JP5309529B2 - 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).

  In this C5 fraction, there are conjugated cyclic diolefins such as cyclopentadiene and methylcyclopentadiene which deteriorate the color of the resin and promote the formation of gels. The physical properties of the resin have changed over time, and quality deterioration has become a problem. Therefore, in general, an aliphatic / aromatic copolymer petroleum resin is produced from a fraction obtained by dimerizing and distilling a conjugated cyclic diolefin that adversely affects the physical properties of these resins (for example, non-patent documents). 1). Further, as a method for removing conjugated cyclic diolefin, α-unsaturated carboxylic acid, α, β-unsaturated carboxylic acid represented by maleic anhydride, maleic acid ester, etc., utilizing the high reactivity of cyclopentadiene Alternatively, a method of adding a derivative thereof and removing it by a chemical reaction is also known (see, for example, Patent Document 5). However, the production method for removing the conjugated cyclic diolefin described above is not preferable because the yield corresponding to the removed monomer is reduced and the productivity is lowered. Further, in terms of performance, the rigidity of the resin derived from the conjugated cyclic diolefin is lowered, the softening point is lowered, and blocking is easily caused.

  Therefore, a method for producing a petroleum resin by polymerizing a conjugated cyclic diolefin such as cyclopentadiene or methylcyclopentadiene as a raw material has been studied. Since the cause of the deterioration of petroleum resins over time is the oxidation of chemical structural sites such as conjugated double bonds and tertiary carbon present in the resin, many studies have been made on antioxidants and radical scavenging action. Effects have been found with phenol-based antioxidants having phosphorus and phosphorus-based or sulfur-based antioxidants having a peroxide decomposing action (see, for example, Non-Patent Document 2). However, an antioxidant alone has little effect and increases the amount of addition, and in the case of compounding, a pre-blend or the like is required, which is not always economical.

  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 6). 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) JP H9-9338 (first page) Japanese Examined Patent Publication No. 43-21737 (first page) JP 2006-028285 (first page) Chemical Economy, March 1976 (page 69) Adhesion technology 2000 Vol20 No2 (page 27)

  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 diligent studies to solve the above problems, the present inventors have found that from diene rubber components, aliphatic / aromatic copolymer petroleum resins having a specific range of olefinic double bond hydrogen area ratios and hindered amine compounds. The present rubber composition was found to be excellent in adhesiveness and mechanical properties, and the present invention was completed.

That is, the present invention relates to an aliphatic / aromatic copolymer petroleum resin 98 to 99.9 having an olefinic double bond hydrogen area ratio of 2 to 11% in the proton NMR spectrum based on 100 parts by weight of the diene rubber component. The present invention relates to a rubber composition comprising 3 to 10 parts by weight of a petroleum resin composition comprising 2 % by weight and 2 to 0.01 % by weight of a hindered amine compound.

  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 includes natural rubber (NR) or synthetic rubber. For example, styrene butadiene rubber (SBR), butadiene rubber (BR) and the like are preferable examples. These may be used alone or in combination.

  The aliphatic / aromatic copolymer petroleum resin in the present invention has a spectrum observed when proton NMR is measured, and the area ratio of olefinic double bond hydrogen observed at 4.5 to 6.0 ppm is 2. It is necessary to satisfy the condition of ˜11%. When the area percentage of the olefinic double bond hydrogen exceeds 11%, the uniform dispersibility is inferior when the rubber composition is kneaded. On the contrary, when the area percentage of olefinic double bond hydrogen is less than 2%, the rubber composition has poor adhesive properties before vulcanization and mechanical properties after vulcanization.

  The softening point in the aliphatic / aromatic copolymer petroleum resin is preferably from 60 to 140 ° C, particularly preferably from 90 to 110 ° C. The weight average molecular weight Mw is preferably 500 to 7000, particularly preferably 1500 to 6500.

  Aliphatic / aromatic copolymer petroleum resin is obtained by dividing C5 fraction having a boiling range of 20 to 110 ° C. obtained by pyrolysis of petroleum and C9 fraction having a boiling range of 140 to 280 ° C. obtained by pyrolysis. An aliphatic / aromatic copolymer petroleum resin produced by mixing is preferable. The aliphatic / aromatic copolymer petroleum resin preferably has a cyclopentadiene content of 20% by weight or less.

