JPH0912778A - Tread rubber composition for studless tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tread rubber composition for studless tires without causing the falling off of an organic resin from a tread part of the tire and without deteriorating the frictional resistance and further braking performances on road surfaces of the ice and snow and useful for ensuring the braking performances of automobiles by blending a rubber with a specific organic resin in a specified proportion. SOLUTION: This tread rubber composition for studless tires is obtained by blending (A) 100 pts.wt. natural rubber or diene-based synthetic rubber with (B) 3-20 pts.wt. rigid organic resin having 150-1700μm average particle diameter (e.g. 6-nylon, 6,6-nylon, 12-nylon or polystyrene) and further mixing (C) a mixture solution of resorcinol-formalin precondensate with a rubber latex in an amount of 10-30 pts.wt. based on 100 pts.wt. component (B).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tread rubber composition for studless tires capable of improving braking performance on icy and snowy road surfaces.

[0002]

2. Description of the Related Art Conventionally, spiked tires have been used to ensure the braking performance of automobiles on ice and snowy roads. However, even on a dry road surface, since the vehicle runs with spiked tires, the road surface is damaged by the spikes,
Dust, noise pollution, etc. were caused, and as a result, production and sales of spiked tires were banned. Therefore, there is a demand for the development of a studless tire having a braking performance equivalent to that of a spiked tire on ice and snow road surfaces. As a tread rubber composition for this type of tire, natural rubber and / or
Alternatively, a diene-based synthetic rubber blended with a particulate hard organic resin has already been proposed. In this tire, the high-hardness organic resin in the tread portion of the tire scratches the icy and snowy road surface, so that the frictional resistance on the icy and snowy road surface is high and the braking performance is high.

[0003]

However, in the above-mentioned conventional technique, the organic resin is simply mixed in the rubber, and the two are not adhered to each other. Therefore, the organic resin falls off from the tread portion due to running, There was a problem that the frictional resistance on the snowy and snowy road surface was lowered and the braking performance was lowered. An object of the present invention is to provide a tread rubber composition for a studless tire that can solve the above problems.

[0004]

In order to achieve the above object, the features of the first tread rubber composition for a studless tire of the present invention (hereinafter, abbreviated as composition (1)) are as follows. Natural rubber and / or diene synthetic rubber 10
In a tread rubber composition for a studless tire, in which 3 to 20 parts by weight of a hard organic resin having an average particle size of 150 to 1700 μm is mixed with 0 parts by weight, 100 parts by weight of the organic resin is mixed with resorcinol at the time of melting.・ Mixed liquid of formalin initial condensate and rubber latex 10-30
The point is that parts by weight are mixed. The second tread rubber composition for studless tires of the present invention (hereinafter, abbreviated as composition (2)) is characterized in that 100 parts by weight of the organic resin, when melted, has an average particle diameter. Is 0.
The point is that 5 to 10 parts by weight of a metal of 1 to 1 μm is mixed. Further, the feature of the third tread rubber composition for a studless tire of the present invention (hereinafter, abbreviated as composition (3)) is that the organic resin is a foamed organic resin.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in order from the composition (1). [Composition (1)] In the composition (1) of the present invention, 3 to 20 parts by weight of a hard organic resin having an average particle diameter of 150 to 1700 μm is used with respect to 100 parts by weight of natural rubber and / or diene synthetic rubber. In a tread rubber composition for a studless tire containing 100 parts by weight, 100 parts by weight of an organic resin,
At the time of melting, 10 to 30 parts by weight of a mixed solution of resorcin-formalin initial condensation product and rubber latex is mixed. Examples of the diene-based synthetic rubber of the composition (1) include polystyrene butadiene rubber (SBR, styrene butadiene copolymer), polyisoprene rubber (IR), polybutadiene rubber (BR) and the like. These diene synthetic rubbers are used alone or in a mixture.

As the hard organic resin blended with the natural rubber and / or the diene-based synthetic rubber, for example, 6-nylon, 6,6-nylon, 12-nylon, polystyrene and the like are used. In addition, the above-mentioned "hard" means "harder than ice"
It means that the hardness is 3 times or more that of rubber. Specifically, on the Rockwell hardness R scale, 60 or more,
It is preferably 80 or more. The average particle diameter of the organic resin is 150 to 1700 μm (mesh 10 to 100 or so). If the average particle size is less than 150 μm, braking performance on ice / snow road surface is not improved, and the average particle size is 1
When it exceeds 700 μm, the workability of the composition (1) is deteriorated and the tensile strength is greatly reduced, which is not preferable.

The amount of the organic resin compounded is 3 to 20 parts by weight based on 100 parts by weight of natural rubber and / or diene synthetic rubber. If the blending amount is less than 3 parts by weight, braking performance on ice and snow road surface will not be improved, and if the blending amount exceeds 20 parts by weight,
This is not preferable because the workability during kneading with a Banbury mixer or rolls is significantly reduced and the abrasion resistance is greatly reduced. To the organic resin, a mixed solution (RFL) of resorcin-formalin initial condensation product (RF) and rubber latex is mixed in order to adhere to the rubber. The mixing is performed at the time of heating and melting during the production of the organic resin, and RFL is uniformly mixed into the organic resin. The organic resin mixed with RFL is pulverized into particles, and the RFL active groups are present on the surface of the organic resin.

The amount of RFL is 10 to 30 parts by weight based on 100 parts by weight of the organic resin. If the blending amount is less than 10 parts by weight, the adhesiveness to rubber is poor, and if the blending amount exceeds 30 parts by weight, the strength of the organic resin decreases, which is not preferable. In addition, FIG. 1 shows an adhesion state with rubber when 6-nylon is used as the organic resin, and 6-nylon is bonded with RF in RFL via hydrogen bond, and After vulcanization, the rubber latex in RFL is bonded to the rubber via the co-crosslinking seat. That is, 6-nylon is bonded to rubber via RFL. As described above, since the organic resin is bonded to the rubber via the RFL, the organic resin does not drop off from the tread portion of the tire during running. Therefore, the frictional resistance on the icy and snowy road surface does not decrease, and the braking performance does not decrease.

[Composition (2)] In the composition (2), a particulate metal is used instead of the RFL of the composition (1), and as in the case of the composition (1), an organic resin is used. When heated and melted, they are uniformly mixed. The organic resin mixed with the metal is pulverized into particles, and the metal is present on the surface of the organic resin. Considering the adhesiveness to rubber, the metal is preferably a transition element or an alloy containing a transition element. As the transition element, zinc or nickel, and as the alloy containing the transition element, brass, bronze, or the like used for plating steel cords of tires are used.

The average particle size of the metal is 0.1 to 1 μm. If the average particle size is less than 0.1 μm, the adhesion to rubber is poor, and if the average particle size exceeds 1 μm, the strength of the organic resin (reinforcing effect) is lowered, which is not preferable. The amount of metal mixed is 5 with respect to 100 parts by weight of the organic resin.
To 10 parts by weight. If the mixed amount is less than 5 parts by weight,
If the adhesiveness to rubber is poor and the amount of the mixture exceeds 10 parts by weight, the strong hardness (reinforcing effect) of the organic resin decreases, which is not preferable.

FIG. 2 shows the state of adhesion to rubber when zinc is used as the metal. After vulcanization, an adhesion layer of zinc oxide or the like is formed at the interface between the organic resin and the rubber. The organic resin is bonded to the rubber. As described above, since the organic resin is bonded to the rubber, the organic resin does not drop off from the tread portion of the tire during running. Therefore, the frictional resistance on the icy and snowy road surface does not decrease, and the braking performance does not decrease.
Also, by mixing a metal into the organic resin, the strong hardness of the organic resin is increased, and the abrasion (abrasion) of the organic resin is suppressed when running on a dry road surface. The scratching effect on the road surface) can be maintained for a long time.

[Composition (3)] In the composition (3), in order to adhere the organic resin to the rubber, RFL or metal is added to the organic resin like the compositions (1) and (2). It is not mixed and the organic resin is a foamed organic resin. The organic resin is
In order to enhance the anchoring effect with the rubber, it is preferable to use one having a high polarity, and in consideration of the decrease in the tenacity and hardness of the organic resin due to foaming, one having a high tenacity is preferable. As such a material, for example, polycarbonate, polyphenylene oxide or the like is used.

Examples of the method of foaming the organic resin include a method of foaming by mechanical stirring, a method of using a reaction product gas, a method of using a foaming agent, a method of removing a soluble substance, a method of spraying and the like. The organic resin is foamed during kneading or vulcanization of the composition (2) by any one of the above methods or a combined method. The expansion ratio is about 2 to 3 times. In the method using the foaming agent, the organic resin is made to absorb the foaming agent such as carbon dioxide gas,
At the time of kneading the composition (2), the foaming agent is vaporized at a temperature of 100 to 150 ° C. to foam the organic resin. In addition, FIG.
When a foamed organic resin is used, the adhesive state with rubber is shown.
During kneading and vulcanization of (1), an air gap (space) is generated, and the rubber around the organic resin enters into the air gap, and the rubber is anchored in the organic resin, and the two are bonded.

[Representative Example of Tread Rubber Composition for Studless Tire] The tread rubber composition of the present invention preferably has good low-temperature characteristics, and representative examples thereof are as follows. First, in order to produce an intermediate product (intermediate), 10 to 100 parts by weight of natural rubber and / or polyisoprene rubber, polybutadiene rubber,
Diene synthetic rubber 90 such as polystyrene butadiene rubber
With respect to 100 parts by weight of the blend rubber composed of not more than parts by weight,
40 to 85 parts by weight of carbon black is blended. At this time, depending on the case, 10 to 30 parts by weight of a hydrophilic inorganic reinforcing agent such as white carbon or silane modified clay may be added, and in addition, a commonly used amount usually used in the rubber processing industry is added. May be.

For example, based on 100 parts by weight of the blended rubber, 2 to 6 parts by weight of zinc oxide, 1 to 3 parts by weight of stearic acid, 20 to 50 parts by weight of process oil, and 1.5 to 5 parts of sulfur.
3.5 parts by weight, vulcanization accelerator 0.5 to 2.5 parts by weight,
1 to 3 parts by weight of each antiaging agent and wax, and a usual amount such as a pigment, a dye and an adhesion improver is added. In the case of the composition (1), the organic resin mixed with RFL is added to the intermediate product obtained as described above, and in the case of the composition (2), the organic resin mixed with metal. In the case of the composition (3), the tread rubber composition for a studless tire of the present invention can be produced by blending a foamed organic resin and kneading the mixture with a Banbury mixer, a roll or the like.

[0016]

The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to the examples. All the following "parts" represent "parts by weight". Example 1 A composition (1) was produced from the components shown in Table 1 below. Incidentally, with respect to 100 parts of the nylon resin, 12 parts of RFL were mixed at the time of heating and melting and then pulverized to have an average particle diameter of 400 μm. Also, as an anti-aging agent,
N- (1,3 dimethylbutyl) -N'-phenyl-p-
Phenylenediamine was used.

[0017]

[Table 1] Natural rubber 70 parts Polybutadiene rubber 30 parts Nylon resin 10 parts Carbon black N339 80 parts Zinc white 6 parts Stearic acid 3 parts Anti-aging agent 3 parts Paraffin wax 2 parts Naphthenic oil 40 parts Vulcanization accelerator MSA 1 part sulfur 2.2 parts

Example 2 A composition (1) was produced in the same manner as in Example 1. The difference from Example 1 is only the mixing ratio of RFL. In Example 2, 20 parts of RFL was mixed with 100 parts of nylon resin.

Comparative Examples 1 to 3 In the same manner as in Example 1,
A composition was produced. The difference from Example 1 is only the mixing ratio of RFL. RFL is 0 parts in Comparative Example 1, Comparative Example 2
In 4 parts, in Comparative Example 3, 8 parts were mixed.

[Test Example 1] Each composition obtained in each Example and each Comparative Example was kneaded with a Banbury mixer and a roll,
This is press-vulcanized (conditions: 150 ° C. for 30 minutes),
Samples of each example and each comparative example were prepared. For this sample, the ice and snow performance was evaluated when it was new and after traveling 1000 km. Table 2 shows the results. In addition, 165R13 tires were used, and regarding the ice and snow performance, the friction coefficient at the time of braking from 30 km / h on ice was measured, and the friction coefficient at the time of new article of Comparative Example 1 was set to 100 and expressed as an index. The larger the value, the larger the friction coefficient and the better the snow and snow performance.

[0021]

[Table 2]

As shown in Table 2, both the example and the comparative example are excellent in ice and snow performance when new. But 1000
After traveling for km, in Comparative Examples 1 to 3, the ice and snow performance is significantly deteriorated, whereas in Examples 1 and 2, the ice and snow performance is not deteriorated.

[Examples 3, 4 and 5] Next, a composition (2) having substantially the same components as in Example 1 was produced. Note that the difference from the first embodiment is that in the third embodiment, instead of RFL,
6 parts of zinc having an average particle diameter of 0.5 μm, 10 parts of zinc having an average particle diameter of 0.5 μm in Example 4, and 6 parts of zinc having an average particle diameter of 0.8 μm in Example 5 were mixed with the nylon resin. That is the point.

