JP5375101B2 - Rubber composition - Google Patents

Description

  The present invention relates to a rubber composition for tires used for tire treads, tire sidewalls, and the like. In particular, the present invention relates to a rubber composition having good adhesiveness before vulcanization and having high mechanical properties after vulcanization.

  Various compounding agents are used in rubber compositions used for tire applications. For example, carbon black (reinforcing agent), sulfur (providing elasticity and durability), vulcanization accelerator, anti-aging agent, tackifying resin, oil and the like.

  A tackifier resin which is one of these compounding agents improves the processability by imparting tackiness to the rubber, and is particularly important in a synthetic rubber having poor tackiness. In addition, in order to improve the adhesion between the tire member and the case cord, to improve the tackiness at the time of molding the tire, and to provide excellent low air permeability (see, for example, Patent Document 1), a high-speed vehicle To improve DRY grip, chunk resistance, heat sag resistance, and workability of tire treads (for example, see Patent Document 2), and to improve cut resistance, chipping resistance, and wear resistance (for example, , See Patent Document 3) and the like. In these prior arts, coumarone resin, phenol resin, terpene resin, petroleum resin, rosin derivative and the like are used alone or in any combination. Above all, petroleum resin is preferably used from the viewpoint of economy. As the petroleum resin, an aliphatic petroleum resin produced from a C5 fraction, an aromatic petroleum resin produced from a C9 fraction, and a dicyclopentadiene-based petroleum resin are used alone or in combination of two or more. In particular, aliphatic petroleum resins are frequently used because they have good compatibility with synthetic rubbers, provide excellent tack to unvulcanized synthetic rubbers, and act as processing aids. Aromatic petroleum resins are used from the viewpoint of improving grip performance (see, for example, Patent Document 4).

  On the other hand, the method of mix | blending a hindered amine compound with petroleum resin and improving heat stability has already been proposed (for example, refer patent document 5). However, there is no mention of a case where a petroleum resin blended with a hindered amine compound is used as a raw material of a rubber composition.

Japanese Patent No. 3320004 (first page) JP 2002-155165 (first page) JP-A-2005-15601 (first page) Japanese Patent Laid-Open No. 5-9338 (first page) JP 2006-028285 (first page)

  An object of the present invention is to provide a rubber composition having a good tack before vulcanization and having high mechanical properties after vulcanization.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a diene rubber component, an olefinic double bond hydrogen area ratio in a specific range, an aliphatic / alicyclic copolymer petroleum resin, and a hindered amine compound. The present inventors have found that a rubber composition containing a rubber composition having excellent adhesiveness and mechanical properties has led to the completion of the present invention.

  That is, the present invention comprises a diene rubber component, an aliphatic / alicyclic copolymer petroleum resin having a olefinic double bond hydrogen area ratio of 13% or less and a hindered amine compound in a proton NMR spectrum. The present invention relates to a rubber composition.

  Hereinafter, the present invention will be described in detail.

  The diene rubber component in the present invention is not limited as long as it is a diene rubber component having a carbon-carbon double bond, and examples thereof include natural rubber (NR) or synthetic rubber. Preferred examples include styrene butadiene rubber (SBR) and butadiene rubber (BR). These may be used alone or in combination.

  The composition of the aliphatic / alicyclic copolymer petroleum resin in the present invention is the spectrum observed when proton NMR is measured, and the area of olefinic double bond hydrogen observed at 4.5 to 6.0 ppm. It is necessary to satisfy the condition that the ratio is 13% or less. When the area ratio of the olefinic double bond hydrogen exceeds 13%, poor dispersion occurs when mixed with the rubber composition.

  The aliphatic / alicyclic copolymer petroleum resin preferably has a softening point of 60 to 140 ° C, particularly preferably 90 to 120 ° C. The weight average molecular weight Mw is preferably from 500 to 7000, particularly preferably from 2000 to 6500.

