Benzoxazine tackifying resin and rubber composition containing same

Abstract

The invention relates to a preparation method of benzoxazine tackifying resin, which comprises the following steps: mixing benzenediol with aniline and paraformaldehyde at 85-95 DEG C to react for 4-7 hours, thereby obtaining the benzoxazine tackifying resin, the benzenediol comprises one or more of resorcinol, catechol and hydroquinone. The benzoxazine tackifying resin can be used for tackifying a rubber composition and has good performance.

Description

Technical Field

[0001] The invention belongs to the technical field of resins and rubbers, and in particular relates to a benzoxazine tackifying resin and a rubber composition containing the benzoxazine resin. The benzoxazine resin is used for tackifying the rubber composition. Background Art

[0002] Phenolic resin has a long history of being used as a tackifier in rubber materials along with the development of synthetic rubber. The use of alkylphenol-formaldehyde resin can effectively improve the self-adhesiveness of synthetic rubber and solve the bonding problem between rubber parts. In particular, tert-butyl and tert-octylphenol-formaldehyde resins have been widely used in the production of tires, hoses, conveyor belts, V-belts, soles, sheets and stamping products.

[0003] However, with the development of society, the requirements for environmental protection of products are gradually increasing. For rubber materials, the heat generated by the deformation of rubber during use causes energy loss on the one hand, and accelerates the aging of rubber materials on the other hand. In tires, it is necessary to improve the rubber material while maintaining adhesion and having a certain heat resistance, which puts higher requirements on various raw materials used in rubber.

[0004] Benzoxazine is a thermosetting resin made from phenols, primary amines, and aldehyde compounds under catalyst conditions through the Mannich reaction. As an attractive new phenolic resin, in addition to the advantages of ordinary phenolic resins, it also has the advantages of no small molecule release during curing, low water absorption, high glass transition temperature (Tg), and dimensional stability. Therefore, it has obvious advantages to improve the mechanical properties of rubber by adding benzoxazine resin.

[0005] However, there is no successful case of using benzoxazine to increase the viscosity of rubber or rubber composition. Based on this, the present application was developed. Summary of the invention

[0006] The present invention aims to overcome the defects of the prior art and provide a benzoxazine tackifying resin, which can be used to tackify a rubber composition and has good performance.

[0007] The present invention also provides a rubber composition containing the benzoxazine tackifying resin and a preparation method thereof.

[0008] To achieve the above object, the present invention adopts the following technical solutions: A method for preparing a benzoxazine tackifying resin, specifically comprising: mixing hydroquinone with aniline and polyformaldehyde for reaction for 4-7 hours at a temperature of 85-95°C, removing the medium solvent used in the reaction, and preparing a benzoxazine tackifying resin having a special structure of two adjacent phenolic hydroxyl groups; the benzoxazine tackifying resin has a certain adhesive force and has the potential to be used as a rubber tackifier; The catechol includes but is not limited to one or more of resorcinol, catechol and hydroquinone.

[0009] Furthermore, in the preparation process of the benzoxazine tackifying resin, hydroquinone, aniline and paraformaldehyde may be mixed in a molar ratio of 1:1-2:2-3, where the paraformaldehyde is calculated as formaldehyde (HCHO).

[0010] The invention provides a benzoxazine tackifying resin prepared by the method.

[0011] The present invention also provides the use of the benzoxazine tackifying resin in tackifying rubber or rubber composition.

[0012] The present invention also provides a rubber composition containing the benzoxazine tackifying resin, which comprises the following raw materials in parts by weight: 20-40 parts of natural rubber, 60-80 parts of butadiene rubber, 1-2 parts of accelerator, 2-4 parts of rubber oil, 1-3 parts of stearic acid, 2-4 parts of antioxidant, Carbon black 60-80 parts, zinc oxide 2-4 parts, 1-2 parts of sulfur, 2-8 parts of the benzoxazine tackifying resin.

[0013] Specifically, the antioxidant may be a mixture of antioxidant 4020 and antioxidant TMQ, such as 1-2 parts of antioxidant 4020 and 1-2 parts of antioxidant TMQ. Further, the accelerator may be accelerator NS.

