breakage rate at the time of manufacture, the initial adhesion performance between the belt cords 20 and 25 and the rubber, the adhesion performance at the time of overvulcanization, the heat resistance adhesion performance, the peeling resistance performance at the belt end and the water resistance performance were examined. Evaluation was performed using eight patterns of Comparative Examples 1 and 2 and Invention Examples 1 to 4. In addition, evaluation of each said adhesive performance referred to JISG3510 (1992), and performed the rubber | gum adhesion test according to this prescription | regulation.

  In the conventional example 1, the cord structure of the belt cord 20 includes three core filaments having a wire diameter of 0.23 mm, nine inner sheath filaments having a wire diameter of 0.23 mm, 15 outer sheath filaments having a wire diameter of 0.23 mm, and a wire diameter. It consists of a layer twist structure of one wrapping filament of 0.15 mm. The core filament, inner sheath filament, all outer sheath filament F, and wrapping filament 24 have brass plating composition ratios of Cu: 63 wt%, Zn: A laminated brass-plated steel comprising a laminated brass-plated steel wire 12 having a 37% by weight brass-plated layer 11 and having an area ratio A of 60% and a volume ratio B of 15% in the proportion of the amorphous portion 11m of all filaments. Consists of line 12. The amorphous part 11m is formed by crystal grains having a particle diameter of 20 nm or less, and the crystalline part 11n is formed by crystal grains having a particle diameter exceeding 20 nm.

  In the conventional example 2, the cord structure of the belt cord 25 is a strand having a layer twist structure of one core filament having a wire diameter of 0.25 mm and five sheath filaments having a wire diameter of 0.25 mm. It consists of a double twisted structure that is bundled and twisted. The core filament and the entire sheath filament E are laminated brass-plated steels having a brass plating layer with a brass plating composition ratio of Cu: 63 wt% and Zn: 37 wt% in both the noncrystalline part 11m and the crystalline part 11n. It consists of a wire 12 and is composed of a laminated brass-plated steel wire with an area ratio A of 60% and a volume ratio B of 15% in the proportion of the amorphous part 11m of all filaments. The amorphous part 11m is formed by crystal grains having a particle diameter of 20 nm or less, and the crystalline part 11n is formed by crystal grains having a particle diameter exceeding 20 nm.

  Comparative Example 1 is formed so that the ratio of the amorphous portion 11m of the outer sheath filament is 98% in the area ratio A and 45% in the volume ratio B in the cord structure of the belt cord 20 of Conventional Example 1. The laminated brass-plated steel wire 12 is composed of 30% (three) of all the outer sheath filaments F, and the other outer sheath filaments, inner sheath filaments, core filaments and wrapping filaments are the same as in the conventional example 1. .

  In Comparative Example 2, in the cord structure of the belt cord 25 of Conventional Example 2, the ratio of the amorphous portion 11m of all the sheath filaments E constituting each strand 28 of Conventional Example 2 is 98% in area ratio A and volume. The laminated brass-plated steel wire 12 formed so that the ratio B is 45% is constituted by 25% with respect to all the sheath filaments E, and the other sheath filaments and core filaments are the same as in the conventional example 2.

  Invention Example 1 is a laminated brass plating in which the ratio of the amorphous portion 11m in the cord structure of the belt cord 20 of Conventional Example 1 is 98% and the volume ratio B is 45%. Except for applying 100% of the steel wire 12 to all the outer sheath filaments F, the configuration is the same as that of the conventional example 1.

  Invention Example 2 is a laminated brass plating in which the ratio of the non-crystalline portion 11m is 98% in the cord structure of the belt cord 20 in Conventional Example 1 and the volume ratio B is 45%. The steel wire 12 is composed of 53% (five) with respect to all the outer sheath filaments F, and the other outer sheath filaments, inner sheath filaments, core filaments and wrapping filaments have the same configuration as that of the conventional example 1.

  Invention Example 3 is the cord structure of the belt cord 25 of Conventional Example 2, and the ratio of the amorphous portions 11m of all the sheath filaments E constituting each strand 28 of Conventional Example 2 is 98% in area ratio A and volume. The structure is the same as that of Conventional Example 2 except that 100% of the laminated brass plated steel wire 12 formed so that the ratio B is 45% is applied to all the sheath filaments E.

