JP2014159524A - Rubber composition, method for manufacturing tire using the same, and rubber member for tire using the rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition and a production method of the composition having excellent storage stability, achieving short-time vulcanization and having excellent resistance to thermal aging, and to provide a method for manufacturing a tire using the composition, and a rubber member for a tire using the rubber composition.SOLUTION: The rubber composition includes, with respect to 100 parts by mass of a diene rubber, 0.1 part by mass to 4.0 parts by mass of a xanthate compound and 50 parts by mass or less of carbon black having a nitrogen adsorption specific surface area (NSA) of 50 m/g or less. In the production method of the rubber composition, a rubber composition having the above compounding composition is kneaded in two or more stages; and carbon black is added and kneaded in a stage prior to, at least by one or more stages, the stage of compounding the xanthate compound.

Description

  The present invention relates to a rubber composition, a method for producing a tire using the rubber composition, and a rubber member for a tire using the rubber composition, and in particular, has excellent storage stability and realizes short-time vulcanization. The present invention relates to a rubber composition excellent in heat aging resistance, a method for producing a tire using the rubber composition, and a tire rubber member using the rubber composition.

  In the manufacture of retread tires (retread tires) in the past, the tread surface of a tire that has been worn out and has finished its primary life (hereinafter referred to as “base tire”) is buffed, and a vulcanized retread tread rubber portion ( = Precured tread) is known as one of the typical methods. This method is called by a name such as a cold (COLD) method or a precure method, and is distinguished from a hot (HOT) method in which an unvulcanized tread rubber is placed on a base tire and mold vulcanized.

  In the COLD system, in order to bond the base tire and the precure tread, an unvulcanized cushion rubber is first applied to the base tire, and further, the precure tread is attached to the vulcanized can. The method of heating at 110 ° C. to 140 ° C. for 2 hours to 3 hours is general. The cushion rubber used in this system flows into the buffs of the base tire, smoothes the adhesive surface, and co-vulcanizes with both the base tire and the pre-cured tread to ensure the adhesion between the pre-cured tread and the base tire. It has a function. Therefore, the cushion rubber is located between the base tire and the pre-cured tread, that is, in a portion where stress is concentrated. When an actual retread tire is used, the adhesive / anti-destructive property of this portion is the durability of the retread tire. (Precure tread should not be peeled off from the base tire).

  In such a COLD type vulcanization, it is necessary to consider that the vulcanized base tire is not over-cured by being reheated. For this reason, between the base tire and the precure tread, The cushion rubber composition (adhesive rubber composition) to be placed is required to have a rubber that can be vulcanized and bonded at a relatively low temperature in a short time. Conventionally, as a blending means for increasing the vulcanization speed, a method of increasing the amount of sulfur or a vulcanization accelerator, or a method of utilizing a so-called super accelerator such as a dithiocarbamine compound as a vulcanization accelerator is usually used. ing.

For example, benzothiazyl disulfide (DM) or mercaptobenzothiazole (M) / tetrabenzylthiuram disulfide (ZTC) or zinc dibenzyldithiocarbamate (TBzTD) / curing amine activation as a compounding means for accelerating rubber vulcanization A method of vulcanizing at a temperature of 95 ° C. to 140 ° C. using a composition containing an agent (amine accelerator) is known (for example, see Patent Document 1).
However, this method cannot sufficiently increase the vulcanization rate (for example, vulcanization time t ₉₉ at a vulcanization temperature of 110 ° C. (heating time necessary to achieve a crosslinking progress of 0.99) is 18.6. The tire has a problem of requiring a vulcanization time of 2 hours at 110 ° C.

