KR100346517B1 - Rubber composition using a cure activator for belt cushion - Google Patents

Abstract

The present invention relates to a compounded rubber composition using a vulcanizing agent, and more particularly, to improve the modulus and tear characteristics of the belt cushion compounded rubber that enters between the belts in order to disperse the stress at the end of the belt in a steel radial tire. The present invention relates to a rubber composition for a belt cushion of a steel radial tire that suppresses generation and improves refining, rolling and extrusion processability.

Description

Rubber composition for belt cushion using vulcanizing agent {RUBBER COMPOSITION USING A CURE ACTIVATOR FOR BELT CUSHION}

The present invention relates to a compounded rubber composition using a vulcanizing agent, and more particularly, modulus of the belt cushion compounded rubber that is interposed between the belts in order to disperse the stress of the belt end in the steel radial tire and The present invention relates to a rubber composition for belt cushioning that improves tearing properties and improves refining, rolling and extrusion processability.

In general, the compound rubber used for the belt cushion is the same as that of the compound rubber used for the belt.As it is placed on the end of the belt, the thickness between the belt and the belt is increased to distribute the stress concentrated on the end of the belt while driving to improve the durability of the tire. It plays a role. In addition, the belt cushion is wrapped around the exposed end of the belt and serves to maintain adhesion with the steel cord.

However, tires running under high speed or high load conditions have high stresses at the belt ends, separation occurs at the belt ends, and the durability of the tires is reduced.

As a means to prevent this, a cap ply is placed on the belt layer to suppress the movement of the belt at the end of the belt, thereby reducing stress, but the process of rolling, cutting, and forming the cap ply as well as increasing tire weight and manufacturing cost. As this is added, there is a problem in that productivity decreases.

In order to increase the modulus of rubber, increasing the addition amount of carbon black and sulfur has been a common conventional technique, but the elongation at break of rubber decreases and the heat generation in the compounding or extrusion process is severe, resulting in scorch and blooming. Caused bad. Therefore, carbon black and sulfur were limited in their addition amount within the range of not causing such defects.

An object of the present invention is to improve the above problems, while increasing the amount of carbon black and sulfur to improve the modulus of the rubber, while preventing the drop of physical properties such as tensile strength, tear strength, elongation, etc. of the belt cushion rubber It is to provide a rubber composition for the belt cushion that can improve the modulus and tear characteristics to suppress the occurrence of the separation and to distribute the stress at the belt end.

The rubber composition of the present invention is a zinc salt mixture of aliphatic and aromatic carboxylic acids as a vulcanizing agent in a rubber composition for belt cushion (manufactured by Aktivator-73: Schill & Seilacher GMBH & Co., density: 1,200 kg / m ³ , zinc Content: 18%, drop point: 113 ° C.) and an alkylated naphthenic resin or an alkylated aromatic resin (Promix 4tear: manufactured by Flow Polymer Inc.).

In the present invention, the zinc salt mixture of aliphatic and aromatic carboxylic acids and alkylated naphthenic resins or alkylated aromatic resins are preferably added in the range of 1 to 5 phr with respect to 100 phr of raw rubber, and more preferably aliphatic and Preferably, the zinc salt mixture of aromatic carboxylic acids is added in an amount of 2 to 4 phr, an alkylated naphthenic resin or an alkylated aromatic resin in the range of 1 to 3 phr. If the addition amount is less than 1 phr does not appear the effect of the invention, if the addition amount is more than 5 phr is not preferable because the effect of the invention on the input amount is reduced or rather reduced and the cost is also increased.

According to the present invention, a carbon salt mixture of aliphatic and aromatic carboxylic acids (Aktivator-73) and alkylated naphthic resins are added as a vulcanizing agent, while adding carbon black in amounts of 50 to 70 phr and sulfur in a range of 3 to 9 phr. Alternatively, the addition of an alkylated aromatic resin (Promix 4tear) in the range of 1 to 5 phr, respectively, suppresses scorch and blooming, sharply lowers the viscosity of the compounded rubber, significantly increases the scorch stability and also provides tear resistance. And at the same time the dynamic properties (dynamic property) can provide an improved rubber composition for the belt cushion.

Components other than the vulcanizing agent in the rubber composition of the present invention may be blended in a conventional range of components used in the rubber composition for a conventional belt cushion.

Preferred examples of the rubber composition according to the present invention are 100 phr of natural rubber, 50 to 70 phr of carbon black, 5 to 10 phr of zinc (ZnO), 1 to 2 phr of antioxidant, 1 to 2 lysosinol formaldehyde resin (RF resin) 2 phr, cobalt salt 1 to 4 phr, aromatic oil (A # 2 oil) 2 to 5 phr, sulfur 3 to 9 phr, vulcanization accelerator 0.5 to 1.5 phr, adhesion promoter 2 to 5 phr, zinc salt mixture of aliphatic and aromatic carboxylic acid (Aktivator (73) 1 to 5 phr, alkylated naphthenic resin or 1 to 5 phr alkylated aromatic resin (Promix 4tear).

The present invention can be understood in more detail by the following examples and comparative examples, the following examples are only for illustrating the present invention and are not intended to limit the protection scope of the present invention.

Examples and Comparative Examples

A rubber composition was prepared according to the composition shown in Table 1, the physical properties were measured, and the results are shown in Table 1.

Table 1

Note 1) Activator 73: mixture of zinc salts of aliphatic and aromatic carboxylic acids (manufactured by Schill & Seilacher GMBH & Co.)

Note 2) Framix 4 Tier: Alkylated Naphthenic Resin or Alkylated Aromatic Resin (manufactured by Flow Polymer Inc.)

As shown in Comparative Example 1, when the addition amount of carbon black and sulfur was increased to increase the modulus of the rubber composition, tensile strength, tear strength and elongation, scorch stability, and the like decreased compared to the conventional example.

However, in Examples 1 and 2 of the present invention, the modulus improvement and tensile strength of the rubber composition by blending a mixture of zinc salts of aliphatic and aromatic carboxylic acid (activator 73) with alkylated naphthenic resin or alkylated aromatic resin (Promix 4tear) Strength, tear strength, scorch stability and fatigue resistance were all improved.

As can be seen from the above, the rubber composition produced according to the present invention is used as a rubber composition for the belt cushion of steel radial tires by using two kinds of specific vulcanizing activator to suppress the occurrence of separation at the end of the belt, thereby improving tire durability. At the same time, there is an effect of improving the overall physical properties and productivity of the rubber composition.

Claims (3)

A rubber composition for belt cushioning of steel radial tires, comprising: 1 to 5 phr of a mixture of zinc salts of aliphatic and aromatic carboxylic acids and 1 to 5 phr of alkylated naphthenic resin or alkylated aromatic resin as a vulcanizing agent. Rubber composition for belt cushion. The rubber composition for a belt cushion according to claim 1, comprising 50 to 70 phr of carbon black and 3 to 9 phr of sulfur. A steel radial tire having a belt cushion made of the rubber composition of claim 1.