  Aliphatic / alicyclic copolymer petroleum resin is produced by mixing C5 fraction having a boiling range of 20-110 ° C. obtained by pyrolysis of petroleum and dicyclopentadiene obtained by pyrolysis. An aliphatic / alicyclic copolymer petroleum resin is preferred.

  Examples of components constituting the C5 fraction include monoolefinic unsaturated carbonization having 4 to 6 carbon atoms such as 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, 2-pentene, and cyclopentene. Hydrogens; straight chain dienes having 4 to 6 carbon atoms such as isoprene and piperylene; cyclopentadiens such as cyclopentadiene and methylcyclopentadiene; cyclopentane, 2-methylpentane, 3-methylpentane, n-hexane, etc. Aliphatic saturated hydrocarbons may be mentioned.

  On the other hand, examples of the dicyclopentadiene include dicyclopentadiene derivatives such as dicyclopentadiene, methyldicyclopentadiene, and dimethyldicyclopentadiene.

  The mixing ratio of the C5 fraction and dicyclopentadiene in the production of the aliphatic / alicyclic copolymerized petroleum resin is such that good roll processability is obtained. A ratio of 80 to 30% by weight of pentadienes is preferable, and a ratio of 30 to 70% by weight of C5 fraction and 70 to 30% by weight of dicyclopentadiene is more preferable.

  In the production of the aliphatic / alicyclic copolymerized petroleum resin, it is preferable to perform polymerization using a catalyst. As the catalyst, a Friedel-Crafts type catalyst can be generally used. More specifically, for example, aluminum trichloride, aluminum tribromide, boron trifluoride or a complex thereof can be mentioned, and a phenol complex of boron trifluoride is particularly preferable.

  The polymerization temperature is preferably 20 to 100 ° C, particularly preferably 30 to 80 ° C. The amount of the catalyst and the polymerization time are not particularly limited, and for example, 0.1 to 2.0% by weight of catalyst with respect to the total of the C5 fraction and dicyclopentadiene is in the range of 0.1 to 10 hours. Can be polymerized. The pressure in the reaction system may be greater than or equal to atmospheric pressure.

  As the hindered amine compound in the present invention, any compound belonging to the category referred to as a hindered amine compound can be used without limitation, and among them, a rubber composition particularly excellent in roll processability can be obtained. It is preferable that it is a hindered amine compound shown by these.

  Here, R1 to R4 in the general formula may be the same or different from each other and may be an alkyl group having 1 to 4 carbon atoms, and R5 may be hydrogen or a substituent having 1 to 1 carbon atoms. 8 is an alkyl group or an alkoxy group. As a C1-C4 alkyl group in R1-R4, a methyl group, an ethyl group, a propyl group, a butyl group etc. are mentioned, for example, Among these, a methyl group is preferable. Examples of the alkyl group having 1 to 8 carbon atoms which may have a substituent of R5 include a methyl group and an octyl group. Specific examples of the alkoxy group having 1 to 8 carbon atoms which may have a substituent Examples include methoxy group, octoxy group and the like. Among these, R5 is preferably hydrogen, methyl group, octyl group or the like, particularly preferably hydrogen or methyl group.

  Specific examples of hindered amine compounds represented by the general formula include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4). -Piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4 -Piperidyl) 1,2,3,4-butanetetracarboxylate, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] and the like, and bis ( , 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate are preferable.

  The hindered amine compounds represented by the general formula are known to have a molecular weight of 400 to 4,000 and are commercially available as hindered amine light stabilizers (HALS) from Ciba Japan Co., Ltd. and ADEKA Corporation. Commercially available books can also be used in the present invention.

  The blending amount of the diene rubber component, the aliphatic / alicyclic copolymer petroleum resin and the hindered amine compound in the rubber composition of the present invention is a diene because a rubber composition having excellent storage stability, adhesiveness and mechanical properties can be obtained. 1 to 15 parts by weight of a petroleum resin composition containing 98 to 99.99% by weight of an aliphatic / alicyclic copolymerized petroleum resin and 0.01 to 2% by weight of a hindered amine compound with respect to 100 parts by weight of a rubber component. The rubber composition preferably contains 3 to 10 parts by weight.

