阅读说明：本技术 橡胶复合母粒及其制备方法 (Rubber composite master batch and preparation method thereof ) 是由 赵海静 刘媛 王金娥 董明 于 2021-01-28 设计创作，主要内容包括：一种橡胶复合母粒及其制备方法,属于功能材料制备领域的技术。该橡胶复合母粒的制备方法包括以下步骤：S1,将偶联剂置于水中水解,然后加入碳纳米管,加热反应,制成碳纳米管混合液,得到表面具有酸性亲水官能团的碳纳米管；S2,向步骤S1制得的混合液中滴加天然胶乳,天然胶乳在碳纳米管表面破乳,形成碳纳米管-天然橡胶絮凝体；S3,将碳纳米管-天然橡胶絮凝体薄通后干燥,得到橡胶复合母粒。本发明的制备方法通过在碳纳米管表面生成结合胶,提高了碳纳米管在混炼胶中的分散性,避免在制造橡胶制品过程中加入炭黑后导致碳纳米管无法均匀分散以及结合力不足等问题,最终提高橡胶制品的导电、导热性能、机械性能、耐久性。(A rubber composite master batch and a preparation method thereof belong to the technology of the field of functional material preparation. The preparation method of the rubber composite master batch comprises the following steps: s1, putting the coupling agent into water for hydrolysis, then adding the carbon nano tube, heating for reaction, and preparing a carbon nano tube mixed solution to obtain the carbon nano tube with the surface having the acidic hydrophilic functional group; s2, natural latex is dripped into the mixed liquid prepared in the step S1, and the natural latex breaks emulsion on the surface of the carbon nano tube to form a carbon nano tube-natural rubber flocculating constituent; and S3, thinning and passing the carbon nano tube-natural rubber flocculating constituent, and drying to obtain the rubber composite master batch. According to the preparation method, the bonding glue is generated on the surface of the carbon nano tube, so that the dispersibility of the carbon nano tube in the rubber compound is improved, the problems that the carbon nano tube cannot be uniformly dispersed and the bonding force is insufficient and the like caused by adding the carbon black in the process of manufacturing the rubber product are solved, and the electric conductivity, the heat conductivity, the mechanical property and the durability of the rubber product are finally improved.)

1. The preparation method of the rubber composite master batch is characterized by comprising the following steps:

s1, putting a silane coupling agent into water for hydrolysis, then adding the carbon nano tube, heating for reaction, and preparing a carbon nano tube mixed solution to obtain the carbon nano tube with the surface having the acidic hydrophilic functional group;

s2, natural latex is dripped into the mixed liquid prepared in the S1, and the natural latex breaks emulsion on the surface of the carbon nano tube to form a carbon nano tube-natural rubber flocculating constituent;

and S3, thinning and passing the carbon nano tube-natural rubber flocculating constituent, and drying to obtain the rubber composite master batch.

2. The method for preparing the rubber composite masterbatch according to claim 1, wherein the silane coupling agent has the following general formula:

Y(CH₂)_nSiX₃(ii) a The Y group is at least one of vinyl, epoxy and mercapto, and the X group is at least one of hydrolysable chlorine, methoxy, ethoxy and acetoxy.

3. The method for preparing the rubber composite masterbatch according to claim 1, wherein in step S1, the weight of the silane coupling agent is 0.05% -2% of the weight of the carbon nanotubes.

4. The method for preparing the rubber composite masterbatch according to claim 1, wherein in step S1, the reaction temperature is 60-100 ℃, and the reaction time is 2-10 h.

5. The method for preparing the rubber composite masterbatch according to claim 1, wherein in step S1, the carbon nanotubes are directly collected from a carbon nanotube synthesizing furnace, and the solid content is 50% to 70%.

6. The method for preparing the rubber composite masterbatch according to claim 1, wherein in step S1, the weight ratio of the carbon nanotubes to the water is 1-20: 100.

7. the method for preparing the rubber composite masterbatch according to claim 1, wherein in step S2, the weight ratio of the natural rubber latex to the carbon nanotubes is 1-10: 1.

