JP2013159677A - Rubber composition, and pneumatic tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition achieving compatibly color developability and a color fading property in an imparted color, and a pneumatic tire using the same.SOLUTION: A rubber composition includes a rubber component containing 20 mass% or more of nondienic rubber, and 0.1-30 pts.mass of organic colored pigment and 0.1-30 pts.mass of inorganic colored pigment, per 100 pts.mass of the rubber component, and a pneumatic tire uses the rubber composition.

Description

  The present invention relates to a rubber composition provided with a color (color) and a pneumatic tire using the rubber composition.

Conventionally, for the purpose of increasing the visibility of rubber products, various rubber products in which a colored rubber composition colored other than black is arranged on the surface have been used. For example, Patent Document 1 proposes a pneumatic tire having a color rubber for identification in which a color rubber not containing carbon black is formed at an appropriate position of the sidewall portion.
Patent Document 2 discloses a colored rubber composition containing butyl rubber and / or halogenated butyl rubber in an amount of 80% by mass or more of a rubber component, and a pneumatic tire in which the colored rubber composition is disposed in a sidewall portion. A yellow pigment is disclosed.
Furthermore, Patent Document 3 discloses a rubber composition for a decorative sidewall of a pneumatic tire made of butyl rubber, diene rubber, and ethylene-propylene-diene terpolymer rubber, and discloses a blue pigment.
However, organic pigments have excellent color developability, but fading due to ultraviolet irradiation has been a problem.

Japanese Patent Laid-Open No. 08-25920 JP 2006-168616 A Special table 2011-524455 gazette

  An object of the present invention is to provide a rubber composition that can achieve both color developability and fading property of a given color, and a pneumatic tire using the rubber composition.

As a result of various experimental analyzes to solve the above problems, the present inventors have found that the problem can be solved by combining specific pigments, and have completed the present invention.
That is, the present invention
[1] A rubber component containing 20% by mass or more of a non-diene rubber, and 0.1 to 30 parts by mass of a chromatic organic pigment and 0.1 to 30 of a chromatic inorganic pigment with respect to 100 parts by mass of the rubber component A rubber composition comprising: a mass part; and [2] the rubber composition described in the above [1], wherein the sidewall part is on the outer side in the tire width direction, the tire shoulder part is on the outer side in the tire width direction, and the bead A pneumatic tire disposed on at least a part of one or more members selected from the outer side in the tire width direction and the bottom of the tread groove.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition which enables coexistence of the coloring property and fading property of the provided color, and a pneumatic tire using the same can be provided.

It is a cross-sectional schematic diagram of one example of the pneumatic tire of the present invention. It is a perspective view of other examples of the pneumatic tire of the present invention.

The present invention is described in detail below.
[Rubber composition]
The rubber composition of the present invention comprises a rubber component containing 20% by mass or more of a non-diene rubber, and 0.1 to 30 parts by mass of a chromatic organic pigment and 100% by mass of a chromatic inorganic pigment with respect to 100 parts by mass of the rubber component. 0.1-30 mass parts is included, It is characterized by the above-mentioned.
Here, the chromatic organic pigment has good color developability, a clear color is obtained, and the coloring power is large and the hue is wide, but the weather resistance is slightly inferior to the inorganic pigment and the hiding power is small. In contrast, a chromatic inorganic pigment has a calm color tone, a narrow hue, a low coloring power, a large hiding power, and excellent weather resistance.
In the present invention, since both the chromatic organic pigment and the chromatic inorganic pigment are included, the disadvantages of both can be compensated and the advantages of both can be exhibited synergistically. It is possible to obtain a rubber composition having both color developability and color fading and having no color unevenness.

