JPH04121205A - Pneumatic tire having colored ornament part and manufacture thereof - Google Patents

Abstract

PURPOSE:To form plural colored ornament parts on a tire side wall without deteriorating bending fatigue resistance and weather resistance on the outer surface by constituting the tire side wall of an uncontaminated inner layer rubber, plural colored ornament parts and a weather resistance cover sheet, and by setting a gage of the ornament part in relation to a side rubber gage at a specified percent or less. CONSTITUTION:When ornament parts 3a and 3b are adjacently provided on a side wall, the side wall consists of weather resistance cover sheets 4a and 4b mutually adjacent to the ornament portions respectively, normal side wall rubbers 2a and 2b, and an inner layer rubber 5 for supporting the ornament parts 3a and 3b. In this case, the cover sheet 4a and 4b are formed by EPDM. Further, an uncontaminated or slightly contaminated rubber containing no contaminated aged resistor is utilized for the inner layer rubber 5. Besides, gages for the ornament parts 3a and 3b are set to be 60 percent or less of a side rubber gage at the same cross section.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pneumatic tire with a colored decorative part, particularly a pneumatic tire with integrated decorative bands of multiple colors, decorative letters, etc., and a method for manufacturing the same. .

(Prior Art) Conventionally, tires having a white annular decorative band or decorative letters on one sidewall of the tire have been widely used. In that case, in order to prevent contamination of the decorative band or decorative characters, white rubber is usually used not only on the surface layer of the exposed surface area but also on the inner rubber layer around it. A typical example of such a layout is shown in Japanese Patent Publication No. 46-41761.

In this case, since staining anti-aging agents cannot be used with white rubber, ethylene propylene diene terpolymer (EODM) is used as the polymer component to ensure the weather resistance of the surface layer. Poor fatigue properties. Therefore, in order to reduce costs, we used 2I1m of white rubber.
An attempt to make the sheet smaller than 1 is shown in Japanese Unexamined Patent Publication No. 52-51603. However, in this case, the problem arises as to whether the white rubber is contaminated by the staining anti-aging agent contained in the rubber surrounding the white rubber. As mentioned above, there is currently no known technology for realizing a multi-colored sidewall decoration part that does not impair the bending fatigue resistance and weather resistance of the outer surface required for tire sidewalls and does not easily become contaminated.

(Problem to be Solved by the Invention) An object of the present invention is to provide a pneumatic tire having sidewall decoration parts in multiple colors that do not impair the bending fatigue resistance required for tire sidewalls and the weather resistance of the outer surface and do not easily become contaminated. The purpose of the present invention is to provide a tire and a method for manufacturing the same.

When realizing multi-colored tire sidewall decoration, if not only the surface layer of the exposed surface part is made of white or colored rubber like the current white tire, but also the inner rubber part around it is made of white or colored rubber, the weather resistance will be improved. Problems include the bending fatigue resistance and cost increase of the EPDM used for this purpose. Due to bending fatigue, the arrangement range is limited, and it is difficult to apply the conventional method of using only one color (white) to multi-coloring. Special Public Service 1977-4
Only in Figure 4 of Publication No. 1761 is there an example in which a non-contaminating sight rubber is wrapped around the inner layer comb of the white part.
The side rubber also constitutes the outer surface, and no consideration is given to achieving both weather resistance and bending fatigue resistance. In Japanese Patent Application Laid-Open No. 52-51603, no consideration is given to preventing contamination by the inner layer comb of the white sheet. Therefore, the above object of the present invention cannot be achieved by a mere combination of these conventional techniques.

(Means for Solving the Problems) As a result of intensive research to solve the above problems, the present inventors appropriately arranged a decorative part made of multiple colors, a non-staining inner rubber layer, and a weather-resistant cover sheet. This led to the completion of this invention after confirming that the above object could be achieved.

That is, the present invention firstly provides a tire sidewall with a decorative part made of a plurality of colors and a size that supports the decorative part and isolates it from the surrounding normal sidewall rubber. A product which integrally comprises a non-contaminating or slightly contaminating sidewall inner layer rubber that forms a sidewall, and a weather-resistant cover sheet that covers at least the exposed surface of the inner comb so that the inner comb is not exposed to the surface. Coloring of a tire characterized in that the gauge of the decorative part measured in the cross-sectional direction of the tire is 60% or less of the total gauge of the decorative part and the gauge of the sidewall inner layer rubber in the same cross section, that is, the side rubber gauge. This is a pneumatic tire with a decorative part.

