Liquid-phase co-coagulated rubber and preparation method therefor

Abstract

The present invention belongs to the technical field of rubber processing and production, and provides liquid-phase co-coagulated rubber and a preparation method therefor. The liquid-phase co-coagulated rubber comprises the following components, in parts by weight: 100 parts of natural rubber, 15-80 parts of carbon black, and 0.2-2 parts of an azo compound. By adding the azo compound to the liquid-phase co-coagulated rubber, the fluidity, stability and fineness of a carbon black dispersion liquid can be improved, contact flocculation is avoided when the azo compound / carbon black dispersion liquid and natural latex are mixed at a normal temperature and a normal pressure, and mechanical turbulent coagulation can be achieved, thereby reducing water body pollution. The heat build-up and rolling resistance of the liquid-phase co-coagulated rubber are reduced while the physical properties of a dry-process rubber compound are retained.

Description

Liquid phase co-precipitation glue and preparation method thereof Technical Field

[0001] The present disclosure relates to the technical field of rubber processing and production, and in particular to a liquid-phase co-precipitation rubber and a preparation method thereof. Background Art

[0002] In the field of rubber applications, carbon black is the most important and most widely used reinforcing material. Traditionally, carbon black materials are used in rubber formulations through dry mixing, which involves uniformly mixing a dozen compounding ingredients, including solid natural rubber, synthetic rubber, reinforcing materials, vulcanizing materials, and anti-aging materials, to create a mixed rubber compound, which serves as the raw material for producing various rubber products. However, traditional dry mixing has always had some drawbacks. For example, the dust problem caused by carbon black materials has always been a dilemma faced by the rubber industry, and the annual investment in environmental protection treatment costs in this area remains high. In addition, the high energy consumption of dry mixing is also a problem for the rubber industry. According to relevant statistics, the mixing process is also the most energy-intensive process in rubber processing, accounting for 40% of the total energy consumption in the tire production process. Reducing energy consumption in rubber mixing has also become one of the development goals of the rubber industry.

[0003] In response to the problems existing in dry rubber mixing, wet mixing technology came into being. Wet mixing technology refers to a method of making pre-processed carbon black, white carbon black and other fillers into an aqueous dispersion, fully mixing it with rubber latex in a liquid state, and then producing rubber compound through processes such as coagulation, dehydration, and drying. Wet mixing of rubber is widely recognized by the tire industry and is a new process and technology that effectively improves tire performance. As early as 2001, Cabot Corporation in the United States developed wet mixing technology and launched the corresponding carbon black liquid phase co-precipitation rubber product. Around 2022, the domestic Black Cat Carbon Black Company also plans to conduct trial production and promotion of carbon black liquid phase co-precipitation rubber.

[0004] In the past 20 years, my country has been very active in technical research and production attempts on wet mixing, but it has mainly focused on the field of white carbon black liquid phase co-precipitation rubber. However, carbon black liquid phase co-precipitation rubber products are rarely seen on the market. There are two main reasons for this: First, carbon black materials are obviously polluting, and the environmental protection technology treatment process requirements at the wet mixing level are very high. Improper process treatment can easily cause environmental pollution; second, under normal conditions, carbon black slurry and natural rubber latex are easily mixed by contact flocculation. It is difficult to fully evenly mix the carbon black slurry and natural rubber latex before flocculation occurs, resulting in uneven dispersion of carbon black in the rubber system, affecting the performance of the finished rubber.

[0005] Currently, companies including Cabot and Black Cat generally use high-pressure jet technology for flocculation. This reduces the unit contact volume of carbon black slurry and natural rubber latex, and then, under high-pressure spray atomization conditions, rapidly physically impacts the two liquid materials, disrupting the latex equilibrium system and forming flocculation, resulting in a semi-finished liquid-phase co-precipitation rubber. The semi-finished liquid-phase co-precipitation rubber is then dehydrated and crushed using conventional physical mechanical crushing and granulation methods or screw extrusion granulation. The wet-process rubber then enters the drying process to produce the finished carbon black wet-process rubber.