8. the method for preparing the rubber composite masterbatch according to claim 1, wherein the drying temperature is 30 to 65 ℃ in step S3.

9. A rubber composite masterbatch, characterized by being prepared by the preparation method of any one of claims 1 to 8.

Technical Field

The invention relates to a technology in the field of functional material preparation, in particular to a rubber composite master batch and a preparation method thereof.

Background

The natural rubber prepared by drying the natural latex has the irreplaceable function of synthetic rubber and is an important industrial raw material and strategic resource. The general process for preparing natural rubber from natural latex is: demulsifying, cleaning, drying and forming to obtain the natural rubber. According to requirements, the natural rubber and other fillers are mixed to obtain a rubber product, and stress relaxation, aging and thermal cracking phenomena are generated by heating in the using process, so that the product performance is influenced finally. Therefore, the improvement of the comprehensive performance of the rubber, particularly the electric conduction performance and the heat conduction performance has very important practical significance.

The Chinese patent application with the application number of 201910278854.9 discloses a preparation method of a high-dispersity carbon nanotube-based rubber composite material, and the Chinese patent application with the application number of 201911016503.7 discloses a carbon nanotube-natural rubber composite masterbatch, a preparation method and a preparation device thereof. The carbon nanotube dispersion liquid required by the process requires that the carbon nanotubes are highly dispersed in the aqueous solution, and the latex is easily separated from the carbon nanotubes in the demulsification process, so that the bonding strength of the carbon nanotubes and rubber cannot be improved, and the dispersion of the carbon nanotubes in the rubber is not facilitated. The chinese patent application No. 201911016237.8 discloses a rubber composite material and a method for preparing the same, which also requires the preparation of highly dispersed carbon nanotube dispersion, and no chemical cross-linking exists between the carbon nanotubes and the rubber, so that no bonding glue can be generated on the surface of the carbon nanotubes, and the bonding performance between the carbon nanotubes and the rubber still needs to be further improved.

The present invention has been made to solve the above-mentioned problems occurring in the prior art.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the rubber composite master batch and the preparation method thereof, and the dispersibility of the carbon nano tubes in the rubber compound is improved by generating the bonding glue on the surfaces of the carbon nano tubes, so that the problems that the carbon nano tubes cannot be uniformly dispersed and the bonding force is insufficient after carbon black is added in the process of manufacturing rubber products are solved, and the electric conductivity, the heat conductivity, the mechanical property and the durability of the rubber products are finally improved.

The invention relates to a preparation method of rubber composite master batch, which comprises the following steps:

s1, putting a silane coupling agent into water for hydrolysis, then adding the carbon nano tube, heating for reaction, and preparing a carbon nano tube mixed solution to obtain the carbon nano tube with the surface having the acidic hydrophilic functional group;

s2, natural latex is dripped into the mixed liquid prepared in the S1, and the natural latex breaks emulsion on the surface of the carbon nano tube to form a carbon nano tube-natural rubber flocculating constituent;

and S3, thinning and passing the carbon nano tube-natural rubber flocculating constituent, and drying to obtain the rubber composite master batch.

Preferably, the silane coupling agent has the general formula: y (CH)₂)_nSiX₃(ii) a The Y group is at least one of vinyl, epoxy and mercapto, and the X group is at least one of hydrolysable chlorine, methoxy, ethoxy and acetoxy.

Preferably, in step S1, the weight of the silane coupling agent is 0.05% to 2%, more preferably 0.5% to 1.0%, 1.2% to 1.4%, and 1.5% to 2% of the weight of the carbon nanotubes.

Preferably, in step S1, the reaction temperature is 60-100 ℃ and the reaction time is 2-10h, more preferably, the reaction temperature is 70-90 ℃ and the reaction time is 3-5 h.

Preferably, in step S1, the carbon nanotubes are directly collected from the carbon nanotube synthesizing furnace, and the solid content is 50% to 70%.