In the second invention, in manufacturing the tire, a part of the normal sidewall rubber is made of non-contaminating or non-contaminating rubber having a size that can isolate the position occupied by the decorative part in the member bonding process (molding process). The sidewall rubber replaced with the slightly polluting sidewall inner layer rubber is pasted together.
Next, a decorative part made of a plurality of colors is pasted on the inner layer rubber in an annular manner in multiple layers, multiple rows, or a mixture thereof so that they are separated from each other. The gauge of the decorative part measured in the direction or the sum of the gauge of the decorative part and the gauge of the sidewall inner layer comb in the same cross section, that is, 60% or less of the side rubber gauge, is selected, and at least the inner layer rubber and the decorative part are selected. Cover the exposed surface of the inner layer rubber and the decorative part in a ring shape with a weather-resistant cover sheet so as not to expose it to the tire surface, and after vulcanization, apply a cover sheet covering the decorative part as desired to the extent that the inner rubber is not exposed. The method for manufacturing the tire includes the step of puffing.

(Function) In this invention, the inner layer rubber must be a non-staining or slightly staining rubber that does not contain a staining anti-aging agent, and by using an inner layer rubber that has good bending fatigue resistance, it is possible to prevent staining of the decorative part. It is possible to achieve both prevention of bending fatigue and prevention of bending fatigue, and the range of types and arrangement of decorative parts can be expanded compared to conventional ones.

It is necessary that the decoration be free of staining anti-aging agents. Whether the rubber polymer component is EPDM or EPDM15
The decorative portion, which is a blend of halogenated butyl rubber and/or diene rubber, can provide the desired weather resistance without using a staining anti-aging agent. It is also possible to add more variation to the coloring by adding unevenness to the decorative part. It is also possible to use EPDM as a part of the rubber polymer component of the inner layer rubber to improve vulcanization adhesion between the decorative rubber and the inner layer rubber. The multi-colored decorative part may be prepared by pasting a plurality of strips of different single colors onto the inner rubber layer in a molding process, by extruding the multi-colored strips simultaneously, or by pre-calendering.

The weather-resistant cover sheet used in the present invention is one in which the rubber polymer component is composed of EPDM alone or a blend of BPDM and halogenated butyl rubber and/or diene rubber, and is susceptible to staining and aging. Contains no inhibitors. By covering the surface of the inner layer rubber with this cover sheet in an annular manner to include a part of the normal sidewall at or beyond the exposed surface, the inner layer rubber, which has poor weather resistance, is exposed to the surface and deteriorates. prevent.

Furthermore, the tire of the present invention is a product tire, and the gauge of the decorative part measured in the cross-sectional direction of the tire is 60% with respect to the site rubber gauge, which is the sum of the gauge of the decorative part and the gauge of the sidewall inner layer comb in the same cross section. % or less is necessary in order to achieve both weather resistance and bending fatigue resistance of the side surface, and if it exceeds 60%, the bending fatigue resistance deteriorates.

An example of the pneumatic tire of this invention is shown in FIG. This tire has two colored bands on one sidewall, that is, colored areas 3a and 3b, which are adjacent to each other, and adjacent to each of which are weather-resistant cover sheets 4a and 4b, as well as ordinary sidewall rubber 2a. , continued in 2b. FIG. 2 shows a partially enlarged schematic cross-sectional view of the tire, centering on the decorative portion. As shown in this figure, a sidewall is formed on a carcass l by ordinary sidewall rubbers 2a, 2b and the inner layer rubber 5.

The two rows of decorative parts 3a and 3b provided on the inner rubber layer are
Their total width is smaller than the width of the outer surface of the inner layer rubber 5,
It is always continuous with the normal sidewall rubber 2a, 2b, ie, the rubber containing the staining anti-aging agent, via the inner layer rubber 5. In addition, the cover sheet 4 covers the surface of the inner layer rubber 5 that should be exposed, that is, the area of the outer surface of the inner layer rubber 5 that is not covered with the decorative portion, the decorative portion, and the outer surface of the end of the normal sidewall rubber 2a, 2b. . Strictly speaking, the width covering the ends of the normal sidewall rubbers 2a, 2b may be zero, but it is preferable to have a width of several widths or more in order to ensure protection of the inner layer rubber from the outside world. After vulcanization, by puffing along the puff line 6, a two-color decorative part appears as shown in FIG.

Figure 3 shows the decorative part 3, which is decorated in two colors and has a small width.
4 is an example of a two-layer structure in which "a" runs through the center of the wide decorative part 3b, and FIG. 4 shows the stage of molding the structure of FIG. 3. FIG. 5 is an example of a two-layer decorative part in which small decorative parts 3a and 3b of two different colors run parallel to each other in a large decorative part 3c. The decorative parts 3a and 3b may be of the same color as required.

Figure 6 shows an example in which decorative parts in two colors are arranged to fill the entire width of the sidewall. Even in such a case, the structure shown in this invention can improve bending fatigue resistance, non-staining property, and weather resistance. It is possible to satisfy.

