JPH0465446A - Colored tire material with improved abrasion resistance, color and color stability - Google Patents

Abstract

PURPOSE:To obtain a material for colored tires which comprises a cross-linking and colorable rubber composition containing an ionically cross-linking agent and a covalently corss-linking agent which forms free radicals, thus the product exhibits improved abration resistance, color and color stability. CONSTITUTION:(A) An ionically cross-linkable and covalently cross-linkable rubber, for example, hydrogenated styrene-butadiene rubber or the like is combined with (B) 10 to 90 wt.% of an ionically cross-linking agent such as a metal salt of carboxylic acid and (C) 10 to 90 wt.% of a free radical-forming covelently cross-linking agent such as a peroxide cross-linking agent.

Description

[Detailed description of the invention] field of invention The present invention relates to colored tire materials.

In particular, the present invention relates to colored tire materials with improved wear resistance, color, and color stability.

In summary, the present invention provides a colored tire material that has improved abrasion resistance, color, and color stability compared to conventional colored tire materials, such as white sidewall material. The colored tire material according to the invention has 10 to 90% ionic crosslinking and 9
It consists of a crosslinked colored rubber composition containing 0-10% covalent crosslinking caused by free radicals. These colored tire materials can be used as functional tire materials, such as colored sidewall materials (e.g., white sidewall materials), or decorative tire materials, such as colored embossed text (e.g., white embossed text) identifying the tire manufacturer.

BACKGROUND OF THE INVENTION Conventional colored tire materials, such as white sidewall tire materials, are generally mixtures of rubbers, typically natural rubber, chlorobutyl rubber or mixtures of SBR and EPDM rubber;
It consists of colored pigments such as iO2; non-black fillers such as clay and sulfur-based vulcanization systems as well as non-oxidizing agents, non-ozonating agents, waxes and the like. However, these conventional colored tire materials tend to change color and lose their attractive appearance when exposed to sunlight or the atmosphere. For example, traditional white sidewall materials tend to yellow fairly easily when exposed to sunlight or the atmosphere. Furthermore, the tires! Double rubbing against the curb often causes wear and tear on the surface of the colored tire material, such as the colored sidewalls and colored embossed lettering, reducing its attractiveness. Therefore, colored tire materials with improved abrasion resistance, color and color stability are highly desired.

SUMMARY OF THE INVENTION The present invention provides a colored tire material with improved abrasion resistance, color and color stability.

The colored tire material consists of a crosslinked colored rubber composition containing 10-90% ionic crosslinking and 90-10% covalent crosslinking caused by free radicals.

The colored rubber composition prior to crosslinking or vulcanization comprises a rubber capable of ionic and covalent crosslinking; an ionic crosslinking agent selected from the group consisting of carboxylic acid metal salts and inorganic metal salts; and free radicals. It consists of a covalent crosslinking agent that gives rise to Alternatively, the colored rubber composition, prior to completion of crosslinking, may consist of a rubber containing neutralized acid groups and a covalent crosslinking agent that generates free radicals.

Compared to conventional tire materials, the colored tire materials of the present invention have an improved color, a more vivid (e.g., white) appearance, and improved color stability, such that they do not yellow or fade when exposed to sunlight or ultraviolet light. There is little tendency. Additionally, this colored tire material has greatly improved abrasion resistance, as demonstrated by laboratory tests and curb-scraped tires.

DETAILED DESCRIPTION OF THE INVENTION As used throughout this specification and the claims therein in conjunction with the term "colored tire material," the term "colored" refers to white, green, red, yellow, blue, Refers to and is limited to non-black colored tire materials, such as brown tire materials. As used throughout this specification, ``neutralized''.

The term refers to both complete or partial neutralization of the acid groups.

The colored tire material according to the invention consists of a crosslinked colored rubber composition containing 10-90% ionic crosslinking and 90-10% covalent crosslinking caused by free radicals.

As indicated above, in some instances, the colored rubber composition prior to crosslinking includes a rubber capable of ionic and covalent crosslinking, i.e., a rubber capable of ionic and covalent crosslinking. Rubbers of this type suitable for use include saturated rubbers, unsaturated rubbers, rubbers containing acid groups, and mixtures thereof.

