JPH04185512A - Pneumatic safety tire - Google Patents

Abstract

PURPOSE:To provide far more excellent continuous running performance than usual under a puncture condition by fixing a prescribed reinforcement layer for side part bend prevention integratedly with a side part inner side, and using a specified compound for the rubber composition of the reinforcement layer. CONSTITUTION:A reinforcement layer 6 for a side part bend prevention is fixed integratedly on an inner liner T at the inner side of a side part 4 over the whole curved range from a bead part 5 to the most thick part of a shoulder part 3 at a tread part 2 in a pneumatic tire 1. With the above constitution, a specified rubber composition is used for the reinforcement layer 6 for side part bend prevention. Besides, the specified rubber composition is constituted by compounding reinforcement carbon black 30-90 weight part, sulfur 2-10 weight part, and chiuram series vulcanization accelerator itself, or mixture with thiazole series vulcanization accelerator or mixture with guanidine series vulcanization accelerator 0.1-4 weight part with regard to polybutadiene rubber itself or blended rubber element 100 weight part including diene series rubber 0-20 weight part besides polybutadiene rubber.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is capable of supporting the vehicle body with the rigidity of the tire sidewall even if a pneumatic tire becomes punctured while the vehicle is running, and the vehicle can continue to drive continuously even as it is. This invention relates to so-called safety pneumatic tires with excellent safety.

(Prior Art) A pneumatic safety tire is a tire whose internal cavity is filled with air under a predetermined internal pressure, which acts on the tire until or after it is released due to an unexpected puncture damage to the tire. By using some means to support the wheel weight from the internal air pressure, it is possible to continue running the tire in a banked state until the tire reaches a place where it can be safely repaired or replaced.

Various types of such wheel load supporting means have been proposed so far (Japanese Patent Publication No. 53-3123, Japanese Patent Publication No. 50681-1981, Japanese Patent Publication No. 41763-1981, Japanese Patent Application Laid-open No. 472-025-1982, Publication No. 54-'53405, etc.).

(Problem to be solved by the invention) Although some of the wheel load support means that have been proposed so far have been put into practical use, none of them are still satisfactory in terms of sustained running performance after a puncture occurs. Instead, there was a desire for further improvements in sustained driving performance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a safe pneumatic tire that can exhibit much better sustained running performance than ever before even in a banked state.

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the inventor of the present invention integrally fixed a predetermined side part buckling prevention reinforcing layer to the inside of the side parts of a pneumatic tire. However, the inventors have discovered that the above object can be achieved by using a specific compounding system for the rubber composition of this reinforcing layer, and have completed the present invention.

That is, the present invention includes a pair of left and right bead portions, a pair of side portions connected to each bead portion, and a trend portion extending between both side portions, and the shoulder portion of the tread portion is connected from the beat portion area to the shoulder portion of the tread portion. A pneumatic chamber in which a reinforcing layer for preventing buckling of the side part is integrally fixed to the inside of the side part, the thickness of which is gradually decreased toward the bead part and the tread part over the entire bending area of the section up to the thickest part. In safety tires, 30 to 90 parts by weight of reinforcing carbon black and 2 parts by weight of sulfur are added to 100 parts by weight of the rubber component of polybutadiene rubber alone or a blend containing 0 to 20 parts by weight of diene rubber in addition to polybutadiene rubber. ~10 parts by weight, thiuram vulcanization accelerator alone or in combination with thiazole vulcanization accelerator or guanidine vulcanization accelerator 0.1~
The present invention relates to a pneumatic safety tire characterized in that a rubber composition containing 4 parts by weight is used as the reinforcing layer for preventing buckling of the side portion.

The present invention will be explained in more detail based on the drawings.

