JP2006063206A - Rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the abrasion resistance of a rubber composition without deteriorating tensile characteristics and viscoelastic characteristics. <P>SOLUTION: This rubber composition comprising an elastomer, a silica-based filler, and a silane coupling agent is characterized by further containing a ketimine group-containing compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rubber composition, and more particularly to a rubber composition having improved wear resistance without adversely affecting tensile properties and viscoelastic properties.

  In recent years, in order to achieve both wet performance and low fuel consumption of pneumatic tires, instead of carbon black, reinforcing fillers such as silica, aluminum hydroxide, and titanium oxide are used as reinforcing fillers for tire rubber compositions. The agent is to be used. In particular, when silica is blended in a rubber composition, the silica tends to agglomerate, and there is a problem that the viscosity of the rubber composition when unvulcanized increases and the processability deteriorates. In order to solve such a problem, a silane coupling agent is used for the purpose of reducing the aggregation of silica. By adding a silane coupling agent to the rubber composition, the rubber reinforcement is dramatically improved. However, the rubber composition is inferior in wear resistance compared to a rubber composition containing conventional carbon black. There's a problem.

  In order to solve this problem, for example, Patent Document 1 proposes a rubber composition in which silica, polysulfated alkoxysilane, aldimine (R—CH═N—R), and a guanidine derivative are blended with a diene elastomer. Although it is described that the addition of aldimine promotes activation of polysulfide alkoxysilane and improves rolling resistance and wear resistance, the effect of improving the wear resistance is not necessarily sufficient, and further improvement is desired. It is.

Japanese translation of PCT publication No. 2003-530443

  Accordingly, an object of the present invention is to provide a rubber composition having improved wear resistance without impairing tensile properties and viscoelastic properties.

  According to the present invention, there is provided a rubber composition further comprising a ketimine group-containing compound in a rubber composition comprising an elastomer, a silica-based filler, and a silane coupling agent.

  According to the present invention, by adding a ketimine group-containing compound to a rubber composition containing a silica filler and a silane coupling agent, the wear resistance of the rubber composition is improved without impairing tensile properties and viscoelastic properties. Can be made.

  The ketimine group-containing compound used in the present invention is represented by the following formula (I) obtained by reacting a polyamine compound having a primary amino group with a carbonyl compound to block the primary amino group in the polyamine compound. It is a protected amino group-containing compound represented. The primary amino group-containing polyamine compound as a raw material may be any of aliphatic, alicyclic and aromatic compounds, and its molecular weight is generally 5000 or less because of its low viscosity and preferable workability. Preferably, 50-2000 is used. One or more primary amino groups may be present in one molecule.

  Specific examples of the polyamine compound include propylamine, butylamine, pentylamine, hexylamine, stearylamine, cyclohexylamine, benzylamine, and 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-amino. Monofunctional amines such as amino group-containing alkoxysilanes such as propylmethyldimethoxysilane and 3-aminopropylmethyldietrixysilane, aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, hexanediamine, and poly (oxypropylene) diamine , Aromatic polyamines such as phenylenediamine, toluenediamine, diaminodiphenylmethane, 1,3-bisaminomethylcyclohexane, norbornanediamine, isophoronediamine, etc. Alicyclic polyamines, and the like. General-purpose ketone compounds such as acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, methyl cyclohexanone, methyl cyclohexyl ketone, acetophenone, benzophenone are suitable as the carbonyl compound for blocking the polyamine compound. Used for. Ketimination can be obtained by mixing polyamine and ketone in an equivalent ratio or an excess amount of ketone, and stirring under room temperature to heating conditions while removing generated water out of the system by azeotropic distillation or the like. In this reaction, a solvent such as toluene or xylene may be used in combination.

  Some of these ketimine group-containing compounds are commercially available, and examples thereof include EpiCure H-3 and EpiCure H-30 manufactured by Japan Epoxy Resin Co., Ltd. and Adeka Hardener EH-235R series manufactured by Asahi Denka Kogyo Co., Ltd.

(In the formula, R ¹ and R ² are each a hydrocarbon group having 1 to 8 carbon atoms including a linear, alicyclic or aromatic ring which may be the same or different, and R ³ is an amino group from a polyamine compound. And is a hydrocarbon group having a molecular weight of 40 to 10000 that may contain N, O, and S, specifically, a residue obtained by removing an amino group from the polyamine compound.