Preferably, in step S1, the weight ratio of the carbon nanotubes to the water is 1-20: 100, further preferably, 2:100, 5:100, 8: 100.

preferably, in step S2, the weight ratio of the natural latex to the carbon nanotubes is 1-10: 1, more preferably 7:1, 5:1, 2: 1.

Preferably, in step S3, the drying temperature is 30-65 ℃.

The invention relates to a rubber composite master batch, which is prepared by adopting the method.

Technical effects

Compared with the prior art, the invention has the following technical effects:

1) general formula is Y (CH)₂)_nSiX₃The silane coupling agent (A) has X group of hydrolyzable chlorine group, methoxy group, ethoxy group, acetoxy group, etc., and can be hydrolyzed in water to form Si (OH)₃(ii) a The surface of the carbon nano tube produced by the synthesis furnace is provided with a large amount of elements such as oxygen, hydrogen, nitrogen, sulfur and the like, the elements form various functional groups such as carboxyl, hydroxyl, quinonyl, sulfydryl and epoxy, the carboxyl on the surface of the carbon nano tube reacts with the hydroxyl generated by the hydrolysis of the silane coupling agent to generate ester groups, and the coupling agent forms a coating layer on the surface of the carbon nano tube through the ester groups, so that the carbon nano tube does not need to be subjected to chemical oxidation modification; the coupling agent grows on the surface of the carbon nano tube, so that the self-agglomeration among the carbon nano tubes can be effectively prevented, and the dispersion prevention effect on the carbon nano tubes is achieved;

2) when the carbon nano tube reacts with the coupling agent hydrolysate, ultrasonic or violent mechanical dispersion treatment is not needed, the shape loss and the length-diameter ratio reduction of the carbon nano tube caused by ultrasonic or violent mechanical dispersion can be greatly reduced, the mechanical property of the carbon nano tube is maintained to the maximum extent, the energy consumption and the time consumption caused by preparing the carbon nano tube dispersion liquid are reduced, and the efficiency is improved;

3) the Y group in the coupling agent growing on the surface of the carbon nano tube can be polymerized with polyisoprene in the natural latex, the polyisoprene-the coupling agent generates the bonding adhesive in the carbon nano tube, and the bonding adhesive can improve the bonding strength of the carbon nano tube and the rubber and reduce the adverse effect of uneven dispersion of the carbon nano tube in a rubber product caused by adsorption of free carbon nano tubes by carbon black in the rubber mixing process;

4) the bonding glue generated on the surface of the carbon nano tube can further promote the deposition of residual polyisoprene in the natural latex, so that the purpose of demulsification is achieved, and the pollution of the demulsifier to the environment and the negative effect of the demulsifier to the rubber performance are avoided.

Drawings

FIG. 1 is an SEM photograph of the carbon nanotube surface coating coupling agent of example 1 at a resolution of 2 μm;

FIG. 2 is an SEM photograph showing the resolution of the coupling agent coated on the surface of the carbon nanotube in example 1 at 200 nm;

FIG. 3 is an SEM photograph of the rubber composite master batch in example 1;

FIG. 4 is XRD test data before and after coating a silane coupling agent with carbon nanotubes in example 1.

Detailed Description

The invention is described in detail below with reference to the drawings and the detailed description. The experimental procedures, in which specific conditions are not specified in the examples, were carried out according to the conventional methods and conditions.

Example 1

The embodiment relates to a preparation method of a rubber composite master batch, which comprises the following steps:

s1, placing 0.2g of silane coupling agent KH550 in 1.0kg of high-purity water for hydrolysis reaction at 85 ℃ for 0.5h, then weighing 20g of carbon nanotubes, adding the carbon nanotubes into the hydrolysate, stirring for reaction for 4h at 85 ℃ to prepare a carbon nanotube mixed solution, and obtaining the carbon nanotubes with the acidic hydrophilic functional groups on the surfaces; the carbon nano tube is directly collected from the carbon nano tube synthetic furnace, and the solid content is 60 percent;

s2, dropwise adding 100g of natural latex into the carbon nanotube mixed solution, and continuously stirring for 0.5h after the dropwise adding is finished to obtain a carbon nanