Silane coupling agent as well as preparation method and application thereof

Abstract

The invention discloses a silane coupling agent and a preparation method and application thereof.The silane coupling agent contains a naphthyl acylhydrazone structure, H in naphthyl in the naphthyl acylhydrazone structure is substituted by-O-R-Si-X3, R is alkane with the carbon number of 1-7, X is a group capable of being hydrolyzed into silanol, and during preparation, the hydroxyl-substituted naphthyl acylhydrazone is dissolved in an organic solvent, and the solution is stirred to be uniform; adding halogenated silane, an inorganic base, a catalyst and an amine ligand, introducing nitrogen to carry out substitution reaction, and treating after the reaction is finished. The preparation method of the silane coupling agent is simple, the silane coupling agent is applied to a rubber material to remarkably improve the dispersion of white carbon black and enhance the interface effect, and the heat generation phenomenon of a composite material is inhibited.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber materials, and in particular relates to a silane coupling agent and a preparation method and application thereof. Background Art

[0002] Rubber materials are used in various industries due to their unique high elasticity. In order to meet the needs of practical application, it is essential to add fillers to fill and strengthen rubber. Compared with carbon black, the most commonly used rubber filler in the prior art, the addition of white carbon black brings lower rolling resistance, that is, lower energy consumption. There are a large number of silanol groups on the surface of white carbon black, which has poor compatibility with non-polar rubber, resulting in weaker interfacial interaction between white carbon black and rubber. At present, some people have proposed methods such as surface modification of white carbon black, modification of rubber matrix, and use of coupling agents to address this problem. Among them, in-situ modification using a suitable silane coupling agent is the most suitable method for industrial production. Silane coupling agents generally follow the bifunctional principle, that is, one group reacts with the rubber molecular chain and the other interacts with white carbon black, thereby achieving the effect of promoting the interface bonding of the composite material. At present, sulfur-containing silane coupling agents such as TESPT, KH590, Si69 and Si747 are commonly used in rubber science and engineering, and sulfur bonds can participate in the rubber vulcanization process. However, the production of this type of silane coupling agent generally involves a more complicated production process and is prone to cause scorching of the rubber, resulting in processing difficulties. Summary of the invention

[0003] In order to overcome the problems in the prior art, the present invention provides a silane coupling agent and a preparation method and application thereof. The preparation method of the silane coupling agent obtained by the present invention is simple, and the silane coupling agent can be applied to rubber materials to significantly improve the dispersion of white carbon black and enhance the interface effect, thereby inhibiting the heat generation of the composite material.

[0004] In order to solve the above technical problems, the technical solution proposed by the present invention is: The present invention provides a silane coupling agent, wherein the silane coupling agent contains a naphthoylhydrazone structure, wherein the H in the naphthyl group in the naphthoylhydrazone structure is -OR-Si-X 3 Substitution, wherein R is an alkane group having 1 to 7 carbon atoms, and X is a group that can be hydrolyzed into a silanol group.

[0005] As an optional embodiment, in the silane coupling agent provided by the present invention, X is an oxygen-containing alkane group.

[0006] As an optional embodiment, in the silane coupling agent provided by the present invention, the structural formula of the silane coupling agent is as follows:

[0007] Among them, R 1 , R 2 , R3 is an alkane group having 1 to 7 carbon atoms, R 1 , R 2 , R 3 are the same or different alkane groups.

[0008] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned silane coupling agent, comprising the following steps: The hydroxy-substituted naphthoylhydrazone is dissolved in an organic solvent, and after adding halogenated silane, inorganic base, catalyst and amine ligand, nitrogen is introduced to cause substitution reaction, and after the reaction is completed, the silane coupling agent is obtained by treatment.

[0009] As an optional embodiment, in the preparation method provided by the present invention, the halosilane compound has a structure as shown in the following formula:

[0010] Where X is a halogen element such as F, Cl, Br, I, R1, R2, R3 are alkyl groups with 1 to 7 carbon atoms, R 1 , R 2 , R 3 are the same or different alkane groups.

[0011] As an optional embodiment, in the preparation method provided by the present invention, the mass ratio of the naphthoylhydrazone to the halosilane is 1:1.5-2.

[0012] As an optional embodiment, in the preparation method provided by the present invention, the catalyst is selected from one of copper iodide or potassium iodide.

[0013] As an optional embodiment, in the preparation method provided by the present invention, the inorganic base is selected from one of sodium carbonate, potassium carbonate or cesium carbonate.

[0014] As an optional embodiment, in the preparation method provided by the present invention, the amine ligand is selected from one of L-proline, ethylenediamine or tetrabutylammonium bromide.

[0015] Based on the same technical concept, the present invention also provides the use of the above-mentioned silane coupling agent or the silane coupling agent prepared by the above-mentioned preparation method of the silane coupling agent in rubber materials.

