Coupling agent composition for inhibiting rubber flooding and application of coupling agent composition in rubber track

Abstract

The invention belongs to the technical field of rubber auxiliaries and rubber tracks, and particularly relates to a coupling agent composition for inhibiting rubber appearance flooding and application of the coupling agent composition in the rubber tracks. The coupling agent composition comprises the following components in percentage by weight: 15%-30% of coupling agent, 1%-15% of metal chloride and 70%-85% of clay mineral. Different from a microcapsule technology only aiming at anti-aging agent migration, the coupling agent composition disclosed by the invention can effectively capture various types of color-flooding source substances including carbon black residues, anti-aging agents, antioxidants and the like by starting from common characteristics (containing unsaturated bonds, heteroatoms and aromatic structures) of color-flooding small molecules and through the synergistic effect of the coupling agent and metal ions, so that the color-flooding source substances can be effectively captured. And the method has wide applicability. In addition, a composite system composed of the clay, the coupling agent and the metal chloride can improve the bonding strength of the rubber and a track framework material, and is suitable for being applied to a heavy-load rubber track.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber auxiliaries, rubber materials and rubber products, in particular to a coupling agent composition for inhibiting the coloration of rubber appearance and its application in rubber tracks. BACKGROUND

[0002] Rubber is an excellent elastomer material with great application value. With the vigorous development of the rubber industry, various functionalized rubber auxiliaries have been rapidly developed. Common ones include reinforcing systems composed of carbon black and white carbon black, softening and plasticizing systems composed of stearic acid, zinc oxide and softening oil, anti-aging systems composed of antioxidants, paraffin and anti-aging agents, vulcanization systems composed of sulfur and accelerators, etc. These components play a key role in improving various properties of rubber products. Under the combined action of these systems, the use of rubber has been greatly expanded and widely applied. However, some small molecule auxiliaries used with rubber will gradually migrate to the surface of the product. This phenomenon can protect rubber, for example, the spraying of protective wax and anti-aging agents can resist the damage of external harsh conditions to the structure of rubber. However, if these components migrate to the surface in large quantities and continuously, they will form bloom on the surface of the rubber, or even coloration. Coloration is essentially the result of molecules with color groups migrating to the surface and adhering to the surface. These substances with color groups are stacked in a certain area, eventually forming a coloration area.

[0003] Rubber tracks are suitable for extreme environments such as snow, mud and mountains, with the lowest ground contact pressure of 50 kPa, significantly improving the vehicle's ability to escape from complex terrain, and are widely used in military vehicles and civilian engineering vehicles. If the rubber track has serious coloration, the more serious coloration is often related to the reduction of rubber track wear resistance, aging resistance and service life, and even some rubber track products often have serious coloration on the surface during deformation and fracture.

[0004] In the prior art, there are also many studies on improving rubber coloration, such as CN112940351A, CN117050384A, etc. using microspheres or encapsulated auxiliaries to prevent rubber products from coloration. However, in fact, the process of using microspheres or encapsulated auxiliaries is relatively complex, which increases the cost and limits large-scale application. In addition, there are many reasons for the coloration of rubber, and a considerable part of rubber auxiliaries contains a certain amount of coloration groups. The use of microspheres to encapsulate single anti-aging agents cannot effectively limit the migration of other auxiliaries that may cause coloration.

[0005] CN120289881A discloses an auxiliary composition for inhibiting the coloration of the surface of rubber products, wherein the content of silica microspheres is 95%-98%, the content of salt-out agent is 1%-3%, and the content of anti-agglomeration agent is 1%-2%. The auxiliary composition can inhibit the coloration of the surface of rubber products caused by various factors and has multi-dimensional and high-efficiency coloration inhibition function. However, in actual use, it is found that the universality of the auxiliary composition is poor, and the inhibitory effect on coloration is not obvious in some rubber systems. Moreover, after the auxiliary composition is added to the rubber system of rubber track, the coloration defect is improved to some extent, but due to the high surface polarity of silica microspheres and the rich silicon hydroxyl groups, there is a problem of poor compatibility when mixed with non-polar rubber products (such as natural rubber and styrene-butadiene rubber), which leads to weak interface bonding and reduces the adhesive strength, thereby limiting its application in heavy-duty rubber tracks. SUMMARY

[0006] The present application provides a coupling agent composition for inhibiting the coloration of rubber appearance and its application in rubber track, which not only has multi-dimensional coloration inhibition function, but also has wide universality. After use, the rubber material has good mechanical properties, and when applied to rubber track, it does not affect the adhesive strength of rubber and skeleton material.

