JP2009191132A - Under tread and method for producing tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an under tread which prevents a tread layer from peeling from a belt layer by enhanced tackiness of a rubber composition, and ensures improved workability in a mixer in a mixing step of the rubber composition. <P>SOLUTION: The under tread laid between a belt layer and a tread layer in tire forming is a rubber sheet of 0.3-1.0 mm thickness which comprises a tacky rubber composition containing a mixture of an alkyl phenolic resin, an aliphatic 5C hydrocarbon resin and aromatic oil having an aromatic hydrocarbon content of 20-30 mass%, in an amount of 1-5 pts.mass based on 100 pts.mass of a rubber component. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adhesive rubber sheet, that is, an undertread, which is laminated between a belt layer and a tread layer when a tread layer is laminated on the belt layer.

  Conventionally, in the tire molding process, a steel belt layer is attached to the crown of a toroidal carcass, then green treads are stacked, and the belt layer and green are rotated while the tire is rotated with a presser called a stitcher. A molding method in which the tread layer is closely integrated is employed.

  Here, in order to ensure the adhesiveness between the belt layer and the green tread, a thin adhesive rubber sheet (hereinafter also referred to as “under tread”) is attached to the back surface (the side in contact with the belt layer) of the green tread. If the undertread has insufficient adhesiveness, there is a problem that the green tread peels off from the belt layer when the tire is rotated while the stitcher is applied. Therefore, the tackiness of the rubber of the under tread is an important process control item.

Conventionally, in order to increase the adhesiveness of rubber, a technique of blending an alkylphenol resin is common. It has been proposed that this alkylphenol-based resin is also used as a tread rubber compounding agent and satisfies the rolling resistance and wear resistance characteristics simultaneously (Patent Document 1).
JP 2004-2588 A

  The present invention improves the adhesiveness of the rubber composition, thereby preventing the green tread from being peeled off from the belt layer when the tire is rotated while applying a stitcher in the tire molding process, and in the rubber composition mixing process. Provides an undertread with improved processability in the mixer. Furthermore, the manufacturing method of the tire which uses this under tread is provided.

  The present invention is an undertread laminated between a belt layer and a tread layer at the time of tire molding, and the undertread is composed of an alkylphenol-based resin, an aliphatic C5 hydrocarbon resin, and 100 parts by mass of a rubber component. It is an adhesive rubber composition containing 1 to 5 parts by mass of a mixture of aromatic oils having an aromatic hydrocarbon content of 20 to 30% by mass. Here, the under tread is preferably a rubber sheet having a thickness of 0.3 to 1.0 mm.

  Further, the blending amount of the alkylphenol-based resin (WA), the blending amount of the aliphatic C5 hydrocarbon resin (WB), and the blending amount of the aromatic oil having a content of the aromatic hydrocarbon of 20 to 30% by mass ( The mixing ratio of WC) desirably satisfies the following formula.

WA: WB: WC = 1: 0.8 to 1.2: 0.8 to 1.2
Furthermore, the present invention relates to a tire manufacturing method including a step of laminating a tread layer with a cylindrical belt layer having an undertread having a thickness of 0.3 to 1.0 mm interposed therebetween, wherein the undertread includes a rubber component 100. It is composed of a rubber composition containing 1 to 5 parts by mass of an aromatic oil mixture of 20 to 30% by mass of an alkylphenol-based adhesive resin, aliphatic C5 hydrocarbon resin, and aromatic hydrocarbon with respect to parts by mass. The present invention relates to a method for manufacturing the tire.

  The present invention improves the tackiness of the rubber composition, thereby preventing the tread layer from peeling off from the belt layer, thereby obtaining an undertread having improved processability in the mixer in the rubber composition mixing step. Further, by using the undertread, the tire molding process in the tire manufacturing process can be improved.

<Tire molding>
The tire manufacturing method of the present invention will be described with reference to FIG. On a tire molding machine (not shown), a carcass ply and a pair of annular bead cores are arranged at both ends thereof to form a cylindrical tire skeleton. Then, the cylindrical tire skeleton is formed into a toroidal tire skeleton. FIG. 1 shows a state in which the toroidal carcass 2 is folded from the inside to the outside around the annular bead core 6. A belt layer made of a plurality of plies 3 is laminated on the crown portion of the toroidal carcass, and a tread layer 4 is laminated thereon via an undertread 5. The ply 3 of the belt layer is a ply in which steel cords are normally arranged in a range of 5 to 40 ° in the tire circumferential direction.

