JPH0470340B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a high-dynamic performance tire that has all-weather performance, and more specifically, it relates to a tire with all-weather performance. ) In addition to the ability to drive on road surfaces, the frictional force between the road surface and the toledo is sufficiently large on dry roads, the ability to easily drive on winding roads or at high speeds, and the ability to drive on straight roads at high speeds. Radial tires for passenger cars, bias tires for passenger cars, and tires for motorcycles that have the ability to run, the ability to run with a short lap time when running on circuits, and the ability to run easily or at high speeds even on wet roads. The present invention relates to a tire that can be applied to the above, and furthermore, a tire that has not only such performance but also improved wear resistance. (Prior Art) Various high-dynamic performance tires have been known. For example, JP-A-55-60539 and JP-A-55-86827 disclose compositions for treaded rubber that improve tread grip on wet road surfaces. has been done. In addition, so-called snow tires and studless tires for driving on icy and snowy roads are also known.
Japanese Patent No. 59-206209 discloses a pneumatic tire whose tread is made of a specific rubber composition to increase its ability to grip icy and snowy treads. (Problems with the prior art) Conventional high-performance tire treads require a large loss of tread rubber near room temperature in order to ensure high tread grip. This goal has been achieved by using large amounts of styrene-butadiene rubber, or by blending large amounts of carbon and oil. However, these treaded rubbers harden at low temperatures, and when running on icy and snowy roads, there is a problem that they cannot obtain sufficient frictional force with the road surface, making it difficult to run easily, and they also have insufficient abrasion resistance. It was hot. On the other hand, so-called snow tires or studless tires, which are intended to easily run on icy and snowy roads, generally use treaded rubber that is soft even at low temperatures, and although they can provide satisfactory performance on icy and snowy roads. However, the hardness of the tread rubber tends to decrease too much near room temperature, resulting in the problem that sufficiently high exercise performance cannot be obtained, and the wear resistance is also insufficient. The purpose of the present invention is to solve the above-mentioned problems of the prior art, and to provide a tire with high maneuverability that can be easily run even on icy and snowy roads, in other words, has all-weather performance. The objective is to provide a tire that has the following characteristics. (Means for Solving the Problems) As a result of intensive research into the materials of tire tread members, the inventors of the present invention have devised a method to increase the viscosity of tread rubber near room temperature in order to obtain a large frictional force with the road surface near room temperature. We have discovered that by selecting a rubber composition in which the elastic properties and the elastic properties of the tread rubber at low temperatures of, for example, -20°C can be independently and freely controlled, a high performance tire with all-weather performance can be obtained. Patent application (1988-)
203181). Subsequently, the present inventors conducted intensive research to further improve such performance, and found that by blending a predetermined amount of a specific reinforcing carbon black into the rubber composition, a tire with better performance than ever before was found. The present inventors have discovered that the following can be obtained, and have completed the present invention. That is, the present invention comprises 10 to 90 parts by weight of at least one diene rubber having a glass transition temperature of -65°C or lower, and 90 to 10 parts by weight of at least one diene rubber having a glass transition temperature of -55°C or higher. Characteristically, 125 to 145 m ² /g per 100 parts by weight of the rubber component consisting of
Nitrogen adsorption amount (hereinafter abbreviated as N ₂ SA) and 99
ml/100g or less dibutyl phthalate oil absorption (hereinafter abbreviated as DBP) and 24000psi (1690Kg/
Dibutyl phthalate oil absorption (hereinafter abbreviated as 24M4DBP) after 4 repeated compressions (cm ² ) 75 to 85
Reinforcement carbon black 40~ with ml/100g
