WO1988009355A1

WO1988009355A1 - Pneumatic tire

Info

Publication number: WO1988009355A1
Application number: PCT/JP1988/000471
Authority: WO
Inventors: Michio Itoh; Hisao Yamamoto; Nobuyuki Okamura
Original assignee: Bridgestone Corporation
Priority date: 1987-05-19
Filing date: 1988-05-18
Publication date: 1988-12-01
Also published as: DE3890400C2; DE3890400T1

Abstract

A pneumatic tire for high-speed running, which has a greatly improved grip of road surface without serious reduction in heat resistance, particularly blow-out resistance and abrasion resistance, and which is characterized by using a tread made from a rubber composition prepared by incorporating 2.5 to 20.0 parts by weight of a phenolic compound having at least one t-butyl group in 2- or 6-position and a sum of 85 to 200 parts by weight of carbon black having a nitrogen adsorption specific surface area of 110 to 190 m2/g and a dibutyl phthalate absorbtion of 100 to 140 ml/100 g and a softening agent, per 100 parts by weight of a synthetic rubber or blend of a synthetic rubber and a natural rubber.

Description

TECHNICAL FIELD The present invention relates to a pneumatic tire, and more particularly, to a tire that can improve gripping property without significantly impairing heat resistance, particularly blowability. It is suitable for pneumatic high-speed traveling tires that use a rubber composition for reds. Background Technology-Recently, rubber products have become more and more demanding to use. In particular, this tendency has become more noticeable with vehicle tires as automobile performance is improved, roads are paved, and highway networks are improved.Therefore, air with high maneuverability, especially high grip performance The demand for entering tires has increased. The grip performance is an important required characteristic represented by acceleration / deceleration performance and turning performance. The higher these characteristics, the faster and more accurate the vehicle can travel.

Conventionally, in order to obtain a high grip performance, a rubber having a high glass transition temperature such as a styrene-butadiene copolymer rubber having a high styrene content is selected as a composition for a tire rubber. Alternatively, the dynamic loss coefficient ta n δ of the rubber composition should be selected by selecting a compounding system with a high filling of carbon black or process oil. It was necessary to increase the value.

In addition, Japanese Patent Laid-Open Publication No. 59-18701 discloses a monomer such as 1.3-butadiene, styrene, or isoprene, and diphenyl 2-isomethacrylate. Tylphosphine diphenyl. 2 —acryloyloxyxylyl phosphate, etc. An acrylic or methacrylic group bearing a diphenylphosphite group. It is described to use a copolymer rubber obtained by copolymerization with a mono-compound. However, if the styrene content of the styrene-butadiene copolymer that is added to the composition for threaded rubber in order to obtain high grip performance is increased, it is certain that the dull performance is temporarily improved. However, there was a problem that the tan 5 value decreased as the temperature of the rubber increased due to tire running, resulting in a sharp drop in damp performance.

In addition, when a compound system with a high filling of carbon black or process oil is selected, the grip performance is improved, but due to such high filling, the heat resistance of the rubber at high temperature, for example, blowability, is improved. There was a problem of a significant decrease. Furthermore, the method described in Japanese Patent Laid-Open No. 59-18701, which prevents the deterioration of the grip performance due to the above-mentioned temperature rise, is not applicable to natural rubber, and the manufacturing conditions Therefore, there has been a problem that the properties of the polymer ', for example, styrene-butadiene copolymer rubber and polybutadiene, are impaired.

On the other hand, a phenol compound has been used as an anti-aging agent, which is one of the rubber compounding agents, and it has been used in 2 or 6 positions. In addition, a phenol compound having a butyl group is also used as an antioxidant, but as an antioxidant, 1 part by weight or less, and at most 1.5 parts by weight or less per 100 parts by weight of the rubber component is used. Only a small amount has been used.

The purpose of the present invention is to increase the styrene-content of the styrene-butadiene copolymer and to improve the grip performance without high filling of carbon black or process oil. It is an object of the present invention to provide a pneumatic tire using a rubber composition for a track, which can be improved and which does not impair the heat resistance and the performance originally possessed by the polymer. DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, have found that a fueno containing a t-butyl group at the 2 or 6 position, which is known as a phenol-type anti-aging agent. The rubber compound was added to the rubber composition in a much larger amount than the compounding amount of 1.5% by weight or less, which is used for the purpose of preventing aging. The inventors have found that the performance is improved and have completed the present invention. -

