KR100704928B1 - The non-contact analysis method to characterize the interface between metal and rubber - Google Patents

Abstract

In the present invention, the mechanism and state of the adhesion interface formation between the metal and the rubber embedded in the rubber by heating the metal and the rubber under a vacuum atmosphere to react the sulfur and the metal from the rubber to form a metal-sulfur compound on the metal surface It relates to a non-contact analysis method for the adhesive interface between the metal and the rubber, so that it can be reproduced and analyzed.

The method includes the steps of placing the uncrosslinked rubber 13 at a position of 1 to 50 mm directly above the metal 12 upper surface; Heating the metal 12 and the rubber 13 arranged up and down in a vacuum atmosphere of 1 Torr or less in a range of 50 to 300 ° C. to form a metal-sulfur compound on the metal 12 surface; Analyzing the metal-sulfur compound.

The analytical method of the present invention eliminates the disadvantages of analytical inaccuracies due to the adhesion interface damage caused by removing the rubber bound to the metal surface and insufficient analyte due to insufficient analysis area, and various types of metals. -There is an advantage that can simulate the rubber adhesion interface.

Steel Cord, Bead Wire, Adhesive Interface, Metal-Sulfur Compound

Description

The non-contact analysis method to characterize the interface between metal and rubber}

BRIEF DESCRIPTION OF THE DRAWINGS The cross-sectional schematic diagram of the vacuum furnace which showed the arrangement state of a metal and rubber | gum.

2 shows a metal-sulfur compound,

  (A) is a photograph of the surface of the metal-sulfur compound formed by heating for 1 minute,

  (B) is a surface photograph of a metal-sulfur compound formed by heating for 5 minutes,

  (C) is a surface photograph of the metal-sulfur compound formed by heating for 10 minutes.

Figure 3 shows a metal-sulfur compound according to the composition of the rubber,

  (A) is a photograph of the surface of the metal-sulfur compound in the case of using the rubber to which the accelerator A is added,

  (B) is a photograph of the surface of a metal-sulfur compound in the case of using a rubber to which accelerator B is added.

Figure 4 is a schematic diagram of a conventional cross-sectional structure for the adhesion interface formed when the steel cord and rubber bonded.

          ((Explanation of symbols for main part of drawing))

           11. Metal charging box 12. Metal

           13. Rubber 14. Vacuum Furnace

           d. Metal-Rubber Distance R. Space

The present invention relates to a method of contactless analysis of an adhesive interface between a metal and a rubber, and more particularly, to place a metal, in particular a copper or a copper alloy, in a bottom inside an upwardly open metal charging box under a vacuum atmosphere, On the upper surface of the metal, by heating with the rubber seated to act as a lid of the metal charging box, the metal from the metal-sulfur compound formed on the metal surface inside the metal charging box sealed by sulfur generated from the rubber and It relates to a non-contact analysis method for the adhesion interface between the metal and the rubber to facilitate the formation of the adhesive interface of the rubber and the fine structure of the metal surface on which the compound with sulfur is formed.

Bead wires or steel cords used as reinforcement materials for tires and belts play a role by forming an adhesive interface with rubber. The surface of the steel wire constituting the bead wire or steel cord in order to increase adhesion to rubber. In general, a copper alloy having good adhesion to rubber is coated.

In other words, if a vulcanization operation is performed by heating and pressurizing a bead wire or a steel cord in a rubber powder, a metal is formed at the interface between the copper alloy and the rubber by the interaction between sulfur and the copper alloy generated in the rubber. An adhesive interface is formed by the formation of a metal sulfide.

Therefore, in order to increase the adhesion between the bead wire or steel cord and the rubber, it is necessary to identify the adhesion mechanism between the metal and the rubber, and many studies have been conducted.

Looking at the conventional analysis method for the adhesive interface formed by the above mechanism, the surface morphology and chemical composition were analyzed after swelling the rubber with a solvent to remove the rubber. The separation of rubber not only damages the shape of the adhesive interface, but also because the analysis method is not standardized, and the deviation is large, it is difficult to accurately determine the shape of the adhesive interface formed between the metal and the rubber.

In addition, the analysis of the surface of the wire-shaped specimen is used, such as auger (Auger Electron Spectroscopy) or X-ray (X-ray Photoelectron Spectroscopy), etc., the spectroscopy using ace, the three-dimensional resolution is excellent while the analysis time is short At the same time, it is widely used in that it is possible to analyze small volumes, but the function of checking the chemical state of atoms in signal form and kinetic energy difference has a disadvantage in that it is somewhat lower than the XPS method.

 In addition, since the wire is a very thin line, the area that can be examined in surface analysis is not only narrow but also flat, so it is necessary to minimize the analysis area. As the technology develops, the minimum area that can be analyzed becomes gradually narrower. There is, but still less than 100μm, there is a problem that the accuracy is also poor.

In order to compensate for the above disadvantages, even when manufacturing a specimen for the adhesion interface analysis of the metal and the rubber by a method of contacting the rubber to the plate, it is difficult to accurately analyze the interface because it is difficult to completely remove the rubber from the metal surface.

