Adhesive resin, preparation method thereof, and rubber composition

Abstract

The present application provides a kind of adhesive resin and its preparation method and rubber composition, and adhesive resin is obtained by reacting phenolic compound and olefinic compound containing aromatic group; Wherein, the weight average molecular weight of adhesive resin is 200 800. The molecular weight of the adhesive resin provided by the present application is lower than the molecular weight of meta-resin product in the prior art, has good compatibility with rubber, effectively reduces the Mooney viscosity of rubber composition, thereby improving mixing efficiency. The adhesive resin provided by the present application is not easy to volatilize when heated, can effectively reduce or even eliminate the problem of fuming during rubber mixing, will not cause adverse effects on the environment and human body, and its production process is environmentally friendly, without wastewater, waste gas generation. No formaldehyde is involved in the adhesive resin synthesis process provided by the present application, no aldehyde compound is contained in the adhesive resin component, and an aromatic olefin structure with strong rigidity is introduced, which is conducive to improving the physical properties and mechanical properties of rubber products.

Description

Technical Field

[0001] The present application relates to the field of rubber technology, and in particular to an adhesive resin, a preparation method thereof, and a rubber composition. Background Art

[0002] In the manufacture of automobile tires, in order to improve the strength of the tire, fibers, nylon, steel wire, etc. are used as the cord layer support skeleton structure. In order to improve the bonding strength between the cord layer and the rubber, m-formaldehyde resin (resorcinol-formaldehyde resin) is usually added before the rubber is vulcanized, so that a resinization reaction occurs during the vulcanization process, forming a vulcanized rubber-resin network, which can enhance the bonding strength between the rubber and the cord as well as the physical and mechanical properties of the rubber products.

[0003] Yet, when this type of adhesive resin is used to prepare rubber products, on the one hand, the content of free resorcinol remaining in the adhesive resin is relatively high, and resorcinol fumes during the rubber processing process, that is, the sizing material is heated and can volatilize, producing heavy, toxic smog that odors, causing environmental pollution and endangering human health. And, if the content of free resorcinol is too low in the adhesive resin, the adhesive properties of the rubber products will be caused to decline. On the other hand, the weight-average molecular weight of existing meta-first-class adhesive resins is all more than 1000, and molecular weight is relatively large, and is relatively poor with rubber compatibility, causing the Mooney viscosity of unvulcanized sizing material to be high, causing mixing efficiency to be low. Therefore, how to improve the fuming problem in the rubber mixing process, improve mixing efficiency and become problems demanding urgent solution. Summary of the Invention

[0004] The purpose of this application is to provide an adhesive resin, a preparation method thereof, and a rubber composition to improve the problems of smoke generation and low mixing efficiency during the rubber mixing process. The specific technical solution is as follows:

[0005] The first aspect of the present application provides an adhesive resin obtained by reacting a phenolic compound and an olefinic compound containing an aromatic group; wherein the weight-average molecular weight of the adhesive resin is 200-800; the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is 1:0.5-1:3; and the phenolic compound is selected from at least one of a monophenolic compound, a diphenolic compound and a triphenolic compound.

[0006] In some embodiments of the present application, the aromatic olefin compound is selected from at least one of styrene, 4-methylstyrene, α-methylstyrene, 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, 1,4-dipropylenebenzene, 4-allylphenol, 4-propylenephenol, cardanol, cardanol diphenol and eugenol.

[0007] In some embodiments of the present application, the phenolic compound is selected from at least one of phenol, 2-methylphenol, 3,5-dimethylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 4-allylresorcinol, 4-propenylresorcinol, 2-tert-butylresorcinol, 4-tert-butylresorcinol, 2,5-dimethylresorcinol, phloroglucinol, cardanol, cardanol and eugenol.

