KR101745135B1 - Improved tire tread with multi compound - Google Patents

Abstract

The present invention relates to a tire tread to which a different kind of rubber material is applied. More specifically, the present invention relates to a multi-tread type tire made of two kinds of rubber materials, which is a heterogeneous material having improved tire performance such as braking performance, The present invention relates to an applied tire tread. The tire tread of the present invention has the effect of simultaneously improving the rolling resistance performance, the braking performance, and the snow performance of the tire during braking or running by applying different kinds of rubber materials to the shoulder portion and the center portion.

Description

IMPROVED TIRE TREAD WITH MULTI COMPOUND [0002]

The present invention relates to a tire tread to which a different kind of rubber material is applied. More specifically, the present invention relates to a multi-tread type tire made of two kinds of rubber materials, which is a heterogeneous material having improved tire performance such as braking performance, The present invention relates to an applied tire tread.

In recent years, high performance targets have been demanded for tire grounding performance such as braking and handling. Tires having excellent braking performance and handling performance tend to deteriorate in rolling resistance characteristics, which is represented by fuel efficiency. Therefore, the tire is being developed to find a suitable balance between the two performances.

Here, the rolling resistance is caused by all the resistance caused by the rolling of the tire on the road surface due to the torsion of the tire or the road surface, the irregularity of the road surface, sliding of the bearing, friction or the like.

The performance of a tire depends largely on the characteristics of the tread rubber material. When the tread rubber is applied mainly to the braking performance, the fuel efficiency or the snow performance deteriorates. On the contrary, when the fuel performance is applied mainly, the performance other than the braking performance and the wear performance Indicating a tendency to deteriorate.

Therefore, there is an increasing demand for a technique that simultaneously works with two materials exhibiting completely different characteristics to produce a synergistic effect.

Japanese Published Patent Application No. 2011-173522

In view of the above, the present invention applies two kinds of rubber materials to a tire tread to suitably arrange the different materials in the tire tread, so that the tire tread excellent in braking performance and fuel economy performance as well as snow performance in tire performance The purpose is to provide.

In order to accomplish the above object, the tire tread of the present invention is constituted by a central portion where the contact pressure of the tire is most strongly distributed in contact with the road surface, a side well constituting the side surface of the tire and a shoulder portion disposed between the center portion, An upper layer having a surface contacting the road surface and a lower layer formed below the upper layer, wherein the upper layer and the lower layer are laminated with different kinds of rubber materials having different characteristics, i.e., two rubber materials, Characterized in that different kinds of rubber materials having different characteristics are cross-disposed on the shoulder portion and the central portion.

The length (a) of the first shoulder portion and the length (c) of the second shoulder portion are set to be 20 (about 20) to the upper layer length (L), and the shoulder portion is divided into a first shoulder portion and a second shoulder portion with respect to the center portion. To 30%, and the difference between the length (a) of the first shoulder portion and the length (c) of the second shoulder portion is 10% or less.

The height (e) of the lower layer is preferably 25 to 35% with respect to the tread height (H).

On the other hand, the dissimilar rubber material is composed of a first rubber material having a fuel consumption performance and a snow performance, a second rubber material having a braking performance and a handling performance, and when the lower layer and the shoulder portion are the first rubber material, The central portion may be a second rubber material, and when the lower layer and the shoulder portion are the second rubber material, the middle portion may be the first rubber material.

And the first rubber material is lower in hardness than the second rubber material and the difference in hardness between the first rubber material and the second rubber material is preferably within 5 and the hardness of the first rubber material is less than the hardness of the shore A shore A) of 60 to 67 and the hardness of the second rubber material is shore A 65 to 72. [

Further, it is preferable that the difference between the modulus of the first rubber material and the modulus of elongation of 300% in the second rubber material is within 50.

The first rubber material has a tangent delta value, which is a loss coefficient, at a temperature of 50 to 70 DEG C lower than that of the second rubber material, for example, at a temperature of 60 DEG C, the tangent delta of the first rubber material ) Value is 0.08, and the tangent delta value of the second rubber material is preferably 0.13 to 0.15.

