KR20120059121A - Tire tread rubber composition and tire manufactured by using the same - Google Patents

Abstract

PURPOSE: A rubber composition for tire tread is provided to have high tear strength, and to improve abrasion resistance and durability. CONSTITUTION: A rubber composition for tire tread comprises 100.0 parts by weight of crude rubber, 5-20 parts by weight of silica, 40-60 parts by weight of carbon black, 3-6 parts by weight of phenol resin of which functional group is substituted to resorcinol and hydrogen element. 5-10 mol% of total functional groups in the phenol resin is substituted to the hydrogen element, 10-20 mol% of total functional groups in the phenol resin is substituted to the resorcinol.

Description

Rubber composition for tire tread and a tire manufactured using the same {TIRE TREAD RUBBER COMPOSITION AND TIRE MANUFACTURED BY USING THE SAME}

The present invention relates to a rubber composition for a tire tread and a tire manufactured using the same, and relates to a rubber composition for a tire tread and a tire manufactured using the same, having high tear strength and improving wear resistance and durability. will be.

In general, the tread portion of the tires for trucks and buses is a thick rubber layer in direct contact with the road surface, and performs a number of functions such as transmitting driving and braking force to the road surface and alleviating impact from the road surface. In order to protect a tire internal structure such as a carcass or a belt layer, the tread is generally resistant to impact and employs a rubber composition having a high wear resistance in order to increase the running life. In order to meet these various purposes, natural rubber or synthetic rubber is generally used as a raw material by adding reinforcing agents, rubber compounding agents, fillers and additives.

Currently, in order to satisfy tire demands such as abrasion resistance and tear resistance, generally, about 5 to 20 parts by weight of silica is mixed with carbon black. However, in this method, SI-69, a coupling agent, is applied to increase the affinity between silica and natural rubber, which causes a problem that the tear strength is lowered. Difficulties and deterioration of physical properties due to adsorption of amine-based accelerators by silica.

It is an object of the present invention to provide a rubber composition for tire treads that can have high tear strength and improve wear resistance and durability.

Another object of the present invention is to provide a tire manufactured using the rubber tread rubber composition.

In order to achieve the above object, the rubber composition for a tire tread according to an embodiment of the present invention is based on 100 parts by weight of the raw material rubber, 5 to 20 parts by weight of silica, 40 to 60 parts by weight of carbon black, the functional group and the hydrogen element 3 to 6 parts by weight of phenol resin substituted with resorcinol and 3 to 6 parts by weight of pentamethoxymethylmelamine.

In the phenol resin in which the functional group is substituted with the hydrogen element and the resorcinol, 5 to 10 mol% of the total functional groups of the phenol resin is substituted with the hydrogen element, and 10 to 20 mol% of the total functional groups of the phenol resin is May be substituted with resorcinol.

The raw rubber may be natural rubber.

The tire tread composition may further include 0.5 to 5 parts by weight of vulcanizing agent and 0.5 to 3 parts by weight of vulcanization accelerator.

A tire according to another embodiment of the present invention is manufactured using the rubber tread rubber composition.

Hereinafter, the present invention will be described in more detail.

The tire tread rubber composition is based on 100 parts by weight of the raw material rubber, 5 to 20 parts by weight of silica, 40 to 60 parts by weight of carbon black, 3 to 6 parts by weight of a phenol resin in which a functional group is substituted with a hydrogen element and a resorcinol, and 3 to 6 parts by weight of pentamethoxymethylmelamine.

The raw material rubber is natural rubber.

The natural rubber may be a general natural rubber or modified natural rubber. The general natural rubber may be used as long as it is known as a natural rubber, the country of origin and the like are not limited.

The silica has a nitrogen adsorption specific surface area (N ₂ SA) of 160 to 200 m 2 / g, CTAB (cetyl trimethyl ammonium bromide) adsorption specific surface area may be 150 to 180 m 2 / g, but the present invention This is not limited to this.

When the silica adsorption specific surface area of the silica is less than 160 m 2 / g, reinforcing performance by silica as a filler may be detrimental, and when it exceeds 200 m 2 / g, the workability of the rubber composition may be detrimental. In addition, when the CTAB adsorption specific surface area of the silica is less than 150 m 2 / g, reinforcing performance by silica as a filler may be detrimental, and when it exceeds 180 m 2 / g, the workability of the rubber composition may be detrimental.

The silica can be used both wet or dry method, and commercially available products such as ultra-sil VN2 (manufactured by Degussa Ag), ultra-sil VN3 (manufactured by Degussa Ag), Z1165MP (manufactured by Rhodia) or Z165GR (manufactured by Rhodia) Can be.

The silica may be included in 5 to 20 parts by weight based on 100 parts by weight of the raw material rubber. When the content of the silica is less than 5 parts by weight, the strength improvement of the rubber may be insufficient and the braking performance of the tire may be reduced. When the content of the silica is more than 20 parts by weight, the wear performance may be reduced.

The carbon black may be a carbon black having a nitrogen adsorption specific surface area of 125 to 135 m ² / g and a DBP (n-dibutyl phthalate) oil absorption of 130 to 135 cc / 100 g.

When the carbon adsorption specific surface area of the carbon black exceeds 135 m ² / g, it may be advantageous in terms of wear resistance and cut chipping resistance, but heat generation may increase, so durability may be reduced, and when 125 m ² / g is less than wear resistance and cut chipping resistance Can be disadvantageous. When the DBP oil absorption of the carbon black exceeds 135cc / 100g, the heat generation resistance is advantageous, but the cut chipping resistance may be lowered, and if the DBP oil absorption is less than 130cc / 100g, the heat generation resistance may be lowered.

The carbon black is included in 40 to 60 parts by weight based on 100 parts by weight of the raw material rubber. When the content of the carbon black is less than 40 parts by weight, the wear resistance may be lowered, and when the content of the carbon black is greater than 60 parts by weight, the heat resistance may be lowered.

The phenol resin in which the functional group is substituted with the hydrogen element and the resorcinol is added as a reinforcing resin, and serves to improve the hardness of the rubber composition by resin vulcanization.

The phenol resin in which the functional group is substituted with the hydrogen element and the resorcinol is obtained by replacing the functional group of the phenol resin with the hydrogen element and the resorcinol, and the hydrogen element is substituted with 5 to 10 mol% of the total functional groups of the phenol resin. The resorcinol may be substituted with 10 to 20 mol% of the total functional groups of the phenol resin. When the hydrogen element is substituted with less than 5 mol%, the active site may not be sufficiently activated, resulting in poor reactivity, and when substituted with more than 10 mol%, the final product may become unstable due to excessive reactivity. In addition, when the resorcinol is substituted with less than 10 mol% does not sufficiently react with pentamethoxymethylmelamine, the tensile properties may not increase sufficiently, and when substituted with more than 20 mol% is also a steric hindrance problem Reactivity with pentamethoxymethylmelamine may be poor.

As the method for replacing the phenol resin with the hydrogen element and resorcinol, all conventional methods for replacing the phenol resin may be used, and thus detailed description thereof will be omitted.

The phenol resin may preferably be p-tert-alkyl phenol formaldehyde resin or resorcinol formaldehyde resin, wherein the p-tert-alkyl phenol formaldehyde resin is p-tert-butyl-phenol formaldehyde resin, p- It may be any one selected from the group consisting of tert-octyl-phenol formaldehyde and combinations thereof, but the present invention is not limited thereto.

The phenol resin substituted with the hydrogen element and the resorcinol may be used in an amount of 3 to 6 parts by weight based on 100 parts by weight of the raw material rubber. If the content of the phenol resin substituted with the hydrogen element and the resorcinol is less than 3 parts by weight, there is no increase in sufficient tear strength. If the content is more than 6 parts by weight, the elongation until breakage of the rubber may be sharply reduced.

The pentamethoxymethylmelamine (PMMM) is added as a crosslinking agent to form a crosslinked structure with the phenol resin substituted with the hydrogen element and resorcinol and at the same time form a permeable network with a crosslinked structure composed of rubber chain and sulfur. It improves the modulus and hardness of the rubber composition by increasing the affinity with the rubber and the crosslink density.

The pentamethoxymethylmelamine is more excellent in that it can improve the heat aging properties of tires compared to hexamethoxymethylmelamine (HMMM) or hexamethylenetetraamine (HMTA), which is usually used as methylene donor.

The pentamethoxymethylmelamine may be included in 3 to 6 parts by weight based on 100 parts by weight of the raw material rubber. If the content of the pentamethoxymethylmelamine is less than 3 parts by weight with respect to 100 parts by weight of the raw material rubber may not play a role as a physical rubber crosslinking agent, if more than 6 parts by weight there is a problem that the heat aging resistance of the rubber is lowered Can be.