[0007] In the first aspect of the present application, a rubber auxiliary is provided by using the following technical solution:

[0008] A coupling agent composition for inhibiting the coloration of rubber appearance, comprising a coupling agent, a metal chloride and a clay mineral; in the coupling agent composition, the content of the coupling agent is 15%-30% by mass fraction, the content of the metal chloride is 1%-15% by mass fraction, and the content of the clay mineral is 70%-85% by mass fraction.

[0009] The preparation method of the coupling agent composition comprises the following steps:

[0010] (1) The clay mineral is added to water in a proportion and stirred and dispersed uniformly;

[0011] (2) The coupling agent is slowly added and stirred at 60-80°C and 300-500 rpm for 1-3 hours;

[0012] (3) The metal chloride is added and the reaction is continued at 40-60°C and 100-200 rpm for 0.5-2 hours;

[0013] (4) After the reaction is completed, the mixture is left to stand for more than 1 hour, centrifuged, the supernatant is discarded, and the precipitate is washed with deionized water for more than 3 times;

[0014] (5) The washed solid product is dried at 60-80°C for 6-12 hours, cooled, ground and sieved through a 100-150 mesh screen to obtain the coupling agent composition.

[0015] The present application directly adds the compounded reduced bloom coupling agent composition in the mixing process to inhibit the migration behavior of bloom small molecules. Due to the diversified microscopic composition of bloom hair small molecules, the present application does not target a single substance (such as an antioxidant), but starts from the common characteristics of various bloom small molecules (all contain many unsaturated bonds, are a kind of mixed substance containing aromatic hydrocarbons or aromatic hydrocarbon derivatives, and are not limited to a single benzene ring. Such substances tend to absorb light of a certain wavelength, and are generally the main source of color). And this kind of polycyclic aromatic hydrocarbon derivative generally has some auxiliary color groups (such as carbon oxygen groups or amine groups), which interact with a large number of unsaturated bond-containing color groups, resulting in bloom, so its composition is very complex, the types of bonding substances and the range of elements involved are wide, and therefore the universality of the added bloom reducing auxiliary for bloom small molecules is also one of the emphases of the present application. The coupling agent composition of the present application has wide universality, and the adapted base material includes various primary rubbers, including natural rubber, ethylene-propylene-diene rubber, nitrile rubber, etc.

[0016] Specifically, the present application adds a certain amount of coupling agent, the hydrophobic end of which can interact with benzene rings and other molecules containing a large number of unsaturated bonds, which is very beneficial to constrain the migration behavior of hair small molecules. On this basis, a certain amount of metal chloride is also added, some of which can form a relatively strong complex with the above-mentioned added coupling agent through electrostatic attraction and covalent interaction, which gives the coupling agent metal coordination effect. Since bloom small molecules generally contain O, N and other elements (a kind of heteroatom containing unbound p electrons, which tends to coordinate with metal ions), this also gives the above-mentioned coupling agent a stronger capture efficiency for bloom small molecules of higher concentration. A certain amount of clay mineral is also added, which provides a large number of loading sites for the coupling agent and metal chloride, and can fix the coupling agent inside the rubber when the coupling agent active site adsorbs the color group, so as to better constrain the bloom small molecules in the rubber matrix. It has good ion exchange characteristics and can provide a natural slow-release medium for metal ions in metal chloride. The clay mineral modified by the hydrophobic coupling agent also has good physical adsorption performance, and can work with the coupling agent and metal chloride to greatly limit the migration behavior of bloom small molecules and have more excellent bloom inhibition effect. In addition, the composite system composed of clay, coupling agent and metal chloride can improve the bonding strength of rubber and track skeleton material, and is suitable for application in heavy load type rubber track.

[0017] Preferably, in the aforementioned coupling agent composition for suppressing rubber coloration, the metal chloride is one of ferric chloride, copper chloride, and magnesium chloride.

[0018] Preferably, in the aforementioned coupling agent composition for suppressing iridescence on the appearance of rubber, the clay mineral is any one or a combination of two of kaolin and montmorillonite.

[0019] Preferably, in the aforementioned coupling agent composition for suppressing the iridescence of rubber, the coupling agent is a silicon-based organic compound.