[Comparative Examples 4 to 7] Compositions were produced in the same manner as in Examples 3 to 5. Incidentally, in Comparative Example 4, zinc was not mixed, and in Comparative Example 5, zinc having an average particle diameter of 0.5 μm was used.
In Comparative Example 6, zinc powder having an average particle diameter of 1.5 μm was added to 6 parts.
In Comparative Example 7, zinc having an average particle diameter of 3.0 μm was added to 6 parts.
Mixed with nylon resin.

[Test Example 2] A sample was prepared in the same manner as in Test Example 1, and the Rockwell hardness of the nylon resin mixed with zinc was measured on the R scale and the ice and snow performance was evaluated.
Table 3 shows the results. In addition, the snow and snow performance was displayed as an index with the measurement result of Comparative Example 4 as 100.

[0026]

[Table 3]

From Table 3, it can be seen that when zinc is mixed, the strong hardness of the nylon resin increases. In addition, both the example and the comparative example are excellent in ice and snow performance when new.
However, after traveling 1000 km, the ice and snow performance was significantly reduced in Comparative Examples 4 to 7, while the ice and snow performance was not significantly reduced in Examples 3 to 5, which is excellent.

Examples 6 and 7 Next, a composition (3) having substantially the same components as in Example 1 was produced. Example 1
The difference between and is that foamed polycarbonate was used in Example 6 and foamed polyphenylene oxide was used in Example 7 instead of nylon resin or RFL.

[Comparative Examples 8 to 11] Compositions were produced in the same manner as in Examples 6 and 7. In Comparative Example 8, unexpanded polystyrene was used, and in Comparative Example 9, expanded polystyrene was used.
In Comparative Example 10, expanded polypropylene was used, and in Comparative Example 11, unexpanded polystyrene was used. In addition, Comparative Example 11
Then, an adhesion-imparting agent to rubber was added and compounded.

[Test Example 3] A sample was prepared in the same manner as in Test Example 1 and evaluated for snow and snow performance and wear resistance. Table 4 shows the results. The wear resistance was evaluated by running the vehicle on an ordinary road and measuring the wear life. Further, the ice and snow performance and the wear resistance are shown as indexes with the measurement result of Comparative Example 8 as 100.
In addition, as for the wear resistance, the larger the value, the longer the wear life,
It is excellent.

[0031]

[Table 4]

As shown in Table 4, in Examples 6 and 7, the abrasion resistance was excellent, and the ice and snow performance was 100 even when new.
It is excellent even after running 0km. On the other hand, Comparative Example 8 to
In No. 10, the abrasion resistance was excellent, but the ice and snow performance was problematic even in the case of a new product except Comparative Example 8, and Comparative Example 8
Then, the snow and ice performance is significantly reduced after traveling 1000 km. Further, in Comparative Example 11, the ice and snow performance is excellent both when new and after traveling 1000 km, but there is a problem in wear resistance.

[0033]

As described in detail above, according to the present invention,
The organic resin does not fall off from the tread portion of the tire due to running. Therefore, the frictional resistance on the icy and snowy road surface does not decrease, and the braking performance does not decrease.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a composition (1) of the present invention.

FIG. 2 is an explanatory view showing the composition (2) of the present invention.

FIG. 3 is an explanatory view showing the composition (3) of the present invention.

Claims (3)

[Claims] 1. Natural rubber and / or diene-based synthetic rubber 1
The average particle size is 150 to 1700 μm with respect to 00 parts by weight.
In a tread rubber composition for a studless tire containing 3 to 20 parts by weight of a hard organic resin, a mixed solution 1 of a resorcin-formalin initial condensate and a rubber latex is added to 100 parts by weight of an organic resin.
A tread rubber composition for a studless tire, characterized by containing 0 to 30 parts by weight. 2. Natural rubber and / or diene-based synthetic rubber 1
The average particle size is 150 to 1700 μm with respect to 00 parts by weight.
In a tread rubber composition for a studless tire, which contains 3 to 20 parts by weight of a hard organic resin, a metal 5 having an average particle diameter of 0.1 to 1 μm when melted with respect to 100 parts by weight of the organic resin. A tread rubber composition for a studless tire, characterized by containing 10 to 10 parts by weight. 3. Natural rubber and / or diene-based synthetic rubber 1
The average particle size is 150 to 1700 μm with respect to 00 parts by weight.
In the tread rubber composition for studless tires containing 3 to 20 parts by weight of the hard organic resin described above, a tread rubber composition for studless tires, wherein the organic resin is a foamed organic resin.