  Invention Example 4 is the cord structure of the belt cord 25 of Conventional Example 2, and the ratio of the amorphous portions 11m of all the sheath filaments E constituting each strand 28 of Conventional Example 2 is 98% in area ratio A and volume. The laminated brass-plated steel wire 12 formed so that the ratio B is 45% is constituted by 50% with respect to all the sheath filaments E, and the other sheath filaments and core filaments are the same as in the conventional example 2.

The eight types of belt cords 20 and 25 were actually produced, and each belt cord 20 and 25 was covered with treat rubber with reference to JIS G3510 (1992) to produce a belt treat as a test piece.
The belt treat is manufactured by arranging the belt cord 20 in the conventional twisted structure 1, comparative example 1 and invention examples 1 and 2 in parallel with an interval of 10 cords / inch, and the belt cord 25 having a double twist structure. Comparative Example 2 and Invention Examples 4 to 6 were prepared in parallel with an interval of 8 cords / inch and sandwiched between treat rubbers.

As shown in Tables 1 and 2 of FIG. The rubber adhesion test for the adhesion performance and heat resistance adhesion performance was conducted under the following conditions.
Regarding the evaluation of the heat-resistant adhesion performance, after vulcanizing 145 ° C. × 300 minutes for the belt treats of Conventional Examples 1 and 2, Comparative Examples 1 and 2 and Invention Examples 1 to 4, the temperature was further increased to 100 ° C. in a high temperature environment. What was left for days was used. The evaluation of each adhesive performance described above was carried out by measuring the amount of rubber adhering to the belt cords 20 and 25 after the test and expressing the amount of rubber as an index (INDEX). Evaluated the result of Conventional Example 1 as an index (INDEX) 100, and Comparative Example 2 and Invention Examples 3 and 4 evaluated the result of Conventional Example 2 as an index (INDEX) 100. When the index (INDEX) is smaller than 100, it indicates that the rubber adhesion amount is small. That is, when the index (INDEX) is small, the adhesiveness is weak.
For the evaluation of the initial adhesion performance, the belt treats of Conventional Example 1, Comparative Example 1 and Invention Examples 1 and 2 were vulcanized at 145 ° C. for 60 minutes.
For evaluation of the adhesive performance during overvulcanization, the belt treats of Conventional Example 1, Comparative Example 1, and Invention Examples 1 and 2 were vulcanized at 145 ° C. for 300 minutes.

Regarding the evaluation of the belt end peel resistance, a tire was actually manufactured using the belt cord 20 (size: 18.00R25) and step loaded at 20 km / h (load; TRA standard 100%, 10 ton internal pressure) A drum test of 800 kPa and a load increase of 20% every 72 hours) was performed. The evaluation of the belt end peeling resistance was performed only for Conventional Example 1, Comparative Example 1, and Invention Examples 1 and 2.
After the tire was run on the drum for 320 hours and stopped, the peel length at the belt end was measured. The peeling length of the belt end portion of Comparative Example 1 is expressed as an index (INDEX) 100, and the smaller the index (INDEX) is, the more the belt end peeling resistance is improved.

  Regarding the evaluation of the disconnection rate, when manufacturing the filaments used for the belt cords 20 and 25, when the steel wire as the material is drawn, the number of disconnections per ton of wire drawing is measured and expressed as an index (INDEX). did. The evaluation of the disconnection rate is based on the result of Conventional Example 1 as index (INDEX) 100 for Comparative Example 1 and Invention Examples 1 and 2, and the result of Conventional Example 2 for Comparative Example 2 and Invention Examples 3 and 4. Was evaluated as an index (INDEX) 100. In each case, when the index (INDEX) is larger than 100, it is easy to disconnect, and when it is small, it is difficult to disconnect.

  The water resistance was evaluated according to Conventional Examples 1 and 2, Comparative Examples 1 and 2, and Invention Examples 1 to 4, and after vulcanization at 145 ° C. for 60 minutes, the end of the belt cord 25 was exposed. The end of the belt treat was cut, and the belt treat was soaked in a 10% sodium hydroxide solution for 48 hours, followed by washing with water, and the rubber elution length of the belt cord 25 was determined. The rubber elution length of Conventional Examples 1 and 2 is set to 100, and the water resistance performance is represented by an index (INDEX). The index (INDEX) is larger than 100, indicating that the water resistance is improved.

