JP5095297B2 - Studless tire and method of manufacturing studless tire - Google Patents

Description

  The present invention relates to a studless tire and a method for manufacturing a studless tire.

  One of the performances required for tires is that the appearance is clean.

  Rubbers such as natural rubber, styrene-butadiene rubber, polybutadiene rubber, and nitrile-butadiene rubber are widely used in rubber compositions for tread parts or sidewall parts of pneumatic tires. These rubber compositions for tires undergo severe bending deformation due to running over a long period of time, are exposed to ultraviolet rays under high temperature conditions, and therefore change over time and cannot withstand use. This phenomenon is called aging degradation.

  Aging of the rubber composition is caused by various factors. External factors include oxygen in the air, oxides, heat, light, ozone, manganese compounds, radiation, and repeated deformation during tire travel. On the other hand, the internal factors include the type of rubber component, the vulcanization conditions and the degree of vulcanization, the type of vulcanizing agent and the type of vulcanization accelerator. These factors interact to cause aging of the rubber.

  The deterioration phenomenon of the rubber composition includes aging due to oxygen and aging due to ozone. In the aging due to oxygen, hydrocarbon radicals and hydrogen radicals are generated under the influence of heat or light in the presence of oxygen in the hydrocarbons of the rubber molecules. The hydrocarbon radical reacts with oxygen to produce hydroperoxide, and this hydroperoxide reacts with hydrocarbons of other rubber molecules to further generate hydrocarbon radicals. When this reaction occurs in a chain manner, the main chain of the rubber molecule is decomposed and its physical properties are lowered.

  On the other hand, diene rubbers such as natural rubber, polyisoprene rubber, polybutadiene rubber and styrene-butadiene rubber are aged by ozone. Ozone reacts electrophilically with the double bond of the rubber molecule and cleaves the double bond portion, and is essentially different from the oxidation reaction. Degradation due to oxygen or ozone is further accelerated by synergistic effects due to repeated bending deformation and temperature rise during tire travel.

  Conventionally, an anti-aging agent is blended in the rubber composition in order to prevent these aging. Even when a large amount of the anti-aging agent is added in advance, the anti-aging agent in the rubber composition reacts with ozone, heat, ultraviolet rays, etc. as the tire is used for a long time, and the amount gradually digests. Therefore, the anti-aging effect is reduced.

  Since the hardness of the rubber composition increases with the progress of the aging phenomenon, there is a method of blending oil in the rubber composition as a method for keeping this hardness constant. This oil generally has the property of moving through the rubber composition, and there are examples in which the hardness is kept constant over a long period of time by preventing this, but simply by adding the oil, the tensile strength of the rubber composition is reduced. Issues such as improvement and improvement of grip performance in the tread portion remain.

  On the other hand, in the tread part of a pneumatic tire, there is an example where a recrosslinking inhibitor is blended in order to suppress changes in its physical properties. However, it is only possible to suppress curing, and a barrier effect against external environmental stimuli cannot be obtained.

  Furthermore, in order to improve the initial performance in the tread portion, there is an example in which an inorganic filler is blended, but there remains a problem that performance degradation can be prevented.

  The present invention relates to a studless tire composed of a rubber member composed of a rubber strip winding body in which rubber strips are spirally wound, and a strip upper layer rubber portion (A) composed of an upper layer rubber (a) on a body to be wound. And a strip lower layer rubber portion (B) made of a lower layer rubber (b) whose strip width is narrower than that of the strip upper layer rubber (a), and the strip lower layer rubber portion (B) is used as a tire by the strip upper layer rubber portion (A). A method of manufacturing a studless tire capable of improving appearance and ozone resistance while adopting a strip wind (STW) method on the basis of using a composite rubber strip that does not appear on the surface, and the manufacturing An object is to provide a studless tire manufactured by the method.

  The present invention relates to a studless tire manufacturing method for manufacturing a studless tire using a rubber member formed of a rubber strip winding body in which rubber strips are spirally wound, and an upper layer rubber (a) is provided on a body to be wound. A strip supply step for supplying a composite rubber strip consisting of a strip upper layer rubber part (A) comprising: and a lower layer rubber part (B) comprising a lower layer rubber (b) having a strip width narrower than the strip upper layer rubber part; A winding step of winding the supplied composite rubber strip around the member to be wound to form the rubber member, and in this winding, the strip lower layer rubber portion (B) is formed by the strip upper layer rubber portion (A). ) Does not appear on the surface of the tire.

  Moreover, this invention consists of the lower layer rubber (b) which contains more anti-aging agents than the strip upper layer rubber part (A) which consists of upper layer rubber (a) in this to-be-wrapped body, and this strip upper layer rubber part. The present invention relates to a method of manufacturing a studless tire that preferably includes a strip supply step of supplying a composite rubber strip having a concentration gradient composed of a strip lower rubber portion (B).