Wherein the second rubber material has a glass transition temperature (Tg) higher than that of the first rubber material, specifically, the glass transition temperature of the first rubber material is -23 ° C or lower, The transition temperature is preferably -18 占 폚 or lower.

The coefficient of friction between the first rubber material and the second rubber material is higher than that of the first rubber material and the abrasion resistance is preferably within 20% based on DIN (deutsche industrie normen) -53, which is a German industrial standard .

The first rubber material and the second rubber material may be natural rubber (NR), solution-styrene butadiene rubber (SBR), or the like. Butadiene rubber (BR) may be used as a base, but not limited thereto, and may include various rubber materials.

The tire tread according to the present invention is manufactured by applying different kinds of rubber materials to the shoulder portion and the central portion to improve the rolling resistance performance, the braking performance, the snow performance, and the like of the tire at the same time. The applied tires have the effect of improving the braking distance by the material of the shoulder which has good friction performance during braking and have the effect of improving the rolling resistance by the rubber material having low fuel consumption and snow performance at the central part during normal driving.

In addition, by controlling the application range of different dissimilar materials, it is possible to minimize the abnormal wear and tear of the tire tread, and by controlling the glass transition temperature (Tg) of the two materials, the snow performance There is an effect that can be satisfied.

1 is a schematic cross-sectional view of a tire tray.
2 and 3 are sectional views of a tire tray to which a different material is applied according to an example of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which illustrate exemplary embodiments of the present invention. The present invention is not limited to these embodiments.

As shown in Fig. 1, the tire includes an inner liner for holding the air of the tire, a tread contacting the road surface formed on a carcass constituting the skeleton of the tire, a belt for increasing the rigidity of the tread, It is made up of a side will.

The tire tread of the present invention will be described in more detail with reference to FIG. 1, in which a central portion 15 having the highest contact pressure of the tire in contact with the road surface, a side wing forming the side surface of the tire, An upper layer 10 formed of a shoulder portion 13 composed of a first shoulder portion 11 and a second shoulder portion 12 and disposed in contact with the road surface at an upper portion thereof, And a lower layer (20).

The upper layer 10 and the lower layer 20 are laminated with different kinds of rubber materials having different characteristics and the upper layer 10 has different characteristics in the shoulder portion 13 and the central portion 15 Are cross-arranged.

The different types of rubber materials having different characteristics used in the tire tread of the present invention include a first rubber material having a fuel consumption performance and a snow performance and a second rubber material having a braking performance and a handling performance, The different types of rubber materials may be based on one or more of natural rubber (NR), solution-styrene butadiene rubber (SBR), and butadiene rubber (BR) Various rubber materials may be included.

2 and 3 are cross-sectional views of a tire tread to which the first rubber material and the second rubber material are applied in accordance with an example of the present invention. The tire tread in FIG. 2 includes a first rubber material, And the second rubber material is applied to the shoulder portion 13 of the upper layer portion 10 while the tire tread in Figure 3 is formed by applying the second rubber material to the lower layer 20 And the first rubber material is applied to the central portion 11 of the upper layer portion 10. The first rubber material is applied to the shoulder portion 13 of the upper layer 10 simultaneously.

As shown in FIGS. 2 and 3, according to the tire tread of the present invention, the length L of the tray is determined by the length a of the first shoulder portion in the width direction of the tread, And a length c of the second shoulder portion. The height H of the tray is made up of the height d of the upper layer and the height e of the lower layer.

The tire tread according to the present invention can exhibit various characteristics depending on the size to which different dissimilar rubber materials are applied. Particularly, the length a of the first shoulder portion, the length b of the center portion, and the length c ), The braking performance, rolling resistance performance, and snow performance of the tire respond sensitively.

2, the first rubber material having the fuel consumption performance and the snow performance is applied to the lower layer 20 and the middle portion 11 of the upper layer, and the braking performance and the handling performance of the upper layer shoulder 13 (B) of the first shoulder portion, the length (c) of the second shoulder portion, the height (d) of the upper layer and the length (c) of the second shoulder portion to which different rubber materials are applied, (E) of the lower layer according to the change in size.