As shown in FIG. 1, the tire of the present invention has a pneumatic tire comprising a pair of left and right bead portions 5, a pair of side portions 4 connected to each bead portion 5, and a tread portion 2 extending between both side portions. In the tire 1, the reinforcing layer 6 for preventing side buckling is applied to the inner side of the side portion 4 over the entire bending region of the section from the bead portion 5 to the thickest portion of the shoulder portion 3 of the tread portion 2. It is fixed integrally on the inner liner 7. Further, the side part buckling prevention reinforcing layer 6 has a shape in which the thickness gradually decreases toward the bead part 5 and the tread part 2.

The present invention is particularly characterized by the compounding system of the rubber composition of the reinforcing layer for preventing side buckling. This compounding system will be explained in detail below.

The polybutadiene rubber used as the rubber component of the reinforcing layer for preventing side buckling is cis-1,4-polybutadiene rubber, trans-1,4-polybutadiene rubber, isotactic-1,4- Examples include polybutadiene rubber, syndiotactic-1,2-polybutadiene rubber, and other polybutadiene rubbers having syndiotactic-1,2-polybutadiene crystals, but should not be limited to these. do not have.

Examples of diene rubbers that can be blended with polybutadiene rubber include natural rubber, isoprene rubber, styrene-butadiene rubber, acronitrile butadiene rubber,
Examples include halogenated butyl rubber, but the material is not limited thereto.

As reinforcing carbon black, the iodine adsorption amount is 30~
150mg/g, dibutylphthal oil absorption 50-16
It is preferable to use one with a ratio of 0d/100g.

Examples of thiuram vulcanization accelerators used as sulfur vulcanization accelerators include tetramethylthiuram disulfide, and examples of thiazole vulcanization accelerators include N-tert.
-butyl-2-benzothiazylsulfenamide and the like. Further, examples of the guanidine-based vulcanization accelerator include diphenylguanidine and the like.

The rubber composition of the side part buckling prevention reinforcing layer according to the present invention may contain compounding agents commonly used in the rubber industry, such as anti-aging agents, vulcanization aids, etc., as necessary. Of course you can.

- (Function) In the present invention, by specifying the compounding system of the rubber composition of the reinforcing layer for preventing side buckling as described above,
It is preferable that the reinforcing layer has the following physical property values.

JIS spring hardness type A Hs (30) Near 3° to 90° Measured at 30°C H
s (130) Near 0° to 90° Measured at 130°C I
s (30) -Hs (130)≦2.0゜50% Modulus: 30~70kg/c+++2 Dynamic elastic modulus E'(30): 1.0~6.0X10'dyn/c+
n'' Measured at 30°C E' (130): 1.0~6
．． 0 x 10 "dyn cm" Measured at 130°C Impact modulus (resilience) 265-85% Measured at 30°C Dynamic modulus tan δ (30): o, os ~0.250 30°
Tan δ (130) measured at C: 0.01-0.2201
Measured at 30°C. In order to improve sustained running performance without reducing tire rigidity due to self-heating caused by repeated compression bending of the sidewall while driving in a banked state, the above-mentioned reinforcement for preventing buckling of the sidewall is necessary. Layer hardness Hs (30) from 73° to 90°, Hs (130) from 70° to 90°
and the difference between Hs (30) - Hs (130) is at most 2. Oo, preferably within 1.5°.

That is, Hs (30) is less than 73° and Hs (
130) is not grooved at 70°, the performance is insufficient to maintain the rigidity of the tire while driving in a banked state. Also,)
Is(30) exceeds 906 and Hs(130) is 90
If it exceeds .degree., the problem arises that the ride quality of the tire during normal running is poor and that brittle fracture is likely to occur when bending due to the high elasticity. Furthermore, H represents a decrease in hardness at high temperatures.
If the difference between s (30) - Hs (130) exceeds 2.0°, the reinforcing effect itself disappears, which is not preferable.

In addition, in order to prevent a decrease in tire rigidity due to self-heating caused by such repeated compression bending, the dynamic loss insurance number tan δ (
30) is 0.05 to 0.250, and tan δ(13
0) is preferably within the range of 0.01 to 0.220.