  The present invention also relates to a method for manufacturing a studless tire in which the composite rubber strip is preferably disposed in a tire tread portion.

  In the present invention, it is preferable that the composite rubber strip is composed of a laminated body in which an upper layer rubber strip piece formed by extruding an upper layer rubber and a lower layer rubber strip piece formed by extruding a lower layer rubber are bonded together. The present invention relates to a method for manufacturing a studless tire.

  The present invention also relates to a method for producing a studless tire, wherein the composite rubber strip is preferably formed of an extruded product obtained by integrally extruding an upper layer rubber and a lower layer rubber with a two-layer extruder.

  Moreover, this invention relates to the manufacturing method of the studless tire with which the said bonding body or the said extrusion molding was made to narrow between calender rolls.

The present invention also provides a studless tire having a rubber member made of a rubber strip wound body formed by winding rubber strips in a spiral shape, wherein the rubber strip is a strip upper layer made of an upper rubber (a). A composite rubber strip comprising a rubber part (A) and a strip lower rubber part (B) comprising a lower rubber (b), wherein the strip thickness Ts of the composite rubber strip is in the range of 0.5 to 6.0 mm. Yes, the strip upper layer rubber portion (A) has a strip width Wa of 5 to 50 mm,
The strip width Wb of the strip lower rubber part (B) is the formula (1):
Wa> Wb (1)
It relates to a studless tire that satisfies the requirements.

Further, the studless tire has a rubber member formed of a rubber strip winding body formed by spirally winding rubber strips, and the rubber strip includes a strip upper layer rubber portion (A) formed of an upper layer rubber (a). ) And a lower layer rubber part (B) made of a lower layer rubber (b), and the compounding amount of the anti-aging agent in the upper layer rubber (a) and the lower layer rubber (b) is a rubber component 100. Each is in the range of 0.3 to 4 parts by weight with respect to parts by weight, and the blending amount (Aa1) of the anti-aging agent of the upper rubber (a) and the blending amount (Bb1) of the anti-aging agent of the lower rubber (b) are Formula (2):
Aa1 <Bb1 (2)
The present invention relates to a studless tire that preferably satisfies the above requirements.

  Further, the present invention provides a strip lower layer rubber portion in which the rubber strip comprises a strip upper layer rubber portion (A) made of an upper layer rubber (a) containing an anti-aging agent and a lower layer rubber (b) containing an anti-aging agent. 9. The studless tire according to claim 8, which is a composite rubber strip comprising (B).

  The present invention also relates to a studless tire in which the composite rubber strip is preferably disposed in a tire tread portion.

  The present invention also relates to a studless tire in which the composite rubber strip is preferably disposed in a tire cap tread portion.

  The present invention relates to a studless tire composed of a rubber member composed of a rubber strip winding body in which rubber strips are spirally wound, and a strip upper layer rubber portion (A) composed of an upper layer rubber (a) on a body to be wound. And a strip lower layer rubber portion (B) made of a lower layer rubber (b) having a strip width shorter than that of the strip upper layer rubber (a), and the strip lower layer rubber portion (B) becomes a tire by the strip upper layer rubber portion (A). A method of manufacturing a studless tire capable of improving appearance and ozone resistance while adopting a strip wind (STW) method on the basis of using a composite rubber strip that does not appear on the surface, and the manufacturing A studless tire manufactured by the method can be provided.

  An embodiment of the present invention will be described with reference to the drawings.

(1) A studless tire (pneumatic tire) having the composite rubber strip of the present invention will be described.
FIG. 1 shows a cross-sectional view of a studless tire (pneumatic tire) 1 of the present embodiment constituted by the composite rubber strip 12 of the present invention. The studless tire 1 includes a tread portion 2, a pair of sidewall portions 3 extending inward in the tire radial direction from both ends thereof, and a bead portion 4 provided at an inner end of each sidewall portion 3, In this example, a tire for a passenger car is shown.

  The studless tire 1 includes, for example, a bead core 5 of each bead portion 4, a carcass 6 extending between the bead cores 5 in a toroidal shape, and a tread reinforcement cord disposed outside the carcass 6 in the tire radial direction and inside the tread portion 2. And the layer 7.

  The carcass 6 is formed of, for example, a single carcass ply having a radial structure. The carcass ply includes, for example, a toroidal main body portion 6a that straddles the bead core 5, and a pair of folded portions 6b that are continuous on both sides and folded around the bead core 5 from the inner side toward the outer side in the tire axial direction. A bead apex rubber 8 extending radially outward from the bead core 5 is disposed between the main body portion 6a and the folded portion 6b of the carcass ply.

  The tread reinforcing cord layer 7 includes a belt 9 formed by stacking two belt plies (9A and 9B) in which metal cords are arranged in the tire circumferential direction, and a tire disposed on the outer side in the tire radial direction. And a band 10 made of a band ply having a cord extending in the circumferential direction. The band 10 can be omitted as necessary.