  Evaluation of optimization of the vulcanization time was performed according to Conventional Example 2, Comparative Example 2 and Invention Examples 3 and 4, and the vulcanization time was 40 minutes, 50 minutes, 60 minutes, 200 minutes, and 300 minutes at a vulcanization temperature of 145 ° C. Five patterns were performed and evaluated by adhesion performance for each vulcanization time.

As shown in Table 1 of FIG. 5, in the belt cord 20 having the layer twist structure, the ratio of the amorphous portion 11m in the all outer sheath filaments F of Comparative Example 1 and Inventive Examples 1 and 2, It can be seen that by including the laminated brass-plated steel wire 12 having a large area ratio A and volume ratio B, the heat-resistant adhesion performance is improved as compared with Conventional Example 1. In particular, as the proportion of the laminated brass-plated steel wire 12 in which the volume fraction B of the amorphous portion 11m is 20% or more and 80% or less and the area proportion A is 80% or more is included in all the outer sheath filaments F, the effect is increased. Become prominent. That is, in Comparative Example 1 and Invention Examples 1 and 2, the volume ratio B of the amorphous part 11m is in the range of 20% to 80% and the area ratio A is 80% or more. This is because the Cu component of the amorphous part 11m and the crystalline part 11n remains sufficiently to generate heat, and Cu can be supplied.
Further, as shown in Table 2 of FIG. 5, in the belt cord 25 having a double twist structure, the ratio of the amorphous portion 11m in the sheath filament E of Comparative Example 2 and Invention Examples 3 and 4 is the area ratio A, volume. It can be seen that by including the laminated brass-plated steel wire 12 having a large proportion B, the heat-resistant adhesion performance is improved as compared with Conventional Example 2. In particular, the effect becomes more remarkable as the ratio of the laminated brass-plated steel wire 12 having a volume ratio B of the amorphous part 11m of 20% or more and 80% or less and an area ratio A of 80% or more to the sheath filament E increases. That is, in Comparative Example 2 and Invention Examples 3 and 4, the volume ratio B of the amorphous portion 11m of the laminated brass-plated steel wire 12 is in the range of 20% to 80%, and the area ratio A is 80. This is because the Cu component of the amorphous part 11m and the crystalline part 11n remains sufficiently with respect to the heat generated when the tire is used, and Cu can be supplied.

  As shown in Table 1 of FIG. 5, the initial adhesion performance hardly changes in Conventional Example 1, Comparative Example 1, and Invention Examples 1 and 2. This is because all the filaments constituting the belt cord 20 are formed by the laminated brass-plated steel wire 12, and the amorphous portion 11m on the surface side of each filament is in contact with the rubber. In particular, in the initial adhesion performance, there are many portions that depend on the area ratio A of the amorphous part 11m, and the area ratio A in the present invention satisfies 20% or more in both the conventional example 1, the comparative example 1, and the invention examples 1 and 2. There is almost no difference. That is, it can be seen that the initial adhesiveness is ensured by forming the amorphous portion 11m.

  As shown in Table 1 of FIG. 5, the adhesive performance at the time of overvulcanization is that the volume ratio B of the amorphous part 11m of Conventional Example 1 is less than 20%. It can be seen that the effect of laminating the part 11n is not obtained well, and the required adhesion performance during overvulcanization is not obtained. In Comparative Example 1 and Inventive Examples 1 and 2, the volume ratio B is 45% and the volume ratio B of the present invention is in the range of 20% to 80%. Since the supply of Cu from the active portion 11n and the amorphous portion 11m works well, the adhesion performance during overvulcanization is improved. However, the improvement rate of the adhesive performance at the time of overvulcanization is lower in Comparative Example 1 than in Inventive Examples 1 and 2. This is because the diameter of the belt cord 20 is large due to the three-layer twisted structure, and when the ratio of the laminated brass-plated steel wire 12 to the total outer sheath filament F is 30%, the non-crystal of all the outer sheath filaments F This is probably because the area where the quality part 11m and the rubber contact is small. From this, in order to improve the adhesiveness at the time of overvulcanization, it is preferable that the ratio of the laminated brass-plated steel wire 12 to the outermost all outer sheath filaments F is 50% or more. it is obvious.

