Tire manufacturing method

Abstract

To provide: a tire manufacturing method which improves a decorative property of a tire, and is hardly cause decoloration of a pigment used for improving a decorative property due to tire deformation; and a tire.SOLUTION: There is provided a tire manufacturing method that comprises: an adhesion step of adhering color powder 7 having a color different from a tire base color onto a tire molding surface 5 of a tire vulcanization mold through a lubricant 6 which is a liquid; and a vulcanization step of, after the adhesion step, pressing an outer surface of an unvulcanized tire onto the tire molding surface 5 to perform vulcanization molding on the tire.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a tire manufacturing method and a tire.

Background Art

[0002] Patent Document 1 describes a tire with improved decorativeness obtained by displaying patterns and characters on a sidewall with a phosphorescent paint. In the example described in this document, a phosphorescent paint is prepared by mixing a phosphorescent pigment with cold water, and the paint is applied to the sidewall of the tire with a brush. In another example, a prefabricated phosphorescent sheet is cut out to form a dial plate, which is then attached by rubber glue or thermocompression bonding. However, there is a concern that the phosphorescent paint applied by such a method may fall off as the tire deforms (for example, deflection of the sidewall during running).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a tire manufacturing method and a tire that can improve the decorativeness of the tire, and in which the dye for improving decorativeness is less likely to fall off due to deformation of the tire.

Means for Solving the Problem

[0005] The tire manufacturing method of the present disclosure includes: an attaching step of attaching colored powder having a color different from the base color of the tire to a tire molding surface of a tire vulcanization mold via a liquid material; and a vulcanization step of, after the attaching step, pressing an outer surface of an unvulcanized tire against the tire molding surface and performing vulcanization molding on the tire.

[0006] The tire disclosed herein has a color powder of a different color from the tire base color that is vulcanized and bonded to its outer surface. [Brief explanation of the drawing]

[0007] [Figure 1] Front view showing the main parts of the tire as seen from the tire axis direction. [Figure 2] Cross-sectional view taken along arrow AA in Figure 1 [Figure 3] Cross-sectional view showing the main part of the tire molding surface of a tire vulcanization mold. [Figure 4] Cross-sectional view showing an example of the adhesion process. [Figure 5] Front view showing the main parts of the modified tire. [Figure 6] Cross-sectional view taken via arrow BB in Figure 5. [Figure 7] Cross-sectional view showing an example of the adhesion process related to a modified example. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described with reference to the drawings.

[0009] Figure 1 is a front view showing the main parts of tire T as seen from the tire axis direction. Tire T is a pneumatic tire comprising a bead portion 1, a sidewall 2 extending radially outward from the bead portion 1, and a tread 3 that forms the contact surface, connected to the radially outer end of the sidewall 2. The tire radial direction is the direction along the diameter of tire T, and corresponds to the vertical direction in Figure 1. In Figure 1, the upper side is the radially outer side of the tire, and the lower side is the radially inner side of the tire. The tire axis direction is the direction parallel to the rotation axis of tire T.

[0010] The sidewall 2 of tire T has the letter "O" formed, which constitutes the marking 4. In reality, multiple letters are arranged along the circumferential direction of the tire, but in Figure 1, letters other than "O" are omitted from the illustration. The circumferential direction of the tire is the direction around the rotation axis of tire T, and roughly corresponds to the left-right direction in Figure 1. Marking 4 displays information such as the manufacturer name, brand name, tire size, and manufacturing year and week of tire T. Marking 4 may include symbols, figures, patterns, etc., in place of or in addition to letters.

[0011] The markings 4 are formed by raised and recessed portions created on the sidewall 2 by vulcanization molding. As shown in Figures 1 and 2, the markings 4 are formed by raised portions 20 formed on the sidewall 2. The raised portions 20 are raised from the surface 2a along the profile of the sidewall 2. The raised portions 20 extend along the contour of the markings 4. The raised portions 20 have a first raised portion 21 that borders the outside of the letter and a second raised portion 22 that borders the inside of the letter. For letters such as "T" or "Y", the raised portions 20 will have only the first raised portion 21.