  Each of the carcass plies of the carcass 6, the belt ply of the belt 9, and the band 10 band ply are each composed of a cord and a topping rubber covering them.

  Outside the carcass 6, a sidewall rubber 3G that forms a tire skin is disposed in the sidewall region, and a clinch rubber 4G is disposed in the bead region. Here, the outer end in the tire radial direction of the clinch rubber 4G is connected to the sidewall rubber 3G, and the inner end in the tire radial direction can contact the metal rim R.

  In the present embodiment, in the studless tire 1, the tread rubber 2 </ b> G is disposed on the outer side in the tire radial direction of the tread reinforcing cord layer 7 via the base rubber portion 11.

  Further, both side edges of the base rubber portion 11 in the tire axial direction are connected to the sidewall rubber 3G.

  The tread rubber 2G of the present invention is made of a rubber strip wound body formed by spirally winding the composite rubber strip 12 of the present invention. For easy understanding, FIG. 1 shows a boundary line between adjacent composite rubber strips 12 in the tread rubber 2G.

(2) The composite rubber strip 12 of the present invention will be described.
FIG. 2 shows a cross-sectional view of one composite rubber strip 12 in the studless tire of the present invention. In this embodiment, the composite rubber strip 12 has a flat rectangular cross section, and one of the composite rubber strips 12 includes a strip upper layer rubber portion 12a made of an upper layer rubber and a lower layer rubber having a strip width shorter than that of the upper layer rubber. And a lower strip rubber portion 12b.

(2-1) The form of the composite rubber strip 12 will be described.
As shown in FIG. 2, the composite rubber strip 12 has a strip width Wa of 5 to 50 mm and a strip thickness Ts in the range of 0.5 to 6.0 mm. When the strip width Wa is less than 5 mm, or when the strip thickness Ts is less than 0.5 mm, the number of turns of the composite rubber strip 12 is remarkably increased when the rubber member is formed by being spirally wound, and the thin strip Work formability is inferior and productivity is reduced. On the contrary, when the strip width Wa exceeds 50 mm or when the strip thickness Ts exceeds 6.0 mm, it is difficult to make a delicate cross-sectional shape. From such a viewpoint, the strip width Wa is preferably 10 to 40 mm, and more preferably 15 to 30 mm. Similarly, the strip thickness Ts is preferably 1.0 to 5.5 mm, and more preferably 2.0 to 5.0 mm.

  In the composite rubber strip 12, the strip width Wa of the strip upper layer rubber portion 12a is preferably in the range of 5 to 50 mm, and the strip thickness Ta is 1.0-2. A range of 0 mm is preferable.

The composite rubber strip 12 of the present invention comprises a strip upper layer rubber portion 12a made of an upper layer rubber and a strip lower layer rubber portion 12b made of a lower layer rubber having a strip width narrower than the upper layer rubber. And the strip width Wa of the strip upper layer rubber portion 12a is in the range of 5 to 50 mm, and the strip width Wb of the strip lower layer rubber portion 12b is represented by the formula (1):
Wa> Wb (1)
It is characterized by satisfying.

  The composite rubber strip 12 of the present invention has a flat rectangular cross section in the present embodiment, and in one of them, a strip upper layer rubber portion 12a made of an upper layer rubber, and a strip lower layer rubber portion 12b made of a lower layer rubber, Are integrally formed.

  As shown in FIG. 2, the strip upper layer rubber portion 12 a made of the upper layer rubber is a surface layer that does not penetrate the composite rubber strip 12 in the thickness direction, and one surface of the composite rubber strip 12 (composite rubber strip 12 12 strip upper layer rubber portion 12a side) F1 is formed, and the strip lower layer rubber portion 12b made of lower layer rubber is composed of the strip upper layer rubber portion 12a of the composite rubber strip 12 and the other side surface (composite rubber strip). 12 strip lower layer rubber portion 12b side surface) F2.

(2-2) The rubber composition of the composite rubber strip 12 will be described.
The upper rubber layer 12a of the strip upper rubber portion 12a and the lower rubber layer 12b of the lower rubber portion 12b constituting the composite rubber strip 12 contain diene rubber, oil, anti-aging agent and wax.

  The diene rubber component contained in the upper layer rubber and the lower layer rubber is not particularly limited. For example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), butyl rubber (IIR) ), Halogenated butyl rubber (X-IIR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), halides of copolymers of isomonoolefin and paraalkyl styrene, etc., and these diene rubbers are They may be used alone or in combination of two or more. Among these, SBR, NR, and BR are preferable, and NR and BR are more preferable because of the balance between steering stability and wear resistance, moldability, and excellent low-temperature characteristics at low temperatures as a studless blend.

  There is no restriction | limiting in particular as NR, For example, what is normally used in rubber industry, such as RSS # 3 and TSR20, can be used.

  The content of NR in the rubber component is preferably 20% by weight or more, and more preferably 30% by weight or more, because it is excellent in wet grip performance and moldability.