[0006] The carbon black liquid co-precipitation rubber produced by the above process has the following disadvantages: (1) The equipment requirements are relatively high: the high-pressure jet device and screw extrusion and puffing granulation require the equipment conditions to have high temperature and high pressure conditions, which is not conducive to open mass production. (2) Impact on physical properties: The back-end processing process of the liquid co-precipitation rubber by screw extrusion and puffing granulation is accompanied by local high temperature, which is easy to cause thermal oxidation degradation of the rubber molecular chain, which is not conducive to physical property control. (3) High cost and difficult to promote in the market: The carbon black liquid co-precipitation rubber product launched by Cabot using the above technical process is close to 60,000 yuan per ton, which is much higher than the cost of conventional dry rubber mixing, so it is difficult to popularize and apply it in the market.

[0007] Summary of the Invention

[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a liquid phase co-precipitation glue and a preparation method thereof.

[0009] To achieve the above object, the technical solution adopted by the present invention is: a liquid phase co-precipitation rubber, comprising the following components in parts by weight: 100 parts of natural rubber, 15-80 parts of carbon black, and 0.2-2 parts of azo compounds.

[0010] In one embodiment, the azo compound is at least one of the following: disodium salt of 6-hydroxy-5-[(4-sulfonatophenyl)azo]-2-naphthalenesulfonic acid, trisodium salt of 1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylic acid, trisodium salt of 1-(4'-sulfonato-1'-naphthazo)-2-naphthol-6,8-disulfonic acid, and azodicarbonamide.

[0011] On the other hand, a method for preparing the liquid phase co-precipitation gel is provided, comprising the following steps:

[0012] Preparation of carbon black dispersion: mixing carbon black, surfactant and water to obtain carbon black dispersion, wherein the mass of surfactant is 0.5-2% of the mass of carbon black;

[0013] Preparing an azo compound dispersion: adding an azo compound to water and stirring evenly to obtain an azo compound dispersion;

[0014] Preparing an azo compound / carbon black dispersion: adding the azo compound dispersion to the carbon black dispersion and stirring evenly to obtain an azo compound / carbon black dispersion;

[0015] Preparation of liquid phase co-precipitation glue: adding azo compound / carbon black dispersion into natural rubber latex, stirring evenly, performing mechanical turbulent stirring, crushing and drying to obtain liquid phase co-precipitation glue.

[0016] In one embodiment, the solid content of the carbon black dispersion is 2-15%.

[0017] In one embodiment, in preparing the azo compound dispersion, the mass ratio of the azo compound to water is 0.5-1:40.

[0018] In one embodiment, in the preparation of the azo compound / carbon black dispersion, the stirring speed is 100-200 r / min and the stirring time is 5-10 min.

[0019] In one embodiment, in the preparation of the liquid phase co-precipitation gel, the rotation speed of the mechanical turbulent stirring is 100-200 r / min, and the time is 1-5 min.

[0020] In one embodiment, in the preparation of the carbon black dispersion, the stirring speed is 1000-2500 r / min and the stirring time is 30-60 min.

[0021] In one embodiment, the surfactant is at least one of sodium dodecylbenzene sulfonate, nonylphenol polyoxyethylene ether, polysorbate, and sodium polyacrylate.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adds an azo compound to a rubber latex by wet mixing to obtain a liquid co-precipitation rubber. The azo compound can improve the fluidity, stability, and fineness of the carbon black dispersion, so that after the azo compound / carbon black dispersion is mixed with natural rubber latex at room temperature and pressure, contact flocculation will not occur, and mechanical turbulent coagulation can be achieved, thereby reducing water pollution.

[0024] 2. The liquid phase co-precipitated rubber disclosed in the present invention reduces the heat generation and rolling resistance of the liquid phase co-precipitated rubber while maintaining the physical properties of the dry mixed rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a process flow chart of the present invention for preparing a liquid phase co-precipitation gel. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0028] In this application, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0029] In the present application, there is no particular limitation on the specific dispersing and stirring treatment methods unless otherwise specified.

[0030] The reagents and instruments used in this application without manufacturer indication are all conventional products that can be purchased commercially.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] The present disclosure provides a liquid phase co-precipitation rubber, comprising the following components: natural rubber, carbon black and an azo compound.

