Anti-cutting rubber composition and preparation method thereof

Abstract

The invention provides an anti-cutting rubber composition capable of remarkably improving the anti-cutting performance and a preparation method of the anti-cutting rubber composition. The anti-cutting rubber composition comprises the following components in parts by weight: 60-80 parts of natural rubber, 15-25 parts of butadiene styrene rubber and 5-15 parts of butadiene rubber, 15 to 25 parts of white carbon black and 30 to 45 parts of carbon black; 1-5 parts of phenolic resin; 1 to 4 parts of hexamethylenetetramine; 1-5 parts of modified short fiber; activating the system; an anti-aging system; a plasticizing system; and a vulcanization system. By introducing a composite reinforcing system composed of phenolic resin, hexamethylenetetramine and modified short fibers, the dynamic cutting resistance of the composition is improved by 30% or above compared with a general formula composition, damage of sharp objects can be effectively resisted, and the situation of early damage of a rubber track is reduced.

Description

Technical Field

[0001] The present invention relates to a rubber composition and a preparation method thereof, in particular to a cut-resistant rubber composition and a preparation method thereof, belonging to the technical field of polymer materials. Background Art

[0002] As a key chassis component for agricultural machinery, excavators, pavers, bulldozers, and other construction vehicles, rubber tracks are often used in diverse and complex operating conditions. During operation, the track's running surface comes into contact with a variety of road surfaces, including gravel, debris, farmland straw, and other sharp foreign objects.

[0003] Although existing rubber tracks for agricultural or engineering use have certain physical and mechanical properties, their cutting resistance is still insufficient when facing the complex and harsh road conditions mentioned above. The rubber on the track running surface is easily cut by sharp foreign objects, resulting in cracks, and in severe cases, rubber blocks may even fall off. This early physical damage not only affects the appearance and integrity of the track, but more importantly, it will cause a series of secondary problems. The cracks caused by cutting will become channels for corrosive substances such as water, air, and mud, directly contacting and corroding the steel wire cord inside the track that plays a key load-bearing role, causing the steel wire to rust and lose strength, and destroying the bonding interface between the steel wire and the rubber, ultimately causing fatal damage such as belt delamination and steel wire breakage, greatly shortening the effective service life of the rubber track, increasing the user's replacement costs and the economic losses caused by equipment downtime.

[0004] Therefore, there is an urgent need in this field to develop a new rubber composition formula and preparation method thereof to improve the cut resistance of the composition, so that it is better suitable for manufacturing rubber products used under harsh working conditions, such as rubber tracks for construction machinery vehicles, and to extend the service life of the rubber tracks. Summary of the Invention

[0005] Based on the above background, the purpose of the present invention is to provide a cut-resistant rubber composition and a preparation method thereof that can significantly improve the cut resistance, so as to solve the technical problem in the prior art that the rubber track is easily damaged by cutting due to the low cut resistance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A cut-resistant rubber composition comprising the following components in parts by weight:

[0008] 60-80 parts of natural rubber, 15-25 parts of styrene-butadiene rubber, 5-15 parts of butadiene rubber;

[0009] 15-25 parts of white carbon black, 30-45 parts of carbon black;

[0010] 1-5 parts of phenolic resin;

[0011] 1-4 parts of hexamethylenetetramine;

[0012] 1-5 parts of modified staple fiber;

[0013] Activation system;

[0014] Anti-aging system;

[0015] Plasticizing system;

[0016] Vulcanization system.

[0017] This formula system is based on the traditional sulfur cross-linked network. By introducing phenolic resin, hexamethylenetetramine as a methylene donor and modified short fibers, a composite reinforcement system with interpenetrating and synergistic resin-reinforced network and fiber-reinforced skeleton is constructed. This system can effectively absorb and dissipate external energy when sharp objects penetrate, thereby significantly improving the material's ability to resist cutting damage.

[0018] Preferably, the activation system includes zinc oxide and stearic acid, the anti-aging system includes an antioxidant and microcrystalline wax, the plasticizing system includes petroleum resin, and the vulcanization system includes insoluble sulfur and an accelerator.

[0019] Preferably, the cut-resistant rubber composition further comprises the following components in parts by weight:

[0020] 1-2 parts of resorcinol or its derivatives;

[0021] 1-2 parts of coupling agent;

[0022] 2.5-3.5 parts of anti-reversion agent.