[0012] In the region enclosed by the raised portion 20, serrations 30 are formed, consisting of numerous ridges 31 arranged parallel to each other. The ridges 31 are formed, for example, by convex ridges with a triangular cross-section. The direction of extension of the ridges 31 is not particularly limited. The height of the ridges 31 relative to the surface 2a is set to be smaller than the height of the raised portion 20, but they may be the same size. It is also possible to omit the serrations 30, and a smooth surface may be formed instead of the serrations 30.

[0013] Such markings 4 are generally formed in the same color as the tire base, making it difficult to distinguish the markings 4 from their surroundings. Therefore, it is desirable to enhance the decorative properties of the tire T to improve the visibility of the markings 4. In this tire T, a color powder 7 of a different color from the tire base is vulcanized and bonded to the outer surface, thereby improving the visibility of the markings 4. In this embodiment, the color powder 7 is vulcanized and bonded to the raised portion 20. More specifically, the color powder 7 is vulcanized and bonded to the corner formed by the top surface and the side surface of the raised portion 20.

[0014] Here, "tire base color" refers to the color of the rubber that makes up the outer surface of the tire T (mainly the outer surface of the sidewall 2 and tread 3), and is usually black. Although rubber other than black (for example, white rubber) may be used in part of the sidewall 2, the tire base color is defined as the color of the rubber that covers the largest exposed area (usually black). Furthermore, "a color different from the tire base color" means that at least one of the three elements of color—hue, lightness, and saturation—is different from the tire base color. It is preferable that at least the hue is different from the tire base color.

[0015] Figure 3 shows a cross-section of the tire molding surface 5 of the tire vulcanization die for molding the tire T, corresponding to the area shown in Figure 2. The tire molding surface 5 is formed on the inner surface of the side mold 10 for molding the sidewall 2. The tire molding surface 5 includes a recessed area for forming a mark 4 on the sidewall 2. The recessed area comprises a recess 40 for forming a raised portion 20 and a recess 50 for forming serrations 30. The recess 50 includes a groove for forming a ridge 31. When the rubber of the sidewall 2 is pressed against the recessed area during vulcanization molding, a mark 4 is formed that has the shape of this recessed area transferred onto it.

[0016] A tire T, in which the colored powder 7 shown in FIGS. 1 and 2 is vulcanized and bonded to the outer surface, can be manufactured through the following steps: an adhesion step of adhering the colored powder 7 to the tire molding surface 5 via a liquid material, and after the adhesion step, a vulcanization step of pressing the outer surface of the unvulcanized tire against the tire molding surface 5 and performing vulcanization molding on the tire. The adhesion step will be described below with reference to FIG. 4. FIG. 4 is an enlarged view showing a part of the uneven portion of the tire molding surface 5. Since the vulcanization step can be carried out in the same manner as conventional vulcanization molding of tires, detailed description thereof is omitted.

[0017] The tire molding surface 5 is generally formed of an iron material or the like, and is subjected to blast cleaning during maintenance work. After blast cleaning, as shown in FIG. 4(A), a rust-preventing lubricant 6 (hereinafter simply referred to as "lubricant 6"), which serves as a rust inhibitor, is applied to the tire molding surface 5. The lubricant 6 is applied, for example, by spraying. In the present embodiment, since the lubricant 6 is a volatile solvent, it vaporizes shortly after application, and during this process, the lubricant 6 accumulates in the corners of the uneven portion as shown in FIG. 4(B). Note that even if a non-volatile liquid material is used, the state shown in FIG. 4(B) can be obtained by adjusting the application amount.

[0018] In a state where the lubricant 6 is accumulated in the corners of the uneven portion, colored powder 7 is applied to the tire molding surface 5 as shown in FIG. 4(C). The colored powder 7 has a color different from the base color of the tire. The colored powder 7 is applied, for example, by spraying. The colored powder 7 adheres to locations where the lubricant 6 has accumulated (in the example of FIG. 4, the corners of the uneven portion). Thereafter, if necessary, air blowing is performed on the tire molding surface 5 to remove the colored powder 7 that has not adhered to the tire molding surface 5 as shown in FIG. 4(D). As a result, the tire molding surface 5 having the colored powder 7 adhered to the corners of the uneven portion is obtained.