[0033] The present invention discloses adding an azo compound to a rubber latex by wet mixing to obtain a liquid-phase co-precipitation rubber. The azo compound can improve the fluidity, stability and fineness of the carbon black dispersion, so that after the azo compound / carbon black dispersion is mixed with natural rubber latex at room temperature and pressure, contact flocculation will not occur, and mechanical turbulent coagulation can be achieved, thereby reducing water pollution.

[0034] Specifically, based on 100 parts by weight of natural rubber, the weight of the carbon black can be 15-80 parts, for example, 15 parts, 20 parts, 25 parts, 30 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts or a range consisting of any two of them, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] More specifically, the weight portion of the carbon black is 35-65 parts.

[0036] When the carbon black content is less than 15 parts, the reinforcing effect is low; when the carbon black content is higher than 80 parts, too much carbon black is difficult to be evenly dispersed in the liquid co-precipitation glue, which increases the difficulty of preparing the liquid co-precipitation glue. At the same time, too much carbon black may agglomerate, resulting in a decrease in the performance of the liquid co-precipitation glue.

[0037] Specifically, based on 100 parts by weight of natural rubber, the weight of the azo compound is 0.2-2 parts, for example, 0.2 parts, 0.4 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, or a range consisting of any two thereof, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] If the content of azo compounds is too little, carbon black cannot be effectively dispersed. If the content of azo compounds is too much, the dispersibility of carbon black cannot be further improved, resulting in a waste of resources.

[0039] In one embodiment, the azo compound is at least one of the following: disodium salt of 6-hydroxy-5-[(4-sulfonatophenyl)azo]-2-naphthalenesulfonic acid, trisodium salt of 1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylic acid, trisodium salt of 1-(4'-sulfonato-1'-naphthazo)-2-naphthol-6,8-disulfonic acid, and azodicarbonamide.

[0040] In the present disclosure, when the azo compound is of the type listed above, the performance of the liquid phase co-precipitation glue can be further improved.

[0041] On the other hand, a method for preparing the liquid phase co-precipitation gel is provided, comprising the following steps:

[0042] Preparation of carbon black dispersion: mixing carbon black, surfactant and water to obtain carbon black dispersion, wherein the mass of surfactant is 0.5-2% of the mass of carbon black;

[0043] Preparing an azo compound dispersion: adding an azo compound to water and stirring evenly to obtain an azo compound dispersion;

[0044] Preparing an azo compound / carbon black dispersion: adding the azo compound dispersion to the carbon black dispersion and stirring evenly to obtain an azo compound / carbon black dispersion;

[0045] Preparation of liquid phase co-precipitation glue: adding azo compound / carbon black dispersion into natural rubber latex, stirring evenly, performing mechanical turbulent stirring, crushing and drying to obtain liquid phase co-precipitation glue.

[0046] The present invention adds an azo compound dispersion as a modifier to a carbon black dispersion, which can improve the stability of the carbon black dispersion, further improve the dispersibility of carbon black particles in water, and at the same time reduce the viscosity of the carbon black dispersion; so that the azo compound / carbon black dispersion has higher fluidity and fine wall hanging, and after mixing with natural latex at room temperature and pressure, no contact flocculation occurs. The azo compound / carbon black dispersion and natural latex can be mechanically turbulently coagulated at a speed of 100-200r / min, and the coagulated micelles have obvious water holding capacity, that is, the water in the azo compound / carbon black dispersion and natural latex is retained in the micelles within 5-10 minutes and will not precipitate quickly. Therefore, the micelles obtained by mechanical turbulent coagulation can be transferred to the processing equipment in time, and will not cause water pollution in the production process.

[0047] When the azo compound is azodicarbonamide, a small amount of carbon black exists in the wastewater generated during the dry-mixing and crushing process, and the loss rate of carbon black is less than 1%. When the azo compound is the disodium salt of 6-hydroxy-5-[(4-sulfonatophenyl)azo]-2-naphthalenesulfonic acid, the trisodium salt of 1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylic acid, and the trisodium salt of 1-(4'-sulfonato-1'-naphthalylazo)-2-naphthol-6,8-disulfonic acid, almost no carbon black exists in the wastewater generated during the dry-mixing and crushing process, and the loss rate of carbon black is less than 0.1%.