[0014] The present invention also provides a method for preparing the rubber composition, which comprises the following steps: The natural rubber, butadiene rubber, carbon black, rubber oil, zinc oxide and stearic acid are uniformly mixed in a mixer at 130-170° C. to obtain a rubber masterbatch; then, benzoxazine tackifying resin and antioxidant are added at 120-140° C., sulfur and accelerator are added at 90-110° C., and the mixture is ground uniformly to obtain the rubber masterbatch.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention innovatively prepares a benzoxazine tackifying resin, and uses the benzoxazine tackifying resin to tackify rubber or rubber composition. In the benzoxazine tackifying resin of the present invention, the special adjacent phenolic hydroxyl structure relies on the various modes of action such as the van der Waals force, covalent bond, hydrogen bond and coordination bond formed, and this structural group can produce excellent bonding properties for almost all inorganic and organic materials. Therefore, the present invention obtains a benzoxazine tackifying rubber material by introducing a benzoxazine tackifying resin containing a special bonding group and a method of high-temperature co-curing with rubber, which broadens the application field of benzoxazine and the space for the selection of rubber tackifying materials. Experiments have shown that the vulcanized rubber material tackified by the benzoxazine tackifying resin of the present invention significantly improves the viscosity and bonding force of the system, and also shows good dynamic mechanical properties and low hysteresis (low Tanδ value), and the strength, hardness and tear strength are significantly improved, and it also has a certain reinforcing effect. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited thereto.

[0017] In the following examples, the raw materials used are all common commercial products or can be prepared by conventional methods in the art. For example, rubber oil was purchased from Qingdao Krohn Chemical Co., Ltd., product model CP-1206. Accelerator NS was purchased from Henan Kailun Chemical Co., Ltd., vulcanization accelerator TBBS.

[0018] Room temperature refers to 25±5°C.

[0019] In the following examples, the benzoxazine tackifying resin used was prepared by the following steps: Through the Mannich reaction, catechol, aniline, and polyformaldehyde (polyformaldehyde is calculated as formaldehyde HCHO) are mixed at a molar ratio of 1: 1: 2 at 90°C and reacted for about 5 hours. After the reaction, the mixed liquid is cooled to room temperature and washed with deionized water three times. Next, the obtained organic phase is dried with magnesium sulfate and recrystallized to obtain a colorless product, which is the benzoxazine tackifying resin. The benzoxazine tackifying resin containing a special structure of two adjacent phenolic hydroxyl groups is prepared, which has a certain adhesive force and has the potential to be used as a rubber tackifier. The prepared benzoxazine tackifying resin is a colorless to light yellow solid. The infrared spectrum analysis shows that the characteristic absorption peak of the benzoxazine ring appears at 928cm.

[0020] Embodiment 1: A rubber composition containing the benzoxazine tackifying resin comprises the following raw materials in parts by weight: 30 parts of natural rubber, 70 parts of butadiene rubber, 2 parts of zinc oxide, 1 part of stearic acid, 3 parts of rubber oil, 1 part of antioxidant 4020, 1.5 parts of antioxidant TMQ, 60 parts of carbon black, 3 parts of benzoxazine tackifying resin, 1 part of accelerator NS, and 1.0 part of sulfur.

[0021] The method for preparing the rubber composition containing the benzoxazine tackifying resin comprises the following steps: The natural rubber, butadiene rubber, carbon black, rubber oil, zinc oxide and stearic acid are mixed uniformly in a mixer at 150°C to obtain a rubber masterbatch. Then, benzoxazine tackifying resin, antioxidant 4020 and TMQ are mixed at about 140°C. Insoluble sulfur and accelerator NS are added at about 100°C, mixed and ground uniformly in an open grinding mixer to obtain the rubber masterbatch.

[0022] The rubber composition to be tested was stored at a constant room temperature (about 23°C) and 50% relative humidity for testing. The dynamic mechanical properties were determined using a rubber processing analyzer. The test results are shown in the table below.

[0023] Embodiment 2: A rubber composition containing the benzoxazine tackifying resin comprises the following raw materials in parts by weight: 30 parts of natural rubber, 70 parts of butadiene rubber, 2 parts of zinc oxide, 1 part of stearic acid, 3 parts of rubber oil, 1 part of antioxidant 4020, 1.5 parts of antioxidant TMQ, 60 parts of carbon black, 5 parts of benzoxazine tackifying resin, 1 part of accelerator NS, and 1.0 part of sulfur.

[0024] The preparation method of the rubber composition containing the benzoxazine tackifying resin is as described in Example 1.

[0025] The above rubber composition to be tested was tested for relevant properties using a rubber processing analyzer. The test results are shown in the table below.

[0026] Embodiment 3: A rubber composition containing the benzoxazine tackifying resin comprises the following raw materials in parts by weight: 30 parts of natural rubber, 70 parts of butadiene rubber, 2 parts of zinc oxide, 1 part of stearic acid, 3 parts of rubber oil, 1 part of antioxidant 4020, 1.5 parts of antioxidant TMQ, 60 parts of carbon black, 7 parts of benzoxazine tackifying resin, 1 part of accelerator NS, and 1.0 part of sulfur.

[0027] The preparation method of the rubber composition containing the benzoxazine tackifying resin is as described in Example 1.