In addition, as a rubber composition that is excellent in scorch prevention and that can be vulcanized and molded at low temperature and in a short time once vulcanization is started, diene rubber, vulcanizing agent, soft carbon as reinforcing agent, and tackifier A rubber composition comprising an aliphatic hydrocarbon, a mixture of a thiazole vulcanization accelerator and a dithiocarbamic acid vulcanization accelerator as a vulcanization accelerator, and a processing aid for reducing the viscosity, In the production of a retreaded tire, the cushioning sheet used for bonding the base tire and the tread part is characterized in that the content of the processing aid is 5 to 10 parts by weight with respect to 100 parts by weight of the diene rubber. A rubber composition to be used is known (for example, see Patent Document 2).
However, in the cushion rubber and the like described in Patent Document 2, a thiazole vulcanization accelerator and a dithiocarbamic acid vulcanization accelerator are blended, and soft carbon is blended as a filler to achieve a low viscosity. However, as in the present invention, the adsorption of the vulcanization accelerator to the carbon black is suppressed by combining the specific vulcanization accelerator different from the above-mentioned Patent Document 2 and the carbon black having specific properties. There is no description or suggestion that the storage stability of the vulcanization rate is improved, and the technical idea is different from the present invention.

  In the production of rectified tires, the vulcanization process is a time-consuming process, and shortening of the vulcanization time is required to improve productivity. It is known that the vulcanization time can be shortened by increasing the vulcanization temperature, but it is accompanied by a decrease in performance such as a decrease in durability of the retread tire as a product and a decrease in rolling resistance. Also, the vulcanization time can be shortened by adding a large amount of vulcanization accelerator to the retread cushion, but in this case, the heat aging property is deteriorated, and there is a concern that the durability may be deteriorated due to the heat history applied during traveling. . Moreover, the storage stability of the vulcanization rate is also important for improving productivity. Rubber vulcanization rates change during storage. Therefore, in order to suppress the effect of changes in the vulcanization speed, it is necessary to set a shorter use date for the cushion rubber or to set a longer vulcanization time so that even the latest vulcanized rubber within the date can be vulcanized. There is the present situation.

Japanese Patent No. 3565954 (Claims, Examples, etc.) JP 05-1176 (Claims, Examples, etc.)

  The object of the present invention is to solve the problems and current state of the prior art, and is excellent in storage stability of the vulcanization rate, can achieve vulcanization for a short time, and It is an object of the present invention to provide a rubber composition excellent in heat aging, a method for producing the same, a method for producing a tire using the same, a tire rubber member using the rubber composition, and the like.

  As a result of intensive investigations on the above-described conventional problems and the like, the present inventors have found that a specific compound serving as a vulcanization accelerator and carbon black having specific characteristics are within a specific amount range with respect to 100 parts by mass of the rubber component. It aims at providing the rubber composition for the said objective by using it, the manufacturing method of the tire using the same, the rubber member for tires using this rubber composition, etc.

The present invention resides in the following (1) to (6).
(1) 0.1 parts by mass to 4.0 parts by mass of a xanthate compound and 50 parts by mass or less of carbon black having a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or less with respect to 100 parts by mass of the rubber component. A rubber composition comprising the rubber composition.
(2) According to JIS K6300-2: 2001, the time (T0.9) required to obtain 90% of the maximum value of the vulcanization torque curve measured at a temperature of 120 ° C. is 14 minutes or less. The rubber composition according to (1) above.
(3) 0.1 parts by mass to 4.0 parts by mass of a xanthate compound and 50 parts by mass or less of carbon black having a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or less with respect to 100 parts by mass of the diene rubber. A method for producing a rubber composition, comprising kneading a rubber composition containing at least two stages and adding and kneading carbon black in at least one stage prior to disposing a xanthate compound.
(4) In the method for manufacturing a tire in which an adherend tire member and a tire member are bonded through an adhesive rubber composition, the rubber composition according to (1) or (2) is used. Tire manufacturing method.
(5) A tire manufactured by the method described in (4) above.
(6) A rubber member for tires using the rubber composition according to (1) or (2).

  According to the present invention, vulcanization during storage is less likely to occur, the rubber composition is excellent in storage stability, can achieve vulcanization for a short time, and is excellent in heat aging, and uses the same. A tire manufacturing method and a tire rubber member using the rubber composition can be provided.