  In a preferred embodiment of the present invention, the ketimine group-containing compound is blended in an amount of preferably 0.1 to 3 parts by weight, more preferably 0.1 to 2.5 parts by weight, per 100 parts by weight of the elastomer. If the amount of the ketimine group-containing compound is within the above range, the wear resistance of the rubber composition can be improved without impairing the tensile properties and viscoelastic properties. On the other hand, when the ketimine group-containing compound is not blended or when the amine produced by the reaction of the ketimine group with water is blended, the effect of improving the wear resistance is not substantially observed.

  Examples of elastomers that can be used in the present invention include various natural rubbers (NR), various polyisoprene rubbers (IR), various polybutadiene rubbers (BR), various styrene-butadiene copolymer rubbers (SBR), and various acrylonitrile-styrenes. -A butadiene copolymer rubber etc. can be mention | raise | lifted and these can be used individually or as arbitrary mixtures.

  The silica-based filler that can be used in the present invention may be any silica conventionally used for tires, such as natural silica, synthetic silica, more specifically dry silica, wet silica. . Silica is preferably blended in an amount of 10 to 120 parts by weight, more preferably 20 to 100 parts by weight, per 100 parts by weight of the elastomer. If the blending amount is too small, there is a possibility that the rubber is not sufficiently reinforcing, and conversely if too large, the processability may be deteriorated.

  As the silane coupling agent that can be used in the present invention, any silane coupling agent that has been conventionally blended with silica, such as for tires, can be used. Specifically, for example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) ) Tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis- (3-trimethoxysilylpropyl) disulfide 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 3-nitropropyltriethoxysilane, 3-nitrop Pyrtrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 2-chloroethyltriethoxysilane, 2-chloroethyltrimethoxysilane, 3-triethoxysilylpropyl-N, N-dimethylthio Carbamoyl tetrasulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3- Trimethoxysilylpropyl methacrylate monosulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide And the like, a coupling agent addition effect and cost-bis terms of compatibility of (3-triethoxysilylpropyl) use of such tetrasulfide are preferable.

  In the present invention, the silane coupling agent is added in an amount of preferably 0.1 to 30% by weight, more preferably 0.2 to 15% by weight, based on the weight of the silica-based filler. If the blending amount is too small, there is a possibility that the rubber reinforcing property cannot be sufficiently exhibited, and conversely if too large, there is a fear of bleeding.

  In addition to the above-described essential components, the rubber composition according to the present invention includes other reinforcing agents (fillers) such as carbon black, vulcanization or crosslinking agents, vulcanization or crosslinking accelerators, various oils, anti-aging agents, Various additives generally blended for tires such as plasticizers and other general rubbers can be blended, and these additives are kneaded by a general method into a composition, which is vulcanized or crosslinked. Can be used for The blending amounts of these additives may be conventional conventional blending amounts as long as the object of the present invention is not adversely affected.

  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.

Examples 1-5 and Comparative Examples 1-3
In each of the formulations shown in preparation Table I sample, it was kneaded for 5 minutes at vulcanization accelerator and internal mixer of the components 1.5 liters, except the sulfur, to obtain a master batch release. A vulcanization accelerator and sulfur were kneaded with this master batch with an open roll to obtain a rubber composition.

  Next, the obtained rubber composition was vulcanized in a 15 × 15 × 0.2 cm mold at 160 ° C. for 20 minutes to prepare a vulcanized rubber sheet. The physical properties of the vulcanized rubber were measured by the following test methods. It was measured. The results are shown in Table I.

Rubber property evaluation test method Tensile properties: 100% modulus (M100), breaking strength (TB) and breaking elongation (EB) were measured according to JIS K-6251.
tan δ (60 ° C.): Using rheograph solid manufactured by Toyo Seiki Seisakusho, viscoelasticity was measured (sample width: 5 mm) at initial strain = 10%, dynamic strain = 2%, frequency = 20 Hz, temperature 60 ° C.
Lambourne wear: wear loss was measured using a Lambourne wear tester (manufactured by Iwamoto Seisakusho Co., Ltd.) under the conditions of a temperature of 20 ° C. and a slip ratio of 50%. The larger the value, the better the wear resistance.