[0048] In addition, since the carbon black slurry treated with azo compounds has good dispersibility and fineness, the semi-finished rubber agglomerates obtained by mechanical turbulent coagulation are looser than conventional agglomerates. Therefore, the semi-finished rubber is usually processed by traditional dehydration and crushing, and does not need to be processed by screw extrusion and granulation. The semi-finished rubber agglomerates disclosed herein can be dry-mixed in conventional rubber dry mixing equipment at room temperature and pressure to obtain highly broken liquid-phase co-precipitated mixed rubber particles, which can then be dried conventionally to obtain the finished liquid-phase co-precipitated rubber product.

[0049] In this disclosure, the order of adding the azo compound / carbon black dispersion and natural rubber latex significantly affects product performance. The concentration of the azo compound / carbon black dispersion is significantly lower than the solids content of the natural rubber latex. Adding natural latex to the azo compound / carbon black dispersion can easily cause premature coagulation in some areas, leading to decreased product performance. Furthermore, the azo compound / carbon black dispersion should be added slowly; rapid, impactful addition can easily cause premature demulsification of the natural latex.

[0050] Specifically, the natural rubber latex is fresh natural rubber latex or concentrated natural rubber latex.

[0051] The preparation method disclosed herein is used to produce liquid-phase co-precipitation glue, which has the effects of simplifying equipment, open production, and reducing costs, and is feasible for mass market promotion.

[0052] In one embodiment, the solid content of the carbon black dispersion is 2-15%, for example, 2%, 4%, 6%, 8%, 10%, 13%, 15% or a range consisting of any two of them, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In one embodiment, in preparing the azo compound dispersion, the mass ratio of the azo compound to water is 0.5-1:40, for example, 0.5:40, 0.6:40, 0.7:40, 0.8:40, 0.9:40, 1:40, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0054] In one embodiment, in preparing the azo compound / carbon black dispersion, the stirring speed is 100-200 r / min, for example, it can be 100 r / min, 120 r / min, 140 r / min, 160 r / min, 180 r / min, 200 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; the stirring time is 5-10 min.

[0055] During the preparation of the azo compound / carbon black dispersion, in order to avoid uneven dispersion of carbon black, the azo compound dispersion needs to be added to the carbon black dispersion under stirring; the obtained azo compound / carbon black dispersion needs to be kept in a stirring state until it is used up to ensure that the carbon black in the azo compound / carbon black dispersion does not locally settle due to stopping the stirring.

[0056] In one embodiment, in the preparation of liquid-phase co-precipitation gel, the rotation speed of the mechanical turbulent stirring is 100-200 r / min, for example, it can be 100 r / min, 120 r / min, 140 r / min, 160 r / min, 180 r / min, 200 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; the stirring time is 1-5 min.

[0057] Specifically, after mixing the azo compound / carbon black dispersion and natural rubber latex, they need to be stirred evenly at a speed of 100-200r / min; in the process of preparing the liquid phase co-precipitation glue, rapid stirring needs to be avoided, as rapid rotation and stirring will cause the natural rubber latex phase equilibrium to break prematurely.

[0058] Under the action of mechanical turbulent stirring, natural rubber latex can be uniformly coagulated to obtain a semi-finished product; the obtained semi-finished product contains a large amount of unprecipitated water, and standing for too long will cause water precipitation, and free carbon black particles that are not combined with natural rubber latex will be brought into the water body as the water precipitates, causing water pollution. Therefore, the obtained semi-finished product needs to be transferred to a dry mixing equipment within 5-10 minutes to achieve dehydration and fragmentation of the carbon black liquid phase co-precipitation rubber, avoiding the introduction of screw extrusion and puffing granulation equipment, which not only simplifies the equipment but also avoids the thermal oxidation degradation of the rubber semi-finished product under high temperature treatment.

[0059] In the process of preparing the carbon black dispersion, there is no particular limitation on the stirring speed and time, as long as the carbon black can be completely and evenly dispersed.