[Rubber component]
The rubber component used in the rubber composition of the present invention contains 20% by mass or more of non-diene rubber, preferably 40% by mass or more, and more preferably 50% by mass or more.
In the present invention, the non-diene rubber means a rubber in which the proportion of units derived from a diene monomer in the monomer units constituting the non-diene rubber is 5 mol% or less. Here, examples of the diene monomer include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, and the like. On the other hand, examples of non-diene-based (non-diene-based) monomers constituting the non-diene rubber include ethylene, propylene, and isobutene. Here, the non-diene rubber may be at least one rubber selected from butyl rubber and ethylene-propylene-diene terpolymer rubber (hereinafter sometimes referred to as “EPDM rubber”). preferable. The butyl rubber is preferably at least one rubber selected from butyl rubber and halogenated butyl rubber, more preferably at least one rubber selected from halogenated butyl rubber, and at least from chlorinated butyl rubber and brominated butyl rubber. It is particularly preferable that the rubber is one selected.
EPDM rubber is obtained by introducing a small amount of a third component into ethylene-propylene rubber (EPM), which is a copolymer of ethylene and propylene, and providing a double bond in the main chain. Various synthetic rubbers are commercially available depending on the type and amount of the third component. Typical examples of the diene component as the third component include ethylidene norbornene (ENB), 1,4-hexadiene (1,4-HD), dicyclopentadiene (DCP), and the like.
The rubber component according to the present invention may contain a diene rubber in the range of 80% by mass or less, preferably 60% by mass or less, and preferably 50% by mass or less, in addition to the non-diene rubber described above. Is more preferable. The diene rubber is preferably at least one selected from natural rubber and synthetic diene rubber. As the synthetic diene rubber, styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR) and the like can be used. Natural rubber and synthetic diene rubber may be used singly or in a combination of two or more.

[Chromatic organic pigment]
The chromatic organic pigment according to the present invention is preferably a pigment selected from at least one of polycyclic pigments, azo pigments, lake pigments, vegetable pigments and animal pigments. Organic pigments are preferred because they have good color developability and are excellent in coloring power and sharpness.

As said polycyclic pigment, the condensed ring compound which has a function as a pigment is mentioned. Many pigments have higher durability than azo pigments. A typical example of the polycyclic pigment is a phthalocyanine pigment. Phthalocyanine pigments are excellent in color, are bright, have high light resistance (relatively less fading), and are robust (excellent in durability). In particular, copper phthalocyanine is called copper phthalocyanine blue (Pigment Blue 15). High chlorinated copper phthalocyanine is called copper phthalocyanine green (Pigment Blue 7), which is known as a representative of blue and green organic pigments. Low chlorinated copper phthalocyanine (brominated chlorinated copper phthalocyanine) (Pigment Blue 36) and metal-free phthalocyanine (Pigment Blue 16) exhibiting a more yellowish green color are also used as pigments.
Among the copper phthalocyanines, Pigment Blue 15: 3, which is the β crystal of copper phthalocyanine, is most often used for the process color, and Pigment Blue 15: 4 is an improved dispersion performance. Also, Pigment Blue 15: 6, which is an ε crystal of copper phthalocyanine, is used.
The chemical structural formula of copper phthalocyanine blue is shown below.

  Other polycyclic pigments include yellow pigments: isoindolinone, quinophthalone, isoindoline, anthraquinone, anthrone, xanthene; orange pigments: diketopyrrolopyrrole, perylene, anthraquinone (anthrone), perinone, quinacridone, indigoid; red pigment: Anthraquinone, quinacridone, diketopyrrolopyrrole, perylene, perinone, indigoid; Purple (dark blue) pigment: Dioxazine, quinacridone, perylene, indigoid, anthraquinone (anthrone), xanthene; Blue pigment: anthraquinone, indigoid; Green pigment: azomethine, perylene Etc.

  Examples of the azo pigment that is a chromatic organic pigment according to the present invention include those having a function as a pigment among azo compounds that are compounds having a double bond between nitrogen atoms. Monoazo pigment with one azo group in the molecular structure, diazo pigment with two azo groups in the molecular structure and high symmetry centered on the central orientation structure, two azo groups in the molecular structure A condensed diazo pigment produced by using a condensation reaction having a high symmetry centering on the central alignment structure is used. Lake pigments in which metal is coordinated to monoazo are also classified as monoazo pigments. Diazo pigments and condensed diazo pigments are characterized by high coloring power. Benzidine Yellow (Pigment Yellow 14) exhibiting medium yellow, Brilliant Carmine 6B (Pigment Red 57: 1) exhibiting bluish red, First Yellow, Disazo Yellow, Naphthol Red, Chromophthal Yellow 3G (Pigment Yellow 93), Chromophthal Yellow 6G (Pigment Yellow 94), chromophthal yellow GR (Pigment Yellow 95), chromophthal scarlet RN, chromophthal red BR, chromophthal red BRN, nickel azo yellow, benzimidazolone yellow and the like.

The lake pigment, which is a chromatic organic pigment according to the present invention, is obtained by ionizing a water-soluble colored substance (dye) and electrically coupling it with a metal ion as a carrier.
Lake red C (red), watching red (red), alizarin lake (red), rhodamine lake (red), quinoline yellow lake (yellow) and the like.