[0023] Preferably, the cut-resistant rubber composition comprises the following components in parts by weight:

[0024] 68-72 parts of natural rubber, 18-22 parts of styrene-butadiene rubber, 8-12 parts of butadiene rubber;

[0025] 16-20 parts of precipitated silica, 36-40 parts of carbon black;

[0026] 4.5-5.5 parts of zinc oxide, 1.7-2.3 parts of stearic acid;

[0027] 1.7-2.3 parts of the first antioxidant, 1.7-2.3 parts of the second antioxidant, and 1.7-2.3 parts of microcrystalline wax;

[0028] Petroleum resin 2.5-3.5 parts;

[0029] 1.6-2.0 parts of insoluble sulfur, 0.6-0.8 parts of the first accelerator, and 0.3-0.5 parts of the second accelerator;

[0030] Resorcinol 1.0-1.4 parts;

[0031] 1.7-2.3 parts of phenolic resin;

[0032] 2.2-2.8 parts of hexamethylenetetramine;

[0033] 2.5-3.5 parts of modified staple fiber;

[0034] 1.3-1.7 parts of silane coupling agent;

[0035] 2.5-3.5 parts of anti-reversion agent.

[0036] A method for preparing any of the above-mentioned cut-resistant rubber compositions comprises the following mixing steps:

[0037] According to the component ratio, natural rubber, styrene-butadiene rubber, butadiene rubber, white carbon black and modified short fiber are mixed in the first stage;

[0038] The rubber compound obtained by the first stage of mixing is added with carbon black and phenolic resin for the second stage of mixing;

[0039] The rubber compound obtained from the second mixing stage is added to the components of the anti-aging system for the third mixing stage;

[0040] The rubber compound obtained by the third stage mixing is added with the components of the vulcanization system and hexamethylenetetramine for final stage mixing.

[0041] By adding different components in stages, the mixing temperature and shear force at each stage can be controlled in a targeted manner to ensure that silica, carbon black and short fibers are fully dispersed. At the same time, the vulcanization system and heat-sensitive components such as hexamethylenetetramine are prevented from reacting or decomposing prematurely at high temperatures, thereby preventing the rubber from scorching and ensuring the stable performance of the final product.

[0042] Preferably, the debinding temperature of the first mixing stage is 150-160°C; the debinding temperature of the second mixing stage is 155-160°C; and the debinding temperature of the final mixing stage is 95-105°C.

[0043] Higher mixing temperatures in the first and second stages are beneficial to reducing the viscosity of the rubber compound and promoting the wetting and dispersion of inorganic fillers, phenolic resins and short fibers. The purpose of significantly lowering the final mixing temperature is to safely mix in the vulcanization system and hexamethylenetetramine, ensuring that the rubber compound does not undergo premature vulcanization during sheeting and storage.

[0044] Preferably, the method for preparing the cut-resistant rubber composition further comprises the following vulcanization step:

[0045] The rubber compound obtained by the final mixing is vulcanized under the following conditions: temperature 145-155°C, pressure 3.5-4.5 MPa, and time 140-160 minutes.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] The present invention discloses a cut-resistant rubber composition and a preparation method thereof. By introducing a composite reinforcement system consisting of phenolic resin, hexamethylenetetramine and modified short fibers, the dynamic cut-resistant performance of the composition is improved by more than 30% compared with a general formula composition. The composition can effectively resist damage from sharp objects and reduce early damage to rubber tracks. While improving the cut-resistant performance, the composition of the present invention also significantly enhances its tensile strength and tear strength, which are improved by approximately 18% and 22% respectively compared with a general formula composition, thereby ensuring the overall strength and durability of the rubber track. The present invention ensures the full dispersion and effective action of each component, especially the functional additives, through a four-stage mixing process, avoids process problems such as rubber scorch, and ensures the stability and uniformity of the performance of the final rubber composition product. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0049] Figure 1 1. It is a diagram of the anti-cutting test device in the performance test of each embodiment and comparative example;

[0050] Figure 2 1. It is a diagram of the anti-cutting test specimens in the performance tests of various embodiments and comparative examples;

[0051] Figure 3 is a comparison chart of the dynamic cutting results of Examples 1-3 and Comparative Examples 1-2;

[0052] Figure 4 1. is a diagram of the tensile test and tear test apparatus in the performance tests of various embodiments and comparative examples;

[0053] Figure 5 1. Graphs of tensile test and tear test specimens in the performance tests of various embodiments and comparative examples;

[0054] Figure 6 is a comparison chart of the tensile strength curves of Examples 1-3 and Comparative Examples 1-2;

[0055] Figure 7It is a comparison chart of the tear strength curves of Examples 1-3 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0056] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the scope of protection of the present invention.