[0008] Among them, cardanol, cardanol diphenol, and eugenol are both phenolic compounds and olefinic compounds containing an aromatic group. When one of the phenolic compound or the olefinic compound containing an aromatic group is selected from cardanol, cardanol diphenol, or eugenol, the phenolic compound and the olefinic compound containing an aromatic group may be the same or different. For example, when the phenolic compound is selected from cardanol, the olefinic compound containing an aromatic group may be selected from cardanol or other compounds.

[0009] In some embodiments of the present application, the phenolic compound is selected from at least one of phenol, cardanol, resorcinol and 4-methylresorcinol; the aromatic olefin compound is selected from at least one of styrene, 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, α-methylstyrene and cardanol.

[0010] In some embodiments of the present application, the weight average molecular weight of the binder resin is 300-700; and / or the molar ratio of the phenolic compound to the aromatic olefin compound is 1:1-1:2.

[0011] The second aspect of the present application provides a method for preparing the adhesive resin described in the first aspect of the present application, which comprises the following steps: mixing the phenolic compound and the acidic catalyst, then adding an olefinic compound containing an aromatic group, reacting at 80°C-150°C for 1h-4h, and after the reaction is completed, adding an alkaline neutralizer for neutralization to obtain the adhesive resin; wherein the acidic catalyst is selected from at least one of oxalic acid, sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid; and the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is 1:0.5-1:3.

[0012] In some embodiments of the present application, the alkaline neutralizing agent is selected from at least one of triethylamine, ethanolamine, triethanolamine, diethanolamine and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0013] In some embodiments of the present application, the reaction further comprises adding a solvent, and the solvent is selected from at least one of toluene and xylene.

[0014] The third aspect of the present application provides a rubber composition comprising the adhesive resin described in the first aspect of the present application.

[0015] In some embodiments of the present application, the rubber composition has a Mooney viscosity ML (1+4) at 100° C. of 65-75.

[0016] The fourth aspect of the present application provides a rubber product, which is prepared using the rubber composition described in the third aspect of the present application.

[0017] Beneficial effects of this application:

[0018] The present application provides an adhesive resin, a preparation method thereof, and a rubber composition. The adhesive resin is obtained by reacting a phenolic compound and an olefinic compound containing an aromatic group; wherein the weight-average molecular weight of the adhesive resin is 200-800; and the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is 1:0.5-1:3. The molecular weight of the adhesive resin provided by the present application is lower than that of the meta-resin product in the prior art, has good compatibility with rubber, and effectively reduces the Mooney viscosity of the rubber composition, thereby improving mixing efficiency. The adhesive resin provided by the present application is not easy to volatilize when heated, and can effectively reduce or even eliminate the problem of smoke generation during the rubber mixing process, and will not cause adverse effects on the environment and human body, and its production process is environmentally friendly, and no wastewater or waste gas is generated. No formaldehyde is involved in the synthesis process of the adhesive resin provided by the present application, and the adhesive resin component does not contain aldehyde compounds, and an aromatic olefin structure with strong rigidity is introduced, which is beneficial to improving the physical and mechanical properties of rubber products.

[0019] Of course, it is not necessary to achieve all the advantages described above at the same time when implementing any product or method of the present application. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the embodiments described are only part of the embodiments of the present application, not all of them. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field based on the present application are within the scope of protection of the present application.

[0021] In a first aspect, the present application provides a binder resin obtained by reacting a phenolic compound with an olefinic compound containing an aromatic group. The binder resin has a weight-average molecular weight of 200-800, preferably 300-700, and a molar ratio of the phenolic compound to the olefinic compound containing an aromatic group of 1:0.5-1:3, preferably 1:1-1:2. The phenolic compound is selected from at least one of a monophenolic compound, a diphenolic compound, and a triphenolic compound.