Examples of plant pigments that are chromatic organic pigments according to the present invention include madder lake (red), pink madder, gunborg (yellow), and dragon blood.
Examples of animal pigments that are chromatic organic pigments according to the present invention include cochineal (red), Kermes lake, Chilean purple, and sepia (dark brown).

  The chromatic organic pigment according to the present invention is required to be contained in an amount of 0.1 to 30 parts by mass, preferably 0.5 to 20 parts by mass, with respect to 100 parts by mass of the rubber component. More preferably, it is contained in parts by mass. If it is 0.1 parts by mass or more, the rubber composition can enjoy color development as a color rubber, and even if it exceeds 30 parts by mass, it is difficult to expect further coloring effect. Is advantageous.

[Chromatic inorganic pigments]
Examples of the chromatic inorganic pigment according to the present invention include natural inorganic pigments and synthetic inorganic pigments.
Natural inorganic pigments include, for example, earth-based pigments: yellow ocher (reddish yellow), tail belt (green), low senna (green), low umber (slightly brownish yellowish brown), Cassel earth (dark brown); Soil: burnt senna (red brown), burnt amber (brown); mineral pigments: lapis lazuli (blue), azurite (blue), malachite (green), opiment (yellow), dredged sand (red), etc.

Suitable examples of the synthetic inorganic pigment include at least one pigment selected from oxide pigments, hydroxide pigments, sulfide pigments, silicate pigments, and phosphate pigments.
Examples of the oxide pigment include cobalt blue, cerulean blue, cobalt violet, cobalt green, light red, and chrome oxide green. Examples of the hydroxide pigment include viridan (green). Examples of the sulfide pigment include cadmium yellow, cadmium red, and vermilion (yellowish red).
Further, examples of the silicate pigment include ultramarine blue, ultramarine violet, ultramarine red, and ultramarine pink. Examples of the phosphate pigment include mineral violet and rose cobalt violet.

  The chromatic inorganic pigment according to the present invention is required to be contained in an amount of 0.1 to 30 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is contained in parts by mass. If it is 0.1 parts by mass or more, the rubber composition can enjoy color development as a color rubber, and even if it exceeds 30 parts by mass, it is difficult to expect further coloring effect. Is advantageous.

[Achromatic inorganic pigment]
The rubber composition of the present invention can ensure the concealment property by the chromatic inorganic pigment, but if the concealment property is insufficient or if it is desired to further improve the concealment property, the achromatic color is further reduced as necessary. Inorganic pigments may be included.
As achromatic inorganic pigments, oxide pigments: titanium oxide (titanium white), zinc oxide (zinc white); hydroxide pigments: alumina white; silicate pigments: talc (white), clay (white or gray); Sulfide pigments: lithopone (white); carbonate pigments: silver white (lead white, basic lead carbonate), calcium carbonate, and the like. Titanium oxide is preferred because it is white and has high concealability.

[Reinforcing filler]
Further, in order to enhance the reinforcing property of the rubber composition of the present invention and improve the fracture resistance after vulcanization, the reinforcing filler preferably includes silica, clay, etc., and particularly preferably includes silica.
Any commercially available silica can be used, among which wet silica, dry silica, and colloidal silica are preferably used, and wet silica is particularly preferably used. The BET specific surface area (measured in accordance with ISO 5794/1) of silica is preferably 40 to 350 m ² / g. Silica having a BET specific surface area within this range has an advantage that both rubber reinforcement and dispersibility in a rubber component can be achieved. From this point of view, the BET specific surface area is more preferably silica in the range of 80~350m ² / g, BET specific surface area of greater than 130m ² / g, more preferably silica or less 350 meters ² / g, a BET specific surface area Silica in the range of 135 to 350 m ² / g is particularly preferred. Examples of such silica include Tosoh Silica Co., Ltd., trade name “Nip Seal AQ” (BET specific surface area = 205 m ² / g), “Nip Seal KQ” (BET specific surface area = 240 m ² / g), trade name manufactured by Degussa. Commercial products such as “Ultrazil VN3” (BET specific surface area = 175 m ² / g) can be used.
As the clay, kaolin clay (manufactured by JM Huber, trade name “Polyfil DL”, etc.) is preferable.