Furthermore, in order to suppress the rapid temperature rise of the reinforcing layer after banking, the rebound modulus is set to 65 to 85%, preferably 7.
It should be within the range of 0 to 82%.

If this value is less than 65%, the effect of suppressing the temperature rise will be small, while if it exceeds 85%, it will lead to a decrease in bending resistance due to a decrease in the breaking strength of the rubber composition, which is not preferable.

Furthermore, the dynamic elastic modulus E' (30) of the reinforcing layer is set to 1.0 to achieve both comfort, riding comfort, and maneuverability of the vehicle.
0-6. OX lo”dyn / cm2, and E
'(130) 1.0~6.0X10"dyn/cm
Keep it within the range of 2.

Specifically, in the present invention, polybutadiene rubber alone is used as the rubber component of the rubber composition of the reinforcing layer for preventing buckling of the side part in order to improve resistance to repeated compression bending fatigue and self-heating resistance. Alternatively, a mixture of 0 to 20 parts by weight of another diene rubber may be used.

Polybutadiene rubber alone is preferable for bending fatigue resistance, self-heating resistance, and suppression of hardness decline under high temperatures. 0 to 20 parts by weight of diene rubber can be blended.

However, if more than 30 parts by weight of the diene rubber is blended, the difference between Hs (30) - Hs (130) in the above formula tends to exceed 2.0° at maximum, resulting in poor bending fatigue resistance. It's my turn.

In addition, in the present invention, one of the important points is the selection of the reinforcing carbon blank and vulcanization system to be blended into the rubber composition, and the type and amount of reinforcing carbon black and the vulcanization system are determined to have resistance to bending fatigue. Since it has a large influence on the properties, heat resistance, and heat resistance, it is selected to ensure the above-mentioned physical properties within the range specified by the present invention according to the purpose and use of the pneumatic safety tire.

That is, when ensuring the above-mentioned physical properties, if the amount of sulfur is 10 parts by weight or more, it will lead to a decrease in bending fatigue resistance, while if it is less than 2 parts by weight, it will cause a decrease in hardness and a decrease in self-heating resistance, which is not preferable.

In addition, if the reinforcing carbon black exceeds 90 parts by weight, it will lead to a decrease in self-heating resistance and bending fatigue resistance.
On the other hand, if it is less than 30 parts by weight, it is not preferable because it causes a decrease in hardness.

Furthermore, if the total amount of the vulcanization accelerator is more than 4 parts by weight, it will easily burn during extrusion in the factory, and if it is less than 0.1 part by weight, the desired hardness will not be obtained.

In order to improve the compression flex fatigue resistance and heat resistance of the present rubber composition, a thiuram vulcanization accelerator may be used alone or in combination with a thiazole vulcanization accelerator or a guanidine vulcanization accelerator. It is always required to incorporate 1 to 4 parts by weight. However, if it exceeds 4 parts by weight, it will easily burn during extrusion in a factory and will be prone to brittle fracture. In addition, even when used in combination with thiazole-based or guanidine-based vulcanization accelerators,
0.1 to 3 parts by weight of the thiuram vulcanization accelerator is always required.

(Example) Next, the present invention will be specifically explained using examples.

According to the formulation (parts by weight) shown in Tables 1 and 2,
Various test rubber compositions were prepared, and these rubber compositions were applied to the reinforcing layer for preventing side buckling shown in FIG. 1 of a radial tire for a passenger car of size P275/40 ZR17.

The physical properties of these rubber compositions were measured as follows.

(a) Hardness Measured according to JIS spring hardness type A.

Hs (30) was measured at 30°C and Hs (130) was measured at 130°C.

(b) 50% Modulus According to JIS K 6301, tensile stress (kg/cm") at 50x elongation was measured at 30°C.

E' (30) and tan δ (30) were measured at 30 °C, and E' (130) and tan δ (
130) was measured at 130°C.