[0022] On the one hand, the adhesive resin provided by the present application is obtained by reacting an olefinic compound containing an aromatic group with a volatile phenolic compound to obtain a low-molecular-weight adhesive resin, thereby increasing the relative boiling point of the adhesive resin and making it difficult for the adhesive resin to volatilize during the heating process, thereby solving the problem of smoke generation during the rubber mixing process. On the other hand, the molecular weight of the adhesive resin provided by the present application is lower than that of the meta-formaldehyde resin products in the prior art, has good compatibility with rubber, effectively reduces the Mooney viscosity of the rubber composition, and thus improves mixing efficiency. In addition, the adhesive resin provided by the present application is different from the meta-formaldehyde resin or phenolic resin in the prior art. No formaldehyde is involved in its synthesis process, the adhesive resin component does not contain aldehyde compounds, and an aromatic olefin structure with strong rigidity is introduced, which is conducive to improving the physical and mechanical properties of rubber products.

[0023] The weight average molecular weight of adhesive resin can be 200,300,400,500,600,700,800 or the scope of any two numerical values.When the weight average molecular weight of adhesive resin is too small, it is unfavorable for improving the relative boiling point of adhesive resin and improving the problem of fuming in the rubber mixing process.When the weight average molecular weight of adhesive resin is too large, it is relatively poor with rubber compatibility, causes the Mooney viscosity of rubber combination (also referred to as unvulcanized rubber material) to be high, causes mixing efficiency to be low.The weight average molecular weight of adhesive resin is within the above scope, lower than the molecular weight of the first adhesive resin product of the prior art, and adhesive resin and rubber compatibility are better, are conducive to improving the problem of fuming in the rubber mixing process, and effectively reduced the Mooney viscosity of rubber combination, thereby improve mixing efficiency.

[0024] For example, the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group can be 1:0.5, 1:0.8, 1:1.5, 1:2.5, 1:2.8, 1:3, or a range consisting of any two of these values. If the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is too high, the tackifying resin will contain fewer rigid aromatic-olefin structures, resulting in a higher content of the phenolic compound, which is detrimental to improving the physical and mechanical properties of the rubber product. If the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is too low, the tackifying resin will contain too many rigid aromatic-olefin structures, which is detrimental to improving the bond strength between the cord layer and the rubber. Regulating the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group within the above range helps balance the physical and mechanical properties of the rubber product with its adhesive properties.

[0025] In some embodiments of the present application, the olefinic compound containing an aromatic group is selected from at least one of styrene, 4-methylstyrene, α-methylstyrene, 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, 1,4-dipropylenebenzene, 4-allylphenol, 4-propylenephenol, cardanol, cardanol, and eugenol. The olefinic compound containing an aromatic group is preferably selected from at least one of styrene, 1,2-divinylbenzene, 1,3-divinylbenzene, 1,4-divinylbenzene, α-methylstyrene, and cardanol. Selecting an olefinic compound containing an aromatic group within the above range can introduce a relatively rigid aromatic-olefin structure into the viscous resin, which is beneficial to improving the physical and mechanical properties of the rubber product.

[0026] In some embodiments of the present application, the phenolic compound is selected from at least one of phenol, 2-cresol, 3,5-xylenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 4-allylresorcinol, 4-propenylresorcinol, 2-tert-butylresorcinol, 4-tert-butylresorcinol, 2,5-dimethylresorcinol, phloroglucinol, cardanol, cardanol, and eugenol. The phenolic compound is preferably selected from at least one of phenol, cardanol, resorcinol, and 4-methylresorcinol. Selecting a phenolic compound within the above range is beneficial for improving the adhesive properties of the adhesive resin, thereby increasing the bond strength between the cord layer and the rubber.

[0027] In the present application, cardanol, cardanol diphenol, and eugenol are both phenolic compounds and olefinic compounds containing an aromatic group. When one of the phenolic compound or the olefinic compound containing an aromatic group is selected from cardanol, cardanol diphenol, or eugenol, the phenolic compound and the olefinic compound containing an aromatic group may be the same or different. For example, when the phenolic compound is selected from cardanol, the olefinic compound containing an aromatic group may be selected from cardanol or other compounds.