(Rubber composition)
The rubber composition of the present invention is a carbon having 0.1 to 4.0 parts by mass of a xanthate compound and a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or less with respect to 100 parts by mass of the rubber component. It contains 50 parts by mass or less of black.

(Rubber component)
The rubber component used in the present invention is not particularly limited. For example, natural rubber, various butadiene rubbers, various styrene-butadiene copolymer rubbers, isoprene rubber, butyl rubber, halogenated butyl rubber, acrylonitrile butadiene rubber, chloroprene rubber, Diene rubbers such as ethylene-propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene copolymer rubber; copolymer of isobutylene and p-methylstyrene Polymer bromide; ethylene-propylene copolymer rubber; chlorosulfonated polyethylene; acrylic rubber; epichlorohydrin rubber; polysulfide rubber; silicone rubber; fluorine rubber;
These can be appropriately selected according to the composition of the rubber of the tire member to be bonded and the rubber of the tire member, and can be appropriately selected to obtain high adhesion, and may be used alone or in combination of two or more. May be.
Among these, diene rubbers, in particular, natural rubber are preferable in terms of tackiness, adhesion between the bonded tire member and the tire member, and ease of sticking to the bonded tire member.

(Xanthate compounds)
The xanthate compound used in the present invention is contained as a vulcanization accelerator.
In the present invention, the xanthate compound used means xanthate having a chemical structure of -OC (= S) -S- and its derivatives.
Specific examples of the xanthate compounds that can be used are not particularly limited and may be appropriately selected depending on the purpose. Sodium isopropylxanthate, zinc ethylxanthate, zinc isopropylxanthate, zinc dibutylxanthate, butyl Examples include zinc xanthate and dibutyl xanthogen disulfide. These may be used individually by 1 type and may use 2 or more types together.
Among these, zinc isopropylxanthate and zinc butylxanthate are preferable in that the maximum torque can be obtained in the vulcanization curve, the elastic modulus after vulcanization is high, and vulcanization can be efficiently performed. In addition, vulcanization accelerators other than xanthate compounds can be used in combination as long as the effects of the present invention are not impaired.

  In the present invention, a xanthate compound is used as a vulcanization accelerator, and by using a specific carbon black described later, a sulfur crosslinking reaction can be promoted at a lower temperature than a conventional vulcanization accelerator. Short vulcanization and improved durability of the product retread tire can be realized.

The content of the xanthate compound to be used is not particularly limited as long as it is 0.1 to 4.0 parts by mass with respect to 100 parts by mass of the rubber component, and can be appropriately selected according to the purpose. However, 0.3 mass part-3.5 mass parts are preferable, 0.5 mass part-3.0 mass parts are more preferable, 0.7 mass part-2.0 mass parts are especially preferable.
If the content of the xanthate compound is less than 0.1 parts by mass, the effects of the present invention cannot be obtained, while if it exceeds 4.0 parts by mass, vulcanization occurs at an early stage, and the adhesive strength ( Peel strength) and processability are reduced.

(Carbon black)
The carbon black used in the present invention is required to have a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or less, preferably 45 m ² / g or less, particularly preferably 30 to 45 m ² / g. It is desirable to use carbon black. In the present invention (including examples and the like to be described later), the nitrogen adsorption specific surface area (N ₂ SA) refers to a value measured according to JIS K 6217-2: 2001.

If the nitrogen adsorption specific surface area (N ₂ SA) of the carbon black to be used exceeds 50 m ² / g, the change in the vulcanization rate during storage becomes large, which is not preferable.
The carbon black that can be used specifically, the nitrogen adsorption specific surface area _(N 2 SA) is less than ^{_{50m 2 / g N660 (N 2}} SA: 35m 2 / g), N550 (N 2 SA: 40m 2 / g), N630 (N ₂ SA: 32 m ² / g), N642 (N ₂ SA: 39 m ² / g), N650 (N ₂ SA: 36 m ² / g), N683 (N ₂ SA: 36 m ² / g) , N765 (N ₂ SA: 34 m ² / g), and the like.
By using carbon black having these characteristics, the storage stability of the vulcanization rate can be improved.