Saturated rubbers that may be used include hydrogenated rubbers such as hydrogenated styrene-butadiene rubber and hydrogenated polybutadiene rubber: butyl rubber and halogenated butyl rubbers such as chlorobutyl rubber and bromobutyl rubber. Such saturated rubbers and methods of making them are well known in the polymer and rubber arts. According to it, hydrogenated styrene-butadiene and polybutadiene rubbers are produced by polymerizing styrene and butadiene or butadiene monomers in solution with an alkyllithium, preferably butyllithium, and the resulting polymer is made of, for example, Raney nickel or nickel diatom. It can be produced by hydrogenation using a suitable hydrogenation catalyst such as an earth catalyst by a known method. Butyl rubber can be made by polymerizing isoolefins such as imbutylene and conjugated dienes such as isoprene in the presence of a metal halide catalyst such as aluminum chloride. Chlorinated butyl rubber can be produced by chlorinating butyl rubber with chlorine atoms in its hexane solution. This procedure is described in U.S. Patent No. 2,944.578.
It is described in. A typical polypropylene rubber is E x
E from xon Chemical Company
It is obtained under the name xxon 1066 and has a chlorine content of 1.1 to 1.3%, a viscosity of ML/(1+8)/
loo°C is 51-60.

Unsaturated rubbers that may be used include natural rubber, styrene-butadiene rubber (SBR), polybutadiene rubber, and E
Includes PDM and mixtures thereof. Such rubbers and methods of making them are known in the art.

As used throughout this specification, the term "EPDM" is used in the sense defined in ASTM-D-1418-64 and refers to a terpolymer of ethylene, propylene, and diene monomers. Examples of methods for making such terpolymers are found in U.S. Patent No. 3,280,082 and British Patent No. 1,030,289. A preferred terpolymer is about 40-80% by weight ethylene and about 1% by weight ethylene.
- Contains 10% diene and propylene balances the terpolymer.

The preferred diene monomers used to form the EPDM terpolymer are non-conjugated dienes. Examples of non-conjugated dienes that may be used are dicyclopentadiene, alkyldicyclopentadiene, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-hebutashene,
2-methyl-1,5-hexadiene, cyclooctadiene, 1,4-octadiene, 1,7-octadiene, 5
-ethylidene-2-norbornene, 5-n-propylidene-2-norbornene, 5-(2-methyl-2-butenyl)-2-norbornene.

Rubbers containing acid groups that may be used include carboxylated rubbers and sulfonated rubbers. Suitable carboxylated rubbers are carboxylated styrene-butadiene rubber, carboxylated polybutadiene rubber and carboxylated nitrile rubber. Suitable sulfonated rubbers are sulfonated styrene-butadiene rubber and sulfonated EPDM rubber. Rubbers containing such acid groups and methods of making them are known in the art. According to it,
For example, carboxylated styrene-butadiene rubber or carboxylated nitrile rubber can be prepared by copolymerizing butadiene and styrene or butadiene and acrylonitrile with an unsaturated acid such as methacrylic acid in an acidic medium. Alternatively, carboxylated rubber can be prepared by copolymerizing butadiene and styrene or butadiene and acrylonitrile with an acrylate or methacrylate ester, such as an alkyl acrylate or alkyl methacrylate, and then hydrolyzing the acrylate or methacrylate ester by heating in an alkaline solution. It can be produced by converting it into an acid. Sulfonated rubbers, such as sulfonated EPDM or sulfonated SBR, can be prepared from EPDM or SBR using a sulfonating agent selected from a sulfur trioxide donor and a complex of Lewis base, acetyl sulfate, propionyl sulfate, and hyptyl sulfate.
It can be produced by sulfonating.

The procedure is described in U.S. Patent No. 3,642.728 and 3°836.511.

As previously indicated, another example of a colored rubber component prior to completion of crosslinking includes a rubber containing neutralized acid groups and a covalent crosslinking agent that generates free radicals.

Neutralized: Rubbers containing acid groups may be, and are preferably, neutralized versions of the carboxylated and sulfonated rubbers described above. Therefore, neutralized carboxylated styrene-butadiene rubber, neutralized carboxylated polybutadiene rubber, neutralized carboxylated nitrile rubber, etc. are used. These can be prepared in known manner by neutralizing the carboxylated rubber with a suitable base, preferably an inorganic metal salt such as zinc oxide, magnesium oxide or mixtures thereof. Neutralized sulfonated rubbers that may be used include neutralized sulfonated styrene-butadiene and neutralized sulfonated EPDM rubber.