[0028] The second aspect of the present application provides a method for preparing the adhesive resin provided in the first aspect of the present application, comprising the following steps: mixing a phenolic compound and an acidic catalyst, then adding an olefinic compound containing an aromatic group, reacting at 80°C-150°C for 1 hour (h)-4 hours, and after the reaction, adding an alkaline neutralizer for neutralization to obtain an adhesive resin; wherein the acidic catalyst is selected from at least one of oxalic acid, sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid; and the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is 1:0.5-1:3, preferably 1:1-1:2. The preparation method provided by the present application is simple and easy to implement, does not involve formaldehyde in the reaction process, and does not generate wastewater or exhaust gas. It is an environmentally friendly method for preparing an adhesive resin.

[0029] In some embodiments of the present application, a phenolic compound, an acidic catalyst, and an olefinic compound containing an aromatic group are mixed and reacted at a temperature of 80°C to 150°C, preferably 100°C to 140°C. For example, the reaction temperature may be 80°C, 90°C, 110°C, 120°C, 130°C, 150°C, or a range consisting of any two of these values. Controlling the reaction temperature within this range facilitates the production of the low molecular weight adhesive resin of the present application.

[0030] In this application, there is no particular limitation on the amount of the acidic catalyst added. The amount of the acidic catalyst added can be adjusted based on the mass of the phenolic compound according to the actual needs of the reaction, as long as the purpose of this application is achieved. For example, the amount of the acidic catalyst added is 0.1% to 3% of the total mass of the phenolic compound.

[0031] In the present application, the above-mentioned olefinic compound containing an aromatic group can be added directly or dropwise during the reaction. There is no particular limitation on this in the present application, as long as the purpose of the present application can be achieved. There is no particular limitation on the order of adding the phenolic compound, the acidic catalyst, and the olefinic compound containing an aromatic group, as long as the purpose of the present application can be achieved.

[0032] In some embodiments of the present application, the alkaline neutralizing agent is selected from at least one of triethylamine, ethanolamine, triethanolamine, diethanolamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene. The alkaline neutralizing agent is selected within the above range so that the prepared adhesive resin is neutral.

[0033] The amount of the alkaline neutralizing agent used in this application is not particularly limited and is adjusted according to the amount of the acidic catalyst, as long as the purpose of neutralizing the binder resin is achieved. For example, the amount of the alkaline neutralizing agent added is 0.02% to 5% of the total mass of the phenolic compound.

[0034] In some embodiments of the present application, a solvent is not required during the reaction, and an alkaline neutralizing agent is added for neutralization to obtain the adhesive resin. In some embodiments of the present application, the reaction further includes the addition of a solvent, and the solvent is selected from at least one of toluene and xylene. In the reaction process in which a solvent is added, after neutralization with an alkaline neutralizing agent, separation is required to obtain the adhesive resin. The present application does not particularly limit the above-mentioned separation method, as long as it can achieve the purpose of the present application. For example, separation can be performed by vacuum distillation.

[0035] For example, the adhesive resin provided in the first aspect of the present application is prepared by the following steps: a phenolic compound, a solvent, and an acidic catalyst are added to a reaction flask equipped with a stirring device, a thermometer, and a reflux condenser, the temperature is gradually increased and stirred to dissolve the phenolic compound, the temperature is increased to 80°C-150°C, an olefin compound containing an aromatic group is gradually added, the reaction is carried out under reflux for 1h-4h, and then the reflux is terminated. After the reaction device is converted into a vacuum distillation device, the temperature is gradually increased to 160°C, an alkaline neutralizer is added for neutralization, and the solvent is removed by vacuum distillation to obtain the adhesive resin.

[0036] The third aspect of the present application provides a rubber composition comprising the adhesive resin of the first aspect of the present application. The rubber composition of the present application has a low Mooney viscosity, which is beneficial to improving mixing efficiency.