The content of carbon black having the above characteristics is required to be 50 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of tackiness that affects workability during production of retread tires. Mass parts to 50 parts by mass are more preferable, and 30 parts to 40 parts by mass are particularly preferable.
If the carbon black content exceeds 50 parts by mass, the tackiness may be insufficient due to insufficient tackiness. Moreover, the effect of this invention can fully be demonstrated by setting it as 20 mass parts or more.

The rubber composition of the present invention contains at least the rubber component, a xanthate compound, and carbon black having the above characteristics, and further requires a vulcanizing agent such as sulfur (including insoluble sulfur), other components, and the like. It can be contained accordingly.
The content of the vulcanizing agent such as sulfur (including insoluble sulfur) is preferably from 0 to 100 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoints of the effects of the present invention and the heat deterioration resistance of the vulcanized rubber. 1 mass part-5.0 mass parts are preferable, More preferably, 1 mass part-4 mass parts are preferable, Especially 2.0 mass parts-3.0 mass parts are more preferable.

  In addition, if necessary, other components such as a tackifier (tackifier), a reinforcing agent, a softener, a filler, a vulcanization aid, a colorant, a flame retardant, Known materials such as lubricants, foaming agents, plasticizers, processing aids, antioxidants, anti-aging agents, UV inhibitors, antistatic agents, anti-coloring agents, and other compounding agents can be appropriately used.

The rubber composition of the present invention configured as described above has a maximum vulcanization torque curve measured at a temperature of 120 ° C. in accordance with JIS K6300-2: 2001 from the viewpoint of suppressing thermal deterioration of the base tire during vulcanization. The time required to obtain 90% of the value (T0.9) is preferably 14 minutes or less, more preferably 11 minutes or less.
In order to set T0.9 to 14 minutes or less, the type and amount of the xanthate compound and carbon black can be appropriately set within the above time.

[Method for producing rubber composition]
The rubber composition of the present invention is produced by kneading a rubber component, a xanthate compound, a carbon black having the above characteristics, a vulcanizing agent such as sulfur (including insoluble sulfur), and other components. However, preferably, from the viewpoint of sufficiently dispersing carbon black and taking the fracture resistance of rubber, it has a kneading process of two or more stages, and at least one or more before the vulcanization accelerator is disposed in the carbon black. It is desirable to manufacture by including the process of adding and kneading in this step.

In the rubber composition of the present invention configured as described above, 0.1 to 4.0 parts by mass of a xanthate compound and a nitrogen adsorption specific surface area (N ₂ SA) are 50 m ^{2 with} respect to 100 parts by mass of the rubber component. By containing 50 parts by mass or less of carbon black of / g or less, it is excellent in storage stability of vulcanization speed, and realizes vulcanization in a short time without impairing various performances such as durability and low exothermic property. A rubber composition excellent in heat aging and a method for producing the same can be obtained. On the other hand, a rubber composition that falls outside the scope of the present invention cannot exhibit the effects of the present invention (this point will be further described in a comparative example described later).

(Tire manufacturing method)
The tire manufacturing method of the present invention (hereinafter simply referred to as “the method of the present invention”) is a method for manufacturing a tire in which a tire member to be bonded and a tire member are bonded via an adhesive rubber composition. The rubber composition of the present invention is used as a rubber composition.
The method for producing a tire according to the present invention includes, for example, a step of bonding a bonded tire member and a tire member via the rubber composition according to the present invention, and an inspection step appropriately selected as necessary. It can be manufactured by including a buff process, a precure tread vulcanization process, a cutting process, a tread winding process, and other processes.
The heating temperature in the bonding step (at the time of vulcanization) is preferably 120 ° C. or less and more preferably 110 ° C. or less from the viewpoint of suppressing thermal deterioration of the base tire.
There is no restriction | limiting in particular as vulcanization time in this adhesion | attachment process (at the time of vulcanization | cure), It adjusts suitably according to a mixing | blending, a vulcanization temperature, a tire size, a vulcanization equipment, etc. Moreover, there is no restriction | limiting in particular as a pressure in this said adhesion process (at the time of vulcanization | cure), It adjusts suitably according to a mixing | blending, a vulcanization temperature, a tire size, a vulcanization equipment, etc.