  In the present invention, a tread is laminated on the belt layer, and the belt layer and the tread layer are closely integrated and molded while rotating the tire with a presser fitting called a stitcher. Here, in order to ensure the adhesion between the belt layer and the tread, an undertread made of an adhesive rubber sheet is attached to the back surface of the tread layer, that is, the side in contact with the belt layer. In the present invention, it is possible to prevent the tread layer from being peeled off from the belt layer when the tire is rotated while the stitcher is applied by increasing the adhesiveness of the under tread.

  The thickness of the undertread of the present invention is preferably in the range of 0.3 mm to 1.0 mm. When the thickness is less than 0.3 mm, the adhesion between the belt layer and the tread layer is insufficient. On the other hand, when the thickness exceeds 1.0 mm, the rolling resistance and the steering are caused by the characteristics of the rubber composition of the under tread. The stability tends to decrease.

<Rubber component>
Examples of the rubber component used in the rubber composition of the undertread of the present invention include diene rubbers that have been conventionally blended in tire rubber compositions, such as natural rubber (NR), various butadiene rubbers (BR), and various types. Styrene-butadiene copolymer rubber (SBR), polyisoprene rubber (IR), butyl rubber (IIR) or the like can be used alone or in any mixing ratio.

<Adhesive rubber composition>
In the present invention, an alkylphenol-based resin (hereinafter also referred to as “A component”), an aliphatic C5 hydrocarbon resin (hereinafter also referred to as “B component”), and aromatic carbonization with respect to 100 parts by mass of the rubber component. It is an adhesive rubber composition containing 1 to 5 parts by mass of a mixture of aromatic oil (hereinafter also referred to as “component C”) having a hydrogen content of 20 to 30% by mass. The present invention can improve adhesiveness and kneading workability by using a mixture of the A component, B component and C component, particularly a mixture having a predetermined blending ratio.

  The alkylphenol-based resin (component A) is superior in adhesive strength to the aliphatic C5 hydrocarbon resin (component B) and the aromatic oil (component C), but increases the viscosity of the rubber and shortens the scorch. Even if it is blended singly, it can not solve the problems of increased viscosity of rubber and scorch property even if it can provide adhesive strength. In particular, when the amount of the alkylphenol-based resin is excessively increased, in the process of mixing the rubber, the rubber composition is in close contact with the inner surface of the mixer, causing problems that are difficult to discharge.

  In the present invention, the blending amount (WA) of the alkylphenol-based resin (component A), the blending amount (WB) of the aliphatic C5 hydrocarbon resin (component B), and the content of the aromatic hydrocarbon are 20 to 30 mass. It is desirable that the mixing ratio of the blending amount (WC) of% aromatic oil (component C) should satisfy the following formula.

WA: WB: WC = 1: 0.8 to 1.2: 0.8 to 1.2
When the blending amount of the component A is small, sufficient adhesion to the rubber composition cannot be obtained. Moreover, when there are few compounding quantities of the said B component, while the viscosity of a rubber composition will rise, sufficient adhesiveness will not be obtained. Furthermore, when there is little C component, the viscosity of a rubber composition will rise and sufficient adhesiveness will not be obtained.

  On the other hand, when there is too much A component, the scorch of a rubber composition will become quick, and it exists in the tendency for a rubber composition to closely_contact | adhere inside a mixer. When there is too much B component, adhesive force will run short. Moreover, when there is too much C component, adhesive force is insufficient similarly. Therefore, in the range of WA: WB: WC = 1: 0.8 to 1.2: 0.8 to 1.2, the tackiness, viscosity, and processability of the rubber composition are comprehensively excellent.

  The mixture of the A component, the B component, and the C component is contained in an amount of 1 to 5 parts by mass, preferably 3 to 5 parts by mass with respect to 100 parts by mass of the rubber component. When the said mixture is less than 1 mass part, the adhesive force of a rubber composition is insufficient, and when it exceeds 5 mass parts, a rubber composition will adhere | attach inside a mixer and will inhibit workability.

<Alkylphenol resin (component A)>
The alkylphenol resin is, for example, a novolak type alkylphenol having a molecular weight of 200 to 10,000, preferably 250 to 5,000. When the molecular weight of the novolak type alkylphenol is less than 200, the modulus and strength of the rubber composition tend to decrease. On the other hand, when the molecular weight exceeds 10,000, the viscosity of the rubber composition increases and the rubber composition is processed during kneading. There is a tendency to decline.

<Aliphatic C5 hydrocarbon resin (component B)>
The C5 petroleum resin used in the present invention is obtained by polymerizing C5 (carbon number 5) petroleum hydrocarbon. Here, the C5-based petroleum hydrocarbon means a C5 fraction (a fraction having 5 carbon atoms) obtained by thermal decomposition of naphtha, and specifically, isoprene, 1,3-pentadiene, dicyclopentadiene. And diolefins such as piperylene and monoolefins such as 2-methyl-1-butene, 2-methyl-2-butene and cyclopentene.