[0037] The rubber composition may further include components such as rubber, carbon black, white carbon black, zinc oxide, an accelerator, and a vulcanizing agent. For example, the rubber may include natural rubber and synthetic rubber. The present application does not particularly limit the components in the rubber composition, and the composition and content may be adjusted according to actual needs, as long as the purpose of the present application can be achieved. The rubber composition described in the present application refers to a rubber compound obtained by mixing components such as rubber, carbon black, white carbon black, zinc oxide, an accelerator, an adhesive resin, and a vulcanizing agent.

[0038] In some embodiments of the present application, the Mooney viscosity ML(1+4) of the rubber composition at 100° C. is 65-75. The Mooney viscosity of the rubber composition within the above range is beneficial to improving mixing efficiency.

[0039] A fourth aspect of the present application provides a rubber product prepared using the rubber composition provided in the third aspect of the present application. The present application does not particularly limit the preparation method and process parameters for the rubber product; commonly used methods and process parameters in the art may be used, as long as the objectives of the present application are achieved. The rubber product of the present application exhibits high adhesion strength between the rubber and the cord layer, resulting in excellent physical and mechanical properties.

[0040] Example

[0041] The following examples and comparative examples are provided to more specifically illustrate the embodiments of the present invention. Various tests and evaluations were performed according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0042] Test methods and equipment:

[0043] Molecular weight test

[0044] The weight-average molecular weight of the binder resin was determined using a gel permeation chromatograph (Waters 1515 separation unit, Waters 2414 differential detector) according to GB / T 27843-2011 ("Chemical Polymers - Determination of Low Molecular Weight Components - Gel Permeation Chromatography Method"). Tetrahydrofuran was used as the elution solvent, with a flow rate of 1.0 mL / min and a sample injection volume of 30 μL. The sample run time was 35 minutes.

[0045] Free phenol content test

[0046] The free phenol content in the binder resin was determined using a Waters 2996PPA high-performance liquid chromatography system. The column was a Waters Sunfire C18 (250 mm × 4.6 mm) and an autosampler. The mobile phase consisted of acetonitrile and water at a flow rate of 1.0 mL / min. The test temperature was 30°C.

[0047] Table 1 Mobile phase gradient elution program list

[0048] Time (min) Acetonitrile (volume percentage concentration) Water (volume percentage concentration) 0.01 30.0 70.0 8.00 30.0 70.0 45.00 60.0 40.0 55.00 80.0 20.0 65.00 85.0 15.0 68.00 95.0 5.0 70.00 100.0 0.0 72.00 100.0 0.0 75.00 30.0 70.0

[0049] Mooney viscosity test

[0050] The Mooney viscosity of rubber compositions was measured according to the standard GB / T 1232.1-2000 ("Unvulcanized Rubber - Determination by Disc Shear Viscometer - Part 1: Determination of Mooney Viscosity"). A large rotor was used for testing at a temperature of 100°C. The Mooney viscosity (ML) (1+4) at 100°C was measured with a preheating time of 1 minute and a rotation time of 4 minutes; the Mooney viscosity (ML) (1+8) at 100°C was measured with a preheating time of 1 minute and a rotation time of 8 minutes. Mooney viscosity measures the torque exerted by the rubber composition on the rotor during rotation. Lower Mooney viscosities indicate better rubber processing properties.

[0051] Scorch performance test

[0052] The scorch performance of rubber compositions was tested according to GB / T 1233-2008 (Determination of Initial Vulcanization Characteristics of Unvulcanized Rubber Using a Disc Shear Viscometer). The test temperature was 151°C, and scorch times Ts5 and Ts35 were measured using a large rotor. Scorch time can reflect the processing safety of the rubber composition; longer scorch times indicate higher operational safety.

[0053] Adhesion performance test

[0054] The bond strength between vulcanized rubber and steel cord was tested according to GB / T 16586-2014 (Determination of Bond Strength between Vulcanized Rubber and Steel Cord). The bond strength was measured by measuring the force required to axially extract a single steel cord from the embedded vulcanized rubber (i.e., rubber product). The bond strength was measured between the rubber product prepared in the example and the B-19-S resin before aging and after heat aging at 100°C for 168 hours.

