阅读说明：本技术 湿法混炼胶料的无酸制备方法 (Acid-free preparation method of wet mixing rubber material ) 是由 陈毅敏 麦千里 秦荣智 谢赤波 麦丰 颜永明 于 2020-07-16 设计创作，主要内容包括：本发明提供一种湿法混炼胶料的无酸制备方法,其以60％浓缩天然胶乳为主体原材料,其包括：白炭黑水分散体的制备以及混炼胶的无酸凝絮的步骤。本发明加工工艺简单,可用最普通的白炭黑获得较理想的各项性能,且整个生产过程的粉尘污染小,较有酸絮凝工艺,可减少生产工艺用水80％(每吨胶料可节约用水20～30吨)；污水减排入放80％以上。胶料生产不受季节和天气的影响,可连续化生产。采用本方法生产的胶料实现了白炭黑的混炼在液相中进行,分散性和均匀性提高。用于制造的轮胎其滚动阻力小,生热低,抗张强度和抗撕强度高,胶料的耐老化性能好。可大幅提高轮胎的燃油经济性和行车安全性能。(The invention provides an acid-free preparation method of wet mixing rubber material, which takes 60% concentrated natural latex as a main raw material and comprises the following steps: preparing the white carbon black aqueous dispersion and performing acid-free flocculation on the rubber compound. The processing technology is simple, the most common white carbon black can be used for obtaining more ideal properties, the dust pollution in the whole production process is small, and compared with an acid flocculation technology, the processing technology can reduce the water consumption of the production technology by 80 percent (each ton of sizing material can save 20-30 tons of water); the sewage is discharged in a reduced amount by over 80 percent. The production of the sizing material is not affected by seasons and weather, and the continuous production can be realized. The rubber material produced by the method realizes the mixing of the white carbon black in a liquid phase, and improves the dispersibility and the uniformity. The tyre used for manufacturing has small rolling resistance, low heat generation, high tensile strength and tearing strength and good ageing resistance of the rubber material. The fuel economy and the driving safety performance of the tire can be greatly improved.)

1. An acid-free method for preparing a wet-mixed rubber compound, comprising: preparing white carbon black aqueous dispersion and performing acid-free flocculation on the rubber compound;

the preparation method of the white carbon black aqueous dispersion comprises the following steps:

soaking the white carbon black dry powder in deionized water;

adding a coupling agent and a surfactant into the soaked white carbon black dry powder, and uniformly mixing in a mechanical stirring manner to prepare white carbon black slurry;

grinding the white carbon black slurry to the white carbon black aqueous dispersion meeting the sedimentation amount standard; the method is characterized in that:

the acid-free flocculation of the rubber compound comprises the following steps:

providing a centrifugally concentrated natural rubber latex;

adding the prepared white carbon black aqueous dispersion into natural latex, and uniformly mixing in a stirring manner to obtain a white carbon black/natural latex mixed solution;

and adding a flocculating agent into the obtained white carbon black/natural latex mixed solution, and synchronously and fully stirring the materials to ensure that the white carbon black/natural latex mixed solution is uniformly flocculated to obtain the wet coagulation rubber compound, wherein the flocculating agent is one or more selected from cyclohexylamine acetate, magnesium oxide and zinc oxide.

2. The acid-free preparation method of a wet mixing size according to claim 1, wherein the step of soaking the dry white carbon black powder in deionized water specifically comprises:

soaking the white carbon black dry powder in deionized water of 60-85 wt% according to 15-40 wt% for 3-6 h.

3. The acid-free preparation method of a wet mixing size according to claim 1, wherein the coupling agent is added in an amount of 1-10 wt% of the content of the dry white carbon black powder, and the surfactant is added in an amount of 0.2-5 wt% of the content of the dry white carbon black powder.

4. The acid-free process of preparing a wet mix compound of claim 1, wherein said slurry of silica is milled by a mill to an aqueous silica dispersion having a settling volume of less than 80 mg/hr.

5. The acid-free process of preparing a wet mix compound of claim 1, wherein the natural rubber latex is a centrifugally concentrated natural rubber latex having a dry gum content of 60 wt%.

6. The acid-free preparation method of the wet mixing rubber material according to claim 1, wherein the prepared white carbon black aqueous dispersion is added into the natural latex and then is continuously stirred for 20-50 min.