[0019] When the side mold 10 having the tire molding surface 5 shown in Fig. 4(D) is mounted on a vulcanizer and vulcanization molding is performed on the tire using the same, the color powder 7 adhering to the tire molding surface 5 is vulcanized and adhered to the outer surface of the tire T (see Figs. 1 and 2). This can improve the decorativeness of the tire T. Moreover, the pigment for improving decorativeness (i.e., the color powder 7) is in a state that it cannot be easily removed even by rubbing, and can flexibly follow the deflection and expansion / contraction of the tire T, so there is little risk of falling off due to deformation of the tire T.

[0020] When the transfer amount of the color powder 7 decreases after repeated vulcanization molding, the color powder 7 is replenished to the tire vulcanization mold (the side mold 10 thereof) mounted on the vulcanizer. The replenishment of the color powder 7 can be performed by applying the lubricant 6, applying the color powder 7, and air blowing as described in Fig. 4. It is conceivable that the replenishment of the color powder 7 is repeatedly performed periodically, for example, every time after a predetermined number of vulcanization molding cycles are completed.

[0021] The color of the color powder 7 is not particularly limited as long as it is a color different from the tire base color, and may be black. Therefore, for example, the decorativeness may be improved by making the outline of the indication mark 4 a darker black than the surrounding area. However, from the viewpoint of making the indication mark 4 more conspicuous, the color of the color powder 7 is preferably other than black, which is generally used as the tire base color, such as white and yellow. Further, the color powder 7 may have phosphorescent properties so as to be conspicuous even at night, and examples of the luminous color in such a case include yellow-green and pink.

[0022] Inorganic pigments are preferably used for the color powder 7. Generally, inorganic pigments have better heat resistance and opacity than organic pigments. Examples of inorganic pigments include metal oxides, carbon black which exhibits black color, ultramarine which exhibits blue color, aluminum powder which exhibits aluminum color, and talc which exhibits white color. Examples of metal oxides include titanium oxide which exhibits white color, chromium oxide which exhibits green color, yellow iron oxide (yellow) which exhibits yellow color, red iron oxide (red iron oxide) which exhibits reddish-brown color, and black iron oxide (black iron oxide) which exhibits black color. In addition to blue, ultramarine modified to violet, rose, or pink color is also available.

[0023] It is also useful to use phosphorescent pigments as inorganic pigments in the color powder 7. Examples of phosphorescent pigments include ceramic powders obtained by calcining aluminum oxide, strontium carbonate, and rare earth elements. Such phosphorescent pigments emit green, blue, or pink light, but other colors are also acceptable.

[0024] Furthermore, blast powder (cleaning powder) used in blast cleaning can be used as color powder 7. Examples of such blast powder include glass beads that appear white, plastic beads that appear white, and stainless steel beads that appear stainless steel color (metal color).

[0025] As described above, in this embodiment, the adhesion process includes a first step of applying a liquid substance to the tire molding surface 5 (see Figure 4(A)) and a second step of applying color powder 7 to the tire molding surface 5 after the first step (see Figure 4(C)). In this embodiment, an example is shown in which lubricant 6 is used as the liquid substance, but the embodiment is not limited to this. However, by using lubricant 6 as the liquid substance, the color powder 7 can be adhered using the lubricant 6 applied to the tire molding surface 5 during maintenance work, thereby improving work efficiency.

[0026] As described above, in this embodiment, in the first step, a volatile solvent lubricant 6 is applied to the tire molding surface 5. In the second step, the color powder 7 is attached via the volatile solvent (lubricant 6) accumulated in the corners of the uneven areas. This makes it possible to easily manufacture a tire T in which the color powder 7 is vulcanized and bonded along the contour of the display mark 4, as shown in Figures 1 and 2. With such a tire T, the decorative aspect is enhanced by emphasizing the contour of the display mark 4, and the visibility of the display mark 4 can be effectively improved.

[0027] Figure 4(B) shows that lubricant 6 has accumulated in the corners of the recess 40, but lubricant 6 may also accumulate in the corners of the recess 50 (the bottom of the grooves for forming the ridges 31). In that case, color powder 7 will adhere to the corners of the recess 50, so the color powder 7 will be vulcanized and adhered to the tip of each ridge 31, thereby decorating the serrations 30. In this embodiment, color powder 7 is attached only to the corners of the uneven parts, but this is not limited to this. For example, color powder 7 may be attached to the entire bottom surface of the recess 40, thereby vulcanizing and adhering the color powder 7 to the entire top surface of the raised part 20.