[0028] The above rubber composition to be tested was tested for relevant properties using a rubber processing analyzer. The test results are shown in the table below.

[0029] The relevant test data of the rubber compositions prepared in Examples 1 to 3 are shown in the table above. It can be seen from the data in the table above that compared with the blank group without adding the benzoxazine tackifying resin, the vulcanized rubber material tackified by the benzoxazine tackifying resin of the present invention significantly improves the viscosity and adhesion of the system, and also shows good dynamic mechanical properties and low hysteresis (low Tanδ value), and the strength, hardness and tear strength are significantly improved, and also has a certain reinforcement effect.

[0030] Embodiment 4: A rubber composition containing the benzoxazine tackifying resin comprises the following raw materials in parts by weight: 30 parts of natural rubber, 70 parts of butadiene rubber, 3 parts of zinc oxide, 2 parts of stearic acid, 2 parts of rubber oil, 2 parts of antioxidant 4020, 1 part of antioxidant TMQ, 60 parts of carbon black, 5 parts of benzoxazine tackifying resin, 1 part of accelerator NS, and 1.0 part of sulfur.

[0031] The preparation method of the rubber composition containing the benzoxazine tackifying resin is as described in Example 1.

[0032] Embodiment 5: A rubber composition containing the benzoxazine tackifying resin comprises the following raw materials in parts by weight: 20 parts of natural rubber, 80 parts of butadiene rubber, 4 parts of zinc oxide, 3 parts of stearic acid, 4 parts of rubber oil, 1 part of antioxidant 4020, 2 parts of antioxidant TMQ, 70 parts of carbon black, 5 parts of benzoxazine tackifying resin, 2 parts of accelerator NS, and 1.0 part of sulfur.

[0033] The preparation method of the rubber composition containing the benzoxazine tackifying resin is as described in Example 1.

[0034] Embodiment 6: A rubber composition containing the benzoxazine tackifying resin comprises the following raw materials in parts by weight: 40 parts of natural rubber, 60 parts of butadiene rubber, 2 parts of zinc oxide, 1 part of stearic acid, 3 parts of rubber oil, 1 part of antioxidant 4020, 1.5 parts of antioxidant TMQ, 80 parts of carbon black, 5 parts of benzoxazine tackifying resin, 1 part of accelerator NS, and 2.0 parts of sulfur.

[0035] The preparation method of the rubber composition containing the benzoxazine tackifying resin is as described in Example 1.

[0036] The rubber compositions to be tested in the above-mentioned Examples 4 to 6 were tested for relevant properties using a rubber processing analyzer. The experimental results show that they all have comparable viscosity, hysteresis, strength, hardness and tear strength to the rubber composition in Example 2.

[0037] In summary, the benzoxazine tackifying resin of the present invention can be used to tackify rubber compositions with good performance.

Claims

1. A method for preparing a benzoxazine tackifying resin, It is characterized in that At a temperature of 85-95°C, hydroquinone, aniline and polyformaldehyde are mixed and reacted for 4-7 hours to obtain; The catechol includes one or more of resorcinol, catechol and hydroquinone.

2. The method for preparing the benzoxazine tackifying resin according to claim 1, It is characterized in that Mix hydroquinone, aniline and paraformaldehyde in a molar ratio of 1:1-2:2-3, where the paraformaldehyde is calculated as HCHO.

3. The benzoxazine tackifying resin prepared by the method of claim 1 or 2.

4. Use of the benzoxazine tackifying resin according to claim 3 in tackifying rubber or rubber composition.

5. A rubber composition comprising the benzoxazine tackifying resin according to claim 3, It is characterized in that The invention comprises the following raw materials in proportion by weight: 20-40 parts of natural rubber, 60-80 parts of butadiene rubber, 1-2 parts of accelerator, 2-4 parts of rubber oil, 1-3 parts of stearic acid, 2-4 parts of antioxidant, Carbon black 60-80 parts, zinc oxide 2-4 parts, 1-2 parts of sulfur, 2-8 parts of the benzoxazine tackifying resin according to claim 3.

6. The rubber composition according to claim 5, It is characterized in that The antioxidant is composed of a mixture of antioxidant 4020 and antioxidant TMQ.

7. The rubber composition according to claim 5, It is characterized in that The accelerator is accelerator NS.

8. A method for preparing a rubber composition according to any one of claims 5 to 7, It is characterized in that The steps include: The natural rubber, butadiene rubber, carbon black, rubber oil, zinc oxide and stearic acid are uniformly mixed in a mixer at 130-170° C. to obtain a rubber masterbatch; then, benzoxazine tackifying resin and antioxidant are added at 120-140° C., sulfur and accelerator are added at 90-110° C., and the mixture is ground uniformly to obtain the rubber masterbatch.

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