  There is no restriction | limiting in particular as BR, For example, what is normally used in rubber industry, such as BR150 by Ube Industries, Ltd., can be used.

  The content of BR in the rubber component is preferably 10% by weight or more, and more preferably 20% by weight or more because it is excellent in low temperature characteristics.

  It is preferable to use carbon black and silica as a filler contained in the upper layer rubber and the lower layer rubber.

  There is no restriction | limiting in particular as carbon black, For example, the thing of grades normally used in rubber industry, such as S-SAF, SAF, ISAF, HAF, and FEF, can be used.

  The amount of filler such as carbon black and silica is preferably 40 parts by weight or more, and 45 parts by weight or more with respect to 100 parts by weight of the diene rubber component because of excellent grip performance, wear resistance and low temperature characteristics. Is more preferable. Further, the blending amount of fillers such as carbon black and silica is preferably 90 parts by weight or less, and 85 parts by weight or less with respect to 100 parts by weight of the diene rubber component because of excellent wear resistance and low temperature characteristics. More preferred.

  There is no restriction | limiting in particular as oil contained in upper layer rubber | gum and lower layer rubber | gum, For example, what is normally used in rubber industry, such as aroma substitute oil or mineral oil, can be used.

  There is no restriction | limiting in particular as anti-aging agent contained in upper layer rubber | gum, and lower layer rubber | gum, For example, what is normally used in rubber industry, such as Antigen 6C or Antigen 6RD, can be used.

The blending amount of the anti-aging agent is in the range of 0.3 to 4 parts by weight with respect to 100 parts by weight of the rubber component because of excellent resistance to deterioration due to ozone resistance and heat resistance. The blending amount (Aa1) of the anti-aging agent of the upper layer rubber 12a and the blending amount (Bb1) of the anti-aging agent of the lower layer rubber of the lower rubber portion 12b are represented by the formula (2):
Aa1 <Bb1 (2)
A blend satisfying the above is preferable.

  There is no restriction | limiting in particular as wax contained in upper layer rubber | gum, and lower layer rubber | gum, For example, what is normally used in rubber industry, such as Sannoc S or Sannoc N, can be used.

The blending amount of the wax is in the range of 0.3 to 4 parts by weight with respect to 100 parts by weight of the rubber component because of excellent ozone resistance and deterioration prevention, and the wax of the upper layer rubber of the strip upper layer rubber part 12a. The blending amount (Aa1) and the blending amount (Bb1) of the wax in the lower rubber of the lower rubber part 12b are represented by the formula (2):
Aa1 <Bb1 (2)
What is necessary is just the composition which satisfy | fills.

(3) The composite rubber strip 12 will be described.
The composite rubber strip 12 of the present invention contains a diene rubber, oil, an anti-aging agent and a wax, a strip upper layer rubber portion 12a made of an upper layer rubber, and a strip lower layer made of a lower layer rubber having a strip width shorter than the upper layer rubber. The rubber portion 12b is integrally included.

  The ratio of the composite rubber strip 12 of the present invention will be described.

  The ratio of the composite rubber strip 12 in the present invention means the ratio of the upper layer rubber and the lower layer rubber. For example, by appropriately adjusting the thickness Ta of the strip upper layer rubber part 12a and the thickness Tb of the strip lower layer rubber part 12b. Can be adjusted.

  Moreover, the composite rubber strip 12 of the present invention can provide a studless tire capable of improving the appearance and ozone resistance because the concentration gradient of the antioxidant and the wax can be controlled.

  Here, since the composite rubber strip 12 of the present invention comprises the strip upper layer rubber portion 12a and the strip lower layer rubber portion 12b, the total ratio of the strip upper layer rubber portion 12a and the strip lower layer rubber portion 12b is set to 100 (%).

  For example, when the thickness Ta of the strip upper layer rubber portion 12a and the thickness Tb of the strip lower layer rubber portion 12b are defined, the ratio of the strip lower layer rubber portion 12b to the composite rubber strip 12 is a chemical having a high anti-aging performance capability in the lower layer rubber portion. It is said that it is possible to prevent precipitation on the tire surface and improve the appearance by reducing the amount of chemicals with high anti-aging performance ability in the upper rubber part of the tire surface part. For the reason, 50 or more is preferable, and 55 or more is more preferable.

  As shown in FIG. 2, for example, when the strip width of the strip upper layer rubber portion 12a of the composite rubber strip 12 and the strip width of the strip lower layer rubber portion 12b are the same, the strip thickness Ta of the strip upper layer rubber portion 12a and the strip By adjusting the strip thickness Tb of the lower rubber portion 12b, the ratio of the strip upper rubber portion 12a and the strip lower rubber portion 12b can be adjusted.