These are known methods, and the above-mentioned U., S. patent 3
．． 642.728 and 3,836,511, the sulfonated rubber is treated with a suitable basic compound, preferably I, It, ■, ■, ■, V of the Periodic Table of the Elements.
It can be produced by neutralizing with 122.3 or tetravalent ions of metals 1-B, 2-B and 2.

The preferred rubber for use in the colored tire material of the present invention is a mixture of chlorobutyl rubber, natural rubber and EPDM. The amount of each rubber used in the mixture can vary somewhat. Thus, the mixture of rubbers includes about 45-50 parts by weight chlorobutyl rubber, about 30-45 parts by weight natural rubber, and about 10-20 parts by weight EPDM. As previously indicated, the colored rubber component prior to crosslinking includes an ionic crosslinking agent selected from the group consisting of metal salts and inorganic metal salts of carboxylic acids.

Suitable metal salts of carboxylic acids include metal salts of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, etc., with metal salts of methacrylic acid (ie, metal methacrylates) being preferred.

Metal methacrylates that may be used include aluminum trimethacrylate, calcium dimethacrylate, magnesium dimethacrylate, and zinc dimethacrylate. A preferred metal dimethacrylate is zinc dimethacrylate.

Metal methacrylates can be produced by known methods.

Generally, metal methacrylates are prepared by combining metal oxide and methacrylic acid in a liquid medium (e.g., water or a volatile organic liquid such as a liquid hydrocarbon) from 0.5 to 0.6 moles of metal oxide per mole of methacrylic acid. , and the resulting metal dimethacrylate product is recovered from the liquid medium and dried. A preferred method for preparing zinc dimethacrylate is to combine zinc oxide and methacrylic acid in a liquid aliphatic hydrocarbon (preferably an alkane, especially hexane) at a concentration of about 0 zinc oxide per mole of methacrylic acid.
．． A method is described in U.S. Pat. I quoted it.

The amount of metal methacrylate used in the colored rubber component depends on how much ionic crosslinking is required and whether the metal methacrylate is used solely to introduce ionic crosslinking or with the ionic crosslinking agent and filler. This will vary considerably depending on a number of factors, including whether it is preferred to use a combination of agents or reinforcing agents herein. When metal methacrylate is used as a combination of an ionic crosslinking agent and a filler, it can be used alone as a filler, or it can be used as a partial substitute for traditional fillers such as clay or beads. I can do things. Generally, the amount of metal methacrylate in the component can range from about 5 to 70 parts by weight per 100 parts by weight of rubber or rubber mixture, with higher amounts (e.g. 40 parts by weight) when metal methacrylate is used as the only filler. above) are used. However, preferred amounts of metal methacrylate range from about 5 to 50 parts by weight, and particularly preferred from 5 to 25 parts by weight, per 100 parts by weight of rubber.

Inorganic metal salts that may be used as ionically binding crosslinking agents include those mentioned above in connection with rubbers containing acid groups. Preferred inorganic metal salts are therefore zinc oxide, magnesium oxide and mixtures thereof. The amount of inorganic metal salt used depends on the concentration of acid groups in the rubber, the degree of ionic crosslinking required, etc. Generally, the inorganic metal salt is used in an amount of about 1 to 20 parts by weight, preferably 2 to 10 parts by weight, per 100 parts by weight of the rubber containing acid groups.

As indicated above, the colored rubber component prior to crosslinking also includes a covalent crosslinking agent that generates free radicals. Preferred covalent crosslinkers that generate free radicals are peroxide crosslinkers.

Peroxide crosslinkers that may be used include dicumyl peroquinde, bis-([-butylperoxy)diisopropylbenzene, t-butyl berbenzoate, di-L-butyl peroxide, 2,5-dimethyl-2,5-di -Including organic peroxides such as t-butylperoxyhexane. Preferred peroxide crosslinkers are bis-(t-butylperoxy)diisopropylbenzene and dicumyl peroxide.

The amount of peroxide crosslinker used in the colored rubber component is widely referred to as the vulcanizing effective amount. Generally it is rubber 10
per 0 parts by weight of peroxide. Preferred amounts of peroxide range from about 0.8 to 1.5 parts by weight per 100 parts of rubber.

As previously indicated, the present invention is for colored tire materials other than black tire materials. Colored tire materials can be produced by mixing various coloring pigments and dyes into rubber components or mixtures.

Therefore, blank white tire materials, such as white sidewalls and white embossed letters, can be produced by incorporating white pigments such as titanium oxide, zinc oxide, and oxidized aluminum into rubber compounds. Other colored tire materials can be made by incorporating various inorganic and organic pigments or dyes into the rubber compound. Typical of such pigments or dyes are Harwi
CK Chemical Corporation under the name Stan-Tone MB Colors.

Examples of pigments and dyes other than black and black that may be used for the production of colored tire materials are the following pigments and dyes, identified by both pigment type and color index designation (hereinafter referred to as C, I): Among them, phthalocyanine NC (C,1,
PB-15: 1), Phthalocyanine R5 (C,1,
Blue pigments such as PB-15); diarylide AAOT (
C,1,PY-14), diarylide AAA (C,I
, PY-12); thioindigo (C,
1, PR-88), Red 2B, CA 5al
Red pigments such as t(C,1,,PR-48:2), phthalo/anine BS(C,1,PC-7), phthalonanine Y
S (C.

1, PG-7) and other green pigments: Virazolone (C.

1, PO-13), ginseng (C, 1, PO-16)
) and brown pigments such as iron oxide, light (C, 1, PB-7), and iron oxide, dark (C, 1, PB-7). Examples of dyes suitable for use are Seriton Yellow, Seriton Orange, Golden Yellow, Goalten Orange 11 Seriton Violet R1 Oil Orange,
These include Para Red, Ceritosol ST, Yellow AB, Brown V1 Seriton Fast Yellow, Soutasengrin, and Sudan Yellow. All of the above special dyes are from The Chemistry of 5ynt
heticDyes and PigmentsXH,
A, Tubs, Re1nhold.

1955, for example. This book lists a number of pigments and dyes that may be used in the production of colored rubber components, along with color indexes.

Colored rubber mixtures contain, in addition to the rubber, crosslinking agents and colored pigments or dyes, the conventional additives normally used in such mixtures, such as non-black fillers such as clays, grates, silicates, and non-pigmented processes. Processing aids such as zinc stearate, sodium dodenyl sulfate, etc.: adhesive resin, plasticizer, non-oxidizing agent, non-ozonating agent, wax, vulcanization accelerator, zinc oxide, stearic acid, U, V, Contains stabilizers, etc. These additives are used in amounts conventionally used for such compounds.

Colored rubber mixtures are generally prepared by mixing the ingredients on a mill. The compound is shaped into the desired dimensions by rolling out a plate from a mill, calendering, or extruding.

The following examples are presented to further illustrate the features of the invention, but are not intended to limit the scope of the invention. Parts and percentages referred to in the examples and throughout the specification are by weight unless otherwise indicated.

The amount of ionic and covalent crosslinks introduced into the rubber in the examples was determined by the following procedure.

Samples of each raw material were vulcanized for 20 minutes under 328°C.

Cut the vulcanized sample into strips, and half of them are divided into THE and H.
, O (80/20) at 50°C for 21 days. Thereafter, the extracted sample was thoroughly dried in a vacuum oven at 50°C until it reached a constant weight. (This extraction method removes oils, waxes, and other low molecular weight components)
. The dry sample was then tested for stress-strain properties,
Application - Crosslink density was calculated from the initial slope of the strain curve.

The other half of the vulcanized strip was prepared using THF/H20/HCL (
80/20/2) at 50°C for 21 days. The extracted samples were then placed in a vacuum oven at 50°.
It was sufficiently dried at C until it reached a constant weight. (This extraction method removes oils, waxes, other low molecular weight components, and zinc salt crosslinks (ionic crosslinks)). The dried samples were tested for stress-strain properties, and again the crosslink density was calculated from the initial slope of the stress-strain curve. The difference in crosslink density from the first and second extractions is taken as the amount of ionic crosslink density in the sample.

Examples 1-2 In these examples, white sidewall materials according to the invention were evaluated for appearance and abrasion resistance. For comparison, a conventional white sidewall material was also included as a standard in the evaluation.

The white sidewall material has the following composition: Experiment Number Ingredients Chlorobutyl Rubber (1) Natural Rubber EPDM” Titanium Dioxide Hard Clay Magnesium Silicate Zinc Dimethacrylate Ultramarine Blue Stearic Acid Wax Process Oil Zinc Stearate Nonylphenol Aldehyde Zinc Oxide Partac # 533 Haruki Nosoku ZMB-2"' Balkamp 40KE"Sulfur Altax"" Total standard weight part 50.00 30.00 20.00 35.00 22.00 23.00 0.60 1.00 2.50 3 .00 50 ,00 30.00 20.00 20 ,00 27.00 28.00 11.00 0.60 1.00 2.50 3.00 Satoshi, 00 50.00 30.00 20.00 25.00 27.00 28.00 6.00 0.60 1.00 2.50 3.00 2.00 2.00 12.00 1.25 1.00 5.00 1.25 1.00 1.25 1. 25 1.00 1.25 0.50 0.75 1,25 1.25 204.60 204.85 204.85 (1) E
Chlorobutyl rubber obtained from xxon Chemical Company under the name Exxon 1066 with a chlorine content of 1.1 to 1.3%, Moone
y viscosity, ML/(1+8)/100°C is 51-60
It is.

(2) Un1royal Chemical
Px tyrene/propylene/dicyclopentadiene terpolymer obtained from Company, with an ethylene:propylene ratio of 68:32 and containing 3% dicyclopentadiene, a Tg of -69°C, a specific gravity of 0.865, Moone
y viscosity, ML/4/125°C1 is 42.

(3) Alkylphenol disulfide on an inert support obtained from PennWalt.

(4) Zinc-4,5-dimethylbenzimidazole (5
) 40% bis-(t-butylperoquino)diisopropylbenzene on a clay carrier.

(6) Benzothiazyl Disulfide The above mixture was prepared using conventional mill mixing procedures with the ingredients on a mill. The difference in color between the standard and experimental mixtures is
Spread the sample of each mixture into a plate shape, and spread the spread mixture to 32"
The color of each mixture was determined by visual observation after vulcanization at F' for 20 minutes. The abrasion resistance of each mixture was determined by vulcanizing a sample of the mixture at 320″F″ for 25 minutes and performing a PicO abrasion test using the Post-Pico abrasion test following the procedure set forth in ASTM D2228-83. Decided. The results are shown in Table ■.

Table 1 Experiment number Crosslinking, % Ionic bond Covalent bond Appearance Pico Abrasion Volume loss Pico ratio Standard 12 Standard white White 0.0395 0.0220 0.0200 +00 Color stability against ultraviolet light using the following procedure for the above mixture First, a 6″ x 6 #X0-050″ sheet of test white sidewall was divided into three sections, namely 6″ 6″
A 6" x 6" x 0100" board was prepared by overlaying a sheet of black sidewall material measuring 0.050" x 0.050". A total of four boards were prepared: two boards with the standard white sidewall as the top sheet and two boards with the white sidewall material of Example 1 as the top sheet. The boards were each cured for 20 minutes at 320"F'. The boards were then cut and the top white sidewall material was separated from the bottom black sidewall material containing all three sections (i.e. contaminated, uncontaminated and contaminated black sidewalls). Make 1″ x 6″ strips that touch.

The test strip is then placed under a rotating table under an ultraviolet lamp and air is blown over the strip. Cover the strip and expose the other parts to the light.

The test strips were visually inspected for discoloration 22 hours after exposure to ultraviolet light. The test strip of standard white sidewall material had discoloration on the contaminated black sidewall material and a slight yellowing on the uncontaminated black sidewall material. The test strip of the white sidewall material of Example 1 showed only slight discoloration on the contaminated black sidewall material and no discoloration on the uncontaminated black sidewall material.

Exposure of the test strip to ultraviolet light continued for an additional 120.5 hours for a total of 142.5 hours. Examination of the standard white sidewall material test strip revealed that the area on the contaminated black sidewall material had a brownish color and the area on the uncontaminated black sidewall material had a distinct yellow color. In contrast, when examining the test strip of the white sidewall material of Example 1, it was found that the area on the contaminated black sidewall material was a light brown color and the area on the uncontaminated black sidewall material was only slightly or pale yellow. Ta.

The standard white sidewall material and the white sidewall material of Example 1 were also evaluated for curb scratch resistance. This is P195/75
A steel radial tire with a white sidewall of R14 size was prepared, and a test was conducted to prevent the tire from hitting a curb.

The curb hit test was performed as follows: each tire was placed in a 14 x 5.5 inch frame, inflated to 30 psi, and mounted on a Chevrolet Celebrit car.
I attached it to the right front wheel of Y. The front right tire of the vehicle remained in contact with the curb at all times while traveling at relatively slow speeds (i.e., 10-15 mph) such that the white sidewall remained in contact with the surface of the curb. During the test, the white sidewall portion of the tire was visually observed and the number of rotations of the tire was continuously counted. A tire is considered to have passed the test if the white sidewall portion shows only slight wear after the tire contacts the curb surface for 50 revolutions.

The results of the curb scratch test were as follows: (a) Tire with standard white sidewall material When the tire rotated 30 times, wear began to appear on the outer edge of the white sidewall. At 50 revolutions, the outer edge of the white sidewall was severely worn, with some areas being worn down to the black material below the white sidewall. This tire does not pass the curb-slip test.

(b) Tire with the experimental white sidewall material of Example 1 After 30 rotations, the tire appeared good with little or no indication of white sidewall wear. After 50 revolutions, there was only slight wear on the outer edges of the white sidewalls. This experimental white sidewall tire therefore passes the curb rub test.

As clearly seen in this test, the experimental white sidewall according to the invention has greatly improved abrasion resistance compared to the standard white sidewall, and the test results compare favorably with those of the Pico abrasion test in the laboratory. Match.

Example 3 - These examples illustrate another white sidewall material according to the present invention. For comparison, a conventional white sidewall material is also included as standard.

The white sidewall material has the following composition: Experiment no.
Enoki! Ingredients Chlorobutyl rubber 50,00 Natural rubber 30.00 EPDM rubber 20.00 Titanium dioxide 35.00 Hard viscosity 22.00 Magnesium silicate 23.00 Zinc dimethyl methacrylate Ultramarine blue 0.60 Stearic acid 1.00 Wax 2.50 Oil 3.00 Nonylphenol 2.00 Formaldehyde 5 (LOO 30,00 20,00 35,00 22,00 50,00 30,00 20,00 35,00 5 (COO 30,00 20,00 35,00 50 ,00 30,00 20,00 35,00 22,00 23,0023,0045,0030,000,60 1,00 2,50 3,00 0,60 1,00 2,50 3,00 0,60 1 ,00 2,50 3,00 0,60 1,00 2,50 3,00 Zinc stearate Zinc oxide Partac #2 2.00 2.00 2.00 2.0012.
00 5.00 5.00 5.00 5.0
01.25 1.25 1.25 125 1
．． 25 Balkiknox ZMB-2 Altax sulfur total 1.00 0.75 0.50 204 , 60 1.00 1.00 1.00 1.00 197.60 197.15 182.60 The above mixture is Example 1 Mix according to the procedure of Mo.

The ny viscosity (ML/4/10o0c) was measured before vulcanization and various properties were tested including stress-strain and anti-abrasion properties. Test conditions and results are shown in Table H.

Table■ Experiment number ＄3 4 5 crosslinking,
% Ionic binding ~-1 ND ND
ND covalent bond I QQ //
// //ML/4/100°0 4
0.2 38.6 38.1 33.8 Curing crack, room temperature (vulcanization: at 20'328"F) 50% modulus, psi 230 260 3
00 265 100% Modulus, psi 395
560 635 535200% modulus,
psi 660 1175 1150 109
5300% modulus, psi 885 1650
1485 1550 tensile strength, psi
1200 1690 1485 1570 Elongation at break% 420 310 300 30
0 Pico abrasion (vulcanization: below 25' 320) Weight loss 0.0650 0.0396 0
．． 0399 0.0475 Volume loss 0.
0480 0.031 0.031 0.039Pic
o ratio 100 154 154 1
23 Examples 7-8 containing both ionic and covalent cross-linking with no specific valency determined These examples also contain dime-ND as the only filler Figure 2 shows a white sidewall material according to the invention containing only zinc taacrylate. The white side wall material has the following composition.
0 Natural rubber 45-00 30.
00EPDM rubber 10.00 20
．． 00 Titanium dioxide 35.00 35
．． 00 Zinc dimethacrylate 50.00 30
．． 00 Zinc oxide 5,00 5.
00 oil 4.5
0 4.50 wax 1.0
0 1.00 Sodium dodecyl sulfate 2,00
2.00 Ultramarine Blue o, ao
o, a.

