KR101376988B1 - Tread rubber composition for retreaded tire and tire manufactured by using the same - Google Patents

Abstract

The present invention relates to a tread rubber composition for tire regeneration and a tire regenerated using the same, wherein a raw material rubber and nitrogen adsorption specific surface area of 20 to 40 parts by weight of natural rubber and 60 to 80 parts by weight of styrene butadiene rubber is 138 to 147 m ² It provides a tread rubber composition for tire regeneration comprising carbon black having a / g, DBP oil absorption of 108 to 117cc / 100g and a tint (TINT) value of 110 to 119 to 48 to 55 parts by weight based on 100 parts by weight of the raw material rubber.
The tread rubber composition for tire regeneration is excellent in abrasion resistance and cut-chipping resistance at the same time can be advantageously used even when driving on unpaved roads such as mountainous terrain or gravel road.

Description

Tread rubber composition for tire regeneration and tires regenerated using the same {TREAD RUBBER COMPOSITION FOR RETREADED TIRE AND TIRE MANUFACTURED BY USING THE SAME}

The present invention relates to a tread rubber composition for tire regeneration and a tire regenerated using the same, and to a tread rubber composition for tire regeneration excellent in both cut-chipping resistance and abrasion resistance, and a tire regenerated using the same. will be.

Most of the researches in the development of tires can be concentrated in the field of structural aspects and application technology development of materials used for tires. Especially, in the material part, researches are being made to improve tire performance while considering energy saving and environmental issues. have.

In addition to increasing demand for tire economy, especially tires used in buses, trucks, or off-road vehicles, the performance of Retreaded Tires, which reattach new treads to worn treads The demands are also growing. Although the tread rubber composition for the regenerated tire of a vehicle used to drive such an unpaved road is hardly generated due to the high speed driving due to the use conditions, durability is not considered important, but it is excellent in wear resistance and cut-chipping resistance. This is required but at the same time difficult to satisfy.

Specifically, in the case of buses, trucks or off-the-road tires that often drive in bad roads, not only the wear resistance is excellent but also the cut-chipping resistance is required.

Conventionally, the raw rubber composed of natural rubber, butadiene rubber, and styrene butadiene rubber has a high nitrogen adsorption ratio surface area and a certain amount of carbon black having a wide range of dibutyl phthalide oil absorption (DBP), thereby improving wear resistance and heat resistance performance. Although the rubber composition is disclosed, the wear resistance is improved as the content of synthetic rubber such as butadiene increases, but there is a problem in that cut-chipping resistance is disadvantageous.

In addition, a high tint SAF grade carbon having a CTAB adsorption ratio surface area of 125 m ² / g, a C-DBP oil absorption of 100 cc / 100 g, and a tint value of 120 is used for raw rubbers made of natural rubber, butadiene rubber and styrene butadiene rubber. The low tint HAF grade carbon black (B) with black (A) and CTAB adsorption ratio surface area of 60 to 85 m ² / g, C-DBP oil absorption of 80 to 115 cc / 100 g and tint value of less than 110 Although the ratio of (A) / (B) is 0.4 to 1.2 so that the characteristics of wear resistance, heat generation and cut-chipping resistance are balanced, the inclusion of 10 to 45 parts by weight of butadiene rubber is in terms of wear resistance. It is advantageous, but cut-chipping resistance is disadvantageous, and carbon black also has a problem that the wear resistance and cut-chipping resistance are simultaneously degraded by using a mixture of low tint HAF grade.

(Patent Document 1) JP1994-192480 A

(Patent Document 2) JP2000-219778 A

(Patent Document 3) KR2011-0073064 A

The present invention is to provide a tread rubber composition for regeneration of tires excellent in both wear resistance and cut-chipping resistance in order to solve the economic and environmental problems of conventional tires and the demand of high-performance tires. do.

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

In order to achieve the above object, the tread rubber composition for tire regeneration according to an embodiment of the present invention is 100 parts by weight of raw rubber, including 20 to 40 parts by weight of natural rubber and 60 to 80 parts by weight of styrene butadiene rubber, and nitrogen adsorption ratio 48 to 55 parts by weight of colloidal carbon black having a surface area of 138 to 147 m ² / g, dibutyl phthalate (DBP) oil absorption of 108 to 117 cc / 100 g, and a tint (TINT) of 110 to 119.