[0028] For areas where you do not want the color powder 7 to adhere, you can consider masking when applying the color powder 7. For example, if you do not want the serrations 30 to be decorated with the color powder 7, you can mask the recesses 50 when applying the color powder 7 to prevent the color powder 7 from adhering to them. For masking, a stencil plate cut into a predetermined shape is preferably used. As shown in Figure 1, if you exclude the serrations 30 and only vulcanize and adhere the color powder 7 to the outline of the display mark 4, the display mark 4 will be outlined by the color powder 7, making the display mark 4 stand out effectively.

[0029] In this embodiment, the adhesion process is shown to include a third step after the second step in which any color powder 7 not adhering to the tire molding surface 5 is removed by air blowing, but it is not limited to this. When masking as described above is used and a state is obtained in which the color powder 7 is adhered only to the necessary areas, the air blowing to remove excess color powder 7 may be omitted.

[0030] In this embodiment, an example is shown in which the adhesion process includes the first and second steps described above, but it is not limited to this. For example, in the adhesion process, a mixture of pre-prepared color powder 7 and a liquid substance may be applied to the tire molding surface 5. Such a mixture can be applied to the required parts of the tire molding surface 5 with a brush, or applied after applying the masking described above. In this case, a general rubber adhesive used to bond rubber members together in tire molding can be used as the liquid substance.

[0031] Rubber glue is a rubber composition dissolved in an organic solvent. Examples of rubber compositions include those made by blending diene rubber with fillers and vulcanizing agents. Examples of diene rubbers include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), and styrene-butadiene rubber (SBR). Common fillers include carbon black or silica. Common vulcanizing agents include sulfur. Examples of organic solvents include rubber-specific volatile organic solvents, toluene, xylene, and other volatile organic solvents that dissolve rubber.

[0032] In this embodiment, the display mark 4 is formed by a raised portion 20 that rises from the surface 2a of the sidewall 2, but is not limited to this. For example, as shown in Figures 5 and 6, it may be formed by a recessed portion 60 that is indented from the surface 2a. In this example, the color powder 7 is vulcanized and bonded to the corner formed between the side surface of the recessed portion 60 and the surface 2a. This makes the outline of the display mark 8 more prominent and improves visibility. The bonding process in this case will be explained with reference to Figure 7. Figures 7(A) to 7(D) correspond to Figures 4(A) to 7(D), respectively, so redundant explanations will be omitted.

[0033] Figure 7 shows the uneven surface of the tire molding surface 5 for forming the display mark 8. This uneven surface includes protrusions 70 for forming recesses 60. First, lubricant 6 is applied to the tire molding surface 5 as shown in Figure 7(A). Then, once the lubricant 6 has accumulated in the corners of the uneven surface as shown in Figure 7(B), color powder 7 is applied to the tire molding surface 5 as shown in Figure 7(C). After that, air blowing is performed on the tire molding surface 5 to remove any color powder 7 that is not adhering to the tire molding surface 5 as shown in Figure 7(D). By performing vulcanization molding using this, a display mark 8 decorated with color powder 7 as shown in Figures 5 and 6 is formed.

[0034] In this embodiment, an example is shown in which the color powder 7 is vulcanized and bonded to the outer surface of the sidewall 2, but the invention is not limited to this, and for example, it may be vulcanized and bonded to the outer surface of the tread 3. In the bonding process, the color powder 7 can be bonded to the tire molding surface formed on the inner surface of the tread mold that forms the tread 3 via a liquid substance such as a lubricant 6. In that case, for example, the color powder 7 can be vulcanized and bonded to the corners formed between the top surface and the side surface of blocks and ribs provided on the tread 3 to enhance the decorative properties of the tire.

[0035] [1] As described above, the tire manufacturing method of this embodiment includes an adhesion step in which a color powder 7 of a different color from the tire base color is attached to the tire molding surface 5 of the tire vulcanization mold via a lubricant 6 (an example of a liquid), and a vulcanization step in which, after the adhesion step, the outer surface of the unvulcanized tire is pressed against the tire molding surface 5 to perform vulcanization molding on the tire. This enhances the decorative properties of the tire T, and there is little concern that the pigment (color powder 7) used to enhance the decorative properties will fall off due to deformation of the tire T.