Figure 7 shows decorative parts 3a and 3b in three colors on two ribs.

This is an example in which a change is made by forming 3c, and FIG. 8 shows the stage of molding this.

FIG. 9 shows a conventional pneumatic tire having a white annular decorative band, in which a weather-resistant cover sheet 4 is provided on white rubber 7. Furthermore, FIGS. 10 and 11 show examples of pneumatic tires having colored decorative parts that do not comply with the present invention. In FIG. Since the decoration part is smaller than the width, the ordinary sidewall rubber 2a and 2 containing a staining anti-aging agent are used.
b, contamination of the decorative part occurs. In FIG. 11, contamination of the decorative parts 3a and 3b does not occur, but since the width of the cover sheet 4 is short, a portion of the inner layer rubber 5 is exposed, and the inner layer rubber is likely to deteriorate.

(Example) This invention will now be illustrated by Examples and Comparative Examples.

Decoration rubber and inner layer rubber, Preparation method of test sample Test samples for ozone crack evaluation are made by kneading the ingredients in a hand mixer according to the specified formulation, and mixing the kneaded rubber with 1
It was produced by press vulcanization at 45°C for 40 minutes.

B. Ozone crack property evaluation method
A test was conducted for 24 hours under C130% constant elongation conditions. The ozone crack resistance was evaluated according to JIS K6301 in 15 grades depending on the number of cracks, the size and depth of the cracks.

C. Compounds of decorative rubber and inner layer rubber and ozone crack test of decorative rubber are shown in Table 1. The amounts in Table 1 are expressed in parts by weight.

From Table 1, EPDM to PHR No. 4 formulation has poor 03 resistance, while diene rubber only formulation (No. 3)
), it can be seen that the 03 resistance is extremely poor.

Examples 1-4. Comparative Examples 1 and 2 Next, the decorative rubber and inner layer rubber shown in Table 1 were combined to evaluate their stainability.

B. Preparation of sample The decorative rubber and inner layer rubber were prepared as a composite as shown in FIG. The decorative rubber parts 3a, 3b and 3c are
The rubber compositions are the same as shown in Table 2 except that the colorants are red, blue, and yellow, respectively, and the composition of the inner layer rubber is also as shown in Table 2. A sample was prepared by stacking the decorative rubber and the inner layer rubber and vulcanizing them. At this time, the total thickness of the decorative rubber was adjusted to 2 mm, and the thickness of the inner layer rubber was adjusted to 4M. The kneading method and vulcanization conditions were the same as in the case of the test sample for ozone crack evaluation described above.

Method for evaluating contamination of mouth and decorative rubber: The sample was heated to 80°C for 48 hours, and then exposed to sunlight.
The presence or absence of discoloration of the decorative rubber was examined.

Contamination test results Shown in Table 2.

As is clear from Table 2, if the inner layer rubber contains a staining anti-aging agent, the decorative part comb will be contaminated, and if it is not contained, staining or no staining will occur.

Examples 5-6. Comparative Example 3 In this example, the case where an inner layer comb containing a micro-staining anti-aging agent was used was compared with the case where each inner layer rubber containing a non-staining and a staining anti-aging agent was used.

B. Preparation of sample The decorative rubber shown in Table 3 and the inner layer rubber were laminated and vulcanized to prepare a sample. At this time, the thickness of the decorative rubber was adjusted to 2 mm in Examples 5 and 6, 10 mm in Comparative Example 3, and the thickness of the inner layer rubber was adjusted to 4th threshold in all cases. The rest was carried out in the same manner as in Examples 1 to 4.

Method for evaluating contamination of decorative rubber: The sample was exposed to sunlight at 100°C for 24 hours, and the degree of contamination of the decorative rubber was expressed as the distance (mm) of discoloration measured from the interface with the inner layer rubber. did.

C. Contamination test results It is shown in Table 3.

As is clear from Table 3, even if the inner layer rubber is slightly contaminated (Example 6), by adjusting the gauge of the decorative rubber, for example, if the normal gauge is set to 1.5W or more, the decorative rubber can prevent contamination.

Examples 7-8. Comparative Examples 4 to 6 A composite as shown in FIG. 5 having the same structure as Examples 1 to 4 was produced, but the rubber of Nα1 in Table 1 was used as the decorative rubber.
Samples were prepared by using the rubber of Nα5 shown in Table 1 as the inner layer rubber, and by changing the ratio of the thicknesses of both rubbers, overlapping them and vulcanizing them. The kneading method and vulcanization conditions are the same as in Examples 1-4.

The rupture rate due to bending fatigue is 10% in the Demacha crack test.
After 0 hr, the breakage rate (%) of the sample is determined by the following formula:
It was evaluated by

Also, the gauge ratio S of the decorative part to the side rubber gauge
The results are shown in Table 4.