  C5 petroleum resin, together with C5 petroleum hydrocarbon, for reforming, styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, Those obtained by polymerizing aromatic olefins such as α-methylstyrene, vinylnaphthalene, vinylanthracene and the like with less than 50% can also be used.

  The C5-based petroleum resin is obtained by polymerizing C5-based petroleum hydrocarbon with an aluminum halide catalyst or the like. The C5 petroleum resin is a method of contacting with hydrogen in an inert solvent in the presence of a catalyst comprising a reaction product of a cobalt-containing organic compound, a nickel-containing organic compound or a mixture thereof and an aluminum-containing reducing agent (special feature). No. 42-8704), nickel, Raney nickel, copper chromate and the like are hydrogenated in the presence of a supported heterogeneous catalyst supported on a support such as alumina or diatomaceous earth (see Japanese Patent Publication No. 43-6636) Alternatively, hydrogenation is carried out in an inert solvent by a method of hydrogenation by contacting with hydrogen in the presence of a catalyst comprising bis (cyclopentadienyl) titanium dichloride and alkyllithium (see JP 59-133203 A). Hydrogenation in the presence of a catalyst yields a hydrogenated product, which is used for the hydrogenation block used in the present invention. They can be synthesized coalescence.

  Specific examples of the C5 petroleum resin include quinton (manufactured by Nippon Zeon Co., Ltd.), Marcaretz (manufactured by Maruzen Petrochemical Co., Ltd.), and alkone (manufactured by Arakawa Chemical Industries, Ltd.).

<Aromatic oil (component C)>
The aromatic oil blended in the rubber composition of the present invention has an aromatic hydrocarbon content in the range of 20 to 30% by mass.

  In general, petroleum-based process oil is a mixture of various types of low-molecular hydrocarbon compounds, and its properties are further determined by the composition ratio of the aromatic component, naphthenic component and paraffinic component, and the microstructure of the compound of each component. Affected by molecular weight, etc. In other words, the components of the oil and the structure of the oil affect the affinity between the rubber and the oil, the molecular behavior of the rubber under dynamic conditions, the oil fluidity and migration in the rubber composition, and the stickiness of the unvulcanized rubber composition. It affects the viscosity and physical properties of the vulcanized rubber.

  When the aromatic hydrocarbon content in the aromatic oil is high, the affinity in the rubber composition becomes strong and tan δ under dynamic conditions increases. Aromatic oils are usually used to save energy when producing rubber products or to improve the processing productivity by reducing the viscosity of the rubber composition. By using it as a mixture, it is possible to improve the adhesiveness of the undertread and improve the workability.

  The aromatic oil blended in the rubber composition of the present invention has an aromatic hydrocarbon content in the range of 20 to 30% by mass, which is most excellent in the above-mentioned adhesiveness and viscosity characteristics.

<Other ingredients>
In addition to the A component, B component and C component, the rubber composition of the present invention includes a reinforcing agent such as carbon black and silica, a vulcanization or crosslinking agent, a vulcanization or crosslinking accelerator, various oils, an anti-aging agent, Various additives generally blended for tires such as plasticizers and other general rubbers can be blended.

  The compounding components can be used for vulcanization or crosslinking by kneading and vulcanizing by a general method to obtain a composition. As long as the amount of these additives is not contrary to the object of the present invention, the conventional general amounts can be used.

Examples 1-3 and Comparative Examples 1-8
According to the composition (parts by mass) shown in Table 1, the rubber other than the vulcanization accelerator and sulfur and the compounding agent were kneaded for 5 minutes with a 1.7 liter Banbury mixer, and then the vulcanization accelerator and sulfur were added to this composition. Was kneaded for 4 minutes with an 8 inch test kneading roll to obtain a rubber composition. These rubber compositions were press vulcanized at 150 ° C. for 30 minutes to prepare predetermined test pieces, subjected to various tests, and measured for physical properties. The results are shown in Table 1.

(Note 1) Natural rubber TSR20.
(Note 2) Carbon N330: “Dia Black” manufactured by Mitsubishi Chemical Corporation.
(Note 3) Alkylphenol resin: “RIBETAK7510” manufactured by Koei Trading Co., Ltd.

Para-t-octylphenol phenol resin.
(Note 4) Aliphatic C5 hydrocarbon resin: “Marcaretz T-100A” manufactured by Maruzen Petroleum Corporation.

