JP3720016B2 - Rubber composition - Google Patents

Description

【００２４】
表Ｉの脚注
^*1：Ｓｔ＝３３％、Ｖｎ＝１４％、Ｔｇ＝−３６℃の乳化重合ＳＢＲ、３７．５phr油展（アロマ）^*16
*2：Ｓｔ＝３３％、Ｖｎ＝１４％、Ｔｇ＝−３６℃の乳化重合ＳＢＲ、３７．５phr油展（パラフィン）^*17
*3：Ｓｔ＝３３％、Ｖｎ＝１４％、Ｔｇ＝−３６℃の乳化重合ＳＢＲ、３７．５phr油展（オイル）^*18
*4：Ｓｔ＝２５％、Ｖｎ＝１６％、Ｔｇ＝−５１℃の乳化重合ＳＢＲ、３７．５phr油展（アロマ）^*16
*5：Ｓｔ＝２５％、Ｖｎ＝１６％、Ｔｇ＝−５１℃の乳化重合ＳＢＲ、３７．５phr油展（パラフィン）^*17
*6：Ｓｔ＝２５％、Ｖｎ＝１６％、Ｔｇ＝−５１℃の乳化重合ＳＢＲ、３７．５phr油展（オイル）^*18
*7：日本ゼオン（株）製Ｎｉｐｏｌ１２２０
^*8：昭和キャボット（株）製ショウブラックＮ２２０
^*9：フレキシス（株）製サントフレックス６ＰＰＤ
^*10：昭和シェル石油（株）製デゾレックス３号
^*11：昭和シェル石油（株）製マシン油２２
^*12：アロマ系オイル（Ｃ_A＝２７％、Ｔｇ＝−４０℃、動粘度（１００℃）＝４７mm²／sec ）
^*13：ヤスハラケミカル（株）製ハイロジン 軟化点：９５℃
^*14：大内新興化学工業（株）製クマロン樹脂 軟化点：９０℃
^*15：大内新興化学工業（株）製ノクセラーＣＺ−Ｇ
^*16：昭和シェル石油（株）製デゾレックス３号
^*17：昭和シェル石油（株）製マシン油２２
^*18：アロマ系オイル（Ｃ_A＝２７％、Ｔｇ＝−４０℃、動粘度（１００℃）＝４７mm²／sec ）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rubber composition, and more specifically, by blending a specific petroleum-based process oil with a specific resin such as aromatic, rosin or coumarone, or a specific novolac-type alkylphenol resin , low fuel consumption, grip TECHNICAL FIELD The present invention relates to a rubber composition that achieves both compatibility and heat aging resistance and is excellent in processability and safety.
[0002]
[Prior art]
As a softening agent blended in a conventional rubber composition, for example, as described in Patent Document 1, typically, an aromatic hydrocarbon content (aroma content) is about 30 to 55%, and a nafuran hydrocarbon (nafuran content). And so-called aroma oil having a paraffinic hydrocarbon (paraffin content) content of about 40 to 65% is used. However, in recent years, there are voices that the amount of polycyclic aromatic components in aroma oil is environmentally problematic.
[0003]
[Patent Document 1]
Patent Publication No. 2948659 [0004]
[Problems to be solved by the invention]
Petroleum-based process oil is a mixture with a very wide variety of low-molecular-weight hydrocarbon compounds, and its properties include the composition ratio of aromatic, naphthenic and paraffinic components, and the micro shape of each component molecule (side chain and cyclic component). Ratio, etc.) and the structure of the oil that combines the molecular weight. This oil structure governs the affinity between rubber and oil, the molecular behavior of the rubber under elongation or dynamic conditions, the oil fluidity in the compound, the migration, etc., and the result is the unvulcanized and cured rubber. Although it seems to reflect on the physical properties, the detailed mechanism has not been elucidated.
[0005]
In general the aromatic hydrocarbon content C _A is large, the affinity becomes stronger, increases tanδ under dynamic conditions. Process oil is used to save energy when manufacturing rubber products, and to improve processing productivity by reducing rubber viscosity. However, other process quality characteristics such as fuel efficiency and grip characteristics of tire products are also included. Also affects.
[0006]
In order to reduce tan δ and improve fuel efficiency, an oil with a low aromatic hydrocarbon content C _A (%) naphthenic or high paraffinic component ratio will increase tan δ to improve grip. It is well known that aromatic oils with high C _A % are suitable. Thus, a petroleum-based process oil that achieves both low fuel consumption and grip performance has not yet been found.