The pentamethoxymethylmelamine is in the same ratio as the phenol resin substituted with the hydrogen element and resorcinol, and the mixing ratio range is not particularly limited.

The tire tread rubber composition may include various additives such as vulcanizing agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents and fillers. Any of the various additives can be used as long as they are commonly used in the field of the present invention.

As the vulcanizing agent, metal oxides such as sulfur vulcanizing agent, organic peroxide, resin vulcanizing agent and magnesium oxide can be used, and sulfur vulcanizing agent can be preferably used as the vulcanizing agent.

When the vulcanizing agent is included in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the raw material rubber, it is preferable in that the raw material rubber is less sensitive to heat and chemically stable.

The vulcanization accelerator refers to an accelerator that promotes the rate of vulcanization or promotes delay in the initial vulcanization stage.

The vulcanization accelerators include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid, aldehyde-amine, aldehyde-ammonia, imidazoline, xanthate and their Any one selected from the group consisting of a combination can be used.

As the vulcanization accelerator, a sulfenamide-based vulcanization accelerator may be preferably used, and more preferably, N-cyclohexyl-2-benzothioazolesulfenamide may be used, and the acceleration of vulcanization may be achieved. It may be included in an amount of 0.5 to 3 parts by weight based on 100 parts by weight of the raw material rubber in order to maximize productivity and enhancement of rubber properties.

The vulcanization accelerator is a compounding agent used in combination with the vulcanization accelerator to complete its promoting effect. Any one selected from the group consisting of inorganic vulcanization accelerators, organic vulcanization accelerators and combinations thereof can be used. .

In particular, zinc oxide and stearic acid may be used together as the vulcanization accelerator, in which case the zinc oxide is dissolved in the stearic acid to form an effective complex with the vulcanization accelerator, thereby producing favorable sulfur during the vulcanization reaction. It facilitates the crosslinking reaction of the rubber.

When using the zinc oxide and the stearic acid together may be used in 1 to 5 parts by weight and 0.5 to 3 parts by weight with respect to 100 parts by weight of the raw rubber, respectively, to serve as a suitable vulcanization accelerator.

The anti-aging agent is an additive used to stop the chain reaction in which the tire is automatically oxidized by oxygen. As the anti-aging agent, any one selected from the group consisting of amine-based, phenol-based, quinoline-based, imidazole-based, carbamic acid metal salts, waxes, and combinations thereof may be appropriately selected.

As the anti-aging agent, preferably, N- (1,3-dimethylbutyl) -N-phenyl-p-phenylenediamine (N- (1,3-Dimethybutyl) -N-phenyl-p-phenylenediamine, 6PPD), N-phenyl-n-isopropyl-p-phenylenediamine (3PPD), poly (2,2,4-trimethyl-1,2-dihydroquinoline (Poly ( 2,2,4-trimethyl-1,2-dihydroquinoline (RD) and combinations thereof may be used.

The anti-aging agent has a high solubility in rubber in addition to the anti-aging action, is low in volatility, inert to rubber, and does not inhibit vulcanization. It may be included in parts by weight.

The filler may further include any one selected from the group consisting of calcium carbonate, clay (aluminum hydrated silica), aluminum hydroxide, lignin, silicate, talc and combinations thereof in addition to silica and carbon black used in the present invention. .

In the case of truck and bus tires, the tread part absorbs and disperses the impact of the ground as it is, so the impact strength and tear strength should be high. Generally, the higher the tear strength, the better the wear resistance. Wear resistance is very closely related to tire life, and the better the wear resistance, the longer the life.

The rubber composition for tire treads according to the present invention having the composition as described above has a relatively low rigidity before vulcanization due to the low softening point of the phenol resin in which the functional group is substituted with hydrogen element and resorcinol. After vulcanization, crosslinking reaction with pentamethoxymethylmelamine used as a resin crosslinking agent forms a cross-penetrating crosslinked structure together with the crosslinked structure of natural rubber, and at the same time, rubber chains and carbon bonds occur, resulting in high tear strength and high hardness. Therefore, there is no fear of lowering the tear strength that appears when a conventional coupling agent is not used, and is useful as a material for increasing the tear strength of the tread.

The rubber tread rubber composition according to the present invention can be used as a new tire tread rubber composition, and can also be used as a regenerated tire tread rubber composition in which a new tread rubber is attached to a worn tread case. .

According to another embodiment of the present invention provides a tire manufactured using the tire tread rubber composition. The tire manufacturing method using the tire tread rubber composition can be applied to any of the methods conventionally used for the production of tires, and thus, detailed description thereof will be omitted.