7. The acid-free preparation method of the wet mixing rubber material according to claim 1, characterized in that 1 wt% -3 wt% of flocculant is added into the obtained white carbon black/natural latex mixed solution, and the materials are fully stirred for 3min synchronously at a stirring speed of 80 rpm.

8. The acid-free method of preparing a wet mix compound of claim 1, further comprising: a step of dewatering and pelletizing, the step comprising:

and (4) feeding the obtained wet-coagulated rubber compound into an extrusion glue granulator for dehydration and granulation.

9. The acid-free method of preparing a wet mix compound of claim 8, further comprising: a step of drying, the step comprising:

and (3) conveying the dehydrated and granulated colloidal particles into a box type drying cabinet for drying at the drying temperature of 90-120 ℃ for 2-5 h.

Technical Field

The invention relates to the technical field of rubber compound preparation, in particular to an acid-free preparation method of a wet-process rubber compound.

Background

Mixing is a key process for rubber compound processing. In a typical rubber processing procedure, raw rubber (dry rubber) is mixed with powdery fillers and other compounding ingredients in batch or continuous manner in an internal mixer or an open mill by strong shearing action between rotors or rollers so that the powders such as fillers are dispersed in the rubber polymer as uniformly as possible, i.e., "dry mixing".

Because the bulk viscosity of the raw rubber (dry rubber) is high, the mixing (dry mixing) is always the most energy-consuming process in the rubber material processing process, and the energy consumption of the mixing (dry mixing) accounts for the majority of the whole rubber processing energy consumption. The differences between batches of rubber compound obtained by dry mixing are large, which not only brings troubles to technicians, but also often has great influence on the quality of subsequent processes. The dry mixing method also causes a great amount of dust scattering, and is the largest dust pollution source of rubber product manufacturers such as tires and the like. Therefore, the rubber industry is constantly searching for methods that can save more energy than the existing dry mixing process and make the compounding ingredients disperse in the rubber better and more uniformly.

"Wet mixing" is a method of producing a rubber compound by adding a filler such as carbon black or white carbon black to a rubber in a state of latex (natural latex or synthetic latex), sufficiently mixing and dispersing the mixture by stirring, and then flocculating (coprecipitating). The polymer-filler homogeneous dispersions prepared in this way are referred to as "coprecipitates". Compared with the dry mixing method, the wet mixing method has the following advantages:

the mixing energy consumption of the rubber can be obviously reduced, and the cost is reduced (the number of mixing sections and the mixing time are reduced);

the dispersion of various reinforcing fillers in the rubber polymer can be improved significantly;

dust pollution can be reduced remarkably;

is beneficial to the realization of advanced continuous mixing process.

In the aspect of rubber material performance, the wet mixing improves the dispersion condition of various reinforcing fillers in rubber polymers, and can improve the physical and mechanical properties of vulcanized rubber so as to improve the quality of products.

White carbon black has been widely used as a reinforcing filler for rubber independent of petroleum resources in rubber products represented by tires. The wet surface gripping performance and the low rolling resistance of the rubber material matched with the white carbon black are superior to those of the carbon black matched rubber material, so that the application of the white carbon black is more and more emphasized in the tire industry.

In practical use, silane hydroxyl groups on the surface of the white carbon black have very strong tendency to form hydrogen bonds and very strong water absorption, so that the silane hydroxyl groups are strong in filler-filler interaction and weak in filler-nonpolar rubber polymer interaction. Therefore, when the traditional dry mixing method is adopted, the white carbon black tends to be combined into an agglomerate form along with the increase of the using amount of the white carbon black, and the agglomerate has great influence on the processing performance of the rubber material, and the concrete expression is as follows:

when the using amount of the white carbon black is larger (more than 15 percent), the white carbon black is difficult to disperse in the rubber material, the technological property is poor, and various physical and mechanical properties of the rubber material are poor;

white carbon black is added in batches, the mixing time is increased, the mixing temperature is strictly controlled, the energy consumption is increased, and the production efficiency is reduced;

the rubber material added with the white carbon black has large heat generation at the later mixing stage, and scorching is easily caused;

the white carbon black flies around in the charging and mixing processes, which causes serious pollution to the production environment.

