JP2009073880A - Rubber composition for clinch, and tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition for clinch which can improve workability in the case of assembling a rim of a tire, and to provide a tire manufactured by using a clinch formed by using the composition. <P>SOLUTION: The rubber composition for forming a clinch of a tire contains a diene rubber and a silylation agent of ≥1.5 parts by mass to ≤5 parts by mass per 100 parts by mass of the diene rubber. The tire is manufactured by using a clinch formed by using the composition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber composition for clinching and a tire, and more particularly to a rubber composition for clinching capable of improving the workability of assembling a rim of a tire and a tire manufactured using a clinching formed using the same.

  In recent years, the demand for tires with a low aspect ratio has been increasing for the purpose of improving the performance of tires. In addition, there is an increasing demand for run-flat tires that can travel a certain distance even when the tire is punctured.

  Such low-flat tires and run-flat tires are characterized by high sidewall hardness and high bending rigidity.

For example, run-flat tires are provided with a side reinforcing rubber layer that extends integrally with a substantially crescent-shaped cross section on the side wall, and this side reinforcing rubber layer is a side that has increased bending rigidity even when the tire is punctured. The wall portion can support the load of the tire. As a result, the vertical deflection of the tire is suppressed, and as a result, it is possible to continuously travel several tens of kilometers.
JP-A-8-337688 Japanese Patent Laid-Open No. 9-87427

  However, in these low-flat tires and run-flat tires, because of the high hardness and bending rigidity of the sidewalls, when assembling the tire to the rim of the tire wheel, the rim assembly work is higher than the high-flat tire. There was a problem that the sex was difficult.

  In addition, due to the high hardness and bending rigidity of the sidewalls of these tires, when attaching a flat tire or run flat tire to a rim with an automatic rim assembly machine, it cannot be automatically assembled to the rim. Even if it can be assembled to the rim, damage such as tearing of the rubber of the clinch part that comes into direct contact with the rim occurs and the tire safety can be significantly reduced and the tire can be used. Sometimes it disappeared.

  In view of the above circumstances, an object of the present invention is to provide a rubber composition for clinch that can improve the rim assembly workability of a tire and a tire manufactured using a clinch formed using the rubber composition. It is in.

  The present invention is a clinching rubber composition for forming a clinching of a tire, comprising a diene rubber and a silylating agent of 1.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the diene rubber. It is a rubber composition for clinch containing.

  Here, in the rubber composition for clinch of the present invention, the silylating agent is preferably contained in an amount of 2 to 4 parts by mass with respect to 100 parts by mass of the diene rubber.

  In the rubber composition for clinch of the present invention, it is preferable that the silylating agent is at least one selected from the group consisting of a chlorosilane compound, an alkoxysilane compound, and a silazane compound.

  Moreover, this invention is a tire manufactured using the clinch formed from the rubber composition for clinch of any one of said.

  ADVANTAGE OF THE INVENTION According to this invention, the tire manufactured using the rubber composition for clinch which can improve the rim assembly workability | operativity of a tire, and the clinch formed using it can be provided.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

  The present inventor uses a rubber composition in which a certain amount of a silylating agent is blended with a diene rubber to form a clinch, and then vulcanizes the tire to form a silylating agent from the surface of the tire clinch. As a result of precipitation, the precipitated silylating agent was found to improve slidability between the tire clinches and the rim during rim assembly work, thereby improving the rim assembly workability. The present invention was completed.

<Diene rubber>
As the diene rubber used in the rubber composition for clinch of the present invention, conventionally known diene rubbers can be used singly or in combination of two or more kinds. For example, natural rubber, styrene-butadiene rubber And at least one selected from the group consisting of butadiene rubber can be used.

<Silylating agent>
As the silylating agent used in the rubber composition for clinch of the present invention, conventionally known silylating agents can be used, and examples thereof include phenyltrichlorosilane, diphenyldichlorosilane, trimethylchlorosilane, tert-butyldimethylchlorosilane, and the like. Chlorosilane compounds; alkoxysilane compounds such as phenyltrimethoxysilane, phenyltriethoxysilane, isobutyltrimethoxysilane, diphenyldimethoxysilane, vinyltris (βmethoxysilane), γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane; Silazane compounds such as hexamethyldisilazane; Acetamides such as N-trimethylsilylacetamide and N, O- (bistrimethylsilyl) acetamide; N, N- (bistrimethyl) Lil) ureas such as urea or the like can be used. These silylating agents may be used alone or in combination of any two or more.

  Among these, from the viewpoint of improving rim assembly workability, it is preferable to use at least one silylating agent selected from the group consisting of a chlorosilane compound, an alkoxysilane compound, and a silazane compound.

  The content of the silylating agent in the rubber composition for clinch of the present invention is 1.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the diene rubber. When the content of the silylating agent is less than 1.5 parts by mass with respect to 100 parts by mass of the diene rubber, the amount of silylating agent deposited on the rubber surface after vulcanization becomes too small, and the rim assembly work The effect of improving the property becomes insufficient, and if it exceeds 5 parts by mass, the adhesion to other tire members will be hindered during the tire molding operation.

  Here, the content of the silylating agent in the rubber composition for clinch of the present invention is preferably 2 parts by mass or more and 4 parts by mass or less with respect to 100 parts by mass of the diene rubber. When the content of the silylating agent is 2 parts by mass or more and 4 parts by mass or less with respect to 100 parts by mass of the diene rubber, the rim assembly workability is further improved and the adhesion to the tire member is also better. It tends to be a thing.

  In the present invention, the content of the silylating agent means the content of the one silylating agent when the silylating agent is composed of one kind, and the silylating agent is composed of two or more kinds. When constituted, it means the total content of the two or more silylating agents.

<Other additives>
In addition to the above-mentioned diene rubber and silylating agent, carbon black, oil, wax, anti-aging agent, stearic acid, zinc oxide, sulfur, vulcanization accelerator, etc. are added to the rubber composition for clinch of the present invention. An agent can be appropriately blended as necessary.

  As carbon black, conventionally well-known carbon black, such as SAF, ISAF, HAF, and FEF, can be used.

  As oil, a conventionally well-known thing can be used, for example, process oil, vegetable oil, or a mixture thereof etc. can be used. As the process oil, for example, paraffinic process oil, naphthenic process oil, aromatic process oil, or the like can be used. As vegetable oils and fats, for example, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice bran oil, beet flower oil, Sesame oil, olive oil, sunflower oil, palm kernel oil, coconut oil, jojoba oil, macadamia nut oil, tung oil, and the like can be used.

  A conventionally well-known thing can be used as a wax, For example, a conventionally well-known natural wax, petroleum wax, etc. can be used.

  As the anti-aging agent, conventionally known anti-aging agents can be used. For example, anti-aging agents such as amine-based, phenol-based, imidazole-based, and carbamic acid metal salts can be used.

  A conventionally well-known thing can be used as a stearic acid, for example, the stearic acid by Nippon Oil & Fat Co., Ltd. can be used.

  As the zinc oxide, conventionally known ones can be used, and for example, Zinc Hana No. 1 manufactured by Mitsui Metal Mining Co., Ltd. can be used.

  Conventionally known sulfur can be used as the sulfur, for example, powder sulfur manufactured by Tsurumi Chemical Co., Ltd. can be used.

