Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/04—Reinforcing macromolecular compounds with loose or coherent fibrous material
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
  • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/12—Light metals
• • D—TEXTILES; PAPER
  • D07—ROPES; CABLES OTHER THAN ELECTRIC
  • D07B—ROPES OR CABLES IN GENERAL
  • D07B1/00—Constructional features of ropes or cables
  • D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core

Definitions

• the present invention relates to a method of manufacturing a steel wire and a method of manufacturing a steel cord.
• the present invention also relates to a steel wire and a steel cord using the manufacturing method, a composite of the steel wire or steel cord and rubber, and a rubber product using the composite.
• a pneumatic radial tire which is a typical example of a rubber product
• its belt or carcass is made of multiple strands of brass-plated steel wire, or a steel cord made of a single steel wire coated with rubber.
• a rubber composite material made of rubber is applied, and reinforcement is mainly done with steel cords.
• the steel cord In order to utilize the steel cord as a reinforcing material for tires, it is necessary to reliably bond the steel cord to its coating rubber, and for this purpose, the circumferential surface of the wire that makes up the steel cord is plated with brass. There is.
• Patent Document 1 proposes cleaning the surface of a brass-plated steel wire with an aqueous solution containing cobalt salt, and coating the obtained steel wire or steel cord with cobalt-free rubber. .
• the present invention has been made in view of the above-mentioned problems, and provides a method for manufacturing a steel wire and a steel cord that have excellent initial adhesion to rubber and excellent deterioration resistance in a process with a small environmental impact.
• deterioration resistance means resistance to the above-mentioned rubber deterioration.
• Another object of the present invention is to provide a steel wire and a steel cord manufactured by the manufacturing method.
• the present invention provides the following [1] to [19].
• [1] A step of applying brass plating to the circumferential surface of the steel wire and then performing a wire drawing process, and a step of cleaning the surface of the steel wire after the wire drawing process with an aqueous solution containing an alkaline earth metal as a salt.
• a method of manufacturing steel wire including: [2] The method for producing a steel wire according to [1], wherein the alkaline earth metal is magnesium.
• the alkaline earth metal salt is selected from a metal chloride, a metal nitrate, a metal sulfate, a metal acetate, a metal citrate, a metal gluconate, and a metal acetylacetonate.
• a method for producing a steel cord comprising the step of twisting together a plurality of steel wires produced by the method for producing a steel wire according to any one of [1] to [3].
• [5] The method for manufacturing a steel cord according to [4], wherein the washing step is performed after the step of twisting the steel wires.
• [8] A steel wire manufactured by the manufacturing method according to any one of [1] to [3]. [9] The steel wire according to [8], wherein the concentration of alkaline earth metal on the surface is 0.5 mg/m 2 or more and 30 mg/m 2 or less. [10] A steel cord manufactured by the manufacturing method according to any one of [4] to [7]. [11] The steel cord according to claim 10, wherein the concentration of alkaline earth metal on the surface of the steel wire is 0.5 mg/m 2 or more and 30 mg/m 2 or less. [12] A rubber composite obtained by coating the steel wire according to [8] or [9] or the steel cord according to [10] or [11] with rubber. [13] The rubber composite according to [12], wherein the content of cobalt in the rubber is 0.01 parts by mass or less based on 100 parts by mass of the rubber component.
• the environmental load can be reduced by cleaning the surface of a brass-plated steel wire with an aqueous solution containing an alkaline earth metal as a salt. Furthermore, by the manufacturing method of the present invention, it is possible to obtain steel wires and steel cords that have excellent initial adhesion to rubber and also have excellent deterioration resistance.
• the method for manufacturing a steel wire of the present invention includes the steps of applying brass plating to the circumferential surface of the steel wire and then performing wire drawing, and the surface of the steel wire after the wire drawing includes an alkaline earth metal as a salt. A step of washing with an aqueous solution is included.
• the steel wire is subjected to brass plating and wire drawing using a known method.
• brass plating is applied to the circumferential surface of a steel wire with a diameter of about 5 mm.
• wire thinning (wire drawing) is performed using a lubricant.
• thinning is performed using a die placed in a liquid lubricant for about 20 passes.
• extreme pressure is generated between the cord and the die and the temperature is extremely high. Therefore, in order to ensure lubricity under extreme pressure and high temperature conditions, phosphoric acid-based lubrication is used. It is customary to use agents.
• This lubricant reacts with the wire surface during wire drawing to form a lubricating film layer, that is, a phosphoric acid compound layer.
• a lubricating film layer that is, a phosphoric acid compound layer.
• the copper in the brass plating diffuses to the rubber side, forms copper sulfide (CuxS), and inhibits the adhesion reaction in which adhesion occurs.
• the surface of a drawn steel wire is cleaned with an aqueous solution containing an alkaline earth metal as a salt.
• the alkaline earth metals refer to magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).
• magnesium is preferred in view of its adhesion to rubber, deterioration resistance, and abundance of resources.