  The upper rubber layer 12a and the lower rubber layer 12b of the upper rubber layer 12a constituting the composite rubber strip 12 of the present invention are diene rubber, oil, anti-aging agent, wax, carbon black, sulfur and other vulcanizing agents, In addition to various vulcanization accelerator short fibers, compounding agents conventionally blended in the tire industry, for example, reinforcing fillers other than carbon black typified by silica, stearic acid, zinc oxide, etc., as appropriate Can be blended.

(4) A method for manufacturing a studless tire (pneumatic tire) having the composite rubber strip 12 of the present invention (strip wind (STW) method) will be described.
3-6 shows the process of making the tread rubber 2G by a strip wind (STW) system using the composite rubber strip 12 of the present invention.

(4-1) The aspect of the composite rubber strip 12 in the tread rubber 2G will be described.
FIG. 3 shows a tread rubber 2G produced by a strip wind (STW) system using the composite rubber strip 12 in the studless tire of the present invention. In FIG. 3, a tread reinforcing cord layer 7 and a base rubber portion 11 are arranged in advance on the molding surface of the molding drum. The base rubber portion 11 in FIG. 3 is formed in an annular shape by continuously winding one rubber strip from one end S1 in the width direction to the other end S2 in a spiral manner with an allowance, for example. Is shown. Such winding of the rubber strip is performed by, for example, fixing one end of a rubber strip continuously supplied from an extruder at a predetermined position in the width direction of the molding drum and rotating the rubber strip while rotating the molding drum. This is done by moving the comb in the direction.

  Next, as shown in FIG. 3, a tread rubber 2G is formed on the outside of the base rubber portion 11 using the composite rubber strip 12 of the present invention.

  In this step, the base rubber portion 11 wound around the molding drum in advance is used as a body to be wound, and as shown conceptually in FIGS. A strip supplying step for supplying the attached body, and a winding step for forming the tread rubber 2G by continuously winding the supplied composite rubber strip 12 on the attached body using a strip winding device having a feed roller. And have.

  The tread rubber 2G according to the present embodiment is wound around the rubber strip by winding the composite rubber strip 12 in a spiral shape with an allowance from one end S1 to the other end S2 of the base rubber portion 11. Formed as a body. The thickness of the rubber strip winding body can be changed, for example, by changing the winding pitch of the composite rubber strip 12 in the width direction. In the example of FIG. 3, the composite rubber strip 12 is moved from one end S1 to the other end S2 to finish winding. For example, the composite rubber strip 12 is turned around at the other end S2 and wound in two layers to be tread rubber 2G. Can also be formed.

  FIG. 4 shows a partially enlarged view of the tread rubber 2G in which the composite rubber strip 12 in the studless tire of the present invention is made by the winding step. In the tread rubber 2G, the composite rubber strip 12 has a predetermined winding pitch P and is sequentially displaced in the width direction.

  Accordingly, the composite rubber strip 12 is spirally wound with the strip upper layer rubber portion 12a facing outward in the radial direction (that is, with the surface F1 facing outward in the radial direction). It becomes possible to expose the upper rubber portion 12a on the outer circumferential surface of the tread rubber 2G in the radial direction. Even after vulcanization molding of the composite rubber strip 12, only the strip upper layer rubber portion 12a, which is a feature of the present invention, can be exposed on the outer peripheral surface because the strip width of the strip lower layer rubber portion 12b is short. .

  Next, the tread rubber 2G made in this way is removed from the molding drum together with the tread reinforcing cord layer 7 and the base rubber portion 11. These are extrapolated to the carcass ply, the side wall rubber 3G, and the clinch rubber 4G wound around the molding former in a cylindrical shape, and are integrated with the carcass ply shaved in a toroidal shape. Thereby, a raw cover is formed. The green cover is vulcanized by a vulcanization mold to produce a studless tire (pneumatic tire) 1.

  The studless tire 1 obtained by vulcanizing such a raw cover has a flat rectangular cross section in the present embodiment, and in one of them, a strip upper layer rubber portion 12a made of an upper layer rubber and a strip upper layer rubber portion 12a. Since it is composed of the composite rubber strip 12 of the present invention that is integrally formed with the lower strip rubber portion 12b made of the lower rubber having a shorter strip width, only the upper strip rubber portion 12a is exposed on the outer peripheral surface. Thereby, the studless tire (pneumatic tire) 1 which can improve an external appearance and ozone resistance can be provided.

  Therefore, according to the present invention, it is possible to provide a studless tire (pneumatic tire) 1 that can improve appearance and ozone resistance while adopting a strip wind (STW) system. Moreover, since the strip width of the strip lower layer rubber portion 12b made of the lower layer rubber is shorter than the strip width of the strip upper layer rubber portion 12a made of the upper layer rubber, only the strip upper layer rubber portion 12a made of the upper layer rubber is the outer periphery at any wear stage. Can be exposed at the surface.