90 parts by weight and 2 to 30 parts by weight of an ester-based low-temperature softener and vulcanization.The elastic modulus at 100% elongation at -20℃ is 40Kg/ ^cm2 or less, and the loss coefficient at 30℃. The present invention relates to an improved high-dynamic performance tire having all-weather performance, characterized in that a vulcanized rubber having a tan δ of 0.3 or more is used for the tread. Examples of diene rubbers with a glass transition temperature of -65°C or lower that are used as component (A) in the present invention include (high cis or low vinyl) polybutadiene rubber, styrene-butadiene rubber with a low styrene content, and ethylene rubber. Examples include -butadiene rubber, propylene-butadiene rubber, butadiene-isoprene rubber, propylene-isoprene rubber, etc., but diene rubber having a glass transition temperature of -70°C or lower is preferably used. It should be noted that if a diene rubber having a glass transition temperature higher than -65°C is used as component (A), it will be difficult to obtain the desired elastic modulus at low temperatures, which is not preferable. Next, examples of diene rubbers with a glass transition temperature of -55°C or higher to be used as component (B) include:
Examples include styrene-butadiene rubber with a large styrene content, α-methylstyrene-butadiene rubber, polybutadiene rubber with a large vinyl content, and styrene-butadiene rubber with a small styrene content but a large vinyl content. It should be noted that if a diene rubber having a glass transition temperature of less than -55°C is used as component (B), it will be difficult to obtain the desired high maneuverability, which is not preferable. In order to maintain the viscoelastic properties near room temperature and the elastic properties at low temperatures of the tread rubber within the scope of the present invention, the mixed rubber component consisting of components (A) and (B) must have specific carbon properties. It is necessary to mix reinforcing carbon black and an ester-based low-temperature softener. As mentioned above, the reinforcing carbon black having these specific characteristics has an N ₂ SA of 125 to 145 m ² /g and a DBP of 99 ml/100 g or less, preferably 80 to 99
ml/100g and 24M4DBP within the range of 75 to 85 ml/g. The reason for selecting such carbon black is as follows. In other words, if N ₂ SA is less than 125 m ² /g, the storage elastic modulus E' at room temperature is small and it is difficult to obtain the desired high exercise performance, which is undesirable. On the other hand, if it exceeds 145 m ² /g, This is because it causes poor dispersion of carbon black, which is also undesirable. Moreover, if the DBP is 100 ml/100 g or more, the elastic modulus becomes too high, making it difficult to obtain the desired elastic modulus even at low temperatures, which is not preferable. Furthermore, if the 24M4DBP is less than 75ml/100g, the wear resistance will deteriorate, while if it exceeds 85ml/100g, excellent braking performance on snow will not be obtained. Furthermore, here
Measurement of 24M4DBP is according to ASTM D3493. In the present invention, it is preferable that the proportion of the reinforcing carbon black having the above-mentioned characteristics is within the range of 40 to 90 parts by weight per 100 parts by weight of the rubber component. This is undesirable because if it is less than 40 parts by weight, the loss coefficient tan δ near room temperature and the storage modulus E′ will become too small, making it difficult to obtain the desired high temperature performance, and if it exceeds 90 parts by weight, the elastic modulus will become too high. This is because it becomes difficult to obtain a desired elastic modulus at low temperatures, which is also undesirable. Examples of ester-based low-temperature softeners include phthalic acid derivatives, such as phthalic acid diesters, fatty acid-based basic acid esters, such as oleic acid derivatives, fatty acid dibasic acid esters, such as adipic acid derivatives, azelaic acid derivatives, and sebacic acid. There are ester-based low-temperature plasticizers such as derivatives and phosphoric acid derivatives, and the most preferred are oleic acid derivatives,
For example, butyl oleate, octyl oleate,
Decyl oleate, octyl tall oil fatty acid, oleic acid, ethylene glycol oleate diester, 1,4-butanediol oleate diester, 1,6-hexanediol oleate diester, 2-ethylhexyl oleate, dodecyl oleate, Examples include decyl myristoleate and oleyl myristoleate, with octyl oleate being particularly preferred. In the present invention, the blending ratio of these ester-based low-temperature softeners is 2 to 2 to 100 parts by weight of the rubber component.
It is preferably within the range of 30 parts by weight. this is,
If it is less than 2 parts by weight, it will not be possible to obtain sufficient ice and snow performance, and if it exceeds 30 parts by weight, the elastic modulus will be too low and it will not be possible to obtain sufficient high exercise performance, but it will also not have sufficient body abrasion performance as a tread rubber. This is because it becomes difficult to obtain. More preferably, the blending ratio is within the range of 3 to 15 parts by weight, and by setting it within this range, high exercise performance and ice and snow running performance can be achieved in an extremely well-balanced manner. Further, in the present invention, as described above, the rubber component consisting of the component (A) and the component (B) has an N ₂ SA of 125 to 125.