  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, as the component constituting the C9 fraction, for example, vinyl aromatics having 8 to 10 carbon atoms such as styrene, α-methyl styrene or β-methyl styrene, vinyl toluene, indene and alkyl derivatives thereof, which are alkyl derivatives thereof, are used. Hydrocarbons; cyclic unsaturated hydrocarbons such as dicyclopentadiene and derivatives thereof; other olefins having 10 or more carbon atoms; saturated aromatics having 9 or more carbon atoms, and the like.

  The mixing ratio of the C5 fraction and the C9 fraction in the production of the aliphatic / aromatic copolymer petroleum resin is such that good roll processability is obtained, so that the C5 fraction is 30 to 90% by weight, and the C9 fraction is 70 to 70%. A proportion of 10% by weight is preferred, and in particular, a proportion of 50 to 90% by weight of C5 fraction and 50 to 10% by weight of C9 fraction is more preferred.

  In the production of the aliphatic / aromatic copolymer 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. For example, 0.1 to 2.0% by weight of the catalyst is used in the range of 0.1 to 10 hours with respect to the total of the C5 fraction and the C9 fraction. 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 having particularly excellent processing characteristics can be obtained. The hindered amine compounds shown are preferred.

ここで、一般式中のＲ１〜Ｒ４は炭素数１〜４のアルキル基であり、Ｒ５は水素又は置換基を持っていても良い炭素数１〜８のアルキル基もしくはアルコキシ基である。Ｒ１〜Ｒ４は互いに同一であっても相違していても良く、炭素数１〜４のアルキル基の具体例としては、例えばメチル基、エチル基等が挙げられ、その中でもメチル基が好ましい。Ｒ５の置換基を持っていても良い炭素数１〜８のアルキル基の具体例としては、例えばメチル基、オクチル基等が挙げられ、置換基を持っていても良い炭素数１〜８のアルコキシ基の具体例としては、例えばメトキシ基、オクトキシ基等が挙げられ、その中でも水素及びメチル基が好ましい。

Here, R1 to R4 in the general formula are alkyl groups having 1 to 4 carbon atoms, and R5 is an alkyl group or alkoxy group having 1 to 8 carbon atoms which may have hydrogen or a substituent. R1 to R4 may be the same as or different from each other, and specific examples of the alkyl group having 1 to 4 carbon atoms include, for example, a methyl group and an ethyl group, and among them, a methyl group is preferable. Specific examples of the alkyl group having 1 to 8 carbon atoms which may have a substituent of R5 include, for example, a methyl group, an octyl group and the like, and an alkoxy having 1 to 8 carbon atoms which may have a substituent. Specific examples of the group include a methoxy group, an octoxy group, and the like, and among them, hydrogen and a methyl group are preferable.

  Specific examples of the hindered amine represented by the general formula are 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. The known amine compounds have a molecular weight of 400 to 4,000, and hindered amine light stabilizers (HALS) are commercially available from Ciba Specialty Chemicals Co., Ltd. and Asahi Denka Kogyo Co., Ltd. it can.

  The blending amount of the diene rubber component, the aliphatic / aromatic copolymer petroleum resin and the hindered amine compound in the rubber composition of the present invention is a diene rubber because a rubber composition excellent in processing characteristics, adhesiveness and mechanical characteristics can be obtained. A rubber composition containing 1 to 15 parts by weight of a petroleum resin composition comprising 98 to 99.99% by weight of an aliphatic / aromatic copolymer petroleum resin and 2 to 0.01% by weight of a hindered amine compound with respect to 100 parts by weight of the component. It is preferable to use a rubber composition containing 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, an aliphatic / aromatic copolymer petroleum resin and a hindered amine compound are blended to obtain a petroleum resin composition. It is preferable to blend a diene rubber component.

  When an aliphatic / aromatic copolymer 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 250 ° C. and a stirring rotational speed of 200 to 500 rpm. At the time of blending, in order to prevent oxidation of the aliphatic / aromatic 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. However, it 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. The kneading method in this case includes, for example, an open kneader such as a kneading roll machine, Banbury, etc. A kneader such as a closed kneader such as a mixer can be used. More specifically, a method of kneading at a temperature of 60 to 100 ° C. using a kneading roll machine 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, adjustment, 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 / aromatic copolymer petroleum resin composition: produced under the conditions described in Production Examples 1-7.
(2) Hindered amine compound: Adekastab light stabilizer LA-77 (Asahi Denka Kogyo Co., Ltd., 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 / aromatic 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, product) No. JNM-GX270), proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR) spectrum analysis was performed at a temperature of 25 ° C., and the area ratio was determined based on the following 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 having an internal volume of 2 L was charged with 200 g (40 wt%) of a C5 fraction having the composition shown in Table 1 and 300 g (60 wt%) of a C9 fraction having the composition shown in Table 2. Next, after heating up to 35 ° C. under a nitrogen atmosphere, boron trifluoride phenol complex (Stella Chemifa Co., Ltd.) is used as a Friedel-Crafts-type catalyst. Polymerization was carried out for 2 hours by adding 0.8% by weight to the total amount. 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 / aromatic copolymer petroleum resin.