[0060] Specifically, in the preparation of the carbon black dispersion, the stirring speed is 1000-2500 r / min, for example, it can be 1000 r / min, 1200 r / min, 1500 r / min, 1800 r / min, 2000 r / min, 2300 r / min, 2500 r / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable; the stirring time is 30-60 min.

[0061] In one embodiment, the surfactant is at least one of sodium dodecylbenzene sulfonate, nonylphenol polyoxyethylene ether, polysorbate, and sodium polyacrylate.

[0062] The present application is further described below with specific examples:

[0063] Example 1

[0064] This embodiment provides a liquid co-precipitation rubber, comprising the following components in parts by weight: 100 parts of natural rubber, 50 parts of carbon black, and 0.8 parts of an azo compound, wherein the azo compound is the disodium salt of 6-hydroxy-5-[(4-sulfonylphenyl)azo]-2-naphthalenesulfonic acid.

[0065] This embodiment also provides a method for preparing a liquid phase co-precipitation gel, comprising the following steps:

[0066] By weight, weigh 100 parts of natural rubber, 50 parts of carbon black, and 0.8 parts of azo compound;

[0067] Preparation of a carbon black dispersion: mixing carbon black, a surfactant, and water, and stirring at a speed of 2000 r / min for 45 minutes to obtain a carbon black dispersion, wherein the surfactant is sodium dodecylbenzenesulfonate, the mass of the surfactant is 1% of the mass of the carbon black, and the solid content of the carbon black dispersion is 10%;

[0068] Preparing an azo compound dispersion: adding the azo compound to water and stirring uniformly at a speed of 150 r / min to obtain an azo compound dispersion; wherein the mass ratio of the azo compound to water is 0.8:40;

[0069] Preparing an azo compound / carbon black dispersion: adding the azo compound dispersion to the carbon black dispersion, and stirring at a speed of 150 r / min for 8 minutes to obtain an azo compound / carbon black dispersion;

[0070] Preparation of liquid co-precipitation glue: add azo compound / carbon black dispersion to natural rubber latex, stir evenly at a speed of 150r / min, and continue to perform mechanical turbulent stirring at the same speed for 3 minutes. The obtained semi-finished product is added to a dry stirring equipment for crushing and drying to obtain a liquid co-precipitation glue.

[0071] Example 2

[0072] This embodiment provides a liquid co-precipitation rubber, comprising the following components in parts by weight: 100 parts of natural rubber, 80 parts of carbon black, and 1 part of an azo compound, wherein the azo compound is the disodium salt of 6-hydroxy-5-[(4-sulfonylphenyl)azo]-2-naphthalenesulfonic acid.

[0073] This embodiment also provides a method for preparing a liquid phase co-precipitation gel, comprising the following steps:

[0074] By weight, weigh 100 parts of natural rubber, 80 parts of carbon black, and 1 part of azo compound;

[0075] Preparation of a carbon black dispersion: mixing carbon black, a surfactant, and water, and stirring at a speed of 2500 r / min for 30 minutes to obtain a carbon black dispersion, wherein the surfactant is sodium dodecylbenzenesulfonate, the mass of the surfactant is 2% of the mass of the carbon black, and the solid content of the carbon black dispersion is 15%;

[0076] Preparing an azo compound dispersion: adding the azo compound to water and stirring uniformly at a speed of 200 r / min to obtain an azo compound dispersion; wherein the mass ratio of the azo compound to water is 1:40;

[0077] Preparing an azo compound / carbon black dispersion: adding the azo compound dispersion to the carbon black dispersion, stirring at a speed of 200 r / min for 5 minutes to obtain an azo compound / carbon black dispersion;

[0078] Preparation of liquid co-precipitation glue: add azo compound / carbon black dispersion to natural rubber latex, stir evenly at a speed of 200 r / min, and continue to perform mechanical turbulent stirring at the same speed for 1 minute. The obtained semi-finished product is added to a dry stirring equipment for crushing and drying to obtain a liquid co-precipitation glue.

[0079] Example 3

[0080] This embodiment provides a liquid co-precipitation rubber, comprising the following components in parts by weight: 100 parts of natural rubber, 15 parts of carbon black, and 0.2 parts of an azo compound, wherein the azo compound is the disodium salt of 6-hydroxy-5-[(4-sulfonic acid phenyl) azo]-2-naphthalenesulfonic acid.

