阅读说明：本技术 一种充炭黑天然橡胶母胶及其制备方法与应用 (Natural rubber masterbatch filled with carbon black and preparation method and application thereof ) 是由 张安强 张德强 林雅铃 于 2020-05-14 设计创作，主要内容包括：本发明属于炭黑天然橡胶母胶的制备技术领域,具体公开了一种充炭黑天然橡胶母胶及其制备方法与应用。本发明首先将炭黑淤浆与与胶乳的混合与絮凝得到凝聚物,然后对凝聚物进行脱水和干燥处理。因采用了离心脱水与挤压脱水膨胀干燥一体化后处理技术,与常规的鼓风干燥相比,干燥时间大大缩短、挤压脱水过程中受到的剪切力较强,既有利于减少炭黑在湿的絮凝产物中再次聚集的几率,又有利于炭黑与橡胶基体之间的相互作用,获得更高的结合胶含量,从而有利于获得具有良好炭黑分散和橡胶/炭黑相互作用的充炭黑母胶产物。其次由于没有添加表面活性剂,克服了因添加表面活性剂所造成的炭黑表面活性降低、结合胶含量下降以及硫化胶力学性能变差等不足。(The invention belongs to the technical field of preparation of carbon black natural rubber master batch, and particularly discloses carbon black-filled natural rubber master batch as well as a preparation method and application thereof. The invention firstly mixes and flocculates the carbon black slurry and latex to obtain the aggregate, and then dehydrates and dries the aggregate. Because the centrifugal dehydration and extrusion dehydration expansion drying integrated post-treatment technology is adopted, compared with the conventional air-blast drying, the drying time is greatly shortened, the shearing force applied in the extrusion dehydration process is stronger, the probability of secondary aggregation of the carbon black in a wet flocculation product is favorably reduced, the interaction between the carbon black and a rubber matrix is favorably realized, and higher bound rubber content is obtained, thereby being favorable for obtaining a carbon black-filled masterbatch product with good carbon black dispersion and rubber/carbon black interaction. And secondly, because no surfactant is added, the defects of reduced surface activity of the carbon black, reduced content of the bound rubber, poor mechanical property of vulcanized rubber and the like caused by the addition of the surfactant are overcome.)

1. A preparation method of carbon black-filled natural rubber master batch is characterized by comprising the following steps:

(1) preparing materials: the ingredients are proportioned according to the following components in parts by weight

Natural latex: 100 parts by weight of dry glue; carbon black: 40-100 parts; water: 1500-3000 parts; operating oil: 0-30 parts of a solvent; coagulant: 1-3 parts;

(2) preparation of carbon black slurry: adding carbon black and water into a colloid mill, keeping the concentration of the carbon black at 2.5-9.0 wt%, and grinding to obtain carbon black slurry;

(3) mixing and flocculation of the carbon black slurry with the latex: adding the carbon black slurry into natural latex under the conditions of normal temperature and high-speed stirring to obtain a latex/carbon black mixed system; then preserving heat for reaction, and adding a coagulant aqueous solution after the reaction is finished; the system generates the condensation and coprecipitation phenomenon, and the aggregates are separated out in a granular shape;

(4) dewatering and drying treatment of the condensate: dehydrating the aggregate; putting the product obtained by dehydration into an extrusion dehydration expansion drying all-in-one machine, wherein the temperature of a machine head is 160-180 ℃, the pressure of the machine head is not less than 10MPa, and performing further extrusion dehydration and expansion drying under high shear to obtain a dried product with the water content of about 5-10%; and then further drying the dried product in a fourdrinier dryer by hot air at the temperature of 80-100 ℃ until the moisture content is below 1 percent to obtain the carbon black-filled natural rubber master batch.

2. The method of claim 1, wherein:

the natural latex in the step (1) is field latex which is not subjected to concentration treatment or natural latex which is subjected to concentration treatment.

3. The method of claim 1, wherein:

the carbon black in the step (1) is ultrahigh wear-resistant carbon black, medium and ultrahigh wear-resistant carbon black, high wear-resistant carbon black or semi-reinforcing carbon black.

4. The method of claim 1, wherein:

the operating oil in the step (1) is alkane oil or aromatic oil; the coagulant is one or more of calcium chloride, sulfuric acid and acetic acid.