(4-2) Production of the tread rubber 2G from the composite rubber strip 12 will be described.
FIG. 5 shows the production of the composite rubber strip 12 in the studless tire of the present invention by the integral extrusion forming apparatus. The composite rubber strip 12 can be formed by a composite rubber strip forming device 13 as shown in FIG. In this example, the composite rubber strip forming apparatus 13 is a two-layer extruder, and the upper rubber layer and the lower layer rubber are integrally extruded by the two-layer extruder 13 to form the composite rubber strip 12 as an extruded molded body 14. Illustrated.

  In addition, also in the extrusion molding 14 shown in FIG. 5, there exists a tendency for a protruding part etc. to be formed in the surface F1 (or F2) of the composite rubber strip 12 by the difference in shrink amount of upper layer rubber and lower layer rubber, Therefore Also in the case of integral extrusion molding, it is preferable that the extrusion molded body 14 is narrowed by calendar rolls 18 and 18 in order to smooth the surface F1 (or F2).

  FIG. 6 shows the production of the composite rubber strip 12 in the studless tire of the present invention by two extruders. Moreover, as a composite rubber strip forming apparatus, as shown in FIG. 6, two independent extruders 15A and 15B can be used. In this case, the strip piece 16a of the strip upper layer rubber portion made of the upper layer rubber of the extruder 15A and the strip piece 16b of the strip lower layer rubber portion made of the lower layer rubber of the extruder 15B are respectively extruded. And the composite rubber strip 12 can also be formed as the bonding body 17 which bonded these strip pieces 16a and 16b together.

  In addition, in order to raise the adhesion between strip pieces 16a and 16b, it is preferable to make the said bonding body 17 narrow between calender rolls 18 and 18. FIG.

  As mentioned above, although the especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.

  In the embodiment of the present invention, as an example, a strip has a flat rectangular cross section, one of which is a strip upper layer rubber portion 12a made of an upper layer rubber, and a lower layer rubber having a strip width shorter than that of the strip upper layer rubber portion 12a. In the composite rubber strip 12 of the present invention, which is configured to integrally include the strip lower layer rubber portion 12b, the upper layer rubber is changed at any wear stage by appropriately changing the blending amounts of predetermined oil, anti-aging agent and wax. This is a composite rubber strip 12 in which only the strip upper layer rubber portion 12a made of can be exposed on the outer peripheral surface, and a studless tire having improved appearance and ozone resistance, and a method for manufacturing the same are shown. However, other formulations can of course be employed according to the performance required for the tire.

  The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described together.
Styrene-butadiene rubber (SBR): N9520 (37.5 wt% oil-extended polymer) manufactured by Sumitomo Chemical Co., Ltd.
Carbon Black: Dia Black I (ISAF, N220) manufactured by Mitsubishi Chemical Corporation
Oil: Process P-200 manufactured by Japan Energy Co., Ltd.
Anti-aging agent: Antigen 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
Wax: Sunnock S manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Stearic acid: Nippon Oil & Fats Co., Ltd. Zinc Hana: Mitsui Mining & Smelting Co., Ltd. Sulfur: Tsurumi Chemical Industry Co., Ltd. Vulcanization Accelerator: Nouchira NS (N-tert-) Butyl-2-benzothiazolylsulfenamide)

(Production of studless tires)
The studless tire of the present invention having the basic structure shown in FIG. 1 can be manufactured by forming the rubber composition for a tread or the rubber composition for a cap tread of the present invention as a tread or a cap tread by a strip wind (STW) method. .

(1) Production of rubber composition for base tread Using a Banbury mixer, chemicals other than sulfur and a vulcanization accelerator were kneaded for 4 minutes at 160 ° C. or lower to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the kneaded product obtained, and kneaded for 2 minutes under a condition of 100 ° C. or lower using an open roll to obtain an unvulcanized rubber composition. Further, the obtained unvulcanized rubber composition was press vulcanized for 15 minutes at 170 ° C. to obtain a rubber composition for base tread.

(2) Production of rubber compositions A to I for cap treads According to the formulation shown in Table 1, chemicals other than sulfur and a vulcanization accelerator were kneaded for 4 minutes under a condition of 160 ° C or lower using a Banbury mixer. And kneaded material was obtained. Next, sulfur and a vulcanization accelerator were added to the kneaded product obtained, and kneaded for 2 minutes under a condition of 100 ° C. or lower using an open roll to obtain an unvulcanized rubber composition. Further, the obtained unvulcanized rubber composition is laminated on a base tread by a strip wind method as a rubber member for cap tread, and press vulcanized at 170 ° C. for 15 minutes to obtain a rubber composition for cap tread. Products A to I were obtained.

(3) Production of studless tires (Examples 1 to 3 and Comparative Examples 1 to 3)
The rubber composition for base tread and the rubber composition for cap tread in an unvulcanized state are extruded into a two-layer tread in the combination shown in Table 2 and Table 3, and the cap tread rubber of the present invention is formed by a strip wind method. The test studless tire DS2 (tire size: 195 / 65R15) of Examples 1 to 3 and Comparative Examples 1 to 3 was manufactured by pasting together with other members and press vulcanizing for 15 minutes at 170 ° C. .