That is, the present invention is based on a blend of synthetic rubber or synthetic rubber and natural rubber, preferably 100 parts by weight of a rubber component having 70% or more synthetic rubber, and at least one t-position at the 2 or 6 position. 2.5 to 20.0 parts by weight, preferably 5 to 10 parts by weight, of a phenol compound having a butyl group, and a nitrogen adsorption specific surface area of 110 to 190 m ² / j, preferably 110 to 150 m ² / g, dibutylf Tale oil absorption 100-140 / 100g. Preferably, a rubber composition containing 100-125 ZlOOg of carbon black and a softening agent in a total amount of 85-200 parts by weight is used. The present invention relates to a pneumatic tire characterized by being used for a rat. BEST MODE FOR CARRYING OUT THE INVENTION Examples of the phenol compound having at least one t-butyl group at the 2 or 6 position used in the present invention include 2,2-methylene-1-bis (4-methyl 6- t-Butylphenol), 2,2'-methyl bis (4 1-ethyl-6-t-butylphenol), 4, 1-butylidene-bis (3-methyl-6-t — Butylphenol), 4,4'-thiobis-one (3-methynole 6-t-butynolephenol), 2,5-di-di-t-butylhydroquinone, 2, 6-di-t-butyl-i 4-Methylphenol, 4,4'-methylphenol (2, 6-di-t-butylphenol), 4,4'-methylbis (2-methanolole 6-t-) There are two types, such as Petil-Fruinol, 2,2-Chibis (4-Methyl-6-t-Putilyl-nor).

Among these compounds, especially the following formula,

(H ₃ C) C (CH ₃ )

(Wherein R ¹ and R ² in the formula each independently represent a methyl group or an ethyl group), more specifically, a compound represented by the following formula:

2,2 ′ represented by C ₂ H: C _Z H: — methylethylenebis (4 1 ethyl 1 6 — t 1 pettyl phenol), the following formula,

(H ₃ C) ₃ C (CH ₃ ) 3

2,2'-methyl bis (4 1-methyl-1 6-t 1-butylphenol) represented by is preferred.

The phenyl compound used in the present invention has the following formula having an acrylate group or a methacrylic group in it.

(Wherein R ³ and R ⁴ are each independently a methyl group, an ethyl group or an isopropyl group, and A is an acryloyl group or a methacryloyl group). For example, as such a compound, 2 —V—Putyl 6 — (3 ′ ― t —Putyl 5 ′ —Methyl 2 ′ —Hydroxylbenzyl) 1 4 —Methyl ヱ, Nilcrylate 2 — t — Butyl 6 — (3 '— t — Butyl 5 ′ — Methyl 1 2 ′ — Hydroxybenzyl) 1 4 — Methylphenylmethacrylate, 2 — t — Butyl 6-(3't-Butyl-5'-Ethyl2'-hydroxylbenzyl) 1 4-Ethylphenyl acrylate, 2-t -Butyl 6-(3 '— t -Butyl 1 5'-Isopropil-2' — Hydroxybenzyl) 1 4 — Isopropinophenenyl acrylate, etc. Particularly preferred of these are 2-t-butyl-6- (3'-t-butyl-5 ', methylzole-2'-hydroxylbenzyl-1,4-methylphenylenezoleate, etc. R ³ and R ⁴ in the formula are methyl groups.

All of the above-mentioned phenolic compounds are already known as funel-type antiaging agents, but as an antiaging agent, they are usually used in an amount of 1.0% by weight or less, and at most 1.5% by weight or less. It's just that.

In the present invention, a phenol compound having at least one t-butyl group at the 2 or 6 position is added to 100 parts by weight of rubber 2. It is required to blend in 5 parts by weight or more, but the reason is that if the amount is less than 2.5 parts by weight, the effect of improving the dull performance is not recognized. On the other hand, if the content is more than 20.0 parts by weight, This deteriorates the blowability of the lead rubber, making it unsuitable for high-speed continuous driving.

Among the various phenolic compounds, the ones that have at least one t-butyl group at the 2 or 6 position were used as the phenolic compounds. This is because this compound is the most excellent in improving the dulling property, and also because this compound is used as a heat resistant anti-aging agent and is easily available.

The carbon black used in the present invention has a nitrogen adsorption specific surface area of 110 to 190 m ² / g and a dibutyl phthalate oil absorption amount of 100 to 140 Z l OOg. It's a check. This is because the rubber composition used in tire tires has a large specific surface area, requires a reinforcing material with a well-developed structure, and requires a carbon braid. This is because the total amount of rubber and softening agent is 85 to 200 parts by weight, and wear resistance cannot be maintained unless a high-strength force bomber is used.

As the softening agent, aroma oil suitable for styrene-butadiene copolymer rubber, paraffin wax suitable for non-polar rubber, other pintals, tall oil and the like can be used.

The relationship between carbon black and the amount of softener

-10 ≤ (parts by weight of one bomb)

I (Parts by weight of softener) ^ 35

I like that. This is because if the value of this intermediate term is more negative than 10, wear resistance will decrease, and if it exceeds 35, grip property will decrease, which is not desirable in any case. In the rubber composition used for the tire tire of the present invention, in addition to these compounding agents, sulfur as a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerating aid, and an amine antiaging agent. As a matter of course, it is possible to appropriately mix the above. -

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

The following tests were conducted on each rubber composition having the compounding ratio (parts by weight) shown in Table 1 below.