[0055] Source of raw materials:

[0056] NR Yunnan 5# standard rubber was purchased from Shanghai Zhengshang Chemical Technology Co., Ltd., N330 carbon black was purchased from Tianjin Tianyi Century Chemical Co., Ltd., VN3 white carbon black was purchased from Evonik, cobalt neodecanoate (cobalt salt, CN20.5%) was purchased from Shepherd, meta-formaldehyde resin (B-19-S resin) was purchased from INDESPEC, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) antioxidant was purchased from Shanghai Jiacheng Chemical Co., Ltd., N-tert-butyl-2-benzothiazolesulfonamide (NS) accelerator was purchased from Shanghai Junpu Chemical Co., Ltd., and hexamethoxymethylmelamine (HMMM, 65% HMMM loaded on white carbon black) was purchased from Huangyan Donghai Chemical Co., Ltd.

[0057] Example 1

[0058] 1 mol of resorcinol, 0.6 mol of 1,4-divinylbenzene, 0.5 g of p-toluenesulfonic acid, and 50 g of toluene were added to a reaction flask equipped with a stirring device, a thermometer, and a reflux condenser. The temperature was gradually raised to 70°C and stirred to completely dissolve the resorcinol. The temperature was then raised to 105°C and reacted under reflux for 2 hours. 0.3 g of triethylamine was added for neutralization, and the mixture was then distilled under reduced pressure to 165°C to obtain a red divinylbenzene-resorcinol resin, i.e., a binder resin. The weight-average molecular weight of the binder resin was 336.

[0059] Example 2

[0060] 0.7 mol of resorcinol, 0.3 mol of cardanol, and 1.0 g of benzenesulfonic acid were added to a reaction flask equipped with a stirring device, a thermometer, and a reflux condenser. The temperature was gradually raised to 70°C and stirred to completely dissolve the resorcinol. The temperature was then raised to 130°C and a mixture of 1.2 mol of styrene and 0.6 mol of 1,4-divinylbenzene was added dropwise. The mixture was reacted under reflux for 2 h. After neutralization with 0.6 g of triethylamine, a red resorcinol-cardanol-styrene-divinylbenzene resin, i.e., a binding resin, was obtained. The weight-average molecular weight of the binding resin was 473.

[0061] Example 3

[0062] 0.5 mol of resorcinol, 0.5 mol of cashew phenol, and 1.0 g of dodecylbenzenesulfonic acid were added to a reaction flask equipped with a stirring device, a thermometer, and a reflux condenser. The temperature was gradually raised to 70°C and stirred to completely dissolve the resorcinol. The temperature was then raised to 150°C and reacted under reflux for 3 hours. After neutralization by adding 0.31 g of triethylamine, a red cashew phenol-resorcinol resin, i.e., a binding resin, was obtained. The weight-average molecular weight of the binding resin was 405.

[0063] Example 4

[0064] 0.5 mol of phenol, 0.5 mol of cashew diphenol, and 1.0 g of dodecylbenzenesulfonic acid were added to a reaction flask equipped with a stirring device, a thermometer, and a reflux condenser. The temperature was gradually raised to 70°C and stirred to completely dissolve the phenol. The temperature was then raised to 130°C and 2.5 mol of styrene was added dropwise under reflux. The reaction was allowed to proceed for 3 h. After neutralization with 0.3 g of triethylamine, a red cashew diphenol-phenol-styrene resin, i.e., a binding resin, was obtained. The weight-average molecular weight of the binding resin was 516.