The natural rubber/white carbon black wet mixed rubber is a rubber material obtained by preparing solid white carbon black into aqueous dispersion with a certain concentration, fully mixing the aqueous dispersion with natural latex in a liquid state, and then flocculating, granulating and drying the mixture. The white carbon black can be added into the natural rubber in a large amount in a liquid state and is dispersed very uniformly. The vulcanized rubber material has excellent physical and mechanical properties, lower heat generation energy, low rolling resistance and stronger wet grip performance, and can greatly improve the fuel economy and safety performance of automobiles. Is the preferred material for manufacturing tires. Meanwhile, the mixing energy consumption and the dust pollution of a tire factory are greatly reduced. Are widely used in the rubber industry and the tire industry.

At present, the production of wet rubber compound adopts the mixing of natural rubber field glue or centrifugal concentrated natural rubber latex and white carbon black dispersoid, and then the electric flocculation is carried out by organic acid (formic acid or acetic acid) or divalent inorganic salt (calcium chloride and the like). After flocculation is complete, the size and wet gel must be washed with a large amount of clear water to remove the flocculant from the size.

In particular, in the case of ionic condensed natural rubber latex, since the latex can be kept in a liquid state during long-term storage and use in order to keep the viscosity of the latex stable for a long period of time, manufacturers of condensed natural rubber latex add a large amount of ammonia and a nonionic surfactant to the latex. The pH value of the latex reaches more than 10. Therefore, in the flocculation process, a large amount of acid or divalent inorganic salt is added to neutralize the alkalinity and flocculate it.

Coagulation is not instantaneous because the micelles are protected by protein and does not immediately coagulate upon addition of acid. The acidified fresh latex thickens only, and over time, coagulum gradually forms. The flocculation period is about 5 hours. The production period is longer and the occupied area is large. Meanwhile, in order to ensure that the physical and mechanical properties of the sizing material are not influenced or the sizing material cannot absorb moisture in the storage process, more clear water than field latex flocculation is needed to clean the sizing material.

During cleaning, the sizing material needs to be continuously mechanically rolled and surface renewed, and is washed by clear water. The water consumption for deacidification and cleaning is 20-30 tons per ton of finished rubber material. This not only consumes a large amount of water resources and energy consumption, but also produces a large amount of waste water pollution.

When the white carbon black/natural rubber wet-process rubber compound is produced by adopting field latex, the normal harvesting period of the Chinese rubber production field is only 8 months because the yield of the field latex is limited by climate and season. Meanwhile, the glue produced by the rubber tree is different in rubber molecular weight and rubber content due to different temperatures and rainfall amounts in different seasons throughout the year. Directly causes poor production continuity and unstable quality consistency of the wet rubber compound. Therefore, it is necessary to provide a further solution to the above problems.

Disclosure of Invention

The invention aims to provide an acid-free preparation method of a wet-process mixed rubber material, which overcomes the defects in the prior art.

In order to solve the technical problems, the technical scheme of the invention is as follows:

an acid-free method for preparing a wet-mixed rubber compound, comprising: preparing white carbon black aqueous dispersion and performing acid-free flocculation on the rubber compound;

the preparation method of the white carbon black aqueous dispersion comprises the following steps:

soaking the white carbon black dry powder in deionized water;

adding a coupling agent and a surfactant into the soaked white carbon black dry powder, and uniformly mixing in a mechanical stirring manner to prepare white carbon black slurry;

grinding the white carbon black slurry to the white carbon black aqueous dispersion meeting the sedimentation amount standard; the method is characterized in that:

the acid-free flocculation of the rubber compound comprises the following steps:

providing a centrifugally concentrated natural rubber latex;

adding the prepared white carbon black aqueous dispersion into natural latex, and uniformly mixing in a stirring manner to obtain a white carbon black/natural latex mixed solution;

and adding a flocculating agent into the obtained white carbon black/natural latex mixed solution, and synchronously and fully stirring the materials to ensure that the white carbon black/natural latex mixed solution is uniformly flocculated to obtain the wet coagulation rubber compound, wherein the flocculating agent is one or more selected from cyclohexylamine acetate, magnesium oxide and zinc oxide.