The comparative example is a tire tread to which a single rubber material is applied. The first rubber material or the second rubber material can be applied to the rubber material, and the tire characteristics of the comparative example can be applied to the tire of Examples 1 to 6 It shows characteristic change.

Item Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 all
Length
prepare
ratio Length a - 25% 23% 43% 45% 25% 25% b - 50% 54% 14% 10% 50% 50% c - 25% 23% 43% 45% 25% 25% Height d - 70% 70% 70% 70% 60% 80% e - 30% 30% 30% 30% 40% 20% Tire characteristics Rolling resistance index 100 110 102 97 90 110 103 Braking distance index 100 110 90 115 115 110 97 Handling index 100 100 90 110 110 90 100

As shown in Table 1, the length (a) of the first shoulder portion and the length (c) of the second shoulder portion of the tire tread constructed as shown in FIG. 2 are 20 %, The braking performance and the handling performance may deteriorate. When the ratio is 30% or more, the portion to which the second rubber material, which is a rubber material focused on the braking performance, is increased, , The length (a) of the first shoulder portion and the length (c) of the second shoulder portion are preferably 20 to 30%, and most preferably about 25%. Here, it is preferable that the difference in the ratio of the length (a) of the first shoulder portion to the length (c) of the second shoulder portion is within 10% with respect to the length L of the upper layer portion.

For example, in a tire having a size of 215 / 55R17, since the length of the tread is 215 mm, the optimum length of the shoulder portion is 53.75 mm which is 25% of the tread length. If the braking performance is to be further increased, The length of the portion can be increased to about 30% of the tread length (L).

And the ratio of the height d of the upper layer to the height e of the lower layer at the height H of the tire tread is greatly influenced by the fuel consumption performance wherein the height e of the lower layer is equal to the height H of the tread 25 to 35%, and if the ratio exceeds 35%, the handling performance may be reduced by the property of the first rubber material applied to the lower layer portion 20. [

In Table 2, a second rubber material having a braking performance and handling performance is applied to the lower layer 20 and the shoulder 13 of the upper layer as shown in FIG. 3, and the middle portion 11 of the upper layer has a fuel consumption performance and a snow performance (B) of the first shoulder portion, the length (c) of the second shoulder portion, the height (d) of the upper layer, and the length of the second shoulder portion of the first rubber material, And the height (e) of the lower layer.

Here, the comparative example is a tire tread to which a single rubber material is applied, and the first rubber material or the second rubber material can be applied to the rubber material, and the index showing the tire performance of the comparative example is 100% The change in tire characteristics of Example 12 is shown.

Item Comparative Example Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 all
Length
prepare
ratio Length a - 20% 15% 30% 35% 20% 20% b - 60% 70% 40% 30% 60% 60% c - 20% 15% 30% 35% 20% 20% Height d - 65% 65% 65% 65% 55% 75% e - 35% 35% 35% 35% 45% 25% Tire characteristics Rolling resistance index 100 105 107 98 90 98 100 Braking distance index 100 108 90 110 113 108 105 Handling index 100 100 98 105 105 110 90

Referring to the results shown in Table 2, the tire tread constructed as shown in FIG. 3 is similar to the tire treads shown in Table 1 and FIG. 2 described above, except that the length of the first shoulder portion the length of the first shoulder portion (a) and the length of the second shoulder portion (c) may be about 20% to 30% of the length of the upper layer L of the tread, the ratio of the length (c) of the first shoulder portion (a) to the length (c) of the second shoulder portion is most preferably 20%. If the ratio is less than 20%, the braking performance is deteriorated. If the ratio exceeds 30%, the rolling resistance performance of the tire may deteriorate.

The characteristics of the handling performance vary depending on the ratio of the height d of the upper layer to the height e of the lower layer at the height H of the tire tread and the height e of the lower layer is in the range of 30 to 35 %. If the ratio is more than 45%, the handling performance may be excellent, but the rolling resistance performance may be poor and the center portion may be scraped off seriously.

On the other hand, in general, the tire tread is most strongly grounded with the road surface at the center portion 11 during normal travel, and the ground pressure is the strongest. When the vehicle is braking, a load of 20% The shoulder portion 13 is strongly grounded on the road surface.

Therefore, when the tire tread is applied as shown in FIG. 2, the fuel rubber is applied to the center portion 11 and the lower layer 20 at the time of normal running, and the shoulder portion 13 ) Is excellent in braking performance due to the second rubber material having a good frictional force.

3, a second rubber material having a good frictional force is applied to the shoulder portion 13 and the lower layer portion 20 similar to those shown in FIG. 2. In the middle portion 11, The first rubber material having a lower hardness and modulus than the first rubber material is applied, thereby exhibiting excellent braking performance and handling performance.

Table 3 shows changes in tire performance depending on the characteristics of different rubber materials used in the present invention. The results are shown in Table 3. The loss factors of tan delta, hardness, tensile stress (M 300%), glass transition temperature Tg), wear index and friction coefficient.

In the present invention, the glass transition temperature is the maximum value of tangent delta (loss factor), hardness is measured according to KS M 6784, tensile strength is measured with dumbbell type 3 according to KS M 6782 . Further, the coefficient of friction was such that the tire tread sample manufactured according to the embodiment of the present invention having a diameter of 800 mm and a thickness of 16 mm was subjected to a friction coefficient of 40% at a speed of 30 km / h and a sanding material of 120 pores at roughness of 70 N, .

Comparative Example
(single) Example 13
(suggestion 1) Example 14
(Proposal 2) Example 15
(Proposal 2) Example 16
(suggestion 1) Shoulder portion
(Material B) Tan delta 60 0.16 0.14 0.14 0.15 0.15 Hardness (Shore A) 70 72 72 70 71 M 300% 110 95 95 110 120 Glass transition temperature (캜) -23 -25 -25 -23 -18 DIN wear index 100 90 90 100 80 Coefficient of friction 1.4 1.45 1.45 1.4 1.5 Center part
(Material A) Tan delta 60 0.15 0.08 0.08 0.07 0.08 Hardness (Shore A) 70 67 67 65 67 M 300% 110 90 90 85 90 Glass transition temperature (캜) -23 -23 -23 -25 -23 DIN wear index 100 100 100 90 100 Coefficient of friction 1.4 1.35 1.35 1.33 1.35 Tire Features Rolling resistance index 100 110 105 105 110 Braking distance index 100 105 108 105 110 Snow performance index 100 100 100 100 100

In Table 3, the comparative example is a tire tread to which a single rubber material is applied, and the first rubber material or the second rubber material may be applied to the rubber material, and 'Proposal 1' shown in Example 13 and Example 16 is a tire tread 2 is a tire tread having the same configuration as shown in FIG. 2, and 'Proposal 2' shown in embodiment 14 and embodiment 15 is a tire tread having a configuration as shown in FIG.

Referring to Table 3, it is preferable that the first rubber material used for the tire tread of the present invention has a hardness lower than that of the second rubber material. Specifically, as shown in Table 3, the hardness of the first rubber material is It is preferable to use a rubber material having a shore A of about 60 to 67 and a hardness of the second rubber material of a shore A level of about 65 to 72. The difference in hardness between the first rubber material and the second rubber material is preferably 5 or less.

Generally, the higher the tan delta at 0 ° C is, the better the braking performance is, and the lower the tan delta at 60 ° C is, the better the fuel efficiency is.

The first rubber material in the present invention preferably has a tangent delta value lower than that of the second rubber material at a temperature of 50 to 70 캜, and at a temperature of 60 캜 as in Table 3, the tangent delta of the first rubber material tan delta value of 0.07 to 0.08 and the tan delta value of the second rubber material is 0.13 to 0.15, so that the first rubber material has better fuel economy than the second rubber material.