145m ² /g and DBP less than 99ml/100g
The modulus of elasticity at 100% elongation at -20°C of the treaded rubber obtained by vulcanizing a reinforcing carbon black with a 24M4DBP of 75 to 85ml/100g and an ester low-temperature softener is 40Kg/cm ² and the loss coefficient tan δ at 30°C is required to be 0.3 or more. The reason for this is that 100
This is because if the elastic modulus at % elongation exceeds 40 Kg/cm ² , it will be difficult to obtain the desired performance on harsh ice and snow roads, so it is preferably 35 Kg/cm ² or less. In addition, if tanδ at 30°C is less than 0.3, it will be difficult to obtain the desired high operating performance.
Preferably it is 0.35 or more. Furthermore, the storage modulus E′ at 30℃ is 110Kg/cm ²
Above, preferably 130Kg/cm ² or above. E′ is 110
This is because if it is less than Kg/cm ² , it will be difficult to obtain sufficiently high operating performance. In the present invention, as the rubber component, component (B) is a copolymer of styrene and conjugated diene obtained by emulsion polymerization, the average bound styrene content of which is 20 to 40%, and the bound styrene content is lower than the bound styrene content. By using a styrene-conjugated diene copolymer rubber with a distribution width of 30% or more, it is possible to improve wear resistance without impairing high exercise performance and ice and snow running performance. Details of such styrene-conjugated diene copolymer rubber can be found, for example, in JP-A-61-
It is disclosed in Publication No. 252210. The distribution width of the styrene content was calculated using the method of Shinya Teramachi (J.
Macromol Sci. Chem. A4 (8) 1785.1970) was cross-fractionated and measured using a cyclohexane/isooctane mixed solvent and benzene/methyl ethyl ketone. In addition to component (A) and component (B) as rubber components in the present invention, butyl rubber or halogenated butyl rubber,
For example, chlorobutyl rubber and bromobutyl rubber can be used in combination. The amount of butyl rubber or halogenated butyl rubber used is 8 to 30 parts by weight,
Preferably it is 10 to 20 parts by weight. By limiting the amount to such a range, the wear resistance, which is another property required of treaded rubber, will be reduced, and the damp road braking performance can be improved. The rubber composition used in the present invention includes sulfur as a vulcanizing agent,
A vulcanization accelerator, a vulcanization accelerator, an anti-aging agent, a softener, a filler, etc. are appropriately added. (Examples) Next, the present invention will be explained by examples and comparative examples. Examples 1 to 5, Comparative Examples 1 to 6 Prior to tire evaluation, rubber compositions having the compounding ratios (parts by weight) shown in Table 1 were tested with a spectrometer at 30°C tan δ and 30°C E', and with a Tensilon test.