[0081] This embodiment also provides a method for preparing a liquid phase co-precipitation gel, comprising the following steps:

[0082] By weight, weigh 100 parts of natural rubber, 15 parts of carbon black, and 0.2 parts of azo compound;

[0083] Preparation of a carbon black dispersion: mixing carbon black, a surfactant, and water, and stirring at a speed of 1000 r / min for 60 minutes to obtain a carbon black dispersion, wherein the surfactant is sodium dodecylbenzenesulfonate, the mass of the surfactant is 0.5% of the mass of the carbon black, and the solid content of the carbon black dispersion is 2%;

[0084] Preparing an azo compound dispersion: adding the azo compound to water and stirring uniformly at a speed of 100 r / min to obtain an azo compound dispersion; wherein the mass ratio of the azo compound to water is 0.5:40;

[0085] Preparing an azo compound / carbon black dispersion: adding the azo compound dispersion to the carbon black dispersion, and stirring at a speed of 100 r / min for 10 minutes to obtain an azo compound / carbon black dispersion;

[0086] Preparation of liquid co-precipitation glue: add azo compound / carbon black dispersion to natural rubber latex, stir evenly at a speed of 100 r / min, and continue to perform mechanical turbulent stirring at the same speed for 5 minutes. The obtained semi-finished product is added to a dry stirring equipment for crushing and drying to obtain a liquid co-precipitation glue.

[0087] Example 4

[0088] This embodiment provides a liquid phase co-precipitation gel and a preparation method thereof, which differs from Example 1 only in that the azo compound is azodicarbonamide, and the other components, contents and steps are the same as those in Example 1.

[0089] Example 5

[0090] This embodiment provides a liquid-phase co-precipitation gel and a preparation method thereof, which differs from Example 1 only in that the azo compound is 1-(4-sulfonic acid phenyl)-4-(4-sulfonic acid phenylazo)-5-pyrazolone-3-carboxylic acid trisodium salt, and the other components, contents and steps are the same as those in Example 1.

[0091] Comparative Example 1

[0092] This comparative example provides a liquid phase co-precipitation rubber, comprising the following components in parts by weight: 100 parts of natural rubber and 50 parts of carbon black.

[0093] This embodiment also provides a method for preparing a liquid phase co-precipitation gel, comprising the following steps:

[0094] By weight, weigh 100 parts of natural rubber and 50 parts of carbon black;

[0095] Preparation of a carbon black dispersion: mixing carbon black, a surfactant, and water, and stirring at a speed of 2000 r / min for 45 minutes to obtain a carbon black dispersion, wherein the surfactant is sodium dodecylbenzenesulfonate, the mass of the surfactant is 1% of the mass of the carbon black, and the solid content of the carbon black dispersion is 10%;

[0096] Preparation of liquid co-precipitation rubber: Add carbon black dispersion to natural rubber latex and stir at a speed of 150r / min. Due to the lack of azo compounds, the latex and carbon black dispersion are easily coagulated when mixed and cannot be effectively dispersed. The resulting semi-finished rubber lumps cannot be loosened and fragmented, and liquid co-precipitation rubber cannot be obtained.

[0097] Application Examples 1-5

[0098] The liquid phase co-precipitated rubber obtained in Examples 1-5 was vulcanized at 145°C for 20 minutes using the basic formula in Table 1 to prepare vulcanized test pieces. The performance of the prepared rubber pieces was tested, and the test results are shown in Table 2.

[0099] Table 1

[0100] Table 2

[0101] In Table 2, the dynamic temperature rise was tested using the constant strain flexure test in Part 3 of GBT1867. The specific experimental conditions were: temperature of 55±1°C, stroke (amplitude) of 4.45 mm, frequency of 30 Hz, and stress applied to the specimen of 1.0 MPa (the lower the dynamic temperature rise, the better the performance). The rolling resistance index refers to the ratio of the rolling resistance of Application Examples 1-5 to the rolling resistance of the control example. The rolling resistance was tested using the ISO 28580 standard. The specific experimental conditions were: constant speed of 80 km / h, 80% load, and air pressure of 210 kPa; (the larger the rolling resistance index, the better the performance).