[0020] Further preferably, in the aforementioned coupling agent composition for suppressing rubber coloration, the coupling agent includes any one or any combination of Si-69, phenyltrimethoxysilane, and diphenyldimethoxysilane.

[0021] A second aspect of the invention provides the use of the above-described coupling agent composition in rubber tracks.

[0022] Preferably, in the aforementioned applications, both the wheel side rubber and the tread side rubber of the rubber track contain the coupling agent composition.

[0023] Preferably, in the aforementioned applications, the raw material formulation of the wheel side rubber, by weight, includes: 80-100 parts of natural rubber, 10-20 parts of butadiene rubber, 45-55 parts of carbon black N220, 10-15 parts of silica, 1-3 parts of sulfur, 0.5-2 parts of accelerator TMTM, 1-2 parts of antioxidant 4010NA, 1-2 parts of antioxidant RD, 2-5 parts of zinc oxide, 1-2 parts of stearic acid, and 3-6 parts of coupling agent composition to inhibit the discoloration of the rubber appearance.

[0024] Preferably, in the aforementioned applications, the raw material formulation of the patterned side rubber, by weight, includes: 70-90 parts natural rubber, 10-20 parts styrene-butadiene rubber, 30-50 parts carbon black N330, 10-20 parts silica, 1.5-2.5 parts sulfur, 1-2.5 parts accelerator TMTM, 1-3 parts antioxidant 4010NA, 1-3 parts antioxidant RD, 1-2 parts microcrystalline wax, 3-5 parts zinc oxide, 1-2 parts stearic acid, 5-8 parts aromatic oil, and 3-8 parts coupling agent composition to inhibit the color fading of the rubber appearance.

[0025] Preferably, in the aforementioned applications, during rubber mixing, the coupling agent composition is added to the internal mixer before the vulcanization system during the mixing stage.

[0026] By implementing the above technical solution, the present invention has the following beneficial effects:

[0027] The coupling agent composition of the present invention differs from microencapsulation technology that targets only the migration of antioxidants. Starting from the common characteristics of chromatic small molecules (including unsaturated bonds, heteroatoms, and aromatic structures), the present invention can effectively capture various types of chromatic source substances, including carbon black residues, antioxidants, and other substances, through the synergistic effect of coupling agents and metal ions, and has broad applicability.

[0028] The coupling agent composition of the present invention uses clay minerals as a carrier, which improves the dispersibility and stability of the coupling agent and metal ions; the introduction of metal ions enhances the coordination and capture ability of polar small molecules, and significantly improves the effect of suppressing iridescence.

[0029] The coupling agent composition of the present invention mainly fixes the color-causing molecules inside the rubber through chemical complexation and physical adsorption (constructing an adsorption-complexation-fixation network during rubber processing to restrict the migration path of color-causing molecules, thereby fundamentally inhibiting the occurrence of color-causing phenomena). It does not destroy the cross-linked structure of the rubber, but rather helps to improve wear resistance and mechanical properties by enhancing the interfacial bonding between the filler and the matrix. When applied to rubber tracks, it can also improve the bonding strength between the rubber and the skeleton material. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments. Contents not described in detail in the following embodiments are all common knowledge in the art.

[0031] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0032] In the following examples and applications, the amount in "parts" refers to parts by weight.

[0033] Example 1:

[0034] This embodiment provides a coupling agent composition for inhibiting surface staining of rubber products, comprising Si-69 (coupling agent), montmorillonite (clay mineral), and copper chloride (metal chloride). The preparation process is as follows: 5 parts of montmorillonite are weighed and dispersed in deionized water, stirred evenly, and 1 part of the coupling agent is slowly added dropwise. The mixture is stirred at 70°C and 450 rpm for 2 hours. Then, 0.1 parts of copper chloride are added, and the stirring speed is reduced to 150 rpm at 50°C for 1 hour. After standing for 1 hour, the solution is centrifuged at 3000 rpm for 5 minutes, and the supernatant is discarded. The precipitate is then washed three times with deionized water by centrifugation, and then dried in a 70°C oven for 6 hours. After cooling, the precipitate is ground into large particles and passed through a 100-mesh sieve to obtain the desired coupling agent composition for inhibiting rubber staining.