There is no restriction | limiting in particular as said to-be-adhered tire member, According to the objective, it can select suitably, For example, a base tire etc. are mentioned.
The rubber material of the adherend tire member is not particularly limited and may be appropriately selected depending on the intended purpose. For example, any of vulcanized rubber, semi-vulcanized rubber, and unvulcanized rubber may be used. In the case of a base tire, it is usually a vulcanized rubber.
Here, the vulcanized rubber is a polymer mixed with sulfur, sulfur compounds, etc., and various sulfur crosslinks such as monosulfide bonds, disulfide bonds, polysulfide bonds, etc. are formed between the carbon main chains, thereby improving rubber elasticity. It is a substance as shown.
The unvulcanized rubber is a concept including a wide range of rubbers that have not yet undergone a crosslinking reaction, regardless of whether they are natural rubber or synthetic rubber.
The semi-vulcanized rubber is a concept including a rubber in which a crosslinking reaction has progressed more than the unvulcanized rubber by heating the unvulcanized rubber.

There is no restriction | limiting in particular as said tire member, According to the objective, it can select suitably, For example, a tread, a base tread, a sidewall etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, the tread is preferable in that the portion with a large amount of wear can be replaced.
The rubber material for the tire member is not particularly limited and may be appropriately selected depending on the purpose. For example, any of vulcanized rubber, semi-vulcanized rubber, and unvulcanized rubber may be used. In the COLD-type renewal tires that use cushion rubber for bonding, tread rubber (vulcanized rubber) that has been vulcanized in advance is used. Compared to the HOT method that requires a mold vulcanizer, multiple vulcanized cans can be used. Since the tire can be vulcanized and bonded at once, it is efficient and economical.

  The combination of the bonded tire member and the tire member is not particularly limited and may be appropriately selected depending on the purpose. However, the vulcanization speed of the bonded tire member and the tire member is not considered. In addition, it is preferable that both the tire member to be bonded and the tire member are vulcanized rubbers in that an adhesive rubber composition (cushion rubber) described later can be vulcanized.

The inspection step is a step of inspecting the appearance, nail holes, scratches, etc. of the retreading tire for obtaining the base tire as the bonded tire member.
In the inspection step, it is determined whether rehabilitation is possible by retrending, and those that cannot be rehabilitated are excluded.
The buffing step is a step of forming a pedestal tire by scraping the outer peripheral surface of a tread of a retreading tire that can be rehabilitated.
The base tire is partially polished or repaired such as filling in holes.

The precure tread vulcanization step is a step of obtaining a precure tread as the tire member by vulcanizing and molding a tread with a pattern from a tread rubber material.
The cutting step is a step of cutting the precure tread as the tire member continuous in a band shape into a predetermined length.
The tread winding step is a step of winding the precure tread as the tire member around the base tire as the adherend tire member. When winding the precure tread, cement is applied to the outer peripheral surface of the base tire and a sheet-like cushion rubber is applied thereto, or a sheet-like cushion rubber is applied directly to the base tire from an extruder. .
For example, such a base tire is rotatably supported, supplied to the base tire on which the precure tread rotates by a feeding device, and wound around the outer peripheral surface thereof.
The front and rear ends of the precure tread wound around the base tire are brought into contact with each other via a cushion rubber and joined by a stapler or the like.

There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a cushion rubber preparation process is mentioned.
The cushion rubber production step is a step of producing a cushion rubber using the adhesive rubber composition.
The method for producing the cushion rubber is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a method of forming a sheet using a rolling roll and a method of forming a sheet using an extruder. .
There is no restriction | limiting in particular as a shape of the said cushion rubber, According to the objective, it can select suitably, For example, a sheet form etc. are mentioned.

