JP2008150553A - Rubber composition for tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eco-friendly rubber composition for a tire by using lecithin as a plasticizer. <P>SOLUTION: The rubber composition for a tire is produced by compounding 100 pts.wt. of a diene rubber with 20-200 pts.wt. of a reinforcing filler and 1-40 pts.wt. of lecithin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tire rubber composition, and more particularly to a tire rubber composition containing lecithin as a plasticizer.

  Conventionally, as a diene rubber plasticizer, aromatic oils have been often used for reasons such as excellent compounding properties. Recently, polycyclic aromatic compounds contained in such aromatic oils have been used. From the viewpoint of environmental safety, for example, the resulting safety and health problems have been pointed out, and studies are underway to regulate the use of aromatic oils as tire plasticizers. Therefore, an effective plasticizer that can replace such aromatic oil is strongly desired.

  From the above viewpoint, as a technique using a natural resource plasticizer in a rubber composition, a technique using a petroleum plasticizer and a high olefin vegetable oil in combination (Patent Document 1), a technique using a vegetable oil having an iodine value of 130 or less (Patent Document 2) ) And a technique (Patent Document 3) using a mineral oil and a terpolymer based on an unsaturated olefin nitrile has been proposed, but it is still not a plasticizer that is easy to use. In addition, a technique for blending lecithin as a natural resource material into a bladder for tire vulcanization (Patent Document 4) and a technique for blending in a rubber for glove formation (Patent Document 5) are also proposed. The lecithin is not used as a plasticizer for tire rubber.

Special table 2004-519551 gazette JP 2003-64222 A JP 2002-338754 A JP 2001-89619 A JP 2004-107483 A

  Therefore, an object of the present invention is to provide an environmentally friendly tire rubber composition by using lecithin as a plasticizer.

  According to the present invention, there is provided a tire rubber composition comprising 100 parts by weight of a diene rubber, 20 to 200 parts by weight of a reinforcing filler and 1 to 40 parts by weight of lecithin.

  Examples of the diene rubber in the present invention include natural rubber (NR), polyisoprene rubber (IR), various styrene-butadiene copolymer rubbers (SBR), various polybutadiene rubbers (BR), acrylonitrile-butadiene copolymer rubbers ( Diene synthetic rubbers such as NBR) and chloroprene rubber (CR) can be used alone or in combination of two or more thereof.

  In general, lecithin is a phospholipid that is abundant in soybeans, egg yolks, and the like, and either crude or purified lecithin can be used as the lecithin used in the present invention. Crude lecithin is mainly composed of phospholipids such as phosphatidylcholine, phosphatidylserine, phosphatidylic acid, phosphatidylethanolamine and phosphatidylinositol, and contains triglycerides, glycolipids, sterols and tocopherols, carbohydrates and the like. Purified lecithin can be obtained by purifying components other than phospholipids contained in the crude lecithin by a purification method using the solubility of the metal salt complex of lecithin, or a column chromatography method using aluminum oxide or silicic acid. It consists of a mixture of the phospholipids removed so as to be in a small amount.

  The lecithin is blended in an amount of 1 to 40 parts by weight, preferably 3 to 30 parts by weight with respect to 100 parts by weight of the diene rubber. If the blending amount is less than 1 part by weight, the desired effect as a plasticizer cannot be exhibited. Conversely, if it exceeds 40 parts by weight, bleeding occurs, which is not preferable.

  As the reinforcing filler to be blended in the rubber composition of the present invention, conventionally used for general tires or special tires, for example, carbon black, silica, surface-treated silica, clay, talc, alumina, hydroxide All of the reinforcing fillers such as aluminum, silicon carbide, calcium metasilicate, titanium dioxide, and calcium carbonate can be used alone or in combination. Moreover, as a compounding quantity of the said reinforcing filler, it is used with the optimal compounding quantity suitable for each use of various tires within the range of 20-200 weight part, More preferably, within the range of 30-150 weight part.

  In the tire rubber composition of the present invention, vulcanization or cross-linking agents, vulcanization or cross-linking accelerators, anti-aging agents, silane coupling agents, various fillers and the like can be further blended as other compounding agents. The compounding amounts of these compounding agents can also be set to conventional conventional amounts as long as they are not contrary to the present invention.

  EXAMPLES Hereinafter, although this invention is further demonstrated by an Example and a comparative example, it cannot be overemphasized that the technical scope of this invention is not limited by these Examples.

Preparation of test sample The components except for sulfur and vulcanization accelerator in the rubber compounding systems shown in Table 1 and Table 2 below were kneaded for 5 minutes with a 1.7 L closed Banbury mixer and released when the temperature reached 165 ± 5 ° C. Sulfur and a vulcanization accelerator were added to the masterbatch and kneaded with an 8-inch open roll to obtain an unvulcanized rubber composition. A part of this rubber composition was subjected to a viscosity test (Mooney viscosity). Next, the remainder of the rubber composition was press vulcanized at 160 ° C. for 20 minutes in a 15 cm × 15 cm × 0.2 cm mold to produce a test piece (rubber sheet) having a hardness of 300% modulus (M300). And subjected to an elongation at break (E _B ) test.

Test / Evaluation Method 1) Mooney Viscosity (ML _{1 + 4} ): In accordance with JIS K 6300-1, a Mooney viscometer is used with an L-shaped rotor (38.1 mm diameter, 5.5 mm thickness), and preheating time The measurement was performed under the conditions of 1 minute, a rotor rotation time of 4 minutes, 100 ° C., and 2 rpm. The result is shown as an index with Comparative Example 1 or 3 as 100. It shows that it is so favorable that a numerical value is small.
2) Hardness: Based on JIS K 6253, the hardness at 20 ° C. was measured using a spring type A hardness tester. The result is shown as an index with Comparative Example 1 or 3 as 100. It shows that it is so favorable that a numerical value is large.
3) 300% modulus (M300): The modulus at 300% elongation was measured according to JIS K 6251. The result is shown as an index with Comparative Example 1 or 3 as 100. It shows that it is so favorable that a numerical value is large.
4) elongation at break (E _B): in compliance with JIS K 6251, punched 2mm rubber sheet at JIS3 dumbbell from the test sample, at a tensile rate conditions of 500 mm / min, to obtain a E _B . The results were expressed as an index with Comparative Example 1 or 3 as 100. It shows that it is so favorable that a numerical value is large.

Examples 1-3 and Comparative Examples 1-3
The results are shown in Table 1 and Table 2 below.

  From the results of Tables 1 and 2, it can be seen that both crude lecithin and purified lecithin, which are friendly to the environment, exhibit rubber processing properties and rubber characteristics that are comparable to conventional aroma oil plasticizers in a predetermined amount.

  Therefore, the lecithin plasticizer according to the present invention can be sufficiently used in a tire rubber composition as a substitute for a conventional aroma oil.

Claims (1)

  A tire rubber composition comprising 100 parts by weight of a diene rubber, 20 to 200 parts by weight of a reinforcing filler and 1 to 40 parts by weight of lecithin.