5. The production method according to claim 1 or 2 or 3 or 4, characterized in that:

and (3) grinding for 30-90 min in the step (2).

6. The method of claim 1, wherein:

the concentration of the natural latex in the step (3) is 5-20 wt%; the concentration of the coagulant aqueous solution is 5-20% wt.

7. The method of claim 1, wherein: the high-speed stirring speed in the step (3) is 3000-6000 rpm; and (4) keeping the temperature of the heat preservation reaction in the step (3) at 70-90 ℃ for 10-15 min.

8. The method of claim 1, wherein: and (3) when the formula in the step (1) contains the operation oil, adding the operation oil after the aggregate is separated out in the step (3), and continuously stirring for 10-15 min.

9. The carbon black-filled natural rubber masterbatch prepared by the method according to any one of claims 1 to 8.

10. The use of the carbon black-filled natural rubber master batch according to claim 9 in tread rubber of truck radial tires, tread rubber of engineering machinery tires and rubber air springs.

Technical Field

The invention belongs to the technical field of preparation of natural rubber master batch, and particularly relates to carbon black-filled natural rubber master batch as well as a preparation method and application thereof.

Background

The technology for preparing a rubber/carbon black composite (also called as masterbatch) by a wet method is a technical method for preparing rubber masterbatch containing carbon black based on a latex/carbon black slurry mixing technology, compared with the high viscosity of rubber dry rubber, the viscosity of the latex is extremely low, carbon black is mixed with low-viscosity latex, and then flocculation and drying are carried out to prepare the carbon black masterbatch containing carbon black, so that the carbon black/carbon black composite is beneficial to reducing the energy consumption for dispersing the carbon black in the rubber and improving the dispersion of the carbon black in the rubber, and therefore the carbon black/carbon black composite is valued by the industry in recent years.

At present, the disclosed technical route for preparing natural rubber master batch containing carbon black by a wet method is roughly as follows:

(1) preparation of carbon black slurry: dispersing carbon black in water by certain shearing force in the presence of surfactant (also called dispersant, emulsifier, etc.) to obtain relatively stable carbon black slurry;

(2) mixing and flocculation of the carbon black slurry with the latex: mixing the carbon black slurry and latex under a certain stirring condition, adding a flocculating agent (acid, monovalent or multivalent water-soluble salt and a mixture of the acid and the salt) after stirring for a certain time to obtain a mixture containing carbon black/wet rubber, and then washing, dehydrating and drying to obtain the natural rubber master batch containing the carbon black.

For example, patent 02152077.1 proposes a method for preparing carbon black-filled powdered rubber: dispersing carbon black in water in the presence of an emulsifier (a nonionic surfactant or an anionic surfactant) to prepare carbon black slurry, mixing the carbon black slurry with latex, heating, flocculating and drying to prepare carbon black filled powder rubber with the particle size of 0.2-1.0 mm; in the method, a certain amount of surfactant is added as a carbon black dispersing agent, so that the stretching stress and strength of the rubber possibly caused by the surfactant remained in the rubber are reduced, and the washed surfactant can also cause the cost of wastewater treatment. Patent publication 201410337186.X provides a preparation method of carbon black-extended styrene-butadiene rubber master batch suitable for non-contact pollution without adding a surfactant, wherein in the preparation stage of carbon black slurry, the surfactant for improving carbon black dispersion is not added, and uniform and stable carbon black slurry is obtained only through strong mechanical shearing and mechanical stirring action; however, this patent does not teach a method for the aftertreatment of the flocculated product produced, i.e.the carbon black-containing/wet rubber mixture. Patent publication 201210266789.6 proposes a wet-refining method for preparing natural rubber-carbon black compound, in which various water-soluble alcohols or ethers are added in the preparation stage of carbon black dispersion, which increases the cost of waste water treatment and causes environmental pollution.

In addition, in the carbon black-containing/wet rubber mixture obtained by the flocculation treatment, since the rubber phase contains much moisture and is not crosslinked, the carbon black therein tends to be aggregated thermodynamically.

Disclosure of Invention

In order to overcome the shortcomings and drawbacks of the prior art, the present invention provides a method for preparing a carbon black-filled natural rubber masterbatch.

The invention also aims to provide the carbon black-filled natural rubber master batch prepared by the method.

The invention further aims to provide application of the carbon black-filled natural rubber master batch in tread rubber of heavy duty radial tires, tread rubber of engineering machinery tires and rubber air springs.