¾ method

(1) Blowout temperature

A vulcanized rubber sample of the test rubber composition having a size of about 7 mm x 7 mm x 3.5 mm was placed in an electric crucible furnace (manufactured by Chair Co., Ltd.) at a temperature of 20 (300 'at 5'C intervals from TC). While raising it to C, it was left for about 20 minutes at each temperature and then taken out, cut into half, and visually confirmed whether bubbles were generated inside,

(2) Road grip property index ―

The road surface grip performance was evaluated by an actual vehicle test for each tire composed of the tested rubber composition as a thread rubber. The road gripping property was expressed as an index by driving the actual vehicle on a circular circuit consisting of straight and curved roads on a dry road surface, and rating the gripping property on the basis of the feeling. The larger the index, the better the grip property.

(3) Wear test ''

Evaluated with a pico abrasion tester,

Abrasion amount of compounded rubber of Conventional Example 1

Wear resistance index = ―: X 100

Wear of control compounded rubber It showed with. The larger the index, the better the abrasion resistance.

The results obtained are also shown in Table 1. one

table

Conventional Example 1 Example 1 Example 2 Example 3 Example 4 Example 4 Example 5 Example 6 Example 7

Styrene butadiene rubber

137. 5 137.5 137.5 5 137,5 137.5 137,5 137.5 137,5

(SBR 1712) * 1

Taka styrene butadiene rubber ― ― ― ―

(SBR 0120) * 1

Low styrene butadiene rubber

One-one- '

(SB 0115) * 1

Natural gum ― ― ―

Rikiichi Bon Black (N110) * 2 ― ― ― ― ― ―

Carbon black (N220) * 2 90 90 90 90 90 90 90 90

Aroma oil 32 32 32 32 32 32 32 32

Stearic acid 1,0 1,0 1.0 1.0 1.0 1.0 1.0 1,0

Noraffin wax 1.0 1,0 1.0 1.0 1,0 1,0 1.0 1.0

Platinum flower 3.0 3,0 3.0 3.0 3,0 3.0 3.0 3,0

Anti-aging agent * 3 1, 0 1,0 1.0 1.0 1.0 L0 1.0 1.0

Vulcanization accelerator * 4 0.2 0.2 0.2 0.2 0,2 0.2 0.2 0.2

Vulcanization accelerator * 5 L4 1.4 1.4 1.4 1.4 L4 1.4 1,4 o Sulfur yellow L5 1.5 L5 1.5 1.5 L5 1.5 1.5

Off _Λ Nord-based compounds * 6 2.75 5.0 10.0 15.0

Phenol compounds * 7 5.0

Phenolic compounds * 8, _, ― ― ― 5.0 ―

Phenol compounds * 9 5.0

Fluorine compound * 10

Blowout temperature CC) 270 268 265 260 238 263 264 264

Road surface drip index 100 103 110 115 113 111 110 110

Abrasion resistance index 100 100 100 100 97

* 4 Diphenylazine * 5 "Dibenzothiazyl disulfide

* 6 2, 2'-methylene bis (4-methyl-1- 6-t-butylphenol)

* 7 2, 2'-methylenebis (4-ethyl-6-t-butylpheno)

* 8 4, 4'-butylidene bis (3-methyl-6-t-butylphenol)

* 9 4, 4'-thiobis (3-methyl-6-t-butylphenol)

In Table 1, Conventional Example 1 is a conventional example which does not contain the phenol compound of the present invention, and Comparative Example 1 is an example in which the total amount of the carbon black and the softening agent is less than 85 parts by weight.

In Examples 1 to 2, when -75, 5.0, 10.0, 15.0 parts by weight of --2,2'-methylene bis (4-methyl-l-t-butylphenol) was added, 100 parts by weight of the rubber component was added. When calculated as the above, 2.0, 3.6, 7.3, and 10.9% by weight are applied, respectively. Examples 5 to 8 are examples in which the phenol compound was changed and the same amount was used.Example 9 is an example in which a high styrene butadiene rubber was blended with SBR 1712, and Example 10 was a low amount in SBR 1712. An example in which styrene-butadiene rubber is compounded, Example 11 is an example in which the force-one black is changed to N110, and Example 12 is an example in which the carbon black and the softening agent are highly compounded. Then, the phenolic compound is the same as in Example 2. Example 13 and Comparative Example 2 are examples in which a blend type of synthetic rubber and natural rubber was used as the rubber component, but Comparative Example 2 did not include the phenol compound. As is clear from the results of the tests in Table 1, the rubber composition for tires according to the present invention shows that the road surface grip performance can be maintained without significantly impairing the plot temperature and the wear resistance. Is improved by 5 to 15%.