  As the vulcanization accelerator, conventionally known ones can be used. For example, sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine or aldehyde-ammonia Further, those containing at least one of imidazoline-based or xanthate-based vulcanization accelerators can be used. Examples of the sulfenamide system include CBS (N-cyclohexyl-2-benzothiazylsulfenamide), TBBS (N-tert-butyl-2-benzothiazylsulfenamide), N, N-dicyclohexyl-2- Sulfenamide compounds such as benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N, N-diisopropyl-2-benzothiazolesulfenamide, and the like can be used. Examples of the thiazole group include MBT (2-mercaptobenzothiazole), MBTS (dibenzothiazyl disulfide), sodium salt of 2-mercaptobenzothiazole, zinc salt, copper salt, cyclohexylamine salt, 2- (2,4-dinitro). Thiazole compounds such as phenyl) mercaptobenzothiazole and 2- (2,6-diethyl-4-morpholinothio) benzothiazole can be used. Examples of thiurams include TMTD (tetramethylthiuram disulfide), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiuram monosulfide, dipentamethylenethiuram tetrasulfide, dipentamethylenethiuram hexasulfide. Further, thiuram compounds such as tetrabutylthiuram disulfide and pentamethylenethiuram tetrasulfide can be used. Examples of thiourea compounds that can be used include thiourea compounds such as thiocarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, and diortolylthiourea. Examples of the guanidine-based compounds include guanidine-based compounds such as diphenylguanidine, diortolylguanidine, triphenylguanidine, orthotolylbiguanide, and diphenylguanidine phthalate. Examples of dithiocarbamate include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate , Complex salt of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecyl (or octadecyl) isopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, diamyl Dithiocarbamate such as cadmium It can be used carbamic acid compounds. As the aldehyde-amine system or aldehyde-ammonia system, for example, an aldehyde-amine system or aldehyde-ammonia system compound such as an acetaldehyde-aniline reaction product, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reaction product, or the like is used. be able to. As the imidazoline-based compound, for example, an imidazoline-based compound such as 2-mercaptoimidazoline can be used. As the xanthate type, for example, a xanthate type compound such as zinc dibutylxanthate can be used. These vulcanization accelerators may be used alone or in combination of two or more.

<Tire>
Clinch is formed by processing the rubber composition for clinch of the present invention into a predetermined shape by extrusion or the like in an unvulcanized state. Then, each tire member including the clinch formed in this manner is prepared at a predetermined position to produce a green tire, and then the rubber composition constituting each member of the green tire is vulcanized. Thus, the tire of the present invention is manufactured.

  FIG. 1 shows a schematic cross-sectional view of the upper left half of an example of the tire of the present invention. Here, the tire 1 includes a tread 2 that serves as a ground contact surface of the tire 1, a pair of sidewalls 3 that extend inward in the tire radial direction from both ends of the tread 2 to form the side surfaces of the tire 1, And a bead core 5 positioned at the inner end. A ply 6 is bridged between the bead cores 5 and 5, and a belt 7 that reinforces the tread 2 with a tagging effect is installed outside the ply 6 and inside the tread 2.

  The ply 6 is, for example, 70 ° to 90 ° with respect to the tire equator CO (virtual line obtained by rotating the center of the width of the outer circumferential surface (ground contact surface) of the tire 1 once in the circumferential direction of the outer circumferential surface of the tire 1). It can be formed from a rubber sheet in which a plurality of cords forming an angle of ° are embedded. Further, the ply 6 is folded and locked around the bead core 5 from the tread 2 through the sidewall 3 to the outside in the tire axial direction.

  The belt 7 can be formed, for example, from a rubber sheet in which a plurality of cords making an angle of 40 ° or less with respect to the tire equator CO is embedded.

  Further, the tire 1 may be provided with a band (not shown) for suppressing the peeling of the belt 7 as necessary. Here, the band is made of, for example, a rubber sheet in which a plurality of cords are embedded, and can be installed by spirally winding the belt 7 outside the belt 7 substantially parallel to the tire equator CO.

  The tire 1 has a bead apex 8 extending outward in the tire radial direction from the bead core 5, and an inner liner 9 is installed inside the ply 6. Are covered with a side wall 3 and a clinch 4 extending inward in the tire radial direction from the side wall 3. The clinch 4 is formed by vulcanizing the rubber composition of the present invention.

  In the tire 1 having the above-described configuration, the clinch 4 is formed by using the tire rubber composition of the present invention. Therefore, when the tire 1 of the present invention is assembled to the rim of the tire wheel, Since the silylating agent is precipitated and the slip property can be expressed between the clinch 4 and the rim, the rim assembly workability can be improved.