[0035] This embodiment also provides the application of the additive composition in rubber tracks. The rubber track in this embodiment conforms to the standard GB / T 20786-2015, and includes wheel side rubber, tread side rubber, core material, and a reinforcing layer (the core material and reinforcing layer constitute the skeleton of the rubber track; the core material is bonded to the wheel side rubber, and the reinforcing layer is bonded to both sides of the wheel side rubber and the tread side rubber, respectively). The reinforcing layer uses steel cord. Specifically, the wheel side rubber and tread side rubber contain a coupling agent composition that can inhibit surface staining of rubber products. In the preparation process of the compounded rubber of the wheel side rubber and tread side rubber, the coupling agent composition that can inhibit surface staining of rubber products is added.

[0036] In this embodiment, the raw material formula for the wheel side adhesive is as follows:

[0037] Raw rubber system: 90 parts natural rubber, 10 parts butadiene rubber;

[0038] Reinforcing system: 45 parts carbon black N220, 15 parts silica;

[0039] Vulcanization system: 2 parts sulfur, 2 parts accelerator TMTM;

[0040] Anti-aging system: 1 part antioxidant 4010NA, 1 part antioxidant RD;

[0041] Processing aid system: 2 parts zinc oxide, 1.5 parts stearic acid, and 5 parts coupling agent composition.

[0042] In this embodiment, the raw material formula for the patterned side adhesive is as follows:

[0043] Raw rubber system: 80 parts natural rubber, 20 parts styrene-butadiene rubber;

[0044] Reinforcing system: 40 parts carbon black N330, 15 parts silica;

[0045] Vulcanization system: 1.5 parts sulfur, 2.5 parts accelerator TMTM;

[0046] Anti-aging system: 1 part antioxidant 4010NA, 1 part antioxidant RD, 1 part microcrystalline wax;

[0047] Processing aid system: 3 parts zinc oxide, 1 part stearic acid, 5 parts aromatic oil, and 6 parts coupling agent composition.

[0048] In this embodiment, the compound of wheel side rubber and tread side rubber is prepared according to the following steps:

[0049] First stage of compounding: Plasticize the raw rubber on a two-roll mill until it completely covers the front roll, cut it twice and then discharge it for later use; add the plasticized rubber to a mixer, then add the reinforcing system, mix evenly, then add the anti-aging system and processing aid system, continue mixing for 5 minutes and then discharge the rubber to obtain the first stage of compounding.

[0050] Two-stage mixing: Put the above-mentioned first-stage compound into a two-roll mill, add the vulcanization system, and after complete mixing, sheet out for later use. After 12 hours of stopping the rubber production, the second-stage compound is obtained and ready for use.

[0051] Example 2:

[0052] Unlike Example 1, in this example, the amount of montmorillonite is 4.5 parts, the amount of Si-69 is 1.5 parts, and the rest are the same.

[0053] Example 3:

[0054] Unlike Example 1, in this example, the amount of montmorillonite is 4.5 parts, the amount of Si-69 is 1.5 parts, the amount of copper chloride is 1 part, and the rest are the same.

[0055] Example 4:

[0056] Unlike Example 1, in this example, kaolin is used instead of montmorillonite.

[0057] Example 5:

[0058] Unlike Example 1, in this example, ferric chloride is used instead of copper chloride.

[0059] Example 6:

[0060] Unlike Example 1, in this example, diphenyldimethoxysilane is used instead of Si-69.

[0061] Comparative Example 1:

[0062] Unlike Example 1, in this comparative example, a composition of montmorillonite and Si-69 was used instead of the coupling agent composition in Example 1. The amounts of montmorillonite and Si-69 were the same as in Example 1.

[0063] Comparative Example 2:

[0064] Unlike Example 1, in this comparative example, a composition of Si-69 and copper chloride is used instead of the coupling agent composition in Example 1. The amounts of Si-69 and copper chloride are the same as in Example 1.

[0065] Comparative Example 3:

[0066] Unlike Example 1, in this comparative example, a composition of montmorillonite and copper chloride is used instead of the coupling agent composition in Example 1. The amounts of montmorillonite and copper chloride are the same as in Example 1.

[0067] Comparative Example 4:

[0068] Unlike Example 1, in this comparative example, copper chloride was used instead of the coupling agent composition in Example 1. The amount of copper chloride used was the same as in Example 1.

[0069] Comparative Example 5:

[0070] Unlike Example 1, in this comparative example, Si-69 was used instead of the coupling agent composition in Example 1. The amount of Si-69 used was the same as in Example 1.