  Furthermore, 99.9% by weight of this aliphatic / aromatic copolymer petroleum resin and a hindered amine compound (product name: Adeka Stub Light Stabilizer LA-77, manufactured by Asahi Denka Kogyo Co., Ltd.) under a nitrogen stream having an oxygen concentration of 2 ppm, 0.1%. % Was blended under the conditions of 150 ° C. and a stirring rotational speed of 300 rpm to obtain a 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.

製造例２〜７
製造例１に記載の製造方法で、Ｃ５留分とＣ９留分の仕込み比率を表３とする以外は同様の方法で、石油樹脂組成物Ｂ，Ｃ，Ｄ，Ｅ、Ｆ及びＧを得た。それぞれの物性、およびオレフィン性二重結合水素面積比率について、表３に示した。

Production Examples 2-7
Petroleum resin compositions B, C, D, E, F and G were obtained by the same method except that the charging ratio of C5 fraction and C9 fraction was changed to Table 3 in the production method described in Production Example 1. . The respective physical properties and the olefinic double bond hydrogen area ratio are shown in Table 3.

Examples 1-16, Comparative Examples 1-4
The composition shown in Table 4 was kneaded at 80 ° C. using a kneading roll machine to obtain a rubber composition. And the adhesive force of this rubber composition was measured. The results are shown in Table 5. Since the petroleum resin composition G uses an aliphatic / aromatic petroleum resin having an olefinic double bond hydrogen area ratio of 11.9%, a large number of gels are generated, which is uniform with the diene rubber component. Could not mix.

  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 16, rubber compositions excellent in adhesive strength before vulcanization and elongation after vulcanization were obtained.

In Comparative Examples 1 and 3, since an aliphatic / aromatic copolymer petroleum resin having an olefinic double bond hydrogen area ratio of 1.5 % was used, the resulting rubber composition had poor adhesion. It was. In Comparative Examples 2 and 4, since the aliphatic / aromatic copolymer petroleum resin was not used, the adhesion and elongation were inferior.

比較例５
製造例１で得たヒンダードアミン化合物を添加しない脂肪族／芳香族共重合石油樹脂を用いた以外は実施例１と同様にゴム組成物の調製を行ったが、ロール加工性に劣り均一混合ができなかった。

Comparative Example 5
A rubber composition was prepared in the same manner as in Example 1 except that the aliphatic / aromatic copolymer petroleum resin not added with the hindered amine compound obtained in Production Example 1 was used, but the roll processability was poor and uniform mixing was possible. There wasn't.

Claims (5)

98 to 99.9% by weight of an aliphatic / aromatic copolymer petroleum resin having an olefinic double bond hydrogen area ratio of 2 to 11% in the proton NMR spectrum and 100% by weight of the diene rubber component and hindered amine compound 2 A rubber composition comprising 3 to 10 parts by weight of a petroleum resin composition comprising ˜0.01% by weight . Furthermore, carbon rubber is contained, The rubber composition of Claim 1 characterized by the above-mentioned. The rubber composition according to claim 1 or 2, comprising 20 to 100 parts by weight of carbon black with respect to 100 parts by weight of the diene rubber component . An aliphatic / aromatic copolymer petroleum resin has a boiling range obtained by pyrolysis of petroleum of 30 to 90% by weight of a C5 fraction having a boiling range of 20 to 110 ° C. and a boiling range of 140 to 280 ° C. obtained by the same thermal decomposition. An aliphatic / aromatic copolymer petroleum resin having a C9 fraction in the range of 70 to 10% by weight and a cyclopentadiene content of 20% by weight or less . The rubber composition in any one. The method for producing a rubber composition according to any one of claims 1 to 4 , wherein the oxygen concentration in the blender when blending the hindered amine compound is 1000 ppm or less .