As an improvement of the acid-free preparation method of the wet mixing sizing material, the step of soaking the white carbon black dry powder in deionized water specifically comprises the following steps:

soaking the white carbon black dry powder in deionized water of 60-85 wt% according to 15-40 wt% for 3-6 h.

As an improvement of the acid-free preparation method of the wet mixing rubber material, the added coupling agent is 1-10 wt% of the content of the white carbon black dry powder, and the added surfactant is 0.2-5 wt% of the content of the white carbon black dry powder.

As an improvement of the acid-free preparation method of the wet mixing rubber material, the white carbon black slurry is ground by a grinding machine until the sedimentation amount of the white carbon black aqueous dispersion is less than 80 mg/h.

As an improvement of the acid-free preparation method of the wet mixing rubber compound, the natural rubber latex is centrifugally concentrated natural rubber latex with the dry rubber content of 60 wt%.

As an improvement of the acid-free preparation method of the wet mixing rubber material, the prepared white carbon black aqueous dispersion is added into the natural latex and then is continuously stirred for 20-50 min.

As an improvement of the acid-free preparation method of the wet mixing sizing material, 1 wt% -3 wt% of flocculating agent is added into the obtained white carbon black/natural latex mixed solution, and the materials are fully stirred for 3min synchronously at the stirring speed of 80 r/min.

As an improvement of the acid-free preparation method of the wet mixing compound of the present invention, the acid-free preparation method further comprises: a step of dewatering and pelletizing, the step comprising:

and (4) feeding the obtained wet-coagulated rubber compound into an extrusion glue granulator for dehydration and granulation.

As an improvement of the acid-free preparation method of the wet mixing compound of the present invention, the acid-free preparation method further comprises: a step of drying, the step comprising:

and (3) conveying the dehydrated and granulated colloidal particles into a box type drying cabinet for drying at the drying temperature of 90-120 ℃ for 2-5 h.

Compared with the prior art, the invention has the beneficial effects that:

(1) the mixing process of the invention is carried out in a liquid phase, so that the dispersibility and uniformity of the white carbon black in the rubber are greatly improved.

(2) The dust flying during rubber mixing in tire factories and rubber product factories is reduced, the working environment is improved, the environmental pollution is reduced, and the energy is saved.

(3) The wet mixing process has less rolling resistance, low heat generation, high tensile strength and tear strength and improved ageing resistance.

(4) The rubber material of the present invention may be used together with natural rubber or synthetic rubber and may have various kinds of carbon black, stuffing and compounding agent mixed into the rubber mixture through conventional dry mixing process. The rubber material has excellent physical and mechanical properties, lower rolling resistance, low heat generation and better wet skid resistance, and is the preferred material for manufacturing tires.

(5) Due to the realization of a cleaning-free process, the water consumption for production and the glue washing energy consumption are greatly reduced, 20-30 tons of water can be saved for each ton of products, and the discharge of sewage is also greatly reduced. The sewage discharge reduction rate reaches 80 percent.

(6) Solves the problems of long mixing time, uneven mixing and large energy consumption when a large amount of white carbon black is needed in tire factories and rubber product factories.

(7) Because the quick flocculation is realized, the production period can be reduced by 30 percent. The production field is compressed by 50 percent. Stable continuous production can be carried out, and the product quality and consistency are improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The processing technology is simple, the most common white carbon black can be used for obtaining more ideal properties, the dust pollution in the whole production process is small, and compared with an acid flocculation technology, the processing technology can reduce the water consumption of the production technology by 80 percent (each ton of sizing material can save 20-30 tons of water); the sewage is discharged in a reduced amount by over 80 percent. The production of the sizing material is not affected by seasons and weather, and the continuous production can be realized. The rubber material produced by the method realizes the mixing of the white carbon black in a liquid phase, and improves the dispersibility and the uniformity. The tyre used for manufacturing has small rolling resistance, low heat generation, high tensile strength and tearing strength and good ageing resistance of the rubber material. The fuel economy and the driving safety performance of the tire can be greatly improved.

The invention particularly provides an acid-free preparation method of a wet-process mixed sizing material, which takes concentrated natural latex as a main raw material, and adds a flocculating agent which has good compatibility with the natural latex, is harmless to the physical and mechanical properties of the sizing material, does not absorb moisture and does not need to be cleaned. The flocculant is flocculated and simultaneously mechanically stirred, so that the flocculant can be quickly dissolved in the latex, and the flocculation period is only 30 minutes.