  In the above description, the case where the tire 1 of the present invention shown in FIG. 1 is a tire for a passenger car has been described. However, the present invention is not limited to this. For example, for passenger cars, trucks, buses, heavy vehicles It can be applied to various tires such as.

<Preparation of unvulcanized rubber composition>
In accordance with the formulation shown in Table 1, components other than sulfur and the vulcanization accelerator were kneaded at 160 ° C. for 3 minutes using a Banbury mixer to obtain a kneaded product. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded at 80 ° C. for 5 minutes using a roll, and the unvulcanized rubber compositions of Examples 1 to 4 and Comparative Examples 1 to 2 were used. I got a thing.

  In addition, the numerical value shown by the column of the rubber | gum of Table 1 has shown the compounding quantity of the natural rubber and butadiene rubber which comprise the diene rubber used in the present Example by the mass%, respectively (that is, In this embodiment, a diene rubber mixed with a mass ratio of natural rubber: butadiene rubber = 60: 40 is used.) Moreover, the numerical value shown in the column of the additive in Table 1 indicates the amount of each additive in terms of parts by mass when the amount of the diene rubber is 100 parts by mass.

(Note 1) Natural rubber: RSS # 3 grade (Note 2) Butadiene rubber: BR150B manufactured by Ube Industries, Ltd.
(Note 3) Carbon black: N550 manufactured by Showa Cabot Corporation
(Note 4) Process oil: Diana Process AH-24 manufactured by Idemitsu Kosan Co., Ltd.
(Note 5) Wax: Sunnock N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
(Note 6) Anti-aging agent: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.
(Note 7) Stearic acid: Stearic acid “Kashiwa” manufactured by NOF Corporation
(Note 8) Zinc oxide: Diana Process AH-24 manufactured by Idemitsu Kosan Co., Ltd.
(Note 9) Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. (Note 10) Vulcanization accelerator CZ: Noxeller CZ manufactured by Ouchi Shinsei Chemical Co., Ltd.
(Note 11) Silylating agent: KBE103 manufactured by Shin-Etsu Chemical Co., Ltd.
<Rim assembly workability>
A clinch was produced by molding the unvulcanized rubber compositions of Examples 1 to 4 and Comparative Examples 1 and 2 produced as described above, and the produced clinch was placed together with other tire members. A green tire was produced. This green tire was vulcanized at 170 ° C. for 15 minutes in a vulcanizer to obtain a 255 / 35R18 size test tire.

In addition, as said test tire, what has the following basic structures was used.
Ply cord angle 90 degrees cord material in the tire circumferential direction Polyester cord 1670 dtex / 2
Belt cord angle 24 ° × 24 ° cord material in the tire circumferential direction Steel cord 1 × 4 × 0.27 configuration And rim by automatic mounter machine (automatic rim assembly machine) using the test tire produced as described above The assembling work was carried out and the rim assembling workability was evaluated. The results are shown in the rim assembly workability column of Table 1.

The rim assembly workability was evaluated by preparing three test tires each using clinch molded from each of the unvulcanized rubber compositions of Examples 1 to 4 and Comparative Examples 1 to 2, and each test. The tires were evaluated according to the following evaluation criteria. The rim assembly workability was evaluated under the same conditions such as the shape and size of the rim other than the test tire.
Evaluation criteria A: No scratches were found on the clinch in all three test tires.
B: Scratches were generated on clinch in one or two of the test tires.
C: All three of the test tires were scratched on the clinch.

<Elongation at break>
A test piece was prepared from the clinch cut out from the test tire prepared as described above, and a tensile test was carried out according to JIS-K6251 “vulcanized rubber and thermoplastic rubber—how to obtain tensile properties”. The elongation at break (EB) was measured. The results are shown in the column of elongation at break in Table 1.