It can be seen that if the decoration part gauge is set to 609°C or less with respect to the site rubber gauge, the bending fatigue resistance of the site surface is reduced.

(Effects of the Invention) As is clear from the Examples and Comparative Examples, the pneumatic tire having the colored decorative part of the present invention has no decorative part because the decorative part is isolated from the rubber containing the contaminating anti-aging agent by the inner layer comb. By keeping the gauge of the decorative part within a specific ratio to the side rubber gauge, the bending fatigue resistance of the decorative part is improved, and the surface of the inner rubber layer that should be exposed is covered with a weather-resistant cover sheet. It has sufficient weather resistance. Therefore, in the tire of the present invention, decorative parts of multiple colors can be freely provided over a wide range on the sidewall, and weather resistance, stain resistance, and good flex fatigue resistance can be achieved at the same time.

[Brief explanation of drawings]

1 is a perspective view of a tire of the present invention having decorative parts in two rows and two colors; FIG. 2 is a partially enlarged schematic cross-sectional view of the tire shown in FIG. FIG. 4 is a schematic partial cross-sectional view of a tire having a two-color, two-layer decoration part according to the invention; FIG. FIG. 6 is a schematic partial cross-sectional view of another tire having a two-layer decorative part; FIG. 6 is a schematic cross-sectional view of a tire in which two decorative parts according to the invention are arranged to fill the width of the sidewall; FIG. FIG. 8 is a schematic partial cross-sectional view of a tire with a decorative portion formed on a rib according to the invention; FIG. FIGS. 10 and 11 are schematic partial cross-sectional views of a pneumatic tire having a conventional white annular decorative band. FIGS. 10 and 11 are schematic partial cross-sectional views showing, for comparison, a pneumatic tire having a colored decorative portion not according to the present invention. . 1...Carcass 2a, 2b...Side wall rubber 3a, 3b,
3cm decorative parts 4, 4a, 4b...Cover sheet 5...Inner layer comb 6...Buff line 7...White comb

Claims (1)

[Claims] 1. A decorative portion in which the tire sidewall is made of a plurality of colors;
a non-staining or slightly staining sidewall inner layer that supports the decorative portion and forms a part of the sidewall and has a size that isolates it from the surrounding normal sidewall rubber containing a staining anti-aging agent; Rubber and a weather-resistant cover sheet that covers at least the exposed surface of the inner layer rubber so that the inner layer rubber is not exposed to the surface are integrally provided, and the gauge of the decorative portion measured in the cross-sectional direction of the tire is A pneumatic tire having a colored decorative part, characterized in that the total gauge of the decorative part and the gauge of the sidewall inner layer rubber in the same cross section is 60% or less of the side rubber gauge. 2. The pneumatic tire according to claim 1, wherein the rubber polymer component of the decorative portion is an ethylene propylene diene terpolymer (EPDM). 3. The rubber polymer component of the decorative part is a blend of 15% by weight or more of ethylene propylene diene terpolymer (EPDM) and at least one polymer selected from the group consisting of halogenated butyl rubber and diene rubber. Claim 1
Pneumatic tires listed. 4. It has a size that allows a part of normal sidewall rubber containing a staining anti-aging agent to be isolated from the position occupied by the decorative part in the component lamination process in the production of pneumatic tires having colored decorative parts. A sidewall rubber substituted with a non-staining or slightly staining sidewall inner layer rubber is laminated, and then a decorative part consisting of multiple colors is arranged annularly in multiple layers, in multiple rows, or in multiple rows on the inner layer rubber so as to be isolated from this. The gauge of the decorative part is the sum of the gauge of the decorative part and the gauge of the sidewall inner layer rubber in the same cross-section, where the thickness of the decorative part and the inner layer rubber is measured in the cross-sectional direction of the tire with a product tire attached to a mixed type; That is, the side rubber gauge should be 60% or less, and after vulcanization, the exposed surface of the inner layer rubber and the decorative portion should be covered in a ring shape with a weather-resistant cover sheet so that at least the inner layer rubber and the decorative portion are not exposed to the tire surface. 4. The air chamber having a colored decorative part according to any one of claims 1 to 3, characterized by the step of buffing a cover sheet covering the decorative part as desired to the extent that the inner layer rubber is not exposed. How tires are manufactured. 5. The manufacturing method according to claim 4, wherein the rubber polymer component of the decorative portion is an ethylene propylene diene terpolymer (EPDM). 6. The rubber polymer component of the decorative part is a blend of 15% by weight or more of ethylene propylene diene terpolymer (EPDM) and at least one polymer selected from the group consisting of halogenated butyl rubber and diene rubber. Claim 4
Manufacturing method described.