[0007]
Therefore, the present invention aims to eliminate the problems in the case of blending the above-described petroleum-based process oil and to achieve both the vulcanized physical properties of the rubber composition, particularly low fuel consumption, grip properties and heat aging resistance. And
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, aromatic hydrocarbon content C _{A is} added to 100 parts by weight of diene rubber containing at least one styrene-butadiene copolymer rubber (SBR) having a glass transition temperature Tg of −55 ° C. or higher. Is 20 to 35% by weight, Tg is −55 ° C. to −30 ° C., kinematic viscosity (100 ° C.) is 20 to 50 mm ² / g, and polycyclic aromatic component amount (PCA) is 3% in petroleum process oil. % Rubber composition comprising 5 to 80 parts by weight of petroleum process oil and 2 to 30 parts by weight of a resin having a softening point of 80 to 130 ° C. selected from aromatic, rosin and coumarone. Is provided.
[0009]
According to the second aspect of the present invention, 100 parts by weight of at least one diene rubber has an aromatic hydrocarbon content (C _A ) of 20 to 35% by weight and a glass transition temperature Tg of −55 ° C. to − Petroleum process oil with 30 ° C., kinematic viscosity (100 ° C.) of 20-50 mm ² / g and 3% by weight or less of polycyclic aromatic component (PCA), and novolak type having a weight average molecular weight of 200-10,000 There is provided a rubber composition comprising a mixture of an alkylphenol resin and 10 to 30 parts by weight of a mixture of 25 to 95% by weight to 5 to 75% by weight of the process oil and the resin.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Petroleum process oil to be blended in the rubber composition of the present invention, the aromatic hydrocarbon content C _A in the process oil 20 to 35% by weight, preferably 25 to 35 wt%, the glass transition temperature Tg (DSC: Differential (Measured with a thermal scanning calorimeter) is -55 ° C to -30 ° C, preferably -45 ° C to -35 ° C. Wherein C _A can be measured by the ring analysis (n-d-M method) (ASTM D3238). The kinematic viscosity (100 ° C.) is 20 to 50 mm ² / sec , preferably 25 to 50 mm ² / sec . The polycyclic aromatic component amount (PCA) is 3% by weight or less. Here, PCA is an aromatic compound in which two or more rings such as polycyclic aromatic are fused, and can be measured by the IP346 / 92 method as a DMSO extract.
[0011]
It is not preferable because the C _A petroleum based process oil is less than 20 wt% used as an indicator of grip performance tan [delta (0 ° C.) is reduced in the present invention, in fuel economy index exceeds 35 wt% in the reverse A certain tan δ (60 ° C.) increases (deteriorates fuel efficiency), which is not preferable. If Tg is lower than −55 ° C., grip performance and heat aging resistance are deteriorated, which is not preferable. Conversely, if Tg is higher than −30 ° C., fuel efficiency is deteriorated, which is not preferable. If the kinematic viscosity (100 ° C.) is less than 20 mm ² / sec , the grip performance deteriorates, which is not preferable. On the other hand, if it exceeds 50 mm ² / sec , high temperature heating during transportation is required, resulting in an increase in usage costs. Therefore, it is not preferable. Further, if PCA exceeds 3% by weight, there is a potential problem of environment and safety, which is not preferable.
[0012]
In the rubber composition according to the first aspect of the present invention, the petroleum process oil is added to 100 parts by weight of a diene rubber containing at least one styrene butadiene copolymer (SBR) having a glass transition temperature Tg of −55 ° C. or higher. 5 to 80 parts by weight, preferably 10 to 70 parts by weight, and 2 to 30 parts by weight of an aromatic, rosin and / or coumarone resin having a softening point of 80 to 130 ° C, preferably 80 to 120 ° C, preferably 2 to 15 parts by weight are blended. If the blending amount of the petroleum-based process oil is too small, the processability of the rubber is deteriorated, which is not preferable. On the other hand, if the amount is too large, the fuel efficiency is deteriorated. Further, when the softening point of the resin is too low, the grip performance is lowered, which is not preferable. On the other hand, when the resin is too high, the softening effect is reduced and the workability is deteriorated. Further, if the amount of the resin is too small, the softening effect is reduced and the workability is deteriorated, which is not preferable. On the other hand, if the amount is too large, the fuel efficiency is deteriorated.
[0013]
The aromatic, examples of rosin-based and / or coumarone-based resins, for example, C ₉ resins, gum rosin, wood rosin, rosin-based resins such as tall rosin, further modified resins, coumarone such rosin ester resin - the like indene resin These are commercially available, for example, as Petrogin manufactured by Mitsui Oil, various rosin ester resins manufactured by An Crude Oil Co., Ltd., Coumaron 100 manufactured by Kobe Oil Chemical Co., Ltd., and the like.