Pal Cup 40KE 1.25 0.
80 Partak #5' 1.25
1.25 total 200.60 1
80.15 E xxon Chemical C
Chlorobutyl rubber obtained from Company under the name Exxon 1068 with chlorine content 1.1-1.3%
and Mooney viscosity, ML/(1+8)/127°
C1 is 50-60.

The mixture was mixed according to the procedure of Example 1, vulcanized, determined for proportion of ionic and covalent crosslinks, and tested for ring tear and Pico abrasion.

For comparison, samples of the standard white sidewall material described above were also vulcanized and tested for the same properties. The test conditions and test results are shown in Table ■.

Table■ Experiment number Crosslinking, % ionic binding covalent nature ring tier (Vulcanized, under 10' 328) 100℃ 150°C Pico abrasion (Vulcanization: at 25'320''F) volume loss Pico ratio Standard 78 0.074 0.032 0.047 The main features and aspects of the invention are as follows.

1. A colored tire material with improved abrasion resistance, color and color stability consisting of a crosslinked colored rubber composition containing 10-90% ionic crosslinking and 90-10% covalent crosslinking caused by free radicals. .

2. The colored tire material according to claim 1, wherein the colored rubber composition before crosslinking is composed of a rubber capable of ionic bonding and covalent bonding crosslinking; a metal salt of carboxylic acid and an inorganic metal salt. consisting of an ionic crosslinking agent selected from the group and a covalent crosslinking agent that generates free radicals.

3. The colored tire material described in the preceding item, in which the rubber is selected from the group consisting of saturated rubber, unsaturated rubber, rubber containing acid groups, and mixtures thereof.

4. The colored tire material described in the preceding item is selected from the group consisting of the aforementioned saturated rubber, hydrogenated styrene-butadiene rubber, hydrogenated polybutadiene rubber, butyl rubber, and hydrogenated butyl rubber.

5. The colored tire material according to item 3, wherein the unsaturated rubber is selected from the group consisting of natural rubber, styrene-butadiene rubber, polybutadiene rubber, ethylene/propylene/diene monomer ternary polymergo, and mixtures thereof. What you have.

6. The colored tire material according to item 3, wherein the acid group-containing rubber is selected from the group consisting of carboxylated rubber and sulfonated rubber.

7. The colored tire material described in the preceding item, wherein the carboxylated rubber is selected from the group consisting of carboxylated styrene-butadiene rubber, carboxylated polybutadiene rubber, and carboxylated nitrile rubber.

8. The colored tire material according to item 6, wherein the sulfonated rubber is selected from the group consisting of sulfonated styrene-butadiene rubber and sulfonated ethylene/propylene/diene monomer terpolymer rubber.

9. The colored tire material according to item 2, wherein the ionic bonding crosslinking agent is a metal salt of carboxylic acid.

10. The colored tire material described in the preceding item, wherein the ionic bonding crosslinking agent is a metal methacrylate.

11. The colored tire material described in the preceding item, wherein the metal methacrylate is selected from the group consisting of aluminum trimethacrylate, calcium dimethacrylate, magnesium dimethacrylate, and zinc dimethacrylate.

12. The colored tire material according to item 2, wherein the ionic bonding crosslinking agent is an inorganic metal salt.

13. The colored tire material described in the preceding section, wherein the inorganic metal salt is a metal oxide.

14. The colored tire material described in the preceding item, wherein the metal oxide is selected from the group consisting of zinc oxide, magnesium oxide, and mixtures thereof.

15. The colored tire material according to item 2, wherein the covalent crosslinking agent that generates free radicals is a peroxide crosslinking agent.

16. The colored tire material described in the preceding paragraph, wherein the peroxide crosslinking agent is bis-(t-butylperoxy)diisopropylbenzene.

17. The colored tire material according to claim 1, wherein the colored tire material is a colored sidewall tire material.

18. The colored tire material described in the preceding item, wherein the colored sidewall tire material is a white sidewall tire material.

19. The colored tire material according to item 2, wherein the colored rubber composition is a white sidewall rubber composition.

Claims (1)

[Claims] 1. A colored tire material with improved wear resistance, color and color stability, consisting of a crosslinked colored rubber composition containing 10-90% ionic crosslinking and 90-10% covalent crosslinking caused by free radicals. .