  The strip thickness Ts of the slip of the composite rubber strip of any one of Examples 1 to 3 and Comparative Examples 1 to 3 was set to 4.0 mm. In any of the examples and comparative examples, the slip width Wa of the strip upper rubber portion 12a was 25 mm, and the slip width Wb of the strip lower rubber portion 12b was 20 mm.

  In Example 1, the strip thickness Ta of the strip upper layer rubber portion 12a is 2.0 mm and the strip thickness Tb of the strip lower layer rubber portion 12b is 2.0 mm. In Table 1, the Ta / Tb ratio (upper layer / lower layer) is shown. ) Was described as 50/50.

(4) Production of studless tire by conventional method (Comparative Example 4)
Using a Banbury mixer, chemicals other than sulfur and a vulcanization accelerator were kneaded for 4 minutes under a condition of 160 ° C. or lower to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the kneaded product obtained, and kneaded for 2 minutes under a condition of 100 ° C. or lower using an open roll to obtain an unvulcanized rubber composition. Further, the obtained unvulcanized rubber composition was press vulcanized for 15 minutes at 170 ° C. to obtain a rubber composition A for cap tread and a rubber composition for base tread.

  The rubber composition for base tread and the rubber composition A for cap tread in an unvulcanized state are bonded together by a conventional method (Table 3), and press vulcanized for 15 minutes at 170 ° C. The test studless tire DS2 (tire size: 195 / 65R15) was manufactured.

  And the external appearance and ozone resistance of the test tire of Examples 1-3 and Comparative Examples 1-4 were measured.

Examples 1-3 and Comparative Examples 1-4
(appearance)
The appearance of the manufactured new tire was visually evaluated by five examiners, and the average was taken as the evaluation value. The appearance of Comparative Example 4 (studless tire according to the conventional method) was evaluated on a 10-point scale with a reference value of 5. The higher the evaluation value, the more the chemical is deposited on the surface and the better the appearance is. In Tables 2 and 3, the external appearance (original) is a value obtained by evaluating the external appearance of the manufactured new tire, and the external appearance (after thermal labor) is the exposure of the manufactured new tire in an atmosphere at a temperature of 80 ° C. for 2 weeks. It is the value which evaluated the subsequent external appearance.

(Ozone resistance)
The manufactured new tire was evaluated for ozone resistance after exposure for 48 hours in an atmosphere having an ozone concentration of 50 pphm according to JIS K6259. The ozone resistance of Comparative Example 4 (studless tire according to the conventional method) was evaluated on a 10-point scale with a reference value of 5. It shows that it is excellent in ozone resistance, so that the value of an evaluation value is high. In Tables 2 and 3, the ozone resistance (original) is a value obtained by evaluating the ozone resistance of the manufactured new tire, and the ozone resistance (after thermal labor) is the ozone atmosphere of the manufactured new tire. It is a value obtained by evaluating the ozone resistance after exposure for 2 hours in an atmosphere of 80 ° C. after exposure below.

  Examples 1 to 3 are studless tires prepared as a tread rubber blend by adopting a strip wind method for a base blend and a cap blend. It can be seen that in the appearance and ozone resistance performance, both the original and after heat aging show good evaluation results.

  Comparative Example 1 is a studless tire in which a base blend and a cap blend are formed as a tread rubber blend by adopting a strip wind method. In the cap blend, a studless tire in which the strip upper layer and the strip lower layer are both A. It can be seen that the external appearance and ozone resistance performance show evaluation results that are inferior to those of the examples both in the original and after heat aging.

  Comparative Example 2 is a studless tire prepared as a tread rubber compound by adopting a strip wind method for the base compound and the cap compound, but the strip upper layer F in which the compounding amount of the anti-aging agent does not satisfy the present invention in the cap compound. Including studless tires. Appearance is good both in the original and after heat aging. However, in the ozone resistance, it can be seen that both the original and after heat aging show evaluation results that are inferior to the examples.

  Comparative Example 3 is a studless tire produced as a tread rubber compound by adopting a strip wind method for a base compound and a cap compound, but the stud compound includes a strip upper layer G in which the compounding amount of wax does not satisfy the present invention in the cap compound. Tire. Appearance is good both in the original and after heat aging. However, in the ozone resistance, it can be seen that both the original and after heat aging show evaluation results that are inferior to the examples.

1 is a cross-sectional view of a studless tire (pneumatic tire) 1 according to an embodiment composed of a composite rubber strip 12 of the present invention. 1 is a cross-sectional view of one composite rubber strip 12 in a studless tire of the present invention. The tread rubber 2G produced by the strip wind (STW) system using the composite rubber strip 12 in the studless tire of the present invention is shown. The composite rubber strip 12 in the studless tire of the present invention is a partially enlarged view of the tread rubber 2G produced by the winding step. The production of the composite rubber strip 12 in the studless tire of the present invention by the integral extrusion forming apparatus is shown. The production of the composite rubber strip 12 in the studless tire of the present invention by two extruders is shown.