[0014]
Examples of the diene rubber that can be used in combination with the SBR in the rubber composition according to the first aspect of the present invention include any diene rubber that has been conventionally blended in a rubber composition, such as natural rubber ( NR), various butadiene rubbers (BR), other styrene-butadiene copolymer rubbers (SBR), polyisoprene rubber (IR), butyl rubber (IIR), etc. may be used alone or as an arbitrary blend depending on the application. it can.
[0015]
In addition to the essential components described above, the rubber composition according to the first aspect 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, and an antioxidant. Various additives that are generally blended for tires such as plasticizers and other general rubbers can be blended, and these blends are kneaded and vulcanized by a general method to form a composition. It can be used for sulfurization or crosslinking. 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. The use of such a rubber composition is not particularly limited, but is suitable for use in, for example, rubber industrial articles such as tire treads, belts, hoses and the like.
[0016]
In the rubber composition according to the second aspect of the present invention, at least 100 parts by weight of the diene rubber, the novolak type alkylphenol having the petroleum process oil and the weight average molecular weight of 200 to 10,000, preferably 250 to 5000 is used. 10 to 30 parts by weight of a mixture of a resin and a weight ratio of the petroleum process oil and the novolak alkylphenol resin is (25 to 95% by weight) / (5 to 75% by weight) as a softening agent. .
[0017]
According to the second aspect of the present invention, desired rubber compound performance can be obtained by blending a novolak-type alkylphenol having a molecular weight of 200 to 10,000, preferably 250 to 5,000, with the petroleum-based process oil. I found out that I can. When the molecular weight of the novolak-type alkylphenol is less than 200, the effect of increasing the modulus in the low elongation region is not recognized. Conversely, when the molecular weight exceeds 10,000, the softening effect in the high elongation region is small, and the rubber mixing processability Is not preferable because it tends to deteriorate. The blending amount with the petroleum-based process oil is in the range of 5 to 75% by weight, preferably 10 to 50% by weight of the novolak type alkylphenol with respect to the total amount of both. If the compounding amount of the novolak alkylphenol is less than 5% by weight, the effect of increasing the modulus cannot be exhibited, and if it exceeds 75% by weight, not only the processability is deteriorated but also the cost is increased, which is not preferable as a tire rubber. The blending amount of the softening agent is 10 to 30 parts by weight with respect to 100 parts by weight of the diene rubber. If the blending amount is too small, the processability of rubber deteriorates, which is not preferable. On the other hand, if the blending amount is too large, fuel efficiency decreases.
[0018]
Examples of the diene rubber that can be used in the rubber composition according to the second aspect of the present invention include any diene rubber that has been conventionally blended in a rubber composition, such as natural rubber (NR), Butadiene rubber (BR), various styrene-butadiene copolymer rubbers (SBR), polyisoprene rubber (IR), butyl rubber (IIR), and the like can be used alone or as any blend depending on the application.
[0019]
In addition to the above-described essential components, the rubber composition according to the second aspect 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, and an antioxidant. Various additives that are generally blended for tires such as plasticizers and other general rubbers can be blended, and these blends are kneaded and vulcanized by a general method to form a composition. It can be used for sulfurization or crosslinking. 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. The use of such a rubber composition is not particularly limited, but is suitable for use in, for example, tire carcass members, tire treads, belts, hoses and the like.
[0020]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further, it cannot be overemphasized that the scope of the present invention is not limited to these Examples. In the following examples, “%” means “% by weight” unless otherwise specified. The physical properties were measured as follows.
1) tan δ (0 ° C. and 60 ° C.): using a viscoelastic spectrometer (elongation type viscoelasticity measuring machine manufactured by Ueshima Seisakusho Co., Ltd.), temperature 0 ° C. and 60 ° C., strain rate 10 ± 2%, frequency 20 Hz Measured with
2) ΔHs: Measured according to JIS K-6301 using a JIS A type hardness meter manufactured by Kobunshi Keiki Co., Ltd. The increase / decrease of the value is shown based on the comparative example.
3) Tensile strength (after aging) (Mpa): According to JIS K-6301, an air heating aging test (100 ° C., 24 hours) was performed, and then a tensile test was performed.