[0036] [2] In the tire manufacturing method described in [1] above, the adhesion step preferably includes a first step of applying a lubricant 6 to the tire molding surface 5, and a second step of applying color powder 7 to the tire molding surface 4 after the first step. This allows the color powder 7 to adhere to the tire molding surface 5 via the lubricant 6 applied to it.

[0037] [3] In the tire manufacturing method described in [2] above, the tire molding surface 5 includes an uneven portion for forming a display mark 4 on the sidewall 2 of the tire T. In the first step, a lubricant 6, which is a volatile solvent, is applied to the tire molding surface 5. In the second step, it is preferable to adhere the color powder 7 via the volatile solvent (i.e., lubricant 6) accumulated in the corners of the uneven portion. This results in a tire T in which the color powder 7 is vulcanized and bonded along the contour of the display mark 4, thereby effectively improving the visibility of the display mark 4.

[0038] [4] In the tire manufacturing method described in [2] or [3] above, the adhesion step may include a third step after the second step in which any color powder 7 that is not adhered to the tire molding surface 5 is removed by air blowing. With such a configuration, excess color powder 7 can be easily removed.

[0039] [5] In the tire manufacturing method described in [1] above, the adhesion step may involve applying a mixture of pre-prepared color powder 7 and liquid to the tire molding surface 5. This mixture may be applied to the required areas of the tire molding surface 5 with a brush, or applied after applying the masking described above.

[0040] [6] Furthermore, in this embodiment, the tire T has a color powder 7 of a different color from the tire base color vulcanized and bonded to its outer surface. This enhances the decorative properties of the tire T, and there is less concern that the pigment (color powder 7) used to enhance the decorative properties will fall off due to deformation of the tire T. Such color powder 7 can be identified in the tire T after vulcanization molding by observing the outer surface of the tire T or the cross-section of the tire T cut with a sharp blade.

[0041] [7] In the tire T described in [6] above, it is preferable that the color powder 7 is attached along the contour of the marking 4 formed on the outer surface of the sidewall 2. This effectively improves the visibility of the marking 4 and further enhances the decorative appeal of the tire T.

[0042] While embodiments of this disclosure have been described with reference to the drawings, it should be understood that the specific configurations are not limited to these embodiments. The scope of this disclosure is defined not only by the above-described embodiments but also by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

[0043] The tire manufacturing method and tire of this disclosure are not limited in any way to the embodiments described above, nor are they limited to the effects described above. The tire manufacturing method and tire of this disclosure can be modified in various ways without departing from the gist of the disclosure. Furthermore, the components used in the embodiments described above can be used in any combination. [Explanation of symbols]

[0044] 2 sidewalls 3 tread 4 Display Marks 5. Tire molding surface 6. Rust-preventive lubricant (an example of a liquid substance) 7 Color Powders 8 Display Marks

Claims

1. An adhesion step of applying a color powder of a different color from the tire base color to the tire molding surface of a tire vulcanization mold via a liquid, The process includes a vulcanization step in which, after the adhesion step, the outer surface of the unvulcanized tire is pressed against the tire molding surface to perform vulcanization molding on the tire, The adhesion process includes a first step of applying the liquid to the tire molding surface, and a second step of applying the color powder to the tire molding surface after the first step. The tire molding surface includes a recessed portion for forming a mark on the sidewall of the tire. In the first step, the liquid substance, which is a volatile solvent, is applied to the tire molding surface. A tire manufacturing method comprising the second step of attaching the color powder via the volatile solvent accumulated in the corners of the uneven portion.

2. An adhesion step of applying a color powder of a different color from the tire base color to the tire molding surface of a tire vulcanization mold via a liquid, The process includes a vulcanization step in which, after the adhesion step, the outer surface of the unvulcanized tire is pressed against the tire molding surface to perform vulcanization molding on the tire, The adhesion process includes a first step of applying the liquid to the tire molding surface, and a second step of applying the color powder to the tire molding surface after the first step. A tire manufacturing method comprising, after the second step, a third step of removing the color powder that is not adhering to the tire molding surface by air blowing.

Images