  As a method for producing the rubber composition of the present invention, since a rubber composition having excellent mechanical properties can be obtained, a hindered amine compound is blended with an aliphatic / alicyclic copolymerized petroleum resin immediately after polymerization, and the petroleum resin composition After that, it is preferably blended with the diene rubber component.

  When an aliphatic / alicyclic copolymerized petroleum resin and a hindered amine compound are blended to obtain a petroleum resin composition, they can be blended at a temperature of 80 to 120 ° C. and a stirring speed of 200 to 500 rpm. At the time of blending, in order to prevent oxidation of the aliphatic / alicyclic copolymer petroleum resin in the molten state due to oxygen, the oxygen concentration in the blender at the time of blending is preferably 1000 ppm or less, and more preferably 100 ppm or less. Is preferably 10 ppm or less.

  The rubber composition of the present invention can be obtained by blending the obtained petroleum resin composition and the diene rubber component, and as a kneading method at that time, for example, a temperature of 60 to 100 ° C. using a roll device. The kneading method can be used.

  The rubber composition of the present invention preferably contains carbon black, and the content of the carbon black is preferably 20 to 100 parts by weight with respect to 100 parts by weight of the diene rubber component.

  In addition, a crosslinking agent such as sulfur, a vulcanization accelerator, a compounding agent such as a silane coupling agent or an antiaging agent, and a filler such as silica may be added to the rubber composition of the present invention.

  Furthermore, the rubber composition of the present invention is, for example, a phenol-based antioxidant, a phosphorus-based antioxidant, or a sulfur-based antioxidant as additives that are usually blended in the resin composition without departing from the object of the present invention. , Lactone antioxidants, UV absorbers, pigments, calcium carbonate, glass beads and the like may be blended.

  TECHNICAL FIELD The present invention relates to a rubber composition for tires, and is a rubber composition that is excellent in adhesiveness when not applied and mechanical properties after application when used in a tire.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention does not receive a restriction | limiting at all by these Examples. In addition, preparation, analysis, and test methods of raw material resins, blends, and compositions used in Examples and Comparative Examples are as follows.
1. Raw material (1) Aliphatic / alicyclic copolymer petroleum resin composition: produced under the conditions described in Production Examples 1-5.
(2) Hindered amine compound: ADK STAB light stabilizer LA-77 (manufactured by ADEKA, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate)
2. Analysis method (1) Content of each component of raw material oil: Analysis was performed using a normal gas chromatographic method.
(2) Weight average molecular weight: Measured by gel permeation chromatography using polystyrene as a standard substance.
(3) Olefinic double bond hydrogen area ratio: Aliphatic / alicyclic copolymer petroleum resin is dissolved in chloroform-d (manufactured by Wako Pure Chemical Industries, Ltd.), and a nuclear magnetic resonance measuring apparatus (manufactured by JEOL, Proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR) spectrum analysis was performed at a temperature of 25 ° C. using a trade name JNM-GX270), and an area ratio was determined based on the following calculation formula.

(4.5-6.0 ppm peak area) / (total of all peak areas) × 100
(4) Softening point: Measured by a method based on JIS K-2531 (1960) (ring and ball method).
3. Test Method (1) Evaluation of Adhesive Strength The adhesive strength after pressure-bonding a non-added dough sheet with 500 gf for 30 seconds was measured and evaluated with a pickup type tack meter.
(2) Evaluation of hardness, tensile strength, elongation, 300% tensile strength and tear strength Measurement and evaluation were performed in accordance with JIS K6301.