• alkaline earth metal salt one or more selected from metal chloride, metal nitrate, metal sulfate, metal acetate, metal citrate, metal gluconate, and metal acetylacetonate. It is preferable that In particular, from the viewpoint of workability, it is preferable to use acetic acid metal salts.
• the phosphoric acid compound layer and zinc oxide layer formed on the circumferential surface of the steel wire are removed. That is, by performing the above-described cleaning treatment, substances that inhibit the adhesion reaction with rubber are removed. Furthermore, alkaline earth metals remain on the surface of the steel wire after cleaning. As a result, a steel wire with excellent adhesion to rubber can be obtained. Therefore, even if the adhesion promoter (cobalt compound) on the rubber side is omitted, the wire and rubber can be reliably bonded. On the other hand, since the adhesion promoter on the rubber side can be omitted, it is also possible to improve the resistance (deterioration resistance) of the rubber to deterioration caused by heat, moisture, or oxygen.
• initial adhesion and deterioration resistance can be significantly improved compared to cleaning using an aqueous solution containing cobalt salt.
• cleaning with an aqueous solution containing a magnesium salt is highly effective in improving initial adhesion and deterioration resistance.
• the reason for this is not certain, but it is thought that the alkaline earth metals attached to the surface of the steel wire have some kind of effect on the crosslinking of the rubber component, such as accelerating the vulcanization rate, which is an unexpected effect. I can say that.
• the use of alkaline earth metal salts has the advantage of reducing environmental impact.
• the pH of the aqueous solution containing the alkaline earth metal as a salt is preferably about 5 to 8.
• the pH of the aqueous solution containing the alkaline earth metal as a salt is preferably about 5 to 8.
• the concentration of alkaline earth metal in the aqueous solution is preferably 0.01 mol/L or more, and 0.05 mol/L or more, considering the removal efficiency of the phosphoric acid compound layer and the zinc oxide layer and the adhesion promoting effect. It is more preferable that the amount is 0.1 mol/L or more, and even more preferably 0.1 mol/L or more. On the other hand, considering the amount of alkaline earth metal remaining on the steel wire surface and processing cost, it is preferably 1 mol/L or less, more preferably 0.5 mol/L or less, and 0.3 mol/L. It is more preferable that it is the following.
• the cleaning time and the temperature of the aqueous solution may be appropriately set depending on the concentration of the aqueous solution, processing cost, and the like.
• the cleaning time can be in the range of 5 to 100 seconds and the temperature can be in the range of 10 to 40°C.
• the cleaning method is not particularly limited, and immersion, spraying, etc. can be applied.
• the steel cord manufacturing method of the present invention includes the step of twisting together a plurality of steel wires manufactured by the above-described steel wire manufacturing method.
• twist structure There is no particular restriction on the twist structure, and twist structures such as single twist, double twist, layered twist, and composite twist of layered twist and multi-twist can be used.
• the steel cord may have a monofilament structure using a single steel wire, a structure in which multiple steel wires are bundled without twisting them together, or a structure in which multiple steel wires are arranged in parallel.
• the cross section can be not only a perfect circle but also an ellipse or a rectangle.
• the relationship between the twisting process and the cleaning process is not particularly limited. Specifically, the following process order can be mentioned. (1) After performing the step of twisting the steel wires, a step of cleaning is performed. (2) After performing the cleaning process, a process of twisting the steel wires is performed. (3) After performing the step of twisting the steel wires together, a step of cleaning is performed, and a step of further twisting the twisted steel wires is performed.
• the process sequence (1) is suitable for producing single-strand and layer-twist steel cords.
• the process order (2) is applicable to manufacturing steel cords of any twisted structure, but is particularly suitable for manufacturing double-twisted steel cords.
• the process order (3) is applicable to manufacturing steel cords of any twisted structure, but is particularly suitable for manufacturing layer-twisted and multi-twisted steel cords.
• the steel wire manufactured by the manufacturing method of the present invention has an oxide layer such as a zinc oxide layer or a phosphoric acid compound layer removed from the surface of the brass plating, and furthermore, an alkaline earth metal is present on the surface of the brass plating.
• the situation is such that As mentioned above, due to the removal of the oxide layer and the alkaline earth metal on the surface, the initial adhesion to rubber and the resistance to deterioration are excellent. Further, the steel cord manufactured using the steel wire manufactured by the manufacturing method of the present invention also has excellent initial adhesion to rubber and deterioration resistance.
• the concentration of alkaline earth metal on the surface of the steel wire manufactured by the manufacturing method of the present invention is preferably 0.5 mg/m 2 or more and 30 mg/m 2 or less.
• the concentration of alkaline earth metal on the surface of the steel wire is preferably 0.5 mg/m 2 or more and 30 mg/m 2 or less.
• the lower limit of the alkaline earth metal concentration is more preferably 1 mg/m 2 or more, and even more preferably 2 mg/m 2 or more.
• the lower limit of the alkaline earth metal concentration is more preferably 25 mg/m 2 or less, and even more preferably 20 mg/m 2 or less.
• the alkaline earth metal concentration in the present invention is a value measured by ICP analysis.
• the "surface of the steel wire" herein refers to the surface layer region up to a depth of 10 nm inside the filament in the radial direction.