Meanwhile, in the acid-free preparation method of the wet mixing rubber material, the centrifugal concentrated latex can be stored for a long time without being limited by seasons, continuous production can be realized, the quality consistency is good, sufficient white carbon black can be added, the white carbon black can be uniformly dispersed, and the acid-free preparation method has the advantages of good processing performance, small environmental pollution and energy conservation.

Specifically, the acid-free preparation method of the wet mixing rubber compound comprises the following steps: preparing white carbon black aqueous dispersion, acid-free mixing of mixed rubber and flocculation of mixed liquor.

The preparation method of the white carbon black aqueous dispersion comprises the following steps:

soaking the white carbon black dry powder in deionized water;

adding a coupling agent and a surfactant into the soaked white carbon black dry powder, and uniformly mixing in a mechanical stirring manner to prepare white carbon black slurry;

and grinding the white carbon black slurry to the white carbon black aqueous dispersion meeting the sedimentation amount standard.

The acid-free mixing flocculation of the rubber compound comprises the following steps:

providing a centrifugally concentrated natural rubber latex;

and adding the prepared white carbon black aqueous dispersion into the natural latex, and uniformly mixing in a stirring manner to obtain a white carbon black/natural latex mixed solution.

The flocculation of the mixed solution comprises the following steps:

and adding a flocculating agent into the obtained white carbon black/natural latex mixed solution, and synchronously and fully stirring the materials to ensure that the white carbon black/natural latex mixed solution is uniformly flocculated to obtain the wet coagulation rubber compound, wherein the flocculating agent is one or more selected from cyclohexylamine acetate, magnesium oxide and zinc oxide.

Therefore, the mixing process of the invention is carried out in a liquid phase, so that the dispersibility and uniformity of the white carbon black in the rubber are greatly improved. Meanwhile, the method is carried out in a liquid phase, thereby reducing the flying of dust when the rubber is mixed in a tire factory and a rubber product factory, improving the working environment, reducing the environmental pollution and saving the energy. And because a large amount of white carbon black can be added into the rubber material mixed by the wet method, the manufactured tire has small rolling resistance, low heat generation, greatly improved tensile strength and tearing strength, and improved aging resistance.

Due to the adoption of the acid-free flocculation process, the cleaning-free process is realized, the water consumption for production and the glue washing energy consumption are greatly reduced, 20-30 tons of water can be saved for each ton of products, and the discharge of sewage is also greatly reduced. The sewage discharge reduction rate reaches 80 percent.

The flocculant is flocculated and simultaneously mechanically stirred, so that the flocculant can be quickly dissolved in the latex, and the flocculation period is only 30 minutes. Therefore, the problems of long mixing time, uneven mixing and large energy consumption when a large amount of white carbon black is needed in tire factories and rubber product factories are solved. Because the quick flocculation is realized, the production period can be reduced by 30 percent. The production field is compressed by 50 percent. Stable continuous production can be carried out, and the product quality and consistency are improved.

In practical use, the obtained wet-set rubber compound can be used together with natural rubber or synthetic rubber, and various carbon blacks, fillers and compounding agents can be mixed into the wet-set rubber compound by adopting a conventional dry mixing method. The rubber material has excellent physical and mechanical properties, lower rolling resistance, low heat generation and better wet skid resistance, and is the preferred material for manufacturing tires.

In the acid-free preparation method of the wet mixing sizing material, the used white carbon black is as follows: precipitated silica and fumed silica.

The coupling agent is gamma-amino triethoxy silane, gamma-glycidoxypropyl trimethoxy silane, bis- (gamma-triethoxysilylpropyl) tetrasulfide or bis (triethoxysilylpropyl) disulfide; any one or two or more of the coupling agents may be mixed in any ratio.

The surfactants used were: anionic surfactants or nonionic surfactants.

Wherein the anionic surfactant is sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium butyl naphthalene sulfonate, and sodium lignosulfonate. The nonionic surfactant is polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, and alkylphenol polyoxyethylene.

The following will illustrate the technical solution of the acid-free process for preparing a wet-mix compound according to the present invention with reference to specific examples.