Explanation of symbols

1 Studless tire (pneumatic tire)
2 Tread part 2G Tread rubber 3 Side wall part 3G Side wall rubber 4 Bead part 4G Clinch rubber 5 Beat core 6 Carcass 6a Carcass ply main part 6a Carcass ply turn part 7 Cord layer 8 Bead apex rubber 9 Belt 9A Belt ply 9B Belt Ply 10 Band 11 Base rubber part 12 Composite rubber strip 12a Strip upper layer rubber part 12b Strip lower layer rubber part 13 Composite rubber strip forming device (two-layer extruder)
14 Extruded body 15A integrally extruded and formed 15A Two extruders 15B Two extruders 16a Upper rubber strip piece 16b Lower rubber strip piece 17 Laminated upper rubber strip piece and lower rubber strip piece 18 Calendar Roll F1 Surface of the upper rubber portion of the composite rubber strip F2 Surface of the lower rubber portion of the composite rubber strip P Winding pitch R Metal rim S1 One end S2 of the rubber strip in the width direction S2 Other end portion Ts Composite rubber strip thickness Ta Strip upper layer rubber portion thickness Tb Strip lower layer rubber portion thickness Wa Strip upper layer rubber portion strip width Wb Strip lower layer rubber portion strip width

Claims (10)

A studless tire manufacturing method for manufacturing a studless tire using a rubber member formed of a rubber strip winding body in which rubber strips are spirally wound,
The wound body includes a strip upper layer rubber portion (A) made of an upper layer rubber (a) and a strip lower layer rubber portion (B) made of a lower layer rubber (b) whose strip width is narrower than the strip upper layer rubber portion. A strip supplying step for supplying a composite rubber strip;
A winding step of winding the supplied composite rubber strip around the wound body to form the rubber member;
And in this winding, the strip lower layer rubber part (B) does not appear on the tire surface by the strip upper layer rubber part (A), The manufacturing method of the studless tire characterized by the above-mentioned. A strip upper layer rubber part (A) made of an upper layer rubber (a) and a lower layer rubber part (B) made of a lower layer rubber (b) containing more anti-aging agent than the strip upper layer rubber part. The method for manufacturing a studless tire according to claim 1, further comprising a strip supplying step for supplying a composite rubber strip having a concentration gradient consisting of: The method for manufacturing a studless tire according to claim 1, wherein the composite rubber strip is disposed in a tire tread portion. The composite rubber strip is composed of a laminated body in which an upper layer rubber strip piece formed by extruding an upper layer rubber and a lower layer rubber strip piece formed by extruding a lower layer rubber are bonded to each other. The manufacturing method of the studless tire of 2 or 3. 4. The method of manufacturing a studless tire according to claim 1, wherein the composite rubber strip is made of an extruded product obtained by integrally extruding an upper layer rubber and a lower layer rubber by a two-layer extruder. The method for manufacturing a studless tire according to claim 4 or 5, wherein the bonded body or the extruded body is subjected to a narrow pressure between calender rolls. A studless tire having a rubber member made of a rubber strip winding body formed by spirally rolling rubber strips,
The rubber strip is a composite rubber strip composed of a strip upper layer rubber part (A) composed of an upper layer rubber (a) and a strip lower layer rubber part (B) composed of a lower layer rubber (b),
A strip thickness Ts of the composite rubber strip is in a range of 0.5 to 6.0 mm;
The strip upper layer rubber portion (A) has a strip width Wa of 5 to 50 mm,
The strip width Wb of the strip lower rubber part (B) is the formula (1):
Wa> Wb (1)
Meet studless tires. A studless tire having a rubber member made of a rubber strip winding body formed by spirally rolling rubber strips,
The rubber strip is a composite rubber strip composed of a strip upper layer rubber part (A) composed of an upper layer rubber (a) and a strip lower layer rubber part (B) composed of a lower layer rubber (b),
The amount of the anti-aging agent in the upper layer rubber (a) and the lower layer rubber (b) is in the range of 0.3 to 4 parts by weight with respect to 100 parts by weight of the rubber component,
Amount of antioxidant upper rubber (a) is intended less than the amount of antioxidant in the lower rubber (b),
The amount of the wax in the upper rubber layer (a) and the lower rubber layer (b) is in the range of 0.3 to 4 parts by weight with respect to 100 parts by weight of the rubber component,
The studless tire according to claim 7 , wherein the amount of the upper rubber layer (a) is less than the amount of the lower rubber layer (b) . The studless tire according to claim 7 or 8 , wherein the composite rubber strip is disposed in a tire tread portion. The studless tire according to claim 7, 8 or 9 , wherein the composite rubber strip is disposed in a tire cap tread portion.

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