• the steel wire and steel cord of the present invention can be applied to various rubber products as a composite with rubber.
• the rubber composite is made by coating a steel wire or steel cord obtained by the manufacturing method of the present invention with rubber.
• the coating rubber preferably does not substantially contain cobalt as an adhesion promoter.
• substantially free means that the content of cobalt in the rubber is 0.01 parts by mass or less based on 100 parts by mass of the rubber component. Therefore, in the rubber composite of the present invention, cobalt is not used or the cobalt content is extremely reduced. More preferably, the content of cobalt in the rubber is 0 parts by mass based on 100 parts by mass of the rubber component.
• cobalt acts as an adhesion promoter, it also becomes a factor that inhibits the deterioration resistance of rubber.
• the steel wire and steel cord obtained by the manufacturing method of the present invention can ensure excellent initial adhesion even when using rubber that does not contain an adhesion promoter. Since the content of cobalt is reduced in either the steel wire or the steel cord or the rubber, the deterioration resistance is particularly excellent.
• the covering rubber is not particularly limited. Rubber that is commonly used in specific applications described below can be used. It is preferable to use a coating rubber containing sulfur as a vulcanizing agent in an amount of 1 to 10 parts by mass based on 100 parts by mass of the rubber component. By containing sulfur in the above range, it is possible to ensure the original adhesive strength of the bond due to vulcanization between sulfur and rubber, and it is also possible to suppress deterioration of heat aging resistance and heat-resistant adhesive properties among the rubber physical properties.
• the above-mentioned rubber composite can be used for tires (pneumatic tires), crawlers, hoses, seismic isolation rubber, etc. If the rubber composite is a pneumatic tire, the steel wire or steel cord obtained according to the invention is applied to the reinforcement of the carcass ply or belt ply.
• the tire structure itself is a general structure.
• sample The surface of a steel wire with a diameter of 1.7 mm was repeatedly plated with copper and then zinc in the order of 63.0% by mass of copper and 37.0% by mass of zinc, followed by thermal diffusion treatment at 550°C for 5 seconds. A copper-zinc binary plating was formed. Thereafter, the steel wire was subjected to wire drawing to obtain a steel wire with an average plating thickness of 0.25 ⁇ m and a diameter of 0.34 mm. A steel cord, which is a twisted cord having a 1+6 structure, was produced using each of the obtained steel wires. Thereafter, the steel cord was immersed in a 0.2 mol/L magnesium acetate aqueous solution for 10 seconds to perform a cleaning treatment.
• the magnesium concentration on the surface of the steel wire after the cleaning treatment was evaluated by the following steps. First, a steel wire was immersed in dilute hydrochloric acid to dissolve the surface of the steel wire. The magnesium concentration in the dilute sulfuric acid after the dissolution treatment was determined by ICP analysis (device: Agilent 5110). The magnesium concentration on the surface of the steel cord in Example 1 was calculated from the magnesium concentration determined by ICP analysis and the dimensions of the immersed steel wire, and was found to be 2.5 mg/m 2 .
• Comparative example 1 A steel cord, which is a twisted cord, was produced in the same process as in Example 1. Without washing the steel cords, 25 steel cords are arranged in parallel at intervals of 50 mm. A rubber composition having the composition shown in "Composition B" in Table 1 is coated on both the upper and lower sides of the steel cord. Thereafter, it was vulcanized at 145° C. for 10 minutes to obtain a sample of Comparative Example 1 (steel cord-rubber composite).
• Example 2 A steel cord, which is a twisted cord, was produced in the same process as in Example 1. Thereafter, the steel cord was immersed in a 0.2 mol/L cobalt acetate aqueous solution for 10 seconds to perform a cleaning treatment. After dipping, the liquid adhering to the surface of the steel cord was removed by air blowing, and the cord was dried at 50° C. for 30 seconds. 25 steel cords obtained through the above steps are arranged in parallel at intervals of 50 mm. A rubber composition having the composition shown in "Composition A" in Table 1 is coated on both the upper and lower sides of the steel cord. Thereafter, it was vulcanized at 145° C. for 10 minutes to obtain a sample of Comparative Example 2 (steel cord-rubber composite).
• Results Table 2 shows the evaluation results of initial adhesiveness and adhesiveness after deterioration.
• Example 1 and Comparative Example 2 have higher coverage rates than Comparative Example 1. From this, as a result of the removal of oxides on the surface of the steel cord by cleaning after brass plating, both the initial adhesion and the adhesion after deterioration are improved. Furthermore, Example 1 has a higher coverage rate than Comparative Example 2. From this, the initial adhesiveness and the adhesiveness after deterioration are improved. The fact that the coverage rates differ even though the rubber compositions were vulcanized under the same conditions is considered to be the result of accelerated vulcanization in the rubber of Example 1. That is, from the results in Table 2, it can be inferred that the magnesium adhering to the surface of the steel cord had some effect on the rubber component, promoting vulcanization.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Ropes Or Cables (AREA)

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Citations (3)

• 2023
  • 2023-08-25 JP JP2024545568A patent/JPWO2024053435A1/ja active Pending
  • 2023-08-25 WO PCT/JP2023/030800 patent/WO2024053435A1/ja not_active Ceased

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