[0057] In the present invention, unless otherwise specified, all parts and percentages are by weight. The equipment and raw materials used are commercially available or commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are all universal standard parts or components known to those skilled in the art. Their structures and principles are known to those skilled in the art through technical manuals or routine experimental methods.

[0058] The following detailed description of the embodiments of the present invention is made in conjunction with the accompanying drawings. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments may be implemented by those skilled in the art without these specific details.

[0059] Petroleum resin, (BT-A120) Puyang Kairuide;

[0060] Modified staple fiber, APM40 / NR (aramid pulp masterbatch) Yingkou Boya;

[0061] Anti-reversion agent, (RF-80), Ruiba Chemical;

[0062] Silane coupling agent, model SI75 (liquid), Jingzhou Jianghan Fine Chemical Co., Ltd.

[0063] Test items: 1. Tensile strength (MPa), elongation at break (%), and 300% modulus (MPa) shall be tested in accordance with GB / T 528-2009. 2. Trouser tear strength (kN / m) shall be tested in accordance with GB / T 529-2008.

[0064] Example 1

[0065] A cut-resistant rubber composition, comprising the following components in parts by weight:

[0066] 60 parts of natural rubber, 25 parts of styrene-butadiene rubber, 15 parts of butadiene rubber; 25 parts of white carbon black, 30 parts of carbon black; 1 part of phenolic resin; 4 parts of hexamethylenetetramine; 5 parts of modified staple fiber; 5 parts of zinc oxide, 2 parts of stearic acid; 2 parts of antioxidant 4020, 2 parts of antioxidant RD, 2 parts of microcrystalline wax; 3 parts of petroleum resin; 1.8 parts of insoluble sulfur, 0.7 parts of accelerator TBSI, 0.4 parts of accelerator DTDM; 2 parts of resorcinol; 2 parts of silane coupling agent; 2.5 parts of anti-reversion agent.

[0067] The preparation method comprises the following steps:

[0068] First stage mixing: Place 60 parts of natural rubber, 25 parts of styrene-butadiene rubber, and 15 parts of butadiene rubber in an internal mixer and mix for 2 minutes. Then add 25 parts of white carbon black, 2 parts of silane coupling agent, and 5 parts of modified staple fiber. Continue mixing and control the discharge temperature at 150°C. Cool the rubber sheet after it is discharged.

[0069] Second stage mixing: Place the rubber compound obtained in the first stage mixing into an internal mixer and add 5 parts zinc oxide, 2 parts stearic acid, 3 parts petroleum resin, 2 parts resorcinol, 2.5 parts anti-reversion agent, 30 parts carbon black, and 1 part phenolic resin. Continue mixing and control the discharge temperature at 155°C. Cool the rubber compound after it is discharged from the sheet.

[0070] The third stage of mixing: put the rubber compound obtained in the second stage of mixing into the internal mixer, add 2 parts of antioxidant 4020, 2 parts of antioxidant RD and 2 parts of microcrystalline wax, mix evenly and then take out the sheet and cool.

[0071] Final mixing: The rubber compound obtained in the third mixing stage is put into an internal mixer, and 1.8 parts of insoluble sulfur, 0.7 parts of accelerator TBSI, 0.4 parts of accelerator DTDM and 4 parts of hexamethylenetetramine are added. The mixing is continued and the discharge temperature is controlled at 100°C.

[0072] Vulcanization: The rubber compound obtained by the final mixing was vulcanized at 150°C and 4 MPa for 150 minutes to obtain a vulcanized rubber sample.

[0073] Example 2

[0074] A cut-resistant rubber composition, comprising the following components in parts by weight:

[0075] 70 parts of natural rubber (NR), 20 parts of styrene-butadiene rubber (SBR1502), 10 parts of butadiene rubber (BR9000); 18 parts of precipitated silica, 38 parts of carbon black (N234); 2 parts of phenolic resin; 2.5 parts of hexamethylenetetramine; 3 parts of modified staple fiber; 5 parts of zinc oxide, 2 parts of stearic acid; 2 parts of the first antioxidant (4020), 2 parts of the second antioxidant (RD), 2 parts of microcrystalline wax; 3 parts of petroleum resin; 1.8 parts of insoluble sulfur (DOT20), 0.7 parts of the first accelerator (TBSI), 0.4 parts of the second accelerator (DTDM); 1.2 parts of resorcinol (R-80); 1.5 parts of silane coupling agent; 3 parts of anti-reversion agent (RF-80).

[0076] The preparation method is the same as that of Example 1, except that the debinding temperature at each stage is controlled as follows: 155° C. for the first stage, 160° C. for the second stage, and 100° C. for the final stage. The vulcanization conditions are the same as those of Example 1.