Production Example 1
A glass autoclave with an internal volume of 2 L is charged with 250 g of a C5 fraction composition a having the composition shown in Table 1 obtained by decomposition of naphtha as a raw oil and 250 g of a dicyclopentadiene fraction (DCPD) having the composition shown in Table 2. (C5 fraction / DCPD = 50/50 wt%). Next, after cooling to 10 ° C. in a nitrogen atmosphere, boron trifluoride phenol complex (Stella Chemifa Co., Ltd.) is composed of a mixture of C5 fraction and DCPD as a Friedel Crafts type catalyst. Polymerization was performed for 2 hours by adding 3.0% by weight to 100 parts by weight of the raw material oil. Thereafter, the catalyst was removed with an aqueous caustic soda solution, and the unreacted oil in the oil phase was distilled to obtain an aliphatic / alicyclic copolymer petroleum resin. As a result of measuring proton NMR of the copolymerized petroleum resin, the olefinic double bond hydrogen area ratio was 9%.

  Further, 99.9% by weight of this aliphatic / alicyclic copolymerized petroleum resin and a hindered amine compound (trade name Adeka Stab Light Stabilizer LA-77, manufactured by ADEKA Co., Ltd.) were added under a nitrogen stream with an oxygen concentration of 2 ppm. 1% by weight was blended under the conditions of 150 ° C. and a sales rotation speed of 300 rpm to obtain petroleum resin composition A. The physical properties of the petroleum resin composition A and the olefinic double bond hydrogen area ratio are shown in Table 3.

Production Examples 2-5
In the production method described in Production Example 1, petroleum resin compositions B, C, D, and E were obtained in the same manner except that the type of C5 fraction and the charging ratio of C5 fraction were changed to Table 3. . The respective physical properties and the olefinic double bond hydrogen area ratio are shown in Table 3.

Examples 1-10, Comparative Examples 1-4
The composition shown in Table 4 was kneaded at 80 ° C. using a roll device to obtain a rubber composition. And the adhesive force of this rubber composition was measured. The results are shown in Table 5. In Comparative Examples 1 and 3 using the petroleum resin composition E, a large number of gels were generated because the aliphatic / alicyclic petroleum resin composition having an olefinic double bond hydrogen area ratio of 14% was used. However, the diene rubber component could not be mixed uniformly.

  Next, this rubber composition was vulcanized with a press at a temperature of 150 ° C. Table 5 shows the physical properties after vulcanization.

  In Examples 1 to 10, rubber compositions excellent in adhesive strength before vulcanization, elongation after vulcanization, and tensile stress were obtained.

  In Comparative Examples 2 and 4, since the aliphatic / alicyclic copolymer petroleum resin was not used, the adhesiveness, elongation, and tensile stress were inferior.

Comparative Example 5
A rubber composition was prepared in the same manner as in Example 1 except that the aliphatic / alicyclic copolymerized petroleum resin not added with the hindered amine compound obtained in Production Example 1 was used. could not.

Claims (6)

A tire rubber composition comprising a diene rubber component, an aliphatic / alicyclic copolymer petroleum resin having a olefinic double bond hydrogen area ratio of 13% or less in a proton NMR spectrum, and a hindered amine compound. 1 to 15 parts by weight of a petroleum resin composition containing 98 to 99.99% by weight of an aliphatic / alicyclic copolymerized petroleum resin and 2 to 0.01% by weight of a hindered amine compound with respect to 100 parts by weight of a diene rubber component The tire rubber composition according to claim 1, comprising: Furthermore, carbon rubber is contained, The rubber composition for tires of Claim 1 or 2 characterized by the above-mentioned. The tire rubber composition according to any one of claims 1 to 3, comprising 20 to 100 parts by weight of carbon black with respect to 100 parts by weight of the diene rubber component. A mixture of an aliphatic / alicyclic copolymerized petroleum resin comprising 20 to 70% by weight of a C5 fraction having a boiling range of 20 to 110 ° C. obtained by thermal decomposition of petroleum and 80 to 30% by weight of dicyclopentadiene The tire rubber composition according to any one of claims 1 to 4, wherein the rubber composition is an aliphatic / alicyclic copolymer petroleum resin produced from a raw material. The method for producing a tire rubber composition according to any one of claims 1 to 5, wherein the oxygen concentration in the blender when blending the hindered amine compound is 1000 ppm or less.