  As shown in Table 1 of FIG. 5, the index (INDEX) of Comparative Example 1 and Inventive Examples 1 and 2 is smaller than the conventional example 1, and the belt edge peel resistance is less than the initial adhesion performance described above. As can be seen from the improved adhesive performance and heat-resistant adhesive performance during overvulcanization, the belt cord 20 and the rubber G are firmly adhered and bonded, so that the peel resistance at the ends of the belts 6a to 6d. Has improved.

As shown in Table 1 of FIG. 5, the index (INDEX) of Comparative Example 1 and Inventive Examples 1 and 2 is larger than that of Conventional Example 1 as shown in Table 1. As can be seen from the improved adhesion performance and heat resistant adhesion performance, the water resistance is improved because the belt cord 20 and the rubber G are firmly adhered and adhered.
Further, as shown in Table 2 of FIG. 5, the index (INDEX) of Comparative Example 2 and Invention Examples 3 and 4 is larger than that of Conventional Example 2, and the belt cord 25 of the present invention is firmly attached to the rubber G. It turns out that it adheres closely.

  As shown in Table 2 of FIG. 5, the disconnection rate can be kept low by reducing the proportion of filaments having a plating layer having the structure of the present invention.

  As shown in Table 2 of FIG. 5, the difference in the adhesion performance for each vulcanization time is shown in Comparative Example 2 and Inventive Example 3 except for the vulcanization time of 145 ° C. × 60 minutes indicating the initial adhesion in the belt cord 25. 4 and 4 show that the adhesion performance for each vulcanization time is improved. In particular, Invention Examples 3 and 4 containing a large number of laminated brass-plated steel wires 12 have a result that the adhesive performance is 100% in any vulcanization time. For example, the adhesion performance has already reached 100% at the initial stage of vulcanization prior to the initial adhesion, and this is a laminate in which the area ratio A of the amorphous part 11m is 98% and the volume ratio B is 45%. This is an effect that the brass-plated steel wire 12 is contained in an amount of 50% or more with respect to all the sheath filaments E of the belt cord 25, and particularly because the area ratio A of the amorphous portion 11m is large. In addition, when the vulcanization time is further increased and overvulcanization adhesion is caused, Cu is precipitated from the crystalline part 11n, so that this Cu and S react slowly so that during the overvulcanization. It can be seen that the adhesion is also maintained. This can be easily understood by comparing Comparative Example 2 with Invention Examples 3 and 4. That is, in Comparative Example 2, since the area where the amorphous portion 11m and the rubber G are in contact with each other is small, sufficient adhesion is not satisfied in the vulcanization time of 40 minutes, and the adhesion performance is higher than that of Invention Examples 3 and 4. Is low. However, compared with Conventional Example 2, Comparative Example 2 has a larger area ratio A and volume ratio B of the amorphous part 11m, so that the adhesion performance is 100% after 50 minutes of vulcanization, and the vulcanization close to overvulcanization is achieved. Although the adhesion performance is slightly improved during the sulfurization time, the improvement as in Invention Examples 3 and 4 is not observed.

From the above results, the belt cord made of layer twist or double twist has the area ratio A and the volume of the amorphous portion 11m in all the sheath filaments E and all the outer sheath filaments F located in the outermost layer constituting the belt cord. The greater the proportion occupied by the laminated brass-plated steel wire 12 having a higher proportion B, the greater the effect of improving the heat resistant adhesion performance and the adhesion performance during overvulcanization. From this, in order to ensure the supply amount of Cu at the time of overvulcanization and wet heat degradation, it is advantageous that the ratio of the laminated brass-plated steel wire 12 to the sheath filament located in the outermost layer is large. .
In particular, the results of satisfying the belt end peeling resistance and water resistance obtained from the heat resistance adhesion performance and the adhesion performance during overvulcanization are as follows. This is the case of the belt cord 25 of Invention Example 3 and Invention Example 4 of the double twist cord. The area ratio A of the amorphous portion 11m is 50% or more in 50% or more of the laminated brass-plated steel wires constituting all the sheath filaments E and all the outer sheath filaments F located in the outermost layers of the belt cords 20 and 25. Thus, it is preferable that the laminated brass-plated steel wire 12 having a volume ratio B of 20% or more and 80% or less is included. In the laminated brass-plated steel wire 12, the amorphous part 11m is more preferably formed so that the area ratio A is 80%, and the volume ratio B may be 45% or more and 80% or less. .