  In the method of the present invention configured as described above, the bonded tire member and the tire member are manufactured via the rubber composition of the present invention, so that the durability of the retread tire as a product is lowered and the rolling resistance is deteriorated. Thus, a tire with improved productivity can be obtained by shortening the vulcanization time in the vulcanization process without deteriorating the tire physical properties.

〔tire〕
The tire of the present invention is not particularly limited as long as it is manufactured by the tire manufacturing method of the present invention, and can be appropriately selected according to the purpose.
There is no restriction | limiting in particular as a shape of a tire of this invention, a structure, a magnitude | size, and a material, According to the objective, it can select suitably.

(Rubber member for tire)
The rubber member for tires of the present invention is characterized by using the above-described rubber composition of the present invention.
The tire rubber member of the present invention is not particularly limited as long as it is used for a tire, and can be appropriately selected according to the purpose. For example, tread, base tread, sidewall, tire repair rubber A member etc. are mentioned.
When the tire rubber member of the present invention is, for example, a tread, a base tread, a sidewall or the like, the rubber composition of the present invention described above is used depending on the application (for automobiles, trucks, buses, etc.). It can be obtained by a conventional method.
Moreover, there is no restriction | limiting in particular as a shape, a structure, and a magnitude | size of the rubber member for tires of this invention, According to the objective, it can select suitably.
The material for the tire rubber member of the present invention is not particularly limited as long as it is formed in the rubber composition of the present invention described above, and can be appropriately selected according to the purpose.

  Furthermore, the rubber composition for tires of the present invention can be used as a tire repair rubber. The object to be repaired may be vulcanized rubber, semi-vulcanized rubber, or unvulcanized rubber.For example, before vulcanizing and bonding the tread, it is buried in the scratches on the base tire and vulcanized. At this time, the rubber composition of the present invention is also vulcanized. Thereby, the use which repairs the damage | wound of a base tire can be performed.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

(Examples 1-6 and Comparative Examples 1-8)
A rubber composition was prepared according to the formulation shown in Table 1 below. For kneading, all materials except the vulcanization accelerator and sulfur were first kneaded using a 3.0 L Banbury mixer at a rotor rotation speed of 85 rpm and a discharge temperature of 150 ° C. The obtained rubber was once cooled to room temperature, and then the remaining vulcanization accelerator and sulfur were added and kneaded at 50 rpm at a temperature at the time of discharge of 65 ° C. or less.
About each obtained rubber composition, the vulcanization | cure speed | rate T0.9 in 120 degreeC, storage stability, and heat aging resistance were measured with the following method.

<Measurement method of vulcanization rate T0.9>
Based on JIS K6300-2, the time (minutes) required to obtain 90% of the maximum value of the vulcanization torque curve measured at a temperature of 120 ° C. was measured. The vulcanization speed T0.9 indicates an index of the vulcanization speed until vulcanization is completed, and the smaller the value, the faster the vulcanization speed.

<Method for evaluating storage stability>
Each rubber composition was stored at 40 ° C. for 7 days, and the vulcanization rate (T0.9) was measured using a Japan Synthetic Rubber Co., Ltd. curast meter. The ratio (%) of vulcanization rate after storage / initial vulcanization rate was evaluated as storage stability. It shows that it is excellent in storage stability, so that this figure is small.

<Method for evaluating heat aging resistance>
When a 2 mm gauge sheet made of each rubber composition is vulcanized at 120 ° C. for 20 minutes, and a sample punched into a JIS-3 dumbbell is subjected to a tensile test in accordance with JIS K 6251: 2004 at the initial stage The breaking strength (TB) after deterioration (100 ° C. × 24 hours) was measured. The ratio (%) of the breaking strength after deterioration / the initial breaking strength was evaluated as heat aging resistance. It shows that it is excellent in heat aging resistance, so that this figure is large.