[0077] Example 3

[0078] A cut-resistant rubber composition, comprising the following components in parts by weight:

[0079] 80 parts of natural rubber, 15 parts of styrene-butadiene rubber, 5 parts of butadiene rubber; 15 parts of white carbon black, 45 parts of carbon black; 5 parts of phenolic resin; 1 part of hexamethylenetetramine; 1 part of modified staple fiber; the amounts of other additives, preparation methods and vulcanization conditions are the same as those in Example 1.

[0080] Comparative Example 1

[0081] A general rubber composition, the components of which are calculated by weight:

[0082] 70 parts of natural rubber, 30 parts of styrene-butadiene rubber; 3445 parts of carbon black N23; 5 parts of zinc oxide, 2 parts of stearic acid; 2 parts of antioxidant 40202 parts, 1 part of antioxidant RD; 5 parts of petroleum resin; 2 parts of sulfur, 1.2 parts of accelerator CZ.

[0083] The preparation adopts a conventional two-stage mixing process.

[0084] Comparative Example 2

[0085] A rubber composition having a formulation substantially identical to that of Example 2, except that the phenolic resin, hexamethylenetetramine, resorcinol, and modified staple fiber are omitted. To maintain hardness, the amount of carbon black is increased to 45 parts. The remaining additives, preparation method, and vulcanization conditions are the same as those of Example 2.

[0086] Performance testing and results

[0087] The vulcanized rubber samples prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests according to relevant standards. The test items included: dynamic cutting resistance (cm 3, volume loss, the smaller the value, the better), tensile strength (MPa), trouser tear strength (KN / m). Cutting resistance test equipment such as Figure 1 As shown, the sample Figure 2 As shown, the dynamic cutting results of Examples 1-3 and Comparative Examples 1-2 are compared. Figure 3 As shown, the tensile test and tear test equipment are as follows Figure 4 As shown, the tensile test and tear test specimens are as follows Figure 5 As shown, the tensile strength curves of Examples 1-3 and Comparative Examples 1-2 are compared. Figure 6 As shown, the tear strength curves of Examples 1-3 and Comparative Examples 1-2 are compared. Figure 7 The final results of the test items are shown in Table 1.

[0088] Table 1 Performance comparison of each embodiment and comparative example

[0089] Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 <![CDATA[Dynamic anti-cutting / cm 3 > 1.80 1.70 1.97 2.83 2.63 Tensile strength / MPa 25.1 25.3 24.6 21.1 21.2 Trouser tearing strength / KN / m 42.1 45.6 39.6 25.8 27.1

[0090] From the test results in Table 1 we can see that:

[0091] The dynamic cutting resistance of the vulcanized rubber samples of Examples 1-3 is significantly better than that of Comparative Example 1 and Comparative Example 2, indicating that the composite reinforcement system introduced by the present invention has played a role in improving cutting resistance. Among them, the effect of Example 2 is the most outstanding. Compared with Comparative Example 1 of the general formula, the cutting resistance has been improved by about 31.4%. Comparative Example 2 and Comparative Example 2 have similar basic formulas, but Comparative Example 2 lacks the composite reinforcement system of the present invention, and its cutting resistance, tensile strength and tear strength are all much lower than those of Example 2. This proves that the combination of phenolic resin, hexamethylenetetramine and modified staple fiber is the key to obtaining excellent performance. The tensile strength and tear strength of Examples 1-3 are also comprehensively better than the two comparative examples, which illustrates that the technical solution of the present invention, while improving cutting resistance, also has a significant enhancing effect on the overall mechanical properties of the material.

[0092] The mechanism of the cut-resistant rubber composition and its preparation method of the present invention is described below. By innovatively introducing phenolic resin, hexamethylenetetramine as a methylene donor, and modified short fibers into a traditional sulfur-crosslinked rubber network, a multi-layered, multi-dimensional composite reinforcement system is successfully constructed for the rubber composition.

[0093] The phenolic resin in the present invention and the hexamethylenetetramine for providing methylene-CH2- under thermal decomposition react in situ during the vulcanization process. The linear phenolic resin molecular chains are interconnected by methylene bridges to form a rigid three-dimensional network structure. The thermosetting resin network and the original flexible sulfur cross-linked rubber network are mutually penetrated to form an interpenetrating polymer network structure, which is equivalent to introducing countless tiny hard points and rigid chains in a soft rubber matrix. Thus, the existence of the rigid resin network significantly improves the hardness and modulus of the rubber matrix itself, making it difficult for deep yielding and deformation to occur when impacted by sharp objects. When external stress acts, the network can effectively disperse and transmit stress, avoiding stress concentration at microscopic defects. Even if microcracks are generated, when they extend to the rigid resin network, they will be effectively passivated or terminated, preventing them from further developing into destructive cracks.