[0016] As an optional implementation, in the application provided by the present invention, the rubber material also includes natural rubber and white carbon black.

[0017] As an optional embodiment, in the application provided by the present invention, the rubber material includes the following raw materials in parts by weight: 100 phr of natural rubber, 20-40 phr of white carbon black, and 1-6 phr of the silane coupling agent described in claim 1.

[0018] A novel silane coupling agent is prepared in the present invention. The coupling agent has the ability to capture free radicals. On the one hand, the siloxy part interacts with white carbon black, and on the other hand, the acylhydrazone part captures free radicals generated during the processing of natural rubber. At the same time, the naphthalene ring in the silane coupling agent in the present invention has the function of stabilizing free radicals, otherwise it will cause the instability of the acylhydrazone structure and the short life of the captured rubber macromolecular free radicals. The silane coupling agent in the present invention does not contain a sulfur bond in its structure, but uses the imine bond in its structure to capture rubber macromolecular free radicals, thereby achieving interaction with the rubber molecular chain.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention prepares a new type of silane coupling agent, the preparation method is simple and easy to operate, has high universality, and has good market application value in the rubber industry.

[0020] (2) The silane coupling agent of the present invention reacts with the rubber molecular chain by capturing the macromolecular free radicals generated by the rubber during the shearing process, and the interfacial adhesion of the prepared silica-rubber composite material is significantly enhanced, thereby improving the dispersion of silica in the rubber matrix, obtaining lower rolling resistance and better anti-slip properties. The new silane coupling agent synthesized by the present invention does not contain sulfur bonds in its structure, has little effect on the scorch behavior of the composite material, and brings better mechanical and dynamic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 is the H NMR spectrum of the silane coupling agent prepared in Example 1; Figure 2 is the H NMR spectrum of the silane coupling agent prepared in Example 2; Figure 3 is the H NMR spectrum of the silane coupling agent prepared in Example 3; Figure 4 This is the reaction mechanism diagram of silane coupling agent with rubber and silica. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0025] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0026] The present invention prepares a new type of silane coupling agent, which reacts with the rubber molecular chain by capturing the macromolecular free radicals generated during the shearing process of the rubber. The reaction mechanism is as follows: Figure 4 shown.

[0027] Example 1 The preparation method of the novel silane coupling agent comprises the following steps: 300 ml of DMF was added to a three-necked flask. First, a hydroxy-substituted naphthoylhydrazone (2.85 g, 0.01 mol) of the following structure was added. The mixture was heated and stirred at 100°C to dissolve. Then, 3-chloropropyltriethoxysilane (4.82 g, 0.02 mol), copper iodide (0.076 g, 0.004 mol), sodium carbonate (3.18 g, 0.03 mol), and L-proline (0.023, 0.002 mol) were added. Then, nitrogen was introduced and stirred for 6 hours. After the reaction was completed, the reaction solution was filtered and cooled to room temperature and then filtered. Then, 600 ml of deionized water was introduced and stirred for 30 minutes. After standing for 1 hour, the solution was filtered. The solid product obtained by filtration was vacuum dried to obtain a purified novel silane coupling agent A1. The reaction equation is as follows:

[0028] The H NMR spectrum of the new silane coupling agent A1 is as follows Figure 1 shown.

[0029] Example 2 The preparation method of the novel silane coupling agent comprises the following steps: 300 ml of DMF was added to a three-necked flask, and naphthoylhydrazone (2.85 g, 0.01 mol) was first added, and heated and stirred at 100 ° C to dissolve it, and then 3-iodopropyltrimethoxysilane (5.8 g, 0.02 mol), copper iodide (0.076 g, 0.004 mol), sodium carbonate (3.18 g, 0.03 mol), L-proline (0.023, 0.002 mol) were added, and then nitrogen was introduced and stirred for 6 hours; after the reaction, the reaction solution was filtered and cooled to room temperature and then filtered, and then 600 ml of deionized water was introduced and stirred for 30 minutes, and then allowed to stand for 1 hour and filtered, and the solid product obtained by filtration was vacuum dried to obtain a purified new silane coupling agent A2, and the reaction equation is as follows:

[0030] The H NMR spectrum of the new silane coupling agent A2 is as follows Figure 2 shown.

[0031] Example 3 The preparation method of the novel silane coupling agent comprises the following steps: 300 ml of DMF was added to a three-necked flask, and naphthoylhydrazone (2.85 g, 0.01 mol) was first added, and heated and stirred at 100 °C to dissolve it, and then 4-bromobutyltrimethoxysilane (5.16 g, 0.02 mol), copper iodide (0.076 g, 0.004 mol), sodium carbonate (3.18 g, 0.03 mol), and L-proline (0.023, 0.002 mol) were added, and then nitrogen was introduced and stirred for 6 hours; after the reaction was completed, the reaction solution was filtered and cooled to room temperature and then filtered, and then 600 ml of deionized water was introduced and stirred for 30 minutes, and then allowed to stand for 1 hour and filtered, and the solid product obtained by filtration was vacuum dried to obtain a purified new silane coupling agent A3, and the reaction equation is as follows:

[0032] The H NMR spectrum of the new silane coupling agent A3 is as follows Figure 3 shown.