Since the belt cords 20 and 25 of the present invention are excellent in initial adhesiveness, heat-resistant adhesiveness, and dynamic adhesiveness, when applied to heavy-duty vehicle tires, construction vehicle tires, and the like, heavy load and long life are achieved. , Even when the shoulder and tread become hot due to the increase in running speed, the shoulder is prevented from lowering the adhesion force of the carcass belt, belt-rubber, belt-tread, etc. due to distortion and heat due to tire deformation. The belt 6a to 6d of the tire can be improved since it can improve the resistance to peeling at the ends of the belts 6a to 6d in the vicinity and the water resistance to prevent rust generated in the belt cords 20 and 25 from moisture entering due to scratches (cut input) of the tread. It was confirmed that failure due to ˜6d can be suppressed. In particular, when the belt cord of the present invention is applied to the belt located in the outermost layer, the durability of the belt located on the inner side can be improved.
In addition, since it has excellent adhesion performance during overvulcanization, it is effective for improving durability in the vicinity of the belt portion, particularly in construction vehicle tires that require a long vulcanization time.

2 Inner liner, 3 carcass, 4 bead wire, 5 bead filler,
6a-6d belt, 7 cover rubber, 8 tread rubber, 9 chafer cord,
11 brass plating layer, 11m amorphous part, 11n crystalline part,
12 laminated brass-plated steel wires, 13 laminated structure parts, 14 non-laminated structure parts,
20 belt cords, 21 core filaments,
22 inner sheath filament,
23s; 23t outer sheath filament, 24 wrapping filament,
25 belt cord, 26 core filament,
27s; 27t sheath filament,
E all sheath filaments, F all outer sheath filaments,
50 steel steel wire.

Claims (4)

Five sheath filaments made of steel wire having a brass plating layer are arranged on the surface so as to surround the outer periphery of one core filament made of steel wire having a brass plating layer on the surface, and four strands in which the layers are twisted are arranged. It is a belt cord of a double twisted tire that is bundled and twisted ,
Bed lath plated layers of all of the sheath filament,
The composition is composed of copper and zinc, of which 55% to 66% by weight of copper, an upper layer made of an amorphous part formed by crystal grains having a grain size of 20 nm or less, and crystal grains having a grain size of more than 20 nm. Formed as a laminated structure part laminated with a lower layer made of a crystalline part consisting of
Volume with an area ratio of the surface occupied noncrystalline portion 20% or more, the noncrystalline part with respect to the total volume of the multilayer structure portion occupied by the multilayer structure portion on the entire surface of the brass plating layer Formed at a ratio of 20% to 80% ,
The brass plating layer of the core filament is
The composition consists of copper and zinc,
Copper 55 wt% to 66 wt%, single layer crystalline part, or
An upper layer composed of an amorphous part formed of crystal grains having a grain size of 20 nm or less, and a lower layer consisting of a crystalline part composed of crystal grains having a grain size exceeding 20 nm; Is formed as a laminated structure portion, and the area ratio occupied by the surface of the amorphous portion of the laminated structure portion with respect to the entire surface of the brass plating layer is less than 20%.
A belt cord, wherein the belt cord is formed with a composition in which a copper supply rate is lower than a copper supply rate supplied from the brass plating layer of the sheath filament . 2. The belt cord according to claim 1, wherein the sheath filament is made of a brass-plated steel wire having a volume ratio of 50% or more with respect to the entire volume of the brass-plated layer of the sheath filament . The sheath filaments claim 1 or, characterized in that the area ratio of the surface occupied of the noncrystalline portions to the entire surface of the brass-plated layer of the sheath filament is composed of more than 80% of brass-plated steel wire The belt cord according to claim 2. A vehicle tire, wherein the belt cord according to any one of claims 1 to 3 is applied to a belt positioned at least in an outermost layer.

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