Rubber composition and use thereof

Abstract

The present invention relates to the technical field of rubber compositions. Disclosed is a rubber composition. Calculated for every 100 parts by weight of rubber, the rubber composition comprises the following components: 30-60 parts of polyisoprene rubber, 10-30 parts of polybutadiene rubber, 25-60 parts of a styrene and butadiene copolymer, 5-20 parts of syndiotactic 1,2-polybutadiene, 10-30 parts of carbon black and 40-100 parts of white carbon black. In the rubber composition disclosed by the present invention, by means of adding syndiotactic 1,2-polybutadiene polymer having a specific melting point, crystallinity and bond content at positions 1 and 2, co-crosslinking between syndiotactic 1,2-polybutadiene and rubber is facilitated, thus the strengthening and toughening performance of a vulcanized rubber material can be effectively increased, the heat generation performance of the rubber material is improved, and the fuel efficiency of a tire is increased.

Description

A rubber composition and its application Technical Field

[0001] The present invention relates to the technical field of rubber compositions, in particular to a rubber composition and application thereof. Background Art

[0002] In recent years, with the rapid development of automobile technology, especially new energy vehicle technology, it requires lower rolling resistance and lower tire defect rate. Among them, inorganic fillers carbon black and white carbon black are used as raw materials for tire rubber compositions. Increased dosage can improve the physical properties of the rubber compound and reduce abnormal damage to the tire, such as "groove cracking" and "block falling". However, the hysteresis heat generation also increases, and the rolling resistance of the tire increases. Therefore, it is difficult to achieve the characteristics of strengthening and toughening the rubber while providing the expected low heat generation performance. In order to achieve the reduction of rolling resistance, there are also methods that modify the structure of diene polymers and copolymers by functionalizing agents, coupling agents or star-branching agents when the polymer is terminated to improve the interaction between the polymer and the filler. However, the physical properties of the rubber compound have not been improved, and the improvement effect on the "groove cracking" and "block falling" problems of the tire is not good.

[0003] Therefore, how to provide a rubber composition that is reinforced, toughened and has low heat generation is a problem that those skilled in the art urgently need to solve. Summary of the Invention

[0004] In view of this, the present invention provides a rubber composition to solve the problem that the strength, toughness, rolling resistance and hysteresis heat generation performance of existing tire rubber compositions cannot be effectively balanced.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A rubber composition comprises the following components per 100 parts by weight of rubber: 30-60 parts of polyisoprene rubber, 10-30 parts of polybutadiene rubber, 25-60 parts of styrene-butadiene copolymer, 5-20 parts of syndiotactic-1,2-polybutadiene, 10-30 parts of carbon black, and 40-100 parts of white carbon black.

[0007] Preferably, in the above rubber composition, the syndiotactic 1,2-polybutadiene has a melting point of 60-150° C. and a crystallinity of 2-30%.

[0008] Preferably, in the above rubber composition, the weight average molecular weight of the syndiotactic 1,2-polybutadiene is 10.0*10 4 -45*10 4 .

[0009] Preferably, in the above rubber composition, the 1,2-bond content of the syndiotactic 1,2-polybutadiene is ≥50%.

[0010] Preferably, in the above rubber composition, the catalytic system for syndiotactic 1,2-polybutadiene comprises an iron-containing organic compound, an azodicyano compound, an organic aluminum compound and a free radical scavenger.

[0011] Preferably, in the rubber composition, the polyisoprene rubber is cis-1,4-polyisoprene rubber.

[0012] Preferably, in the above rubber composition, the polybutadiene rubber is a high-cis synthetic rubber with a cis content greater than 96%.

[0013] Preferably, in the above rubber composition, the nitrogen adsorption specific surface area of ​​the carbon black is ≥120m 2 / g, DBP oil absorption value ≥120cm 3 / 100g.

[0014] Preferably, in the above rubber composition, the BET specific surface area of ​​the white carbon black is ≥120m 2 / g, DBP oil absorption value ≥1.5cm 3 / g.

[0015] On the other hand, the present invention also provides a tire comprising any of the above-mentioned rubber compositions.

[0016] The present invention provides a rubber composition, which has the following advantages compared with the prior art:

[0017] The rubber composition of the present invention is more conducive to the formation of co-crosslinking between the syndiotactic 1,2-polybutadiene polymer and the rubber by adding the syndiotactic 1,2-polybutadiene polymer with a specific melting point, crystallinity and 1,2-bond content, and can effectively improve the reinforcement and toughening properties of the vulcanized rubber compound, improve the heat generation performance of the rubber compound, and improve the fuel efficiency of the tire. DETAILED DESCRIPTION

[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] An embodiment of the present invention provides a rubber composition, which includes the following components per 100 parts by weight of rubber: 30-60 parts of polyisoprene rubber, 10-30 parts of polybutadiene rubber, 25-60 parts of styrene-butadiene copolymer, 5-20 parts of syndiotactic-1,2-polybutadiene, 10-30 parts of carbon black, and 40-100 parts of white carbon black.