The styrene butadiene rubber has a styrene content of 22 to 25 wt%, a vinyl content in butadiene 15 to 17 wt%, a number average molecular weight (Mn) of 55,000 to 59,000 g / mol, and a weight average molecular weight (Mw) of 260,000 To 320,000 g / mol and a molecular weight distribution (MWD) may be 3.8 to 4.2.

The tread rubber composition for tire regeneration may further include 10 to 22 parts by weight of processed oil based on 100 parts by weight of the raw material rubber.

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

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

The tire composition for regenerating tires includes raw rubber and carbon black.

The raw material rubber may include 20 to 40 parts by weight of natural rubber and 60 to 80 parts by weight of styrene butadiene rubber, preferably 25 to 35 parts by weight of natural rubber and 65 to 75 parts by weight of styrene butadiene rubber.

In order to improve the cut-chipping resistance, butadiene rubber having high mechanical rigidity can be used at 60 to 80 parts by weight without the use of butadiene rubber, which is advantageous for abrasion resistance but greatly disadvantageous for cut-chipping resistance, and has a high green strength. Excellent natural rubber can be used in 20 to 40 parts by weight. When the natural rubber is used in less than 20 parts by weight, the green strength decreases, so that the fracture strength, fatigue properties, and aging properties of the rubber are greatly detrimental. Fragmentation may occur, and when used in excess of 40 parts by weight, the mechanical rigidity and cut-chipping resistance may be lowered, and the unit price of the raw material may be increased to reduce commercial viability.

The natural rubber may be a general natural rubber or a modified natural rubber.

The above-mentioned general natural rubber may be used as long as it is known as natural rubber, and the country of origin and the like are not limited. The natural rubber includes cis-1,4-polyisoprene as a main component, but may also include trans-1,4-polyisoprene depending on required characteristics. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main component, natural rubber including trans-1,4-isoprene as a main component, such as balata, Rubber may also be included.

The modified natural rubber means that the general natural rubber is modified or purified. For example, examples of the modified natural rubber include epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber.

The styrene butadiene rubber is a kind of synthetic rubber obtained by copolymerizing styrene and butadiene. Specifically, the styrene content is 22 to 25% by weight, the vinyl content in the butadiene is 15 to 17% by weight, and the number average molecular weight (Mn) is 55,000. To 59,000 g / mol, a weight average molecular weight (Mw) may be 260,000 to 320,000 g / mol, and a molecular weight distribution (MWD) may be 3.8 to 4.2. Styrene butadiene rubber having the above characteristics has high modulus at low elongation and low modulus at high elongation, which is advantageous for chipping performance and cutting performance, respectively.

In addition, the styrene butadiene rubber may not contain an oil. In the case of styrene butadiene containing an oil, the styrene butadiene rubber may not exhibit the above-mentioned effective properties.

The carbon black is included in an amount of 48 to 55 parts by weight based on 100 parts by weight of the raw rubber. When the content of the carbon black is less than 48 parts by weight, the reinforcement may be insufficient to reduce wear and physical properties, and when the content of the carbon black exceeds 55 parts by weight, cut-chipping resistance may be reduced.

The carbon black has a nitrogen adsorption specific surface area of 138 to 147 m ² / g, a DBP (n-dibutyl phthalate) oil absorption of 108 to 117 cc / 100 g, a TINT value of 110 to 119, and a colloidal property. It may be a carbon black having.

When the nitrogen adsorption specific surface area of the carbon black exceeds 147m ² / g, the carbon black is greatly reduced in dispersibility, so that when the rubber is mixed, the viscosity of the pattern may be greatly increased and workability may be disadvantageous, and when the carbon black is less than 138m ² / g, wear and cut resistance Chipping can be disadvantageous. When the carbon black's DBP (n-dibutyl phthalate) oil absorption exceeds 117cc / 100g, it is advantageous in terms of heat resistance but cut-chipping resistance and abrasion resistance may be lowered.When it is less than 108cc / 100g, the decrease in modulus increases physical properties. This can be disadvantageous. In addition, when the TINT value of the carbon black exceeds 119, it may be disadvantageous in terms of fracture strength and cut-chipping resistance, and when it is less than 110, physical properties may be degraded.