<Ozone resistance test>
A test piece was produced from the clinch cut out from the test tire produced as described above, and the frequency of reciprocating motion was set to 0. 0 according to JIS-K6259 “vulcanized rubber and thermoplastic rubber—how to obtain ozone resistance”. The ozone resistance was evaluated under the conditions of 5 ± 0.025 Hz, ozone concentration 50 ± 5 pphm, 40 ° C., 24 hours. The results are shown in the ozone resistance column of Table 1.

  In addition, in the ozone resistance column of Table 1, the number of cracks increases in the order of the number of cracks (A, B, C, D, E. In other words, A has the least number of cracks, E Indicates the largest number of cracks), and the numbers on the right side indicate the size and depth of the cracks (the size and depth of the cracks increase in the order of 1, 2, 3, 4, 5). 1 indicates the smallest crack size / depth, and 5 indicates the largest crack size / depth. Therefore, the column of ozone resistance in Table 1 indicates that the ozone resistance is excellent in the order of D4, C3, C2, and C1 (that is, C1 has the highest ozone resistance).

<Evaluation results>
As is apparent from the results shown in Table 1, the silylating agent is 1.5 parts per 100 parts by mass of the diene rubber in which natural rubber and butadiene rubber are mixed at a mass ratio of natural rubber: butadiene rubber = 60: 40. When clinch was formed using the unvulcanized rubber composition of Example 1 in which 5 parts by mass of silylating agent and Example 1 in which 5 parts by mass of the silylating agent had been added, 100 parts by mass of the diene rubber described above. As compared with the case where clinch was formed using the unvulcanized rubber composition of Comparative Example 1 in which 10 parts by mass of the silylating agent was blended and Comparative Example 2 in which no silylating agent was blended, the clinch was damaged. It was confirmed that rim assembly workability was improved.

  Further, as is apparent from the results shown in Table 1, 2 parts of silylating agent were added to 100 parts by mass of diene rubber in which natural rubber and butadiene rubber were mixed at a mass ratio of natural rubber: butadiene rubber = 60: 40. When clinch was formed using the unvulcanized rubber composition of Example 3 in which 4 parts by mass of Example 3 and 4 parts by mass of the silylating agent were compounded, with respect to 100 parts by mass of the above diene rubber In comparison with the case where clinch was formed using the unvulcanized rubber composition of Comparative Example 1 in which 10 parts by mass of the silylating agent was blended and Comparative Example 2 in which no silylating agent was blended, the clinch was damaged. It was confirmed that rim assembly workability was improved.

  Furthermore, when clinch was formed using the unvulcanized rubber composition of Examples 1 to 4, compared with the case where clinch was formed using the unvulcanized rubber composition of Comparative Examples 1 and 2, It was confirmed that the elongation at break and the balance of ozone resistance were excellent.

  Therefore, it was confirmed that the unvulcanized rubber compositions of Examples 1 to 4 are suitable for forming clinch as compared with the unvulcanized rubber compositions of Comparative Examples 1 and 2, respectively.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  ADVANTAGE OF THE INVENTION According to this invention, the tire manufactured using the rubber composition for clinch which can improve the rim assembly workability | operativity of a tire, and the clinch formed using it can be provided.

It is typical sectional drawing of the upper left half of an example of the tire of this invention.

Explanation of symbols

  1 tire, 2 tread, 3 sidewall, 4 clinch, 5 bead core, 6 ply, 7 belt, 8 bead apex, 9 inner liner.

Claims (4)

A rubber composition for clinch for forming tire clinch,
A rubber composition for clinch, comprising a diene rubber and 1.5 to 5 parts by mass of a silylating agent with respect to 100 parts by mass of the diene rubber.   The rubber composition for clinch according to claim 1, wherein the silylating agent is contained in an amount of 2 parts by mass to 4 parts by mass with respect to 100 parts by mass of the diene rubber.   The rubber composition for clinch according to claim 1 or 2, wherein the silylating agent is at least one selected from the group consisting of a chlorosilane compound, an alkoxysilane compound, and a silazane compound.   A tire manufactured using the clinch formed from the rubber composition for clinch according to any one of claims 1 to 3.

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