  The reinforcing filler is preferably used in an amount of 20 to 150 parts by mass with respect to 100 parts by mass of the rubber component. If it is 20 mass parts or more, it is preferable from a viewpoint of the reinforcement property improvement of a rubber composition, and if it is 150 mass parts or less, it is preferable from a viewpoint of rolling resistance reduction. Furthermore, it is more preferable to use 30-100 mass parts.

In the case where the rubber composition of the present invention contains silica as the reinforcing filler, it is preferable to further contain a silane coupling agent from the viewpoint of further enhancing the reinforcing filler.
Specific examples of the silane coupling agent that can be used in combination with the reinforcing filler include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (3-methyldimethoxysilylpropyl). ) Tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-methyldimethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-methyldimethoxysilylpropyl) trisulfide, bisulfide (2-triethoxysilylethyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) tetrasulfide, bis (3-monoethoxydimethylsilylpropyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) disulfide, bis (3-monomethoxydimethylsilylpropyl) tetrasulfide, bis (3-monomethoxydimethylsilylpropyl) trisulfide, bis (3-monomethoxydimethylsilylpropyl) disulfide, bis (2-monoethoxydimethylsilylethyl) tetrasulfide, Bis (2-monoethoxydimethylsilylethyl) trisulfide, bis (2-monoethoxydimethylsilylethyl) disulfide, 3-hexanoylthiopropyltriethoxysilane, 3-octanoyl Opropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthio Ethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltri Methoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2-decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysila Average composition formula (CH ₃ CH ₂ O) ₃ Si— (CH ₂ ) ₃ —S ₂ — (CH ₂ ) ₆ —S ₂ — (CH ₂ ) ₃ —Si (OCH ₂ CH ₃ ) ₃ , average composition Formula (CH ₃ CH ₂ O) ₃ Si— (CH ₂ ) ₃ —S ₂ — (CH ₂ ) ₁₀ —S ₂ — (CH ₂ ) ₃ —Si (OCH ₂ CH ₃ ) ₃ , average composition formula (CH _{3 CH 2 O) 3 Si- (CH} 2) 3 -S 3 - (CH 2) 6 -S 3 - (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula (CH ₃ CH ₂ O) ₃ Si— (CH ₂ ) ₃ —S ₄ — (CH ₂ ) ₆ —S ₄ — (CH ₂ ) ₃ —Si (OCH ₂ CH ₃ ) ₃ , average composition formula (CH ₃ CH ₂ O) ₃ Si— ( _{CH 2) 3 -S- (CH 2} ) 6 -S 2 - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula (CH ₃ CH ₂ O) _{3 Si- (CH 2) 3 -S- (} CH 2) 6 _{-S 2.5 - (CH 2) 6} -S- (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH _{2) 6 -S 3 - (CH} 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S _{- (CH 2) 6 -S 4} - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) ₃ -S- (CH ₂ ) ₁₀ -S _2- (CH ₂ ) ₁₀ -S- (CH ₂ ) ₃ -Si (OCH ₂ CH ₃ ) ₃ , average composition formula (CH ₃ CH ₂ O) ₃ Si- ( _{CH 2) 3 -S 4 - (} CH 2) 6 -S 4 - (CH 2) 6 -S 4 - (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula (CH ₃ CH ₂ O ) ₃ Si— (CH ₂ ) ₃ —S ₂ — (CH ₂ ) _{6 -S 2 - (CH 2)} 6 -S 2 - (CH 2) 3 -Si (OCH 2 CH 3) 3, the average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- _{(CH 2) 6 -S 2 -} (CH 2) 6 -S 2 - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3) 3, Momentive Performance Materials Co., Ltd. under the trade name " NXT Low-V Silane ”, manufactured by Momentive Performance Materials, trade name“ NXT Ultra Low-V Silane ”, manufactured by Momentive Performance Materials, trade name“ NXT-Z ”.
In this invention, a silane coupling agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  As for the compounding quantity of the silane coupling agent of the rubber composition of this invention, it is preferable that mass ratio {silane coupling agent / reinforcing filler} is (1/100) to (20/100). If it is (1/100) or more, the effect of improving the low heat build-up of the rubber composition will be more suitably exhibited. If it is (20/100) or less, the cost of the rubber composition will be reduced, and the economic efficiency This is because it improves. Furthermore, the mass ratio (3/100) to (20/100) is more preferable, and the mass ratio (4/100) to (10/100) is particularly preferable.