Therefore, if the study of simulating and analyzing the bonding interface using not only wire but also planar specimen by non-contact, the formation mechanism of the bonding interface can be more accurately identified, which will be very useful for improving the adhesion between metal and rubber. As expected, to date, there is no clear way to simulate the adhesive interface between metal and rubber by a non-contact method.

The present invention was devised to solve various problems of the conventional contact method for analyzing the adhesion mechanism between the metal and the rubber and the properties of the adhesive interface, and the metal and rubber contact without contacting the metal with the rubber. In this state, it is possible to form a similar metal-sulfur compound at the bonding interface between the metal and the rubber formed on the metal surface, thereby accurately matching the mechanism of forming the bonding interface between the metal and the rubber. It is an object of the present invention to provide a non-contact analysis method for an adhesive interface.

The above object of the present invention is achieved by a vacuum heating method of heating a metal and a rubber together in a state in which the metal and the rubber are spaced at suitable intervals in a vacuum atmosphere.

In the non-contact analysis method of the adhesive interface between the metal and the rubber of the present invention, the rubber is placed in a space immediately above the metal in a vacuum atmosphere and then heated to the rubber's vulcanization temperature to generate a sulfur component from the rubber, and the sulfur and the metal react. By doing so, there is a technical feature to form a metal-sulfur compound on the metal surface, which will be described in detail as follows.

Rubber and sulfur are heated under a vacuum atmosphere of 1 torr or less, which prevents metal and air from contacting each other when rubber is vulcanized by pressurized heating with a bead wire or steel cord embedded in rubber powder. In order to prevent or minimize the formation of oxides on the metal surface due to contact between metal and air.

In this case, when the vacuum degree is 1 Torr or more, oxides are formed on the metal surface more than necessary, thereby preventing the formation of the metal-sulfur compound, and the metal-oxygen-sulfur compound is formed, making it difficult to perform an interface analysis during accurate non-contact. do.

In addition, the degree of vacuum is preferably less than 1 Torr, but the closer to pure vacuum, the more equipment and costs required for vacuuming are increased, so that it is appropriately controlled within a range not exceeding 1 Torr.

The heating conditions under the vacuum atmosphere are heated for 30 seconds to 300 minutes at 50 to 300 ° C., which is the vulcanization temperature of the rubber, which is changed depending on the vulcanization conditions of the rubber powder into which the metal is embedded.
That is, the rubber composition used in the tire production, the compounding ratio of the components of the composition varies depending on the use, such as tires for passenger cars, truck tires, etc., generally made in the range of 130 ~ 250 ℃ bar, the present invention is a metal In order to experimentally identify the mechanism of forming the adhesive interface between the rubber and the rubber, it is heated to the vulcanization temperature range of the tire rubber composition, but also to the metal-sulfur compound formed in the temperature range below and above. The temperature range was extended beyond the vulcanization temperature range.
However, when it is less than 50 degreeC or exceeds 300 degreeC, the experimental utility is not at all.

The arrangement of rubber and metal is important under the above-mentioned atmosphere and heating conditions. The rubber should be placed 1-50mm above the metal surface so that the upper surface of the metal and the bottom of the rubber face each other. If the distance does not reach 1mm, The metal and rubber can be brought into contact with each other and adhered to each other. If the thickness exceeds 50 mm, the time for forming the metal-sulfur compound on the metal surface becomes longer than necessary.

At this time, the rubber is placed directly on the metal, because the sulfur generated in the rubber is moved downward, when the metal is placed directly on the rubber, the metal-sulfur compound is not effectively formed on the metal surface.

In addition, the metal and the rubber are put in the vacuum furnace, the metal and the rubber may be simply loaded into the vacuum furnace, as shown in Figure 1, at the bottom of the upwardly open metal charging box 11 In the state in which the metal 12 is seated, rubber 13 is laminated on the top surface of the metal loading box 11 to seal the inside of the metal loading box 11, and the rubber 13 and the metal 12 are prepared metal. It is also preferable to charge the charging box 11 into the vacuum furnace 14.

That is, the closed space R is formed between the metal 12 and the rubber 13 smaller than the content of the vacuum heating furnace, whereby the metal-sulfur compound can be formed more effectively.

In addition, the metal used in the method of the present invention is not related to its shape such as wire or flat plate and forms a compound with sulfur. Specific examples thereof include copper, tin, zinc, copper / tin alloy, copper / zinc, and the like. The rubber is a rubber which is sulfur-added but not crosslinked.

The formation process of the metal-sulfur compound formed on the surface of the metal by the above method is very similar to the metal-sulfur compound formed on the adhesion interface of the bead wire or steel cord surface embedded in rubber, The reaction mechanism of the metal and sulfur can be identified from the metal surface obtained by the non-contact method without analyzing the partially damaged adhesive interface obtained from the metal embedded in the rubber or the specimen made by contacting the metal with the rubber. Let's look at this through the implementation.