The tire tread rubber composition may optionally further include various additives such as additional vulcanizing agents, vulcanization accelerators, vulcanization accelerators, fillers, anti-aging agents or softeners. The various additives can be used as long as they are commonly used in the field to which the present invention belongs. The content thereof is not particularly limited as long as it depends on a compounding ratio used in a rubber composition for a tire tread.

The vulcanizing agent may be a sulfur-based vulcanizing agent, an organic peroxide, a resin vulcanizing agent, or a metal oxide of magnesium oxide, and preferably a sulfur-based vulcanizing agent.

The vulcanizing agent is preferably included in an amount of 1.0 to 3.0 parts by weight based on 100 parts by weight of the raw material rubber, in that the raw material rubber is less sensitive to heat and chemically stable.

The vulcanization accelerator refers to an accelerator that promotes the vulcanization rate or accelerates the retardation in the initial vulcanization step.

Examples of the vulcanization accelerator include sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamate, aldehyde-amine, aldehyde-ammonia, imidazoline, Or a combination thereof.

As the vulcanization accelerator, preferably sulfenamide-based N-cyclohexyl-2-benzothiazylsulfenamide may be used, and 100 parts by weight of the raw material rubber may be used to maximize productivity and rubber properties by promoting vulcanization rate. It may be included in an amount of 1.0 to 2.0 parts by weight.

The vulcanization accelerating assistant may be any one selected from the group consisting of an inorganic vulcanization accelerator aid, an organic vulcanization accelerator aid, and a combination thereof, which is used in combination with the vulcanization accelerator to complete the promoting effect thereof .

In particular, the zinc oxide and the stearic acid may be used together as the vulcanization accelerating assistant. In this case, the zinc oxide is dissolved in the stearic acid to form an effective complex with the vulcanization accelerator, Thereby facilitating the crosslinking reaction of the rubber.

When the zinc oxide and the stearic acid are used together, the zinc oxide may be used in an amount of 1.0 to 5.0 parts by weight and 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the raw material rubber, respectively, as a suitable vulcanization accelerator. If the content of the zinc oxide and the stearic acid is less than the above range, the vulcanization rate may be slow and the productivity may be deteriorated. If the content exceeds the above range, the scorch phenomenon may occur and the physical properties may be deteriorated.

The rubber composition for a tire tread may further include a filler. The filler may be selected from the group consisting of silica, calcium carbonate, clay (hydrated aluminum silicate), aluminum hydroxide, lignin, silicate, talc, and combinations thereof.

The softening agent is added to the rubber composition in order to impart plasticity to the rubber to facilitate processing or to decrease the hardness of the vulcanized rubber, and means an oil or other material used in rubber compounding or rubber production. The softening agent means an oil contained in a process oil or other rubber composition. The softener may be selected from the group consisting of petroleum oils, vegetable oils, and combinations thereof, but the present invention is not limited thereto.

The petroleum-based oil may be selected from the group consisting of paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof.

However, when the content of polycyclic aromatic hydrocarbons (hereinafter referred to as PAHs) contained in the aromatic oils is 3 wt% or more with the recent increase of environmental awareness, it is known that cancer is likely to occur. Treated distillate aromatic extract (MES) oils, mild extraction solvate (MES) oils, residual aromatic extract (RAE) oils or heavy naphthenic oils may be preferably used, more preferably naphthenic oils having a PAH content of 3% or less. have.

The softening agent is preferably used in an amount of 10 to 30 parts by weight based on 100 parts by weight of the raw material rubber, in terms of improving processability of the raw material rubber, and more preferably 10 to 20 parts by weight. In the case where the softener is used in the rubber composition, the workability can be greatly increased and the dispersibility of the carbon black can be increased, thereby improving the physical properties and cut-chipping resistance of the rubber. However, when the softener is used in excess of 30 parts by weight of the process oil than the effect of improving the dispersibility of the carbon black is greater than the mechanical properties and physical properties can be reduced as well as the cut-chip chipping resistance.