[0021]
Examples 1-4 and Comparative Examples 1-4
In accordance with the formulation (parts by weight) shown in Table I , the rubber other than the vulcanization accelerator and sulfur and the compounding agent were kneaded in a 1.7 liter Banbury mixer for 5 minutes, and then the vulcanization accelerator and sulfur were added to the compound. A rubber composition was obtained by kneading for 4 minutes with an 8-inch test kneading roll. These rubber compositions were pressed at 150 ° C. for 30 minutes to prepare target test pieces, and various tests were performed to measure their physical properties. The results are shown in Table I.
[0022]
The physical properties are tan δ (60 ° C.) and ΔHs, and the wear resistance is a lambone wear tester manufactured by Iwamoto Seisakusho (measurement conditions: load = 3.0 kg, surface speed of the grindstone = 40 m / min, slip rate 25) %, Test time = 5 minutes, amount of sand fall = 20 g / min), the measurement temperature was room temperature, the volume loss (cc) was examined, and the value of Comparative Example 1 was shown as an index. The larger this value, the better the wear resistance.
[0023]
[Table 1]

[0024]
Table I footnotes
^{* 1} : Emulsion polymerization SBR with St = 33%, Vn = 14%, Tg = −36 ° C., 37.5 phr oil (Aroma) <sup>* 16
* 2</sup> : St = 33%, Vn = 14%, Tg = −36 ° C. emulsion polymerization SBR, 37.5 phr oil extended (paraffin) <sup>* 17
* 3</sup> : Emulsion polymerization SBR of St = 33%, Vn = 14%, Tg = −36 ° C., 37.5 phr oil exhibition (oil) <sup>* 18
* 4</sup> : St = 25%, Vn = 16%, Tg = -51 ° C. emulsion polymerization SBR, 37.5 phr oil exhibition (aromatic) <sup>* 16
* 5</sup> : Emulsion polymerization SBR with St = 25%, Vn = 16%, Tg = −51 ° C., 37.5 phr oil extended (paraffin) <sup>* 17
* 6</sup> : Emulsion polymerization SBR with St = 25%, Vn = 16%, Tg = −51 ° C., 37.5 phr oil exhibition (oil) <sup>* 18
* 7</sup> : Nipol 1220 manufactured by Nippon Zeon Co., Ltd.
^{* 8} : Show Black N220 manufactured by Showa Cabot Co., Ltd.
^{* 9} : Santoflex 6PPD manufactured by Flexis Co., Ltd.
^{* 10} : Desolex No. 3 manufactured by Showa Shell Sekiyu KK
^{* 11} : Machine oil 22 manufactured by Showa Shell Sekiyu KK
^{* 12} : Aromatic oil (C _A = 27%, Tg = −40 ° C., kinematic viscosity (100 ° C.) = 47 mm ² / sec)
^{* 13} : Hyrosin, Yashara Chemical Co., Ltd. Softening point: 95 ° C
^{* 14} : Coumarone resin manufactured by Ouchi Shinsei Chemical Co., Ltd. Softening point: 90 ° C
^{* 15} : Nouchira CZ-G manufactured by Ouchi Shinsei Chemical Co., Ltd.
^{* 16} : Desolex 3 manufactured by Showa Shell Sekiyu KK
^{* 17} : Showa Shell Sekiyu Co., Ltd. machine oil 22
^{* 18} : Aromatic oil (C _A = 27%, Tg = −40 ° C., kinematic viscosity (100 ° C.) = 47 mm ² / sec)

Claims (2)

100 parts by weight of a diene rubber containing at least one styrene-butadiene copolymer rubber (SBR) having a glass transition temperature Tg of −55 ° C. or higher has an aromatic hydrocarbon content (C _A ) of 20 to 35% by weight, A petroleum system having a Tg of −55 ° C. to −30 ° C., a kinematic viscosity (100 ° C.) of 20 to 50 mm ² / sec , and a polycyclic aromatic component amount (PCA) of 3% by weight or less in the petroleum-based process oil. A rubber composition comprising 5 to 80 parts by weight of process oil and 2 to 30 parts by weight of a resin having a softening point of 80 to 130 ° C selected from aromatic, rosin and coumarone. 100 parts by weight of at least one diene rubber has an aromatic hydrocarbon content (C _A ) of 20 to 35% by weight, a glass transition temperature Tg of −55 ° C. to −30 ° C., and a kinematic viscosity (100 ° C.) of 20 to 50 mm ² / sec at and polycyclic aromatic component amount (PCA) petroleum and petroleum-based process oil process 3 wt% or less in the oil, the novolak type phenol resin having a weight average molecular weight of 200 to 10,000 And a rubber composition comprising 10 to 30 parts by weight of a mixture in which the weight ratio of the process oil and the resin is 25 to 95% by weight / 5 to 75% by weight.