Mixture of aliphatic and modified aliphatic hydrocarbon resins and hydrogenated hydrocarbon resins.
(Note 5) Aromatic oil: “NC300S” manufactured by Japan Energy Co., Ltd.
50/50 wt% mixture of petroleum hydrocarbon and straight asphalt. Aromatic hydrocarbon content is 27 mass%.

In Table 1, the common compounding components are as follows.
Zinc oxide (Mitsui Kinzoku Co., Ltd.) 8 parts Stearic acid (Nippon Yushi Co., Ltd.) 1.5 parts Anti-aging agent FR (Flexis Co., Ltd.) 2 parts Insoluble sulfur (Shikoku Chemicals Co., Ltd. Mucron OT20) 5 parts (Manufactured by Seiko Chemical Co., Ltd.) 0.8 parts Physical properties were measured as follows.
(1) Mooney viscosity index It is the data which measured the compounding rubber | gum before vulcanization using the Mooney viscosity tester by cutting out 4 x 4 cm in length x width and 7-9 mm in thickness.

Measurement conditions: Mooney viscometer SMV-202 manufactured by Shimadzu Corporation was used as a test machine.
The test temperature was 130 ° C., using a small rotor, preheating for 1 minute from the start of measurement, and then measuring the viscosity when 4 minutes passed. The measured viscosity is shown as a relative value with Example 1 as 100. The larger the index, the greater the viscosity.
(2) Undertread adhesion index A numerical value obtained by measuring a rubber sheet roll-rolled with a width of 120 mm and a thickness of 0.5 mm using a Tack Tester TAK101 manufactured by Rheology under five conditions under a load of 0.30 kgf and a speed of 300 mm / min. Was indexed. The higher the value, the greater the tackiness.
(3) Presence / absence of rubber adhesion in the mixer in the mixing step The rubber compounding was mixed for 2 minutes with a Banbury mixer BB240 (effective volume 240L) 11D rotor manufactured by Kobe Steel at a rotor speed of 60 revolutions, and a rubber temperature of 150 ° C. After discharging the mixer lower drop door for 6 seconds, there was no contact if the door was closed normally, and if the door was not closed, it was considered that there was contact with undrained rubber.

In addition, 20 sheets of the same kind of rubber were continuously mixed, and “No” was set when no adhesion occurred.
(4) Existence of occurrence of tread peeling in the molding process Using a low cover with a tire size of 185 / 65R, after attaching the green tread with a tire molding machine, the stitcher work was performed for 15 seconds at 50 rotations. If it was 0.01% or less, the occurrence was “none”.

<Results of characterization>
Examples 1-3 are examples in which 1.2 parts, 3 parts, and 4.8 parts of a mixture of the A component, the B component, and the C component were blended, respectively.

  It can be seen that as the blending amount of the mixture increases, the viscosity of the rubber composition of the undertread decreases and the adhesion index of the undertread increases. However, when the blending amount of the mixture is 6 parts as in Comparative Example 7, the rubber adhesion in the mixer in the mixing step is deteriorated.

  The undertread of the present invention can be applied to tires of various categories such as passenger car tires, truck bus tires, and L / T tires, and can solve the problem of peeling off of the tread layer at the time of tire molding.

It is the schematic of the tire structure which shows the manufacturing method of the tire of this invention.

Explanation of symbols

  1 tire, 2 carcass, 3 ply, 4 tread layer, 5 under tread, 6 bead core.

Claims (4)

  An under tread laminated between a belt layer and a tread layer at the time of molding a tire, and the under tread is composed of 100 parts by mass of a rubber component, an alkylphenol resin, an aliphatic C5 hydrocarbon resin, and an aromatic hydrocarbon. The undertread is an adhesive rubber composition containing 1 to 5 parts by mass of a mixture of aromatic oils having a content of 20 to 30% by mass.   The undertread according to claim 1, which is a rubber sheet having a thickness of 0.3 to 1.0 mm. Mixing ratio of blending amount of alkylphenol-based resin (WA), blending amount of aliphatic C5 hydrocarbon resin (WB), and blending amount of aromatic oil with aromatic hydrocarbon content of 20-30% by mass (WC) The undertread according to claim 1 satisfying the following formula.
WA: WB: WC = 1: 0.8 to 1.2: 0.8 to 1.2   In the method for manufacturing a tire including a step of laminating a tread layer by interposing an undertread having a thickness of 0.3 to 1.0 mm on a cylindrical belt layer, the undertread is based on 100 parts by mass of a rubber component. And a rubber composition containing 1 to 5 parts by mass of a mixture of an aromatic oil having an alkylphenol-based adhesive resin, an aliphatic C5 hydrocarbon resin and an aromatic hydrocarbon content of 20 to 30% by mass. The manufacturing method of the said tire.

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