The antioxidant is an additive used to stop the chain reaction in which the tire is autoxidized by oxygen. As the anti-aging agent, any one selected from the group consisting of an amine type, a phenol type, a quinoline type, an imidazole type, a carbamic acid metal salt, a wax and a combination thereof can be appropriately selected and used.

As the amine antioxidant, as the antioxidant, N- (1,3-dimethylbutyl) -N-phenyl-p-phenylenediamine (N- (1,3-Dimethylbutyl) -N-phenyl-p-phenylenediamine , 6PPD), N-phenyl-n-isopropyl-p-phenylenediamine (3PPD) and poly (2,2,4-trimethyl-1,2-dihydro A compound selected from the group consisting of quinoline (Poly (2,2,4-trimethyl-1,2-dihydroquinoline, RD) and combinations thereof can be preferably used. More preferably, N- (1,3-dimethyl Butyl) -N-phenyl-p-phenylenediamine can be used.

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

A tire according to another embodiment of the present invention is manufactured using the tread rubber composition for tire regeneration. The tire manufacturing method using the tread rubber composition for tire regeneration can be applied to any method conventionally used for tire regeneration.

Specifically, a method of manufacturing a regenerated tire using the tread rubber composition for tire regeneration may use a method of hot cure and cold cure, but the present invention is not limited thereto. The case may be used by applying a new tread rubber to the case or by vulcanization, but any method may be used as long as it is not limited thereto.

The tires may be used as off-the-road tires, truck tires, bus tires, passenger car tires, racing tires, airplane tires or agricultural machinery tires, and the like, in particular off-the-road tires. It can be preferably used as a tire, truck tire or bus tire, and more preferably as an off-the-road tire.

The tread rubber composition for tire regeneration of the present invention is excellent in abrasion resistance and cut-chipping resistance, and thus can be advantageously used even when driving on unpaved roads such as mountainous terrain or gravel roads.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out 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.

[ Manufacturing example : Preparation of rubber composition]

To prepare a tread rubber composition for tire recycling according to the following Examples and Comparative Examples using the composition shown in Table 1. The preparation of the rubber composition was in accordance with a conventional method for producing tire tread rubber. In Table 1, Comparative Example 1 used the ratio of raw rubber, Comparative Examples 2 and 3 used carbon black and carbon black, and Comparative Example 4 used different oils.

[Unit: parts by weight] Compounding agent Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 caoutchouc 50 30 30 30 30 30 30 Styrene Butadiene Rubber1 ⁽¹⁾ 50 70 70 30 70 - 70 Styrene Butadiene Rubber2 ⁽²⁾ - - - - - 70 - Butadiene Rubber ⁽³⁾ 40 Carbon Black 1 ⁽⁴⁾ 50 - 60 50 50 50 50 Carbon Black 2 ⁽⁵⁾ - 50 - - - - - Zinc oxide 4 4 4 4 4 4 4 Stearic acid 3 3 3 3 3 3 3 Process Oil ⁽⁶⁾ 15 15 15 15 25 15 15 Antioxidant ⁽⁷⁾ 2 2 2 2 2 2 2 brimstone 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Accelerators ⁽⁹⁾ 1.3 1.3 1.3 1.3 1.3 1.3 1.3

(1) Styrene butadiene rubber 1: 22 to 25 wt% styrene content, 15 to 17 wt% vinyl content in butadiene, number average molecular weight (Mn) 55,000 to 59,000 g / mol, weight average molecular weight (Mw) 260,000 to 320,000 g / mol, molecular weight distribution (MWD) is 3.8 to 4.2, no oil.

(2) styrene butadiene rubber 2: 13 to 18% by weight of styrene, 22 to 27% by weight of vinyl in butadiene, number average molecular weight (Mn) 45,000 to 49,000 g / mol, weight average molecular weight (Mw) 200,000 to 250,000 g / mol, molecular weight distribution (MWD) is 2.0 to 2.0, no oil.

(3) Butadiene rubber: Cis-1,4 content 96% or more, Tg temperature: -104 to -107 ° C

(4) Carbon Black 1: Nitrogen adsorption specific surface area 140 to 146m ² / g, DBP oil absorption 110 to 114cc / 100g, TINT value 112 to 116

(5) Carbon Black 2: Nitrogen adsorption specific surface area 118 to 122 m ² / g, DBP oil absorption 124 to 128 cc / 100 g, TINT value 119 to 122

(6) Process oil: Process OIL (NAPHTHENIC BASE), PAH Content 3% or less

(7) Antioxidant: N- (1,3-Dimethybutyl) -N'-Phenyl-p-Phenylenediamine

(8) Vulcanization accelerator: N-Cyclohexyl-2-benzothiazolesulfenamide, sulfenamide

[ Experimental Example : Measurement of physical properties of the prepared rubber composition]

The rubber composition having the above compounding ratio was evaluated through rubber in the laboratory, physical properties, cut-chipping resistance, fatigue resistance, exothermic performance and wear resistance of the rubber.

Modulus was measured by a tensile tester (Instron Co., Ltd.) by cutting the specimen into dumbbell-shaped, 100% modulus refers to the stress acting on the specimen when the specimen is stretched 100%.

Workability was measured on MV2000. Elongation was measured by the method of expressing the strain value in percent until the test piece is broken in the tensile tester.

Fatigue resistance was determined by measuring crack growth length at 19,000 Kcycle after 24 hours aging at 100 ° C using a Demattia tester.

Abrasion resistance, cut-chipping and heat resistance were manufactured by hot cure method in 12R22.5 and 11R22.5 standard and mounted on actual trucks and buses to evaluate wear resistance and cut-chipping resistance. Thermal properties were evaluated using an indoor durability tester.

The measurement results are shown in Table 2 below and indexed based on Example 3 except for modulus and elongation. The smaller the value shown in Table 2 below as a reference example 3, the lower the performance.

Performance Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Machinability (Index) 93 104 65 75 110 95 100 Modulus (kgf / cm ² , 100%) 30 31 41 33 28 33 34 Elongation (%) 475 467 376 497 509 470 461 Fracture Strength (Index) 99 97 92 95 95 100 100 Cut-Chipping Resistance (Index) 94 88 85 50 96 95 100 Wear Resistance (Index) 98 95 107 112 94 97 100 Fatigue Resistance (Index) 108 99 78 105 97 104 100 Heat resistance (Index) 107 108 82 108 95 105 100

As shown in the results of Table 2, the Examples are excellent in overall fracture strength, cut-chipping resistance, wear resistance, fatigue resistance and heat resistance compared to Comparative Examples 1 to 4, in particular having properties that are mutually opposite It can be seen that abrasion resistance and cut-chipping resistance were simultaneously improved.

More specifically, when the content of carbon black is increased (Comparative Example 3), the wear resistance is improved compared to the embodiment, but the opposite characteristics of cut-chip chipping resistance can be confirmed, and different types of carbon black are used (Comparative Example). 2) In the case of both wear resistance and cut-chip chipping resistance was more disadvantageous than the embodiment, it can be seen that the cut-chip chipping resistance is significantly reduced. In addition, when butadiene rubber (Comparative Example 4) is used as the raw material rubber, the cut-chipping resistance is significantly lowered to less than half even if the wear resistance is improved, but the cut-chipping resistance and It can be seen that it is possible to provide a tread rubber composition for tire regeneration excellent in both wear resistance.

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 (4)

100 parts by weight of raw rubber, including 20 to 40 parts by weight of natural rubber and 60 to 80 parts by weight of styrene butadiene rubber,
48 to 55 parts by weight of colloidal carbon black having a nitrogen adsorption specific surface area of 138 to 147 m ² / g, dibutyl phthalate (DBP) oil absorption of 108 to 117 cc / 100 g, and a TINT value of 110 to 119, and
10 to 20 parts by weight of the processing oil,
The styrene butadiene rubber has a styrene content of 22 to 25% by weight, a vinyl content in butadiene 15 to 17% by weight, a number average molecular weight (Mn) of 55,000 to 59,000 g / mol, and a weight average molecular weight (Mw) of 260,000 To 320,000 g / mol and a molecular weight distribution (MWD) of 3.8 to 4.2. delete delete A tire regenerated using the rubber composition for tire regeneration according to claim 1.