Table I footnote * 1: Nippon Zeon Co., Ltd. Oil Expo SBR (oil content: 37.5 parts by weight)
* 2: Nippon Sil AQ manufactured by Nippon Silica Industry Co., Ltd.
* 3: Sigus made by Deggusa Co., Ltd.
* 4: EpiCure W manufactured by Japan Epoxy Resin
* 5: Albemarle etacure 300

  * 6: 100 g of 1,3-bisaminomethylcyclohexane (reagent: manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 215 g of diisopropyl ketone (reagent: manufactured by Tokyo Kasei Kogyo Co., Ltd.) of 1.5 times the amino group, And 200 g of toluene were mixed, and in the presence of an acetic acid catalyst, heating and stirring were continued for 3 days while water produced was removed azeotropically. After completion of the reaction, excess ketone and toluene were removed under reduced pressure to obtain the target ketimine compound (ketimine 1).

  * 7: The same procedure as in Ketimine 1 was performed, except that 100 g of norbornanediamine (Mitsui Chemicals Co., Ltd.) was used as the amine, 167 g of methyl isopropyl ketone (Kuraray Co., Ltd.) was used as the ketone, and no acetic acid catalyst was used. 15 hours later, the desired ketimine 2 was obtained.

  * 8: Operation similar to ketimine 1 except that 100g of EpiCure W from Japan Epoxy Resin Co. is used for amine, 200g of cyclopentanone (reagent: Tokyo Chemical Industry Co., Ltd.) is used for ketone, and no acetic acid catalyst is used. 10 hours later, the target ketimine 3 was obtained.

  * 9: The same procedure as in Ketimine 1 was performed except that 100g of Albemarle Etacure 300 was used for the amine, 200g of cyclopentanone (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used for the ketone, and no acetic acid catalyst was used. Ten hours later, the desired ketimine 4 was obtained.

  * 10: 100 g of 3-aminopropyltrimethoxysilane (A1110; manufactured by Nihon Unicar Co., Ltd.) and 72 g of methyl isopropyl ketone (manufactured by Kuraray Co., Ltd.) were mixed and stirred at 40 ° C. for 30 hours. Water produced by ketimination was consumed by hydrolysis and condensation reaction of alkoxysilane in the system, and finally, a mixture of ketiminate and excess ketone and methanol produced by hydrolysis and condensation was obtained. Thereafter, excess ketone and methanol were removed under reduced pressure to obtain the desired ketiminated siloxane (ketimine 5).

* 11: Three types of zinc oxide manufactured by Shodo Chemical Industry Co., Ltd. * 12: Stearic acid manufactured by Nippon Oil & Fats Co., Ltd. * 13: Nocrack 6c manufactured by Ouchi Shinsei Chemical Industries
* 14: Oil treatment sulfur manufactured by Karuizawa Refinery * 15: Noxeller CZ-G manufactured by Ouchi Shinsei Chemical Co., Ltd.
* 16: Sumocile DG manufactured by Sumitomo Chemical Co., Ltd.

  As described above, the rubber composition according to the present invention can improve the wear resistance without adversely affecting the tensile properties and viscoelastic properties. For example, as a tire, a conveyor belt, a hose, or a rubber bearing. Useful.

Claims (6)

  A rubber composition comprising an elastomer, a silica-based filler, and a silane coupling agent, further comprising a ketimine group-containing compound.   The rubber composition according to claim 1, wherein the ketimine group-containing compound is a compound having two ketimine groups in the molecule.   The rubber composition according to claim 1 or 2, wherein the amount of the ketimine group-containing compound is 0.1 to 3 parts by weight per 100 parts by weight of the elastomer.   The elastomer according to any one of claims 1 to 3, wherein the elastomer is at least one elastomer selected from natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, and acrylonitrile-styrene-butadiene copolymer rubber. The rubber composition as described.   The rubber composition according to any one of claims 1 to 4, wherein the amount of the silica-based filler is 10 to 120 parts by weight per 100 parts by weight of the elastomer.   The rubber composition according to any one of claims 1 to 5, wherein the amount of the silane coupling agent is 0.1 to 30% by weight based on the weight of the silica-based filler.