[0071] The technical solution of the present invention will be further explained below in conjunction with appearance testing and performance testing.

[0072] Appearance test:

[0073] After the vulcanized rubber samples used for appearance testing have been left for 10 days, observe whether the surface of the rubber samples shows any discoloration under the same light conditions.

[0074] Performance testing:

[0075] Tensile properties were tested according to GB / T528, using type 1 specimens.

[0076] Akron wear was determined according to GB / T1689.

[0077] The bonding strength between the core metal and the rubber was determined in accordance with GB / T7760, and the test sample was prepared from the semi-finished product.

[0078] The bonding strength between steel wire cord and rubber was determined according to GB / T16586, using method B, and the test sample was prepared from a semi-finished product.

[0079] The test results are shown in Table 1.

[0080] Table 1: Test results of relevant rubber material properties for each example and comparative example

[0081]

[0082] The foregoing general description of the invention and its specific embodiments should not be construed as a limitation on the technical solution of the invention. Those skilled in the art, based on the disclosure of this application, can add, reduce, or combine the disclosed technical features in the foregoing general description and / or specific embodiments (including examples) without departing from the constituent elements of the invention, to form other technical solutions within the scope of protection of this application.

Claims

1. A coupling agent composition for suppressing staining on the appearance of rubber, characterized in that: It includes coupling agents, metal chlorides, and clay minerals; in the coupling agent composition, by mass percentage, the coupling agent content is 15%-30%, the metal chloride content is 1%-15%, and the clay mineral content is 70%-85%; The preparation method of the coupling agent composition includes the following steps: (1) Add clay minerals to water and stir to disperse them evenly; (2) Add the coupling agent slowly and stir the reaction at 60-80℃ and 300-500 rpm for 1-3 hours; (3) Add metal chloride and continue the reaction at 40-60℃ and 100-200 rpm for 0.5-2 hours; (4) After the reaction is complete, let it stand for more than 1 hour, centrifuge, discard the supernatant, and wash the precipitate with deionized water more than 3 times. (5) Dry the washed solid product at 60-80℃ for 6-12 hours, cool it, grind it and pass it through a 100-150 mesh sieve to obtain the coupling agent composition.

2. The coupling agent composition according to claim 1, characterized in that: The metal chloride is any one of ferric chloride, copper chloride, and magnesium chloride.

3. The coupling agent composition according to claim 1, characterized in that: The clay minerals mentioned are one or a combination of two of kaolinite and montmorillonite.

4. The coupling agent composition according to claim 1, characterized in that: The coupling agent is a silicon-based organic compound.

5. The coupling agent composition according to claim 4, characterized in that: The coupling agent includes any one of Si-69, phenyltrimethoxysilane, and diphenyldimethoxysilane.

6. The use of the coupling agent composition according to any one of claims 1-5 in rubber tracks.

7. The application according to claim 6, characterized in that: The coupling agent composition is contained in both the wheel side rubber and the tread side rubber of the rubber track.

8. The application according to claim 7, characterized in that: The raw material formulation of the wheel side rubber, by weight, includes: 80-100 parts of natural rubber, 10-20 parts of butadiene rubber, 45-55 parts of carbon black N220, 10-15 parts of silica, 1-3 parts of sulfur, 0.5-2 parts of accelerator TMTM, 1-2 parts of antioxidant 4010NA, 1-2 parts of antioxidant RD, 2-5 parts of zinc oxide, 1-2 parts of stearic acid, and 3-6 parts of coupling agent composition to inhibit the discoloration of the rubber appearance.

9. The application according to claim 7, characterized in that: The raw material formulation of the patterned side rubber, by weight, includes: 70-90 parts natural rubber, 10-20 parts styrene-butadiene rubber, 30-50 parts carbon black N330, 10-20 parts silica, 1.5-2.5 parts sulfur, 1-2.5 parts accelerator TMTM, 1-3 parts antioxidant 4010NA, 1-3 parts antioxidant RD, 1-2 parts microcrystalline wax, 3-5 parts zinc oxide, 1-2 parts stearic acid, 5-8 parts aromatic oil, and 3-8 parts coupling agent composition to inhibit the color fading of the rubber appearance.

10. The application according to claim 7, characterized in that: During rubber compounding, the coupling agent composition is added to the internal mixer before the vulcanization system during the mixing stage.

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