[0102] As can be seen from Table 2, using the liquid phase co-precipitation rubber disclosed in the present invention as a raw material, the biggest performance improvement of the rubber is the significant reduction in the heat generation of the formula, which forms a corresponding guiding trend with the improvement of the rolling resistance index. From the data of Example 1, Example 4, and Example 5 filled with 50 parts of carbon black, the heat generation of the formula rubber has decreased by 35%, which is much higher than the bottleneck of reducing heat generation in traditional dry mixing (the heat generation reduction of dry mixing formula has reached 10%, which is close to the limit), and has the trend of green tire development; from the physical property data of the formula, including tensile stress, tensile strength, tear strength and other properties, there is not much difference from the traditional dry mixing data, but the hardness data is significantly reduced, which means that rubber-using companies can also appropriately add reinforcing materials to the fixed formula during the application of liquid phase co-precipitation rubber to further reduce production costs. In addition, it can be seen from the data of Example 2 and Example 3 that the performance of the liquid-phase co-precipitated rubber filled with 80 parts of carbon black is basically equivalent to that of the liquid-phase co-precipitated rubber with 50 parts after being diluted to the same ratio in the back-end rubber mixing formula. However, the liquid-phase co-precipitated rubber filled with 15 parts of carbon black has too low a liquid filling ratio. After balancing the rubber formula system (supplementing some dry carbon black materials), the overall heat generation reduction is not large, which further illustrates the technical advantage of the liquid-phase co-precipitated rubber of this technology in reducing the heat generation of the formula.

[0103] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A liquid phase co-precipitation glue, characterized in that: The invention comprises the following components in parts by weight: 100 parts of natural rubber, 15-80 parts of carbon black and 0.2-2 parts of azo compounds.

2. The liquid phase co-precipitation glue according to claim 1, wherein The azo compound is at least one of the following: disodium salt of 6-hydroxy-5-[(4-sulfonatophenyl)azo]-2-naphthalenesulfonic acid, trisodium salt of 1-(4-sulfonatophenyl)-4-(4-sulfonatophenylazo)-5-pyrazolone-3-carboxylic acid, trisodium salt of 1-(4'-sulfonato-1'-naphthazo)-2-naphthol-6,8-disulfonic acid, and azodicarbonamide.

3. A method for preparing a liquid phase co-precipitation glue as claimed in claim 1 or 2, characterized in that: The following steps are involved: Preparation of carbon black dispersion: mixing carbon black, surfactant and water to obtain carbon black dispersion, wherein the mass of surfactant is 0.5-2% of the mass of carbon black; Preparing an azo compound dispersion: adding an azo compound to water and stirring evenly to obtain an azo compound dispersion; Preparing an azo compound / carbon black dispersion: adding the azo compound dispersion to the carbon black dispersion and stirring evenly to obtain an azo compound / carbon black dispersion; Preparation of liquid phase co-precipitation glue: adding azo compound / carbon black dispersion into natural rubber latex, stirring evenly, performing mechanical turbulent stirring, crushing and drying to obtain liquid phase co-precipitation glue.

4. The preparation method according to claim 3, wherein The solid content of the carbon black dispersion is 2-15%.

5. The preparation method according to claim 3, wherein In the preparation of the azo compound dispersion, the mass ratio of the azo compound to water is 0.5-1:

40.

6. The preparation method according to claim 3, wherein In the preparation of the azo compound / carbon black dispersion, the stirring speed is 100-200 r / min and the stirring time is 5-10 min.

7. The preparation method according to claim 3, wherein In the preparation of the liquid phase co-precipitation gel, the rotation speed of the mechanical turbulent stirring is 100-200 r / min, and the time is 1-5 min.

8. The preparation method according to claim 3, wherein In the preparation of the carbon black dispersion, the stirring speed is 1000-2500 r / min and the stirring time is 30-60 min.

9. The preparation method according to claim 3, wherein The surfactant is at least one of sodium dodecylbenzene sulfonate, nonylphenol polyoxyethylene ether, polysorbate, and sodium polyacrylate.

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