[0065] Example 5

[0066] 1.0 mol of cashew diphenol and 1.0 g of p-toluenesulfonic acid were added to a reaction flask equipped with a stirring device, a thermometer and a reflux condenser, and then the temperature was raised to 140°C. 0.8 mol of divinylbenzene (a mixture of three isomers of 1,2-divinylbenzene, 1,3-divinylbenzene and 1,4-divinylbenzene, with a mass ratio of 55:25:20) was added dropwise under reflux. The reaction was carried out for 5 hours. After neutralization with 0.6 g of triethylamine, a red cashew diphenol-divinylbenzene resin, i.e., a binding resin, was obtained. The weight average molecular weight of the binding resin was 686.

[0067] Example 6

[0068] 2.0 mol of cardanol, 1.0 g of dodecylbenzenesulfonic acid, and 1.0 g of p-toluenesulfonic acid were added to a reaction flask equipped with a stirring device, a thermometer, and a reflux condenser. The temperature was then raised to 155°C and the reaction was carried out for 5 hours. After neutralization by adding 0.9 g of triethylamine, a red cardanol dimer, i.e., a binding resin, was obtained. The weight-average molecular weight of the binding resin was 716.

[0069] Example 7

[0070] 100 parts of natural rubber (NR Yunnan 5# standard rubber), 42 parts of N330 carbon black, 10 parts of VN3 white carbon black, and 8 parts of zinc oxide (ZnO) were added to a 1.6-liter Banbury mixer (FARREL) and mixed and heated to 155°C. The temperature was then lowered, and at 140°C, 2.5 parts of the adhesive resin prepared in Example 1, 2.5 parts of 6PPD antioxidant, and 1.2 parts of cobalt salt (CN20.5%) were added to the mixer. The mixture was then cooled to 90°C, and 5 parts of sulfur, 1.25 parts of NS accelerator, and 5 parts of HMMM were added and mixed. The mixture was then kneaded at 50°C for 5 minutes to obtain a rubber composition.

[0071] The rubber composition obtained in the above steps was vulcanized and molded on a BH-25T flat vulcanizer (Bohai Experimental Machinery Factory, Zhenwu Town, Jiangdu District) at a vulcanization temperature of 150° C., a time of 30 min, and a pressure of 15 MPa to obtain a rubber product.

[0072] Example 8

[0073] Except that the adhesive resin prepared in Example 2 is used to replace the adhesive resin prepared in Example 1, the rest is the same as Example 7.

[0074] Example 9

[0075] Except that the adhesive resin prepared in Example 3 is used to replace the adhesive resin prepared in Example 1, the rest is the same as Example 7.

[0076] Example 10

[0077] Except that the adhesive resin prepared in Example 4 is used to replace the adhesive resin prepared in Example 1, the rest is the same as Example 7.

[0078] Example 11

[0079] Except that the adhesive resin prepared in Example 5 is used to replace the adhesive resin prepared in Example 1, the rest is the same as Example 7.

[0080] Example 12

[0081] Except that the adhesive resin prepared in Example 6 is used to replace the adhesive resin prepared in Example 1, the rest is the same as Example 7.

[0082] Comparative Example 1

[0083] The process is the same as that of Example 7 except that the adhesive resin prepared in Example 1 is replaced by B-19-S resin.

[0084] The test results of the embodiments and comparative examples are shown in Tables 2 and 3.

[0085] Table 2

[0086] Free phenols Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 B-19-S resin Free resorcinol (%) 0.54 0.32 1.8 / / / 13.56 Free phenol (%) / / / 0.1 / / / Free cardamom diphenol (%) / / 4.1 0.51 2.3 / / Free cardanol (%) / 1.5 / / / 0.38 /

[0087] “ / ” indicates the absence of the substance, and “%” indicates the mass percentage.

[0088] Table 3

[0089]

[0090] It can be seen from Examples 1-6 that when the molar ratio of the phenolic compound to the olefinic compound containing an aromatic group is within the range of the present application, the prepared adhesive resin has a lower weight average molecular weight.