Also, the second rubber material has a glass transition temperature (Tg) higher than that of the first rubber material, preferably the first rubber material is -23 ° C or less, and the second rubber material has -18 Lt; 0 > C or less, the tire tread of the present invention can have a minimum snow performance.

In order to minimize abnormal wear and tear of the tire, the first rubber material and the second rubber material, which are different rubber materials of the present invention, should exhibit a modulus difference of less than 50 at an elongation of 300% It is preferable that the friction coefficient of the second rubber material is higher than the friction coefficient of the first rubber material and the deviation thereof is less than 0.15. The abrasion resistance is preferably 20% or less based on DIN (deutsche industrie normen) -53516, The abrasion phenomenon can be minimized.

As described above, the tire tread according to the embodiment of the present invention can improve the rolling resistance performance, braking performance, and snow performance of the tire at the same time by using different kinds of materials having different characteristics at the shoulder portion and the center portion, It is possible to minimize the abnormal wear and tear of the tire tread and to satisfy the general snow performance of the tire by controlling the glass transition temperature (Tg) of the different rubber materials.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory only and are not restrictive of the invention, as claimed, and will be fully understood by those of ordinary skill in the art. The present invention is not limited thereto. It will be apparent to those skilled in the art that various substitutions, modifications and variations are possible within the scope of the present invention, and it is obvious that those parts easily changeable by those skilled in the art are included in the scope of the present invention .

10: Upper layer
11: first shoulder
12: second shoulder
13: Shoulder portion
15:
20: Lower layer

Claims (16)

A tire tread comprising a central portion in which a contact pressure of a tire is most strongly distributed in contact with a road surface and a shoulder portion disposed between the side portion of the tire and the center portion,
An upper layer having a surface contacting the road surface at an upper portion thereof; And
And a lower layer formed below the upper layer with a height (e) of 25 to 35% with respect to a height (H) of the tread,
Wherein the upper layer and the lower layer are laminated with different kinds of rubber materials having different characteristics,
Wherein a length a of the first shoulder portion or a length c of the second shoulder portion is greater than a length L of the upper layer portion of the upper shoulder portion, The difference between the length (a) of the first shoulder portion and the length (c) of the second shoulder portion is 10% or less,
A first rubber material having a fuel consumption performance and a snow performance with different kinds of rubber materials having different characteristics at the shoulder portion and the center portion in the upper layer; And a second rubber material having a braking performance and a handling performance, wherein the shoulder portion and the lower layer of the upper layer are formed of a first rubber material, and the middle portion of the upper layer is formed of a second rubber material,
Wherein the hardness of the second rubber material is Shore A 65 to 72, wherein the difference in hardness between the first rubber material and the second rubber material is within 5 and the first rubber material is less than the second rubber material And a relatively low hardness. delete delete delete delete delete delete delete delete The method according to claim 1,
Wherein a difference between a modulus of the elongation of 300% in the first rubber material and a modulus of the elongation in the second rubber material is within 50. The method according to claim 1,
Wherein the first rubber material has a tangent delta value lower than the second rubber material at a temperature of from 50 to 70 占 폚. 12. The method of claim 11,
Wherein the tangent delta value of the first rubber material is 0.08 and the tangent delta value of the second rubber material is 0.13 to 0.15 at a temperature of 60 占 폚. The method according to claim 1,
Wherein the second rubber material has a glass transition temperature (Tg) higher than that of the first rubber material, a glass transition temperature of the first rubber material is -23 ° C or lower, a glass transition temperature Lt; RTI ID = 0.0 > 18 C. < / RTI > The method according to claim 1,
Wherein the coefficient of friction of the second rubber material is higher than the coefficient of friction of the first rubber material. The method according to claim 1,
Wherein the abrasion resistance of the first rubber material and the second rubber material is within 20% based on DIN (Deutsche Industrie Normen) -53516, a German industrial standard. The method according to claim 1,
The first rubber material and the second rubber material may include one or more of natural rubber (NR), solution-styrene butadiene rubber (SBR), and butadiene rubber (BR) Features a tire tread.

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