The elastic modulus at 100% elongation at 20°C was measured. Thereafter, 11 types of tires with tire sizes of 185/70SR14 were made using the rubber composition as tread rubber, and each tire was evaluated for wet road braking performance, dry road handling stability, snow braking performance, and abrasion resistance. The obtained results are also listed in Table 1 below. In the table, Comparative Example 1 corresponds to a conventional high motion performance tire. Moreover, Comparative Example 2 corresponds to a conventional snow tire. Furthermore, Comparative Examples 5 and 6 were obtained from the earlier patent application (Japanese Patent Application 1986-
This corresponds to Examples 6 and 4 of No. 203181). The tire using the high performance tread rubber for summer tires in Comparative Example 1 was used as a control tire, and the performance of each tire is shown in the table as an index relative to the control. The method for measuring the physical properties and the method for evaluating the performance are as follows. (b) Glass transition temperature (T _g ) Using a DSC (differential running calorimeter), record a thermogram at a heating rate of 20°C/min, and calculate the temperature at the midpoint of the tangent line shown in Figure 1 as T _g . did. (b) Elastic modulus at 100% elongation at -20°C Measured in a -20°C constant temperature bath (precooled for 10 minutes) based on JIS K 6301 tensile test method. The vulcanization conditions for the sample were such that the vulcanization time was 1.2 times the time at which the torque reached its maximum value using a rheometer. (c) Storage modulus E' and loss coefficient tanδ Measured using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho under conditions of a frequency of 50 cps, static strain rate of 5% elongation, and dynamic strain rate of 1%. The sample was in the form of a strip with a length between chucks of 20 mm, a width of 5 mm, and a thickness of 2 mm. The vulcanization conditions were the same as in item (a) above. (d) Wet road braking resistance At a speed of 40km/h on a wet asphalt road
Sudden braking was applied from each speed of 100 km/h, 70 km/h, and 100 km/h, and the distance traveled until it came to a complete stop was determined, and the average value was expressed as an index with Comparative Example 1 set as 100. The larger the value, the better. (e) Dry road handling stability The lap time of the tires on a circuit consisting of straight roads, curves, banks, etc. was measured on a sunny day and expressed as an index with the time of the tire of Comparative Example 1 set as 100. The larger the value, the better. (f) Braking resistance on snow Regarding braking performance on snow, the speed is 20km/hour,
The brakes were applied while driving at 30 km/hour and 40 km/hour, the stopping distance was measured, the average value was calculated, and the value of the tire of Comparative Example 1 was set as 100 and expressed as an index. The larger the value, the better. (g) Wear resistance The distance traveled per 1 mm of abrasion was calculated as wear resistance from the remaining groove after driving an actual vehicle for 40,000 km on a general road, and the value of the tire of Comparative Example 1 was set as 100 and expressed as an index.
The larger the value, the better.

【table】

【table】

[Table] In terms of tire performance in Table 1, snow braking performance of 115 or less and wear resistance of 110 or less are not practical, but the tires of the present invention have snow braking performance of 115 or less and wear resistance of 110 or less. It had abrasive properties. That is, the tire of the present invention was able to significantly improve the braking performance on snow and the wear resistance performance without deteriorating the damp road surface braking performance and the dry road surface handling stability as in Comparative Example 2. (Effects of the Invention) As explained above, the tire of the present invention has
A predetermined rubber composition is selected in which the viscoelastic properties of the treaded rubber near room temperature and the elastic properties of the treaded rubber at a low temperature of -20°C, for example, can be independently and freely controlled, and a specific reinforcement is added to the rubber composition. By blending a predetermined amount of carbon black,
The effect is that it is possible to obtain a high motion performance tire having all-weather performance and further improved braking performance on snow. Furthermore, by using a styrene-conjugated diene copolymer rubber having an average bound styrene content of 20 to 40% and a bound styrene content distribution width of 30% or more as the specific rubber component of the rubber composition, The effect is that wear resistance can be improved without impairing high exercise performance and ice and snow running performance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the temperature used to obtain the glass transition temperature (T _g ) and the specific heat.

Claims (1)

[Scope of Claims] 1. 10 to 90 parts by weight of at least one diene rubber having a glass transition temperature of -65°C or lower, and at least one diene rubber having a glass transition temperature of -55°C or higher.
4 times at 24000psi (1690Kg/ ^cm2 ) with a nitrogen adsorption amount of 125-145m2 ^/ g and a dibutyl phthalate oil absorption amount of 99ml/100g or less for 100 parts by weight of a rubber component consisting of 90-10 parts by weight. Dibutyl phthalate oil absorption after repeated compression 75-85ml/
40 to 90 parts by weight of reinforcing carbon black having a weight of 100g and 2 to 30 parts by weight of an ester low-temperature softener are blended and vulcanized, and the elastic modulus at 100% elongation at -20℃ is 40Kg/cm. ² or less and a loss coefficient tan δ of 0.3 or more at 30°C is used for the tread. 2 A copolymer of styrene and conjugated diene obtained by emulsion polymerization as a diene rubber with a glass transition temperature of -55°C or higher, with an average bound styrene content of 20 to 40% and a An improved high-performance tire having all-weather performance according to claim 1, which uses a styrene-conjugated diene copolymer rubber having a distribution width of 30% or more.