[0091] Generally, the higher the free resorcinol content in the binder resin, the more readily it volatilizes when heated, resulting in the problem of heat-induced fuming. As can be seen in Table 2, compared to the commercially available B-19-S resin, the binder resins provided in Examples 1-3 of this application contain a lower mass percentage of free resorcinol, resulting in lower volatility when heated, thereby effectively reducing the problem of fuming during the rubber mixing process. Because the free cardanol and cardanol diphenol in the binder resin do not cause fuming when heated, the free phenol in the binder resin provided in Example 4 comprises only 0.1% phenol and 0.51% free cardanol diphenol, and the free phenol in the binder resins provided in Examples 5-6 is cardanol or cardanol diphenol. When these binder resins, which do not contain free resorcinol, are used in rubber compositions, they can even eliminate the problem of fuming during the rubber mixing process.

[0092] It can be seen from Examples 7-12, Comparative Example 1 and Table 3 that, compared with the rubber composition containing the commercially available B-19-S resin, the rubber composition containing the adhesive resin provided by the present application has a lower Mooney viscosity, a longer scorch time, a comparable bonding strength before aging, and better bonding strength after heat aging at 100°C for 168h, indicating that the addition of the adhesive resin provided by the present application can improve the mixing performance and processing performance of the rubber compound.

[0093] In summary, the molecular weight of the adhesive resin provided by the present application is lower than that of the meta-formaldehyde resin products in the prior art, and it has good compatibility with rubber, effectively reducing the Mooney viscosity of the rubber composition, thereby improving the mixing efficiency. The adhesive resin provided by the present application is not easy to volatilize when heated, and can effectively reduce or even eliminate the problem of smoke generation during the rubber mixing process, and will not cause adverse effects on the environment and the human body. In addition, its production process is environmentally friendly, and no wastewater or waste gas is generated. No formaldehyde is involved in the synthesis process of the adhesive resin provided by the present application, and the adhesive resin component does not contain aldehyde compounds, and an aromatic olefin structure with strong rigidity is introduced, which is beneficial to improving the physical and mechanical properties of rubber products.

[0094] It should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method or article that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements that are inherent to such process, method or article.

[0095] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0096] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application are included in the scope of protection of the present application.

Claims

1. A rubber composition comprising a binder resin obtained by reacting resorcinol with an olefinic compound containing an aromatic group; wherein: The weight average molecular weight of the adhesive resin is 200-800; The molar ratio of the resorcinol to the aromatic olefin compound is 1:0.5-1:3; The aromatic olefin compound is selected from at least one of 1,2-divinylbenzene, 1,3-divinylbenzene and 1,4-divinylbenzene.

2. The rubber composition according to claim 1, wherein The weight average molecular weight of the adhesive resin is 300-700; and / or the molar ratio of the resorcinol to the aromatic olefin compound is 1:1-1:

2.

3. The rubber composition according to claim 1 or 2, wherein The preparation method of the adhesive resin comprises the following steps: mixing the resorcinol and an acidic catalyst, then adding an olefin compound containing an aromatic group, reacting at 80° C. to 150° C. for 1 hour to 4 hours, and after the reaction is completed, adding an alkaline neutralizer for neutralization to obtain the adhesive resin; The acidic catalyst is selected from at least one of oxalic acid, sulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid; and the molar ratio of the resorcinol to the aromatic olefin compound is 1:0.5-1:

3.

4. The rubber composition according to claim 3, wherein The alkaline neutralizing agent is at least one selected from triethylamine, ethanolamine, triethanolamine, diethanolamine and 1,8-diazabicyclo[5.4.0]undec-7-ene.

5. The rubber composition according to claim 3, wherein The reaction further comprises adding a solvent, wherein the solvent is selected from at least one of toluene and xylene.

6. The rubber composition according to claim 1 or 2, wherein The rubber composition has a Mooney viscosity ML (1+4) at 100° C. of 65-75.

7. A rubber product prepared using the rubber composition according to any one of claims 1 to 6.

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