The purpose of the invention is realized by the following scheme:

a preparation method of carbon black-filled natural rubber master batch comprises the following steps:

(1) preparing materials: the ingredients are proportioned according to the following components in parts by weight

Natural latex: 100 parts (based on dry glue); carbon black: 40-100 parts; water: 1500-3000 parts; operating oil: 0-30 parts of a solvent; coagulant: 1-3 parts;

(2) preparation of carbon black slurry: adding carbon black and water into a colloid mill, keeping the concentration of the carbon black at 2.5-9.0 wt%, and grinding to obtain carbon black slurry;

(3) mixing and flocculation of the carbon black slurry with the latex: adding the carbon black slurry into natural latex under the conditions of normal temperature and high-speed stirring to obtain a latex/carbon black mixed system; then preserving heat for reaction, and adding a coagulant aqueous solution after the reaction is finished; the system generates the condensation and coprecipitation phenomenon, and the aggregates are separated out in a granular shape;

(4) dewatering and drying treatment of the condensate: dehydrating the aggregate; putting the product obtained by dehydration into an extrusion dehydration expansion drying all-in-one machine, wherein the temperature of a machine head is 160-180 ℃, the pressure of the machine head is not less than 10MPa, and performing further extrusion dehydration and expansion drying under high shear to obtain a dried product with the water content of about 5-10%; and then further drying the dried product in a fourdrinier dryer by hot air at the temperature of 80-100 ℃ until the moisture content is below 1 percent to obtain the carbon black-filled natural rubber master batch.

The natural latex in the step (1) is field latex which is not subjected to concentration treatment or natural latex which is subjected to concentration treatment; the carbon black is ultrahigh wear-resistant carbon black (SAF), medium super wear-resistant carbon black (ISAF), high wear-resistant carbon black (HAF) or semi-reinforcing carbon black (SRF); the operating oil is common operating oil or filling oil in the rubber industry, and is specifically alkane oil or aromatic oil; the coagulant is one or a mixture of calcium chloride, sulfuric acid and acetic acid;

and (3) grinding for 30-90 min in the step (2). The size of the carbon black dispersion in the carbon black slurry obtained in the step (2) is 300nm or less.

The concentration of the natural latex in the step (3) is 5-20 wt%;

and (4) the high-speed stirring speed in the step (3) is 3000-6000 rpm.

And (4) keeping the temperature of the heat preservation reaction in the step (3) at 70-90 ℃ for 10-15 min.

The concentration of the coagulant aqueous solution in the step (3) is 5-20% wt, preferably 10% wt.

And (3) when the formula in the step (1) contains the operation oil, adding the operation oil after the aggregate is separated out in the step (3), and continuously stirring for 10-15 min.

A natural rubber masterbatch filled with carbon black is prepared according to the method.

The carbon black-filled natural rubber master batch has good application in occasions requiring excellent dispersion of carbon black in natural rubber and good combination between the carbon black and the rubber, such as tread rubber of a truck radial tire, tread rubber of an engineering mechanical tire, a rubber air spring and the like.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the carbon black-filled natural rubber masterbatch prepared by the method adopts an integrated post-treatment technology of centrifugal dehydration and extrusion dehydration expansion drying, compared with the conventional air-blast drying, the drying time is greatly shortened, the shearing force applied in the extrusion dehydration process is stronger, the method is not only beneficial to reducing the probability of the carbon black in the wet flocculation product, but also beneficial to the interaction between the carbon black and the rubber matrix, and obtaining higher bound rubber content, thereby being beneficial to obtaining the carbon black-filled masterbatch product with good carbon black dispersion and rubber/carbon black interaction.

(2) The carbon black-filled natural rubber master batch prepared by the method of the invention obtains the carbon black slurry with the carbon black dispersed in the water in a metastable state by improving the preparation process, and the preparation method is simple and has good repeatability. It is not necessary to add a surfactant for improving the dispersibility of the carbon black in water.

(3) The method for preparing the natural rubber masterbatch filled with the carbon black overcomes the defects of reduced surface activity of the carbon black, reduced content of the combined rubber, poor mechanical property of vulcanized rubber and the like caused by adding the surfactant because the surfactant is not added, and avoids the defect of increased wastewater treatment cost caused by the emulsifier.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.