[Weatherproofing agent]
In order to improve the weather resistance, the rubber composition of the present invention further comprises a phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a triazine. It is preferable to include a weathering agent selected from at least one selected from a UV absorber, a salicylate UV absorber, a cyanoacrylate UV absorber, and a hindered amine light stabilizer.

  Examples of the phenol-based antioxidant include 2,6-di-tert-butyl-4-methylphenol (BHT, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 200”), mono (or di). Or (tri) (α-methylbenzyl) phenol (made by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK SP, SP-N”), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) (Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK NS-5”), 2,2′-methylenebis (4-methyl-6-tert-butylphenol) (Ouchi Shinsei Chemical Co., Ltd., trade name “ Nocrack NS-6 "), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol) (Ouchi Shinsei Chemical Co., Ltd., trade name" NOCRACK NS-3 ") "), 4,4'-thiobis (3-methyl -6-tert-butylphenol) (Ouchi Shinko Chemical Industrial Co., Ltd., and trade name" Nocrac 300 ") and the like.

  Examples of the phosphorus antioxidant include tetrakis (2,4-di-tertiarybutyl-5-methylphenyl) -4,4′-biphenylenediphosphonite (manufactured by Sakai Chemical Industry Co., Ltd., trade name). "GSY-P101"), tris (nonyl phenyl) phosphite (Ouchi Shinsei Chemical Co., Ltd., trade name "NOCRACK TNP") and the like. When the phosphorus-based antioxidant is used in combination with the phenol-based antioxidant, a synergistic weather resistance effect can be obtained.

  Examples of the sulfur-based antioxidant include dilauryl thiodipropionate (manufactured by API Corporation, trade name “DLTP“ Yoshitomi ”), distearyl thiodipropionate (manufactured by API Corporation, Trade name “DSTP“ Yoshitomi ””), dimyristyl thiodipropionate (manufactured by API Corporation, trade name “DMTP“ Yoshitomi ”) and the like. By using a sulfur-based antioxidant in combination with a phenol-based antioxidant, a synergistic weather resistance effect can be obtained.

  Examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-tert-amylphenyl) benzotriazole, and polyethylene. Examples include 3- [3- (benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionic acid ester of glycol.

  Examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxy- Examples include benzophenone-5-sulfonic acid.

  Examples of the triazine-based ultraviolet absorber include 2,4-bis [2-hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, 85% 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hydroxyphenyl and oxirane [(C10-C16 mainly C12-C13 alkyloxy) methyl] Reaction product with oxirane, 2- (2,4-dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester Reaction product of 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] phenol, 1,3,5-triazine-2 4, 6 (IH, 3H, 5H) - trione, 1,3,5 [[3,5-bis - (1,1-dimethylethyl) -4-hydroxyphenyl] methyl], and the like.

Examples of the salicylate-based ultraviolet absorber include phenyl salicylate and 4-t-butylphenyl salicylate.
Examples of the cyanoacrylate ultraviolet absorber include ethyl-2-cyano-3,3′-diphenyl acrylate, 2-ethylhexyl-2-cyano-3,3′-diphenyl acrylate, and the like.
Examples of the oxanilide ultraviolet absorber include 2-ethoxy-2'-ethyloxalic acid bisanilide, 2-ethoxyn-5-t-butyl-2'-ethyloxalic acid bisanilide, and the like. It is done.

  Examples of the hindered amine light stabilizer (commonly referred to as “HALS”) include 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2′-n-butylmalonate bis. (1,2,2,6,6-pentamethyl-4-piperidyl), bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl) -4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate and the like.

[Other ingredients]
In addition to the above compounding agents, the rubber composition according to the present invention is compounded with a vulcanizing agent, a vulcanization accelerator, and a vulcanizing activator, and, if necessary, a softening agent and the like. Examples of the vulcanizing agent include sulfur. Although it does not specifically limit as a vulcanization accelerator, For example, thiazole type | system | groups, such as M (2-mercaptobenzothiazole) and DM (dibenzothiazolyl disulfide), CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) ), Sulfenamides such as NS (N-tert-butyl-2-benzothiazolylsulfenamide), or guanidine-based vulcanization accelerators such as DPG (1,3-diphenylguanidine). Examples of the vulcanization activator include organic acids such as stearic acid and resin acid, and zinc oxide (zinc white). Examples of the softener include non-contaminating naphthenic process oil and paraffinic process oil.

Next, the pneumatic tire of the present invention will be described with reference to the drawings. . FIG. 1 is a schematic cross-sectional view of an example of the pneumatic tire of the present invention, and FIG. 2 is a perspective view of another example of the pneumatic tire of the present invention.
A pneumatic tire 1 according to the present invention includes a pair of bead portions 2 that contact the rim, a pair of sidewall portions 3 that are connected to the bead portion 2 and face each other, a tread portion 5 that contacts the road surface, and a tread portion of the tread portion. The tire shoulder portion 4 extends from the tread end 51 on the outer side in the width direction toward the inner side in the tire radial direction and continues to the sidewall portion 3.
In the pneumatic tire 1 according to the present invention, the rubber composition according to the present invention includes the sidewall portion 3 in the tire width direction outside, the tire shoulder portion 4 in the tire width direction outside, the bead portion 2 in the tire width direction outside, and the tread groove bottom portion 55. It is arranged on at least a part of one or more members selected from the above. 1 and 2, the rubber composition having a chromatic color of the present invention is arranged in a ring shape on the periphery of the sidewall portion 3 to form a chromatic rubber portion 3a.
In FIG. 1 and FIG. 2, the chromatic rubber portion 3 a is disposed on the sidewall portion 3 on the inner side in the tire radial direction from the maximum tire width of the pneumatic tire 1 (that is, on the bead portion 2 side from the maximum tire width). However, it is not limited to this.
By disposing the chromatic rubber portion 3a having a chromatic color imparted to the rubber composition obtained by the method of the present invention on a member of the pneumatic tire 1 that can be visually recognized when the vehicle is running or stopped, the pneumatic tire 1 As well as enhancing the aesthetics of the tire, it is possible to ensure the distinguishability of the pneumatic tire 1.

  In the example of the pneumatic tire 1 shown in FIG. 1 according to the embodiment of the present invention, the bead fillers 13 and 14 extend outward from the bead cores 11 and 12 in the tire radial direction. The carcass 15 is folded back at the bead cores 11 and 12 to the outside in the tread width direction of the bead fillers 13 and 14 to form a skeleton of a horseshoe-shaped tire case. A belt layer 18 composed of a plurality of belt layers is disposed outside the carcass 15 in the tire radial direction. A belt reinforcing layer 19 is disposed on the outer side in the tire radial direction of the belt layer 18 as necessary. In addition, an inner liner 16 is provided as an air permeation preventive layer on the inner side in the tire radial direction and the inner side in the width direction of the carcass 15.

  The rubber composition in the present invention is kneaded using a Banbury mixer, roll, intensive mixer, kneader, twin screw extruder or the like. Then, it is extruded in an extrusion process and formed as various members for tires. Subsequently, it is pasted and molded by a normal method on a tire molding machine to form a raw tire. The green tire is heated and pressurized in a vulcanizer to obtain a pneumatic tire.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
[Evaluation method]
<Color development>
The color developability was evaluated by measuring using a spectrocolorimeter (CM-700D manufactured by Konica Minolta Co., Ltd.). For evaluation, displays as an index value when the saturation √ in Comparative Example 1 (a ² + b ²⁾ is 100, the number is chromogenic the larger the better. The evaluation results are shown in Table 1. Note that a and b are chromaticness indices.
Color developability (index) = {(√ (a ² + b ² ) of test sample) / (√ (a ² + b ² ) of sample of Comparative Example 1)} × 100
<Color fading>
The fading property was evaluated by measuring using a spectrocolorimeter (CM-700D manufactured by Konica Minolta Co., Ltd.). About the sample obtained by each Example and the comparative example, exposure evaluation was performed outdoors and the color difference of 30 days after exposure and the initial stage was evaluated. About evaluation, it displays as an index value when the color difference of the comparative example 1 is set to 100, and a color difference becomes small and a fading property becomes favorable, so that a numerical value is large. The evaluation results are shown in Table 1.
Fading property (index) = {(color difference of test sample) / (color difference of sample of comparative example 1)} × 100

Example 1 and Comparative Examples 1 and 2
According to the blending contents shown in Table 1, kneading was carried out with a Banbury mixer, and three types of rubber compositions of Example 1 and Comparative Examples 1 and 2 were obtained. These three types of rubber compositions were evaluated for color developability and color fading by the above methods. The evaluation results are shown in Table 1.

[note]
* 1: EPDM rubber manufactured by JSR Corporation, trade name “EP35”
* 2: Brominated butyl rubber manufactured by JSR Corporation, trade name “BROMOBUTYL 2244”
* 3: Made by Tosoh Silica Co., Ltd., trade name “Nip Seal AQ”, BET specific surface area 205 m ² / g
* 4: Bis (3-triethoxysilylpropyl) disulfide (average sulfur chain length: 2.35), silane coupling agent manufactured by Evonik, trade name “Si75” (registered trademark)
* 5: Titanium oxide (rutile type) manufactured by Ishihara Sangyo Co., Ltd.
* 6: 2,6-di-tert-butyl-4-methylphenol (BHT), manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 200”
* 7: Copper phthalocyanine blue (Pigment Blue 15)
* 8: Ultramarine blue * 9: Di-2-benzothiazolyl disulfide, manufactured by Sanshin Chemical Industry Co., Ltd., trade name “Sunseller DM”
* 10: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller CZ-G”

  As is clear from Table 1, the rubber composition of Example 1 was better in both color development and fading than the rubber compositions of Comparative Examples 1 and 2.

Three types of rubber compositions of Example 1 and Comparative Examples 1 and 2 were disposed on the sidewall portion, the tire shoulder portion and the bead portion on the outer side in the tire width direction and on the bottom of the tread groove, and the tire size 195 / 65R15 A pneumatic radial tire for passenger cars was manufactured in a conventional manner. Compared with the tires of Comparative Examples 1 and 2, the tire of Example 1 had good color developability and excellent aesthetics.
When these three types of tires were exposed to sunlight on the rooftop for 6 months after filling the standard internal pressure, the tires of Comparative Examples 1 and 2 faded, but the tires of Example 1 were good without any fading. .

Since the rubber composition of the present invention is excellent in both coloring and fading of the imparted color, it is used for passenger cars, small trucks, light passenger cars, light trucks and large vehicles (for trucks and buses, construction vehicles). Etc.) etc. etc. etc. etc. etc., it is used suitably as each member of the tire width direction outer side of a sidewall part, a tire shoulder part, and a bead part, or a tread groove bottom part. Moreover, since the obtained various pneumatic tires are excellent in aesthetics and have good distinguishability, they are suitably used as pneumatic tires for the above tire applications.
[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Bead part 3 Side wall part 3a Chromatic rubber part 4 Tire shoulder part 5 Tread part 51 Tread end 55 Tread groove bottom part 11, 12 Bead core 13, 14 Bead filler 15 Carcass 16 Inner liner 18 Belt layer 19 Belt reinforcement layer

Claims (9)

  A rubber component containing 20% by mass or more of a non-diene rubber, and 0.1 to 30 parts by mass of a chromatic organic pigment and 0.1 to 30 parts by mass of a chromatic inorganic pigment with respect to 100 parts by mass of the rubber component A rubber composition comprising:   The rubber composition according to claim 1, wherein the non-diene rubber is a rubber selected from at least one of a butyl rubber and an ethylene-propylene-diene terpolymer rubber.   The rubber composition according to claim 2, wherein the butyl rubber is a rubber selected from at least one selected from chlorinated butyl rubber and brominated butyl rubber.   The rubber composition according to any one of claims 1 to 3, wherein the chromatic organic pigment is a pigment selected from at least one of a polycyclic pigment, an azo pigment, a lake pigment, a vegetable pigment, and an animal pigment.   The rubber composition according to claim 4, wherein the polycyclic pigment is a pigment selected from at least one selected from phthalocyanine pigments.   The rubber according to any one of claims 1 to 5, wherein the chromatic inorganic pigment is a pigment selected from at least one selected from oxide pigments, hydroxide pigments, sulfide pigments, silicate pigments and phosphate pigments. Composition.   The rubber composition according to claim 6, wherein the silicate pigment is a pigment selected from at least one of ultramarine blue, ultramarine violet, ultramarine red, and ultramarine pink.   In addition, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, benzotriazole UV absorbers, benzophenone UV absorbers, triazine UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers The rubber composition according to claim 1, comprising at least one weathering agent selected from an agent and a hindered amine light stabilizer.   The rubber composition according to any one of claims 1 to 8 is one or more kinds selected from the tire width direction outside of the sidewall portion, the tire width direction outside of the tire shoulder portion, the tire width direction outside of the bead portion, and the tread groove bottom portion. A pneumatic tire provided on at least a part of a member.

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