The measurement conditions are as follows: Measuring device: Viscoelastic spectrometer manufactured by Iwamoto Seisakusho Hina (
VB2-F type) Initial strain = 5%, dynamic strain = 1% Frequency: 50Hz Sample shape: 20mm (length) x 4.7mm (width)
X211+111 (thickness) Temperature increase condition = 3°C/min (d) Resilience % Measured with a Dunlop tribometer.

Sample shape is 30mm (length) x 8. Omm (width)
X4. O++in (thickness).

The actual test samples were vulcanized at 160° C. for 20 minutes using a mold that had a shape suitable for the measurements described in (1) to (d) above, and then left at that temperature for one day, and the above-mentioned physical properties were measured.

The obtained results are also listed in Tables 1 and 2.

Furthermore, the tire durability was evaluated by running the tire on a drum at a speed of 80 b/hr with an internal air pressure of 0, and measuring the running distance until the tire broke. In Table 1, the tire of Comparative Example 2 was used as a control, and in Table 2, the tire of Comparative Example 5 was used as a control and expressed as an index. The higher the value, the better the result.

-7゛*l...Cis-1,4-polybutadiene (manufactured by Japan Synthetic Rubber ■, trade name: BR01) *2...Crystal type 5yn-L2-polybutadiene-containing polybutadiene (manufactured by Ube Industries ■, trade name: VCR412
)*3...80% trans-1,4-polybutadiene*4...Polystyrene-butadiene rubber (manufactured by Japan Synthetic Rubber ■, trade name: SBR1500) *5...Chlorinated butyl rubber (manufactured by Nippon Synthetic Rubber ■).

Product name: Chlorobutyl 1068) *6... Cis-1-methyl polyisoprene rubber (manufactured by Nippon Gosei Rubber Co., Ltd., product name: IR2200) *7... Product name: R3S #4 *8... FEF carbon black (N 550) *9
...I SAF carbon blank (N 220) *1
0...(1,3-dimethylbutyl)-N-phenyl-
P-phenylenediamine*11...1,2-dihydro-2,2,4-trimethylquinoline*12...tetramethylthiuram disulfide*13...N-tert-butyl-2-benzothiazylsulfene Amide*14...Diphenylguanidine (effect of the invention) As can be seen from the test results shown in Tables 1 and 2, the pneumatic safety tire of the present invention has a predetermined reinforcing layer for preventing side buckling. It is integrally fixed to the inside of the side part, and the rubber composition of this reinforcing layer has a specific compounding system, which has the effect of being able to demonstrate superior sustained running performance in warmth than conventional safety tires. It will be done.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the left half of the pneumatic safety tire of the present invention. 1... Pneumatic safety tire 2... Trend 3... Shoulder part 4... Side part 5... Bead part 6... Side part buckling prevention reinforcing layer 7... Inner liner No. Figure 1

Claims (1)

[Scope of Claims] 1. A pair of left and right bead portions, a pair of side portions connected to each bead portion, and a tread portion extending between both side portions, and a shoulder portion of the tread portion from the bead portion area to the shoulder portion of the tread portion. A side part buckling prevention reinforcing layer whose thickness gradually decreases toward the bead and tread parts is integrally fixed to the inside of the side part over the entire bending area in the section up to the hump where the wall thickness is the thickest. In pneumatic safety tires, 30 to 30 parts by weight of reinforcing carbon black is added to 100 parts by weight of the rubber component of polybutadiene rubber alone or a blend containing 0 to 20 parts by weight of diene rubber in addition to polybutadiene rubber.
A rubber composition containing 90 parts by weight, 2 to 10 parts by weight of sulfur, and 0.1 to 4 parts by weight of a thiuram vulcanization accelerator alone or in combination with a thiazole vulcanization accelerator or a guanidine vulcanization accelerator. A pneumatic safety tire characterized in that the reinforcing layer for preventing buckling of the side portion is used.