Next, the blowout temperature was measured according to the above-mentioned test method using each rubber composition having the compounding ratio (parts by weight) shown in Table 2 below.

Further, with respect to each tire configured with these rubber compositions as a thread rubber, Comparative Example 2 was controlled according to the above test method, and the road surface dull performance was evaluated by an actual vehicle test. The results obtained are also shown in Table 2.

Toto Yanagi 9 腳 ill 5 Application ιΠβ Ma 'Example 17 Example 18

Q n 1 7 1 1Q7 "ϊ 1Q 1375 1375 1375 1375 'Sof,' (Ki99 (\) on qn qn qn Qfl qn qn 90 90 Ile ϋ wm Q 32 32 32 32 Styrene lysoic acid >> 'Re 1 o 10 1 o 1 0 10 hoop 1 fi w 1 fi 1 Ω

m M Q 0 3 o Q 0 30 3 o 30 3 o 3 o

* ^ Bftih ¾l 1 1 fi 1 0 10 1 o 1 o 1 fl 10 10 Vulcanization standard: ¾ | 1 fi 1 R 1 R 1 R 1 fi 1 6 16

■ 1 5 1 5 1 5 15 15 15 15》 —ASiii * Q 5 fi in Ω

Fenoichinore * 4 5.0

Funnel compounds * 5 5.0

Funnel compounds * 6 5.0

Resolecin 5.0 Outer temperature C) 270 270 265 265 260 215 265 265 265 235 Road surface grit (index) 100 100 111 125 133 161 127 125 125 105

* 1 N—Cyclohexyl-1 N ′ —Fenylene p—Furen diamine

* 2 Jiff ;! A mixture of 0.2 parts by weight of urguanidin and 1.4 parts of shrimp dibenzothiazyl disulfide

* 3 2—t—Putyrup 6— (3 ′ —t—Putyrup 5 ′ —Methyl—2 ′ —Hydroxybenzyl) —4—Methyl-fruyl Atarilate * 4 2—t—Butyl 1 6— (3 ′ 1 t— Butyl-1 5'-methyl-1 2'-methylhydroxybenzyl) 1-41-methylphenyl methacrylate * 5 2-t-butyl-1 6- (3'-t-butyl-1 5'-ethyl-1 2'-hydroxybenzyl) One 4-Ethylphenyl acrylate

* 6 2—t—Putyl 6— (3 ′ —t—Butyl-5 ′ —Isopropyl 1 2 ′ —Hydroxybenzyl) 1 4 —Isopropylphenyl chloride

As is clear from the test results shown in Table 2, the road surface dull performance can be improved even in Examples 13 to 18 in which a predetermined amount of the fuyunol compound according to the present invention was blended. There was no sudden drop in the temperature of the art. INDUSTRIAL APPLICABILITY The rubber composition used for the tire of the present invention does not drastically lower the dull performance at high temperature like a rubber composition having an increased SBR styrene content. In addition, blowout temperature and abrasion resistance are not significantly deteriorated at a high temperature such as rubber composition filled with force-ichi bomber and process oil at high temperature. It is possible to improve road surface gripping property 5 to 15% without damaging it. Therefore, the pneumatic tire of the present invention can be used not only as an athletic running tire having excellent grip performance and heat resistance, but also as a tire for traveling on ice and snow roads and as an all-weather tire. It can also be used favorably as a tire, and is an important invention as a tire for high load and high speed running.

Claims

The scope of the claims

1. To 100 parts by weight of a blend of synthetic rubber or synthetic rubber and natural rubber, 2.5 to 20.0 parts by weight of a fuunol compound having at least one t-butyl group at the 2 or 6 position. Parts, nitrogen adsorption specific surface area U0 ~ 190 ² / g, dibutyl phthalate oil absorption 100 ~

A pneumatic tire comprising a rubber composition containing a total of 85 to 200 parts by weight of the softening material and the softening material in a thread.

2. The relationship between the blending amount of LIQUICHI BOMBRACK and the blending amount of softening agent is

-10 ≤ (weight of carbon black)

(1) The pneumatic tire according to claim 1, which satisfies (the number of parts by weight of the softening agent) ≤35.

3. The above fuyunol compound has the following general formula:

The pneumatic tire according to claim 1, which is a compound represented by the formula (R ¹ and R ² in the formula each independently represent a methyl group or an ethyl group).

4. The above-mentioned phenolic compound has the following general formula:

(!? ³ and R ⁴ in the formula are each independently a methyl group, an eytyl group or an isopropyl group, and A is an acrylate group or a methacrylic group). The pneumatic tire according to claim 1 or 2, which is a compound.