[0033] Application Examples A method for preparing a rubber composite material comprises the following steps: (1) Natural rubber, white carbon black and new silane coupling agent A1 were added into an internal mixer in sequence and mixed at 130°C for 8 minutes to obtain a mixed rubber.

[0034] (2) The rubber mixture is placed in an open mixer, and a vulcanization bag is added for secondary mixing at room temperature. After the secondary mixing, the rubber mixture is left for 24 hours and then hot-pressed at 143°C for a positive vulcanization time to prepare a vulcanized rubber. The mixture contains 5 g zinc oxide, 2 g stearic acid, 1.2 g accelerator CZ, 1.5 g accelerator D, and 2 g sulfur.

[0035] The main difference between the different application examples 1-6 and the application comparative examples 1-2 is the different raw material ratios, see Table 1 below for details.

[0036] Table 1: Raw material ratio

[0037] The rubber composite materials prepared by Application Examples 1-6 and Comparative Examples 1-2 were subjected to mechanical property tests, and the test results are shown in Table 2, wherein the tensile strength, elongation at break and 300% elongation stress of Application Examples 1-6 and Comparative Examples 1-2 were determined according to ISO37-2005, the test temperature was room temperature, and the stretching rate was 500 mm / min; the fatigue heat generation was determined according to ISO 4666-3:2016; the rolling resistance was measured by a rubber processing analyzer (the tan δ value at 7% strain measured at a frequency of 10 Hz represents the rolling resistance). The wet skid resistance was measured by DMA (tan δ value at 0°C at 0.5% strain and 10 Hz frequency).

[0038] Table 2: Performance test results

[0039] By analyzing Table 2, it can be seen that the silica-rubber composite material prepared by the preparation method of the present invention has excellent comprehensive properties. This new silane coupling agent can capture and stabilize the macromolecular free radicals currently generated during the processing, forming a stronger interface bond and a more uniform filler dispersion network. The addition of the new silane coupling agents A1, A2, and A3 has a significant effect on the silica / rubber composite material: the room temperature tensile strength and the elongation stress at 300% strain of the silica / rubber composite material show a significant improvement; the fatigue temperature rise and rolling resistance of the composite material show a downward trend; in addition, the anti-slip property of the composite material is also improved.

[0040] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A silane coupling agent, characterized in that: The silane coupling agent contains a naphthoylhydrazone structure, in which the H in the naphthyl group is replaced by -OR-Si-X3, wherein R is an alkane group with a carbon number of 1-7, and X is a group that can be hydrolyzed into silanol.

2. The silane coupling agent according to claim 1, characterized in that The X is an oxygen-containing alkane group.

3. The silane coupling agent according to claim 1, characterized in that: The structural formula of the silane coupling agent is as follows: Among them, R1, R2, and R3 are alkyl groups having 1 to 7 carbon atoms, and R1, R2, and R3 are the same or different alkyl groups.

4. The method for preparing a silane coupling agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: The hydroxy-substituted naphthoylhydrazone is dissolved in an organic solvent, and after adding halogenated silane, inorganic base, catalyst and amine ligand, nitrogen is introduced to cause substitution reaction, and after the reaction is completed, the silane coupling agent is obtained by treatment.

5. The method for preparing a silane coupling agent according to claim 4, characterized in that: The halosilane compound has a structure as shown in the following formula: Wherein X is a halogen element such as F, Cl, Br, I, etc., R1, R2, and R3 are alkane groups having 1 to 7 carbon atoms, and R1, R2, and R3 are the same or different alkane groups.

6. The method for preparing a silane coupling agent according to claim 4, characterized in that: The mass ratio of the hydroxy-substituted naphthoylhydrazone to the halogenated silane is 1:1.5-2.

7. The method for preparing a silane coupling agent according to claim 4, characterized in that: The catalyst is selected from one of copper iodide and potassium iodide; the inorganic base is selected from one of sodium carbonate, potassium carbonate or cesium carbonate; and the amine ligand is selected from one of L-proline, ethylenediamine or tetrabutylammonium bromide.

8. Use of the silane coupling agent according to any one of claims 1 to 3 or the silane coupling agent prepared by the preparation method of the silane coupling agent according to any one of claims 4 to 7 in rubber materials.

9. The use according to claim 8, characterized in that: The rubber material also includes natural rubber and white carbon black.

10. The use according to claim 8, characterized in that: The rubber material comprises the following raw materials in parts by weight: 100 phr of natural rubber, 20-40 phr of white carbon black, and 1-6 phr of the silane coupling agent described in claim 1.

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