The tire may be a passenger car tire, a racing tire, an airplane tire, a farm tire, an off-the-road tire, a truck tire or a bus tire. Preferably, it can be used with any one selected from the group consisting of heavy duty tires, truck tire treads and bus tire treads.

In addition, the tire may be a tire in which a tread portion of a worn case is regenerated by the rubber tread rubber composition.

A method of manufacturing a regenerated tire by using the tire tread rubber composition may include a method of hot cure and cold cure, but the present invention is not limited thereto. Any method can be applied as long as it is used to regenerate tires that are used by applying new tread rubber or by vulcanization.

The rubber composition for tire treads of the present invention has high tear strength and can improve wear resistance and durability performance.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[Production Example: Production of Rubber Composition]

Next, the rubber composition for tire treads according to the following examples and comparative examples was prepared using the composition shown in Table 1. Preparation of the rubber composition for tire treads followed the conventional manufacturing method of the rubber composition for tire treads.

Item Comparative Example 1 Comparative Example 2 Example 1 Natural rubber 100 100 100 Silica ^① 20 20 20 Carbon Black ^② 50 50 50 Phenolic resin with functional group substituted by hydrogen element and resorcinol ^③ - 5 3 PMMA - - 4 brimstone 5 5 5 Vulcanization accelerator ^④ 2 2 2

(Unit: parts by weight)

(1): silica having N ₂ SA of 175 m ₂ / g and CTAB adsorption specific surface area of 165 m ₂ / g

②: carbon black with N ₂ SA of 135㎡ / g and DBP oil absorption 135cc / 100g

③: p-tert-butyl-phenol formaldehyde resin in which the hydrogen element is substituted with 10 mol% of the total functional groups of the phenol resin and 15 mol% of the total functional groups of the phenol resin.

④: tertiary butyl benzothiazole sulfenamide (TBBS)

After the rubber compositions for tire treads of the prepared examples and comparative examples were vulcanized at 150 ° C. for 30 minutes to prepare specimens, physical properties were measured in the following manner. The results are shown in Table 2 below. However, the value shown in Table 2 below shows a relative value based on the measured value of the comparative example, the larger the value, the better.

Hardness was measured according to DIN 53505. Hardness indicates steering stability. The higher the value, the better the steering stability.

100% modulus (Modulus, unit kgf / cm 2) is the tensile strength at 100% elongation, measured according to the ISO 37 standard, and the higher the value, the better the strength.

Tensile strength (Kgf / cm ² ) was measured by the method of ASTM D 790, the higher the value indicates the stronger the elongation.

Elongation (%) means the elongation at break, which was measured by the method of expressing the strain value in percent until the test piece is broken in the tensile tester. The higher the value, the more flexible the rubber, the more elongated.

Item Comparative Example 1 Comparative Example 2 Example 1 Tensile Properties Hardness 100 102 104 Modulus 100 108 112 The tensile strength 100 102 118 Elongation (%) 100 98 96

Referring to Table 2, the rubber composition of Example 1, which uses a mixture of silica and carbon black in natural rubber and a functional group containing a phenol resin and pentamethoxymethylmelamine (PMMM) substituted with a hydrogen element and resorcinol Shows increased modulus and tear strength properties compared to Comparative Examples 1 and 2. It confirmed that it was more suitable for manufacture of a tire tread part.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (5)

For 100 parts by weight of raw material rubber,
5 to 20 parts by weight of silica,
40 to 60 parts by weight of carbon black,
3 to 6 parts by weight of a phenol resin having a functional group substituted with a hydrogen element and resorcinol, and
3 to 6 parts by weight of pentamethoxymethylmelamine
Rubber composition for a tire tread comprising a. The method of claim 1,
In the phenol resin in which the functional group is substituted with the hydrogen element and the resorcinol, 5 to 10 mol% of the total functional groups of the phenol resin is substituted with the hydrogen element, and 10 to 20 mol% of the total functional groups of the phenol resin is A rubber composition for tire treads that is substituted with resorcinol. The method of claim 1,
The rubber composition for tire tread, wherein the raw material rubber is natural rubber. The method of claim 1,
The tire tread composition further comprises 0.5 to 5 parts by weight of vulcanizing agent and 0.5 to 3 parts by weight of vulcanization accelerator. A tire manufactured using the rubber composition for tire tread according to any one of claims 1 to 4.