[0020] Furthermore, the rubber composition includes the following components per 100 parts by weight of rubber: 40-50 parts of polyisoprene rubber, 15-25 parts of polybutadiene rubber, 30-50 parts of styrene-butadiene copolymer, 5-15 parts of syndiotactic 1,2-polybutadiene, 10-20 parts of carbon black, and 50-80 parts of white carbon black.

[0021] Furthermore, the rubber composition includes the following components per 100 parts by weight of rubber: 40 parts of polyisoprene rubber, 20 parts of polybutadiene rubber, 30-35 parts of styrene-butadiene copolymer, 10-20 parts of syndiotactic 1,2-polybutadiene, 10 parts of carbon black, and 70 parts of white carbon black.

[0022] In some embodiments of the present invention, the syndiotactic 1,2-polybutadiene has a melting point of 60-150°C and a crystallinity of 2-30%, with minimal or no gel. Crystallinity is a measure of the heat of fusion and indicates the degree of crystallinity, which can be derived from the melting peak measured by a differential scanning calorimeter. Syndiotactic 1,2-polybutadiene participates in crosslinking in the vulcanized rubber composition, enhancing the physical properties of the rubber and improving the fuel efficiency of the tire. Therefore, the crystallinity of syndiotactic 1,2-polybutadiene is preferably 5% or higher, more preferably 10% or higher. However, excessive crystallinity increases the melting point, making co-vulcanization and crosslinking difficult, which can degrade tire performance. Therefore, it is believed that the crystallinity of syndiotactic 1,2-polybutadiene is preferably 30% or lower, preferably 25% or lower, and more preferably 23% or lower.

[0023] In some embodiments of the present invention, the weight average molecular weight of the syndiotactic 1,2-polybutadiene is 10.0*10 4 -45*10 4 Within a certain weight average molecular weight range, the higher the weight average molecular weight of syndiotactic 1,2-polybutadiene, the better the physical properties of the rubber compound and the higher the fuel efficiency of the tire. Therefore, the weight average molecular weight of syndiotactic 1,2-polybutadiene is 10.0*10 4 Above, preferably 15.0*10 4 More than 20.0*10 4 On the other hand, in order to make the syndiotactic 1,2-polybutadiene smoothly form co-crosslinking with the rubber to prevent the deterioration of tire performance, the molecular weight of syndiotactic 1,2-polybutadiene is 45*10 4 Below, preferably 40.0*10 4 Below, more preferably 35.0*10 4 the following.

[0024] [Corrected 02.02.2024 according to Rule 26] In some embodiments of the present invention, the 1,2-bond content of the syndiotactic 1,2-polybutadiene is ≥50%, preferably ≥65%, and more preferably ≥80%. In order to make the syndiotactic 1,2-polybutadiene more conducive to co-crosslinking with the rubber and further enhance the physical properties of the rubber compound and improve the fuel efficiency of the tire, the 1,2-bond content of the syndiotactic 1,2-polybutadiene can be, for example, 85% or more, or 88% or more.

[0025] [Corrected 02.02.2024 according to Rule 26] The molecular structure of syndiotactic 1,2-polybutadiene is as follows: [XXXX]

[0026] [Corrected 02.02.2024 according to Rule 26] The molecular spatial configuration of syndiotactic 1,2-polybutadiene is as follows:

[0027] [Corrected 02.02.2024 in accordance with Article 26]

[0028] [Corrected 02.02.2024 in accordance with Article 26]

[0029] In some embodiments of the present invention, the syndiotactic 1,2-polybutadiene catalytic system comprises an iron-containing organic compound, an azodicyano compound, an organoaluminum compound, and a free radical scavenger. This system introduces short covalently bonded chains or rigid networks into the polymer network, which, under external force, can break before the main chain, acting as sacrificial bonds. Under low strain, the short chains or rigid networks contribute to the modulus and maintain the material's high elasticity. As the strain increases, the short chains or rigid networks are preferentially stretched until they break, dissipating significant energy and inducing orientation in the long chains or flexible networks, resulting in high strength. Furthermore, a higher content of 1,2 bonds in the molecular structure improves the heat generation of the rubber compound.

[0030] In the present invention, syndiotactic 1,2-polybutadiene is used in the rubber composition as a reinforcing particle with elastomeric properties. It is a semi-crystalline high molecular polymer. Its introduction has a typical "sacrificial bond" effect. Spider silk, bones, and mussel byssus in nature have high strength and toughness. Studies have shown that the multi-level structure of energy-dissipating units contained in these natural materials is an important reason for their excellent mechanical properties. These dissipative units are called "sacrificial bonds". "Sacrificial bonds" can bear part of the force during the deformation process of the material, and they are destroyed and dissipate energy before the covalent bonds of the polymer main chain break, thereby achieving the effect of strengthening and toughening.

[0031] In some embodiments of the present invention, the polyisoprene rubber is cis-1,4-polyisoprene rubber. Cis-1,4-polyisoprene rubber is a high-cis synthetic rubber derived from isoprene, produced using a solution polymerization process. Because its structure and properties are similar to those of natural rubber, it is also known as synthetic natural rubber. It can replace natural rubber in the manufacture of truck and off-road tires, as well as various rubber products. Like natural rubber, cis-1,4-polyisoprene rubber exhibits good elasticity and wear resistance, excellent heat resistance, and good chemical stability. Its quality uniformity and processing properties are superior to those of natural rubber.

[0032] The polybutadiene rubber is a high-cis synthetic rubber with a cis content greater than 96%. The preferred polybutadiene rubber has a cis content of ≥98%, and more preferably ≥99%. The polybutadiene rubber can further enhance the strength and toughness of the rubber composition by combining with carbon black.

[0033] The nitrogen adsorption specific surface area of ​​the carbon black is ≥120m 2 / g, preferably ≥150m 2 / g, more preferably 200m 2 / g, for example, 130m 2 / g, 160m 2 / g, 180m 2 / g, 220m 2 / g, etc.; DBP oil absorption value ≥120cm 3 / 100g, preferably ≥150cm 3 / 100g, more preferably 200cm 3 / 100g, for example, 130cm 3 / 100g、160cm 3 / 100g、180cm 3 / 100g、220cm 3 / 100g, etc. Carbon black is used as a reinforcing material in rubber compositions.

[0034] The BET specific surface area of ​​the white carbon black is ≥120m 2 / g, preferably ≥150m 2 / g, more preferably 200m 2 / g, for example, 130m 2 / g, 160m 2 / g, 180m 2 / g, 220m 2 / g, etc.; DBP oil absorption value ≥1.5cm 3 / g, preferably ≥1.8cm 3 / g, more preferably 2.0cm 3 / g, for example, 1.6 cm3 / g, 1.8cm 3 / g, 2.0cm 3 / g, 2.5cm 3 / g, etc. Compounding white carbon black with carbon black can improve the cut resistance and puncture resistance of the rubber compound, and adding white carbon black to the rubber composition can reduce the wear resistance of the tire, improve the wet skid resistance and increase the heat generation, and obtain the appropriate hardness.

[0035] On the other hand, another embodiment of the present invention provides a tire comprising the rubber composition described in any of the above embodiments; preferably, the rubber composition is used for at least the component of the tire tread that contacts the road surface. Because the tire comprises the above-described rubber composition, it possesses all the advantages of the rubber composition, which will not be further elaborated. Overall, the tires according to the embodiments of the present invention all have lower rolling resistance and lower tire defect rates.

[0036] The present invention will be described below by specific embodiment, and it will be appreciated by those skilled in the art that the specific embodiment below is only for illustrative purposes, and does not limit the scope of the present invention in any way. In addition, in the following examples, unless otherwise stated, the reagent and equipment used are all commercially available. If in the following examples, concrete treatment conditions and treatment process are not clearly described, then conditions and methods well known in the art can be adopted to process.

[0037] The mixing of the rubber composition in the embodiments of the present invention can be accomplished using methods known to those skilled in the art of rubber mixing. For example, typically, the components are mixed in at least two stages, namely, at least one non-productive mixing stage followed by a productive mixing stage. The rubber and polymer resin are mixed in one or more non-productive mixing stages.

[0038] Among them, the syndiotactic 1,2-polybutadiene used in the embodiments of the present invention includes syndiotactic 1,2-polybutadiene-1 and syndiotactic 1,2-polybutadiene-2, and their catalytic systems include iron acetylacetonate, azobisisobutyronitrile, triisobutylaluminum, and antioxidant 3010. The amount of each component used and the properties of the syndiotactic 1,2-polybutadiene finally prepared are shown in Table 1.

[0039] Table 1

[0040]

[0041] Example 1

[0042] The rubber compositions specified in Table 2 were prepared in a BR Banbury internal mixer using two separate mixing stages: a non-productive mixing stage and a productive mixing stage. The non-productive mixing stage lasted approximately 2-3 minutes, until the rubber temperature reached 160°C. The productive mixing stage was completed until the rubber temperature reached 100°C.

[0043] Comparative Example 1 in Table 2 is a rubber composition in which no syndiotactic 1,2-polybutadiene polymer is used.

[0044] Table 2

[0045]

[0046] The comparative example 1 and the example samples prepared in Table 2 were vulcanized at 151° C. for about 30 min, and the physical properties of the vulcanized samples were tested. The results are shown in Table 3.

[0047] Table 3

[0048]

[0049] Note: The value obtained for the comparative composition was determined as 100 as a benchmark.

[0050] As can be seen from Table 3, the anti-slip performance of all rubber compounds in Examples 1-4 is reduced because the steric hindrance effect of the side group is not as strong as that of the benzene ring in the styrene-butadiene copolymer; at the same time, the syndiotactic 1,2-polybutadiene with a high 1,2 bond content shows excellent wear resistance, low heat generation characteristics and toughening and strengthening effect on the tensile strength of the rubber compound. Example 2

[0051] The rubber compositions of the composition specified in Table 4 were prepared in a BR Banbury internal mixer using two separate mixing stages: a non-productive mixing stage and a productive mixing stage. The non-productive mixing stage was completed by mixing for approximately 2-3 minutes, until the rubber temperature reached 160°C. The productive mixing stage was completed by mixing until the rubber temperature reached 100°C.

[0052] Comparative Example 1 in Table 4 is a rubber composition in which no syndiotactic 1,2-polybutadiene polymer is used.

[0053] Table 4

[0054]

[0055] The comparative example 1 and the example samples prepared in Table 4 were vulcanized at 151° C. for about 30 min, and the physical properties of the vulcanized samples were tested. The results are shown in Table 5.

[0056] Table 5

[0057]

[0058] Note: The value obtained for the comparative composition was determined as 100 as a benchmark.

[0059] As shown in Table 5, varying the amount of dispersant, anti-skid resin, etc. added has little effect on the performance of the vulcanized rubber. Therefore, it can be confirmed that syndiotactic 1,2-polybutadiene makes a significant contribution to improving the physical properties and low heat buildup of the rubber compound. The addition of syndiotactic 1,2-polybutadiene ultimately resulted in the design of a tire composition with superior performance.

[0060] In summary, the rubber composition of the present invention, by adding a syndiotactic 1,2-polybutadiene polymer having a specific melting point, crystallinity and 1,2-bond content, is more conducive to the formation of co-crosslinks between the syndiotactic 1,2-polybutadiene and the rubber, which can effectively improve the reinforcement and toughening properties of the vulcanized rubber, as well as improve the heat generation performance of the rubber and improve the fuel efficiency of the tire.

[0061] In the description of this specification, the descriptions with reference to the terms "one embodiment", "another embodiment", "yet another embodiment", "some embodiments", "some specific embodiments", "some other specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are mutually inconsistent. In addition, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0062] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rubber composition, characterized in that: The invention comprises the following components based on 100 parts by weight of rubber: 30-60 parts of polyisoprene rubber, 10-30 parts of polybutadiene rubber, 25-60 parts of styrene-butadiene copolymer, 5-20 parts of syndiotactic 1,2-polybutadiene, 10-30 parts of carbon black and 40-100 parts of white carbon black.

2. The rubber composition according to claim 1, characterized in that The syndiotactic 1,2-polybutadiene has a melting point of 60-150° C. and a crystallinity of 2-30%.

3. The rubber composition according to claim 1, characterized in that The weight average molecular weight of the syndiotactic 1,2-polybutadiene is 10.0*10 4 -45*10 4 .

4. The rubber composition according to claim 1, characterized in that The 1,2-bond content of the syndiotactic 1,2-polybutadiene is ≥50%.

5. The rubber composition according to any one of claims 1 to 4, characterized in that The catalytic system of syndiotactic 1,2-polybutadiene comprises an organic compound containing iron, an azodicyano compound, an organic aluminum compound and a free radical scavenger.

6. The rubber composition according to claim 1, characterized in that The polyisoprene rubber is cis-1,4-polyisoprene rubber.

7. The rubber composition according to claim 1, characterized in that The polybutadiene rubber is a high cis synthetic rubber with a cis content of more than 96%.

8. The rubber composition according to claim 1, characterized in that: The nitrogen adsorption specific surface area of ​​the carbon black is ≥120m 2 / g, DBP oil absorption value ≥120cm 3 / 100g.

9. The rubber composition according to claim 1, characterized in that: The BET specific surface area of ​​the white carbon black is ≥120 m 2 / g, DBP oil absorption value ≥1.5cm 3 / g.

10. A tire, characterized in that: The rubber composition comprises the rubber composition according to any one of claims 1 to 9.

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