[0094] During the mixing process, the modified short fibers are evenly dispersed throughout the rubber matrix, forming a three-dimensional, randomly distributed fiber-reinforced skeleton. The fiber surface exhibits excellent interfacial adhesion to the rubber matrix. When the rubber compound is subjected to stress, the stress is effectively transferred from the matrix to the high-strength fibers, which bear the primary load. When a growing crack encounters a fiber, its propagation path is forcibly deflected or terminated. For the crack to continue advancing, it must expend enormous energy to break the fibers or extract them from the matrix, a process that consumes significant cutting energy.

[0095] These two reinforcement mechanisms work synergistically. When the rubber composition is cut, the rubber matrix, microscopically reinforced by the resin network, first resists impact, improving its resistance to initial penetration. If the external force is strong enough to generate microcracks, these microcracks will encounter resistance from the fiber skeleton on their propagation path. At this time, the matrix, reinforced by the resin network, can more firmly secure the fibers, requiring more energy to extract the fibers, significantly enhancing the toughness of the rubber composition.

[0096] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A cut-resistant rubber composition, characterized in that: The cut-resistant rubber composition comprises the following components in parts by weight: 60-80 parts of natural rubber, 15-25 parts of styrene-butadiene rubber, and 5-15 parts of butadiene rubber; 15-25 parts of white carbon black, 30-45 parts of carbon black; 1-5 parts of phenolic resin; 1-4 parts of hexamethylenetetramine; 1-5 parts of modified staple fiber; Activation system; Anti-aging system; Plasticizing system; Vulcanization system.

2. A cut-resistant rubber composition according to claim 1, characterized in that: The activation system comprises zinc oxide and stearic acid, the anti-aging system comprises an antioxidant and microcrystalline wax, the plasticizing system comprises petroleum resin, and the vulcanization system comprises insoluble sulfur and an accelerator.

3. The cut-resistant rubber composition according to claim 1, characterized in that: The cut-resistant rubber composition further comprises the following components in parts by weight: 1-2 parts of resorcinol or its derivatives; 1-2 parts of coupling agent; 2.5-3.5 parts of anti-reversion agent.

4. The cut-resistant rubber composition according to claim 1, characterized in that: The cut-resistant rubber composition comprises the following components in parts by weight: 68-72 parts of natural rubber, 18-22 parts of styrene-butadiene rubber, 8-12 parts of butadiene rubber; 16-20 parts of precipitated silica, 36-40 parts of carbon black; 4.5-5.5 parts of zinc oxide, 1.7-2.3 parts of stearic acid; 1.7-2.3 parts of the first antioxidant, 1.7-2.3 parts of the second antioxidant, and 1.7-2.3 parts of microcrystalline wax; Petroleum resin 2.5-3.5 parts; 1.6-2.0 parts of insoluble sulfur, 0.6-0.8 parts of the first accelerator, and 0.3-0.5 parts of the second accelerator; Resorcinol 1.0-1.4 parts; 1.7-2.3 parts of phenolic resin; 2.2-2.8 parts of hexamethylenetetramine; 2.5-3.5 parts of modified staple fiber; 1.3-1.7 parts of silane coupling agent; 2.5-3.5 parts of anti-reversion agent.

5. A method for preparing the cut-resistant rubber composition according to any one of claims 1 to 4, characterized in that: The method comprises the following mixing steps: According to the component ratio, natural rubber, styrene-butadiene rubber, butadiene rubber, white carbon black and modified short fiber are mixed in the first stage; The rubber compound obtained by the first stage of mixing is added with carbon black and phenolic resin for the second stage of mixing; The rubber compound obtained from the second mixing stage is added to the components of the anti-aging system for the third mixing stage; The rubber compound obtained by the third stage mixing is added with the components of the vulcanization system and hexamethylenetetramine for final stage mixing.

6. The method for preparing a cut-resistant rubber composition according to claim 5, wherein: The debinding temperature of the first mixing stage is 150-160°C; the debinding temperature of the second mixing stage is 155-160°C; and the debinding temperature of the final mixing stage is 95-105°C.

7. The method for preparing a cut-resistant rubber composition according to claim 5, wherein: The preparation method of the cut-resistant rubber composition further comprises the following vulcanization step: The rubber compound obtained by the final mixing is vulcanized under the following conditions: temperature 145-155°C, pressure 3.5-4.5 MPa, and time 140-160 minutes.

Images