Example

On the surface of steel plate of 30mm (width) × 30mm (length) × 1mm (thickness), specimens in which zinc, brass, and copper layers were sequentially plated with a thickness of 10 μm were prepared, and 50mm (width) × 50mm (length) The specimen is placed on the bottom of a metal charging box made of ceramic and has a volume of) × 10 mm (height), and the rubber sheet stored on the top surface of the metal charging box is not vulcanized and is not exposed to moisture. Each was sequentially loaded in a vacuum furnace.

And it heated at 100 degreeC for 1 minute, 5 minutes, and 10 minutes, respectively, maintaining the vacuum degree inside a heating furnace at 1 Torr.

As a result of the above test, sulfur gas was ejected from the rubber during heating to react with the copper alloy to form a copper-sulfur compound, and the color of the metal surface was changed according to the shape and composition of the metal-sulfur compound. The nano-surface morphology of one specimen was observed using atomic force microscopy and scanning electron microscopy, which simulated the same contact interface as the copper alloy and rubber contacted to observe the interface. It was determined that the surface photograph over time is shown in FIG.

As shown, it can be confirmed that the form of the plate-grown form of the initial copper-sulfur compound, added to the rubber composition as shown in Table 1 when heated to the same conditions for 5 minutes at 100 ℃ under 1 Torr According to the type of additive to be used, as shown in the surface photograph of FIG. 3, it can be seen that a copper-sulfur compound in the form of a plate is formed when the accelerator A is used, and a spherical copper-sulfur compound is formed when the accelerator B is used. .

At this time, the accelerator serves to decompose the sulfur in the ring form added to the rubber and to accelerate the vulcanization process, there are a variety of materials, mercaptobenzothiazole and its derivatives, dithiocarbamate (dithiocarbamate) And derivatives thereof, sulfur donors, guanidine and aldehyde-amine reaction products, for example, in the case of accelerators based on mercaptobenzothiazole, for example, heat in rubber When it is added, the accelerator decomposes to form mercaptobenzothiazole and amine, and the amine not only forms a complex with zinc salt, but also serves to decompose another accelerator.

That is, the composition of the gas ejected from the rubber changes according to the type of accelerator, and accordingly, copper-sulfur compounds of different forms can be formed. Therefore, by selecting and using an appropriate accelerator according to the rubber to be analyzed, You can do analysis.

     ingredient      Weight (g)   Natural ointment        100   Carbon black         55   Oxidized zinc        3.0   Stearic acid        0.5         sulfur        3.0   Benzo azole        0.5   Aromas oil        1.5  Rezo Shin come resin        1.0

In the above embodiment, the plate specimen was used, and thus, the area of the analysis target was narrow, so that the shortcomings of the conventional contact analysis method, which were difficult to accurately analyze, could be overcome, and the chemical composition of the surface compound could be easily analyzed.

In addition, in the present invention, although the pressure, which is a vulcanization condition when the metal and the rubber are actually bonded, is excluded, the schematic diagram of FIG. 4, which is conventionally disclosed with respect to the adhesion interface formed when the steel cord and the rubber are bonded, is represented by FIG. 4 (WJ Van Ooij, Rubber). In the same manner as the copper-sulfur compound is formed in Chem. Technol. 57 (1984), p 421), it can be observed in FIG. 2 that the copper-sulfur compound in the form of a plate is formed by a non-contact method. It is judged that the non-contact analysis method can effectively simulate the adhesion interface between the actual metal and the rubber.

As described above, the non-contact analysis method for the adhesion interface between the metal and the rubber of the present invention is based on the inaccuracy caused by analyzing the damaged adhesion interface in the state where the rubber is removed after the metal and the rubber are actually contacted, and the lack of analysis area. It can solve the shortcomings of insufficient analysis, and it is possible to simulate various types of metal-rubber adhesion interface by freely changing the heating conditions and metal and rubber components, and to improve adhesion with the identification of adhesion mechanism between metal and rubber. It is expected to be of great help.

Claims (6)

Arranging the rubber 13 and the metal 12 up and down in a spaced state such that the rubber 13 is positioned directly on the upper surface of the metal 12; The metal 12 and the rubber 13 spaced apart up and down are charged in a vacuum furnace 14 in which a vacuum atmosphere of 1 Torr or less is formed and then heated to generate sulfur from the rubber 13, and sulfur and metal Allowing a reaction of (12) to form a metal-sulfur compound on the surface of the metal (12); A method of contactless analysis of an adhesive interface between a metal and a rubber, comprising the step of analyzing a metal-sulfur compound formed on the metal (12) surface. 2. A method according to claim 1, wherein the distance between the surface of the metal (12) and the bottom of the rubber (13) is 1-50 mm. The method of claim 1, wherein the heating is within a range from 50 to 300 ° C. 3. The method of claim 1, wherein the metal (12) is a metal that forms a compound with sulfur. The method of claim 1, wherein the rubber (13) contains a sulfur component and is a non-crosslinked material. The method of claim 1, wherein the metal 12 is placed on the bottom of the upwardly open metal charging box 11, the rubber 13 is characterized in that the laminated arrangement on the open top surface of the metal charging box (11). Non-contact analysis of the bonding interface between metal and rubber.

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