* 1 to * 8 in Table 1 are as follows.
* 1: RSS # 3
* 2: N660 (N ₂ SA: 35 m ² / g, manufactured by Tokai Carbon Co., Ltd., Seast V)
* 3: N550 (N ₂ SA: 40 m ² / g, manufactured by Tokai Carbon Co., Ltd., Seast F)
* 4: N339 (N ₂ SA: 91 m ² / g, Thai carbon black, Thai black N339)
_{* 5: N234 (N 2 SA} : 119m 2 / g, manufactured by Tokai Carbon Co., Ltd., SEAST 7HM)
* 6: Zinc isopropyl xanthate (Ouchi Shinsei Chemical Co., Ltd., Noxeller ZIX)
* 7: Zinc butylxanthate (Ouchi Shinsei Chemical Co., Ltd., Noxeller ZBX)
* 8: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller CZ”

  As is clear from the results in Table 1 above, the rubber compositions of Examples 1 to 6 that fall within the scope of the present invention are superior in storage stability compared to the rubber compositions of Comparative Examples 1 to 8 that fall outside the scope of the present invention. It was also found that the rubber composition can achieve vulcanization for a short time and is excellent in heat aging.

(Test Examples 1 to 4: Trial manufacture and evaluation of retreaded tires)
In addition, using the cushion rubbers of Comparative Example 1 and Example 1, a corrected tire was prototyped by the following method, and the peel strength was measured by the following method. The results are shown in Table 2 below.
Each of the rectified tires has a cushion rubber that has been processed into a sheet of 1 mm thickness by a roll in advance on the tread portion of a retreading tire (radial tire for trucks and buses, size 11R22.5). Place a pre-cured tread and wrap it in a rubber bag called an envelope, then place it in a vulcanizing can at room temperature, set the maximum temperature to 120 ° C and pressurize and vulcanize to 6.0 MPa in the vulcanizing can. Rehabilitated tires were manufactured. In Test Examples 1 and 2, the cushion rubber of Comparative Example 1 was vulcanized for 90 minutes and 120 minutes, and in Test Examples 3 and 4, the cushion rubber of Example 1 was vulcanized for 90 minutes and 120 minutes.

[Peel strength measurement method (peeling test method)]
Produced a sample of a prepure tread / cushion rubber and a base tire for a peel test with a width of 1 inch, and in accordance with JIS K6256-1: 2006, the peel strength of the adhesive interface between the tread and the base tire is measured. It was measured. The peel strength of the test sample taken from the modified tire of Comparative Example 1 was expressed as an index with the peel strength being 100. It shows that peeling strength is so large that an index value is large.

  As is clear from the results in Table 2 above, the retreaded tire using the cushion rubber of Example 1 of Test Examples 3 and 4 is compared with the retreaded tire using the cushion rubber of Comparative Example 1 of Test Examples 1 and 2, It was found that even if the vulcanization time is short, the peel strength is excellent and vulcanization can be realized for a short time.

  The rubber composition and tire manufacturing method of the present invention can be suitably used particularly for the manufacture of retreaded tires.

Claims (6)

Containing 100 parts by mass of diene rubber, 0.1 part by mass to 4.0 parts by mass of a xanthate compound and 50 parts by mass or less of carbon black having a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or less. A rubber composition characterized by the above.   According to JIS K6300-2: 2001, the time (T0.9) required to obtain 90% of the maximum value of the vulcanization torque curve measured at a temperature of 120 ° C. is 14 minutes or less. Item 2. The rubber composition according to Item 1. A rubber containing 0.1 to 4.0 parts by mass of a xanthate compound and 50 parts by mass or less of carbon black having a nitrogen adsorption specific surface area (N ₂ SA) of 50 m ² / g or less with respect to 100 parts by mass of a diene rubber. A method for producing a rubber composition, wherein the composition is kneaded in two or more stages, and carbon black is added and kneaded in at least one or more stages prior to disposing the xanthate compound.   A tire characterized by using the rubber composition according to any one of claims 1 to 3 in a method for manufacturing a tire in which an adherend tire member and a tire member are bonded together via an adhesive rubber composition. Manufacturing method.   A tire manufactured by the method according to claim 4.   A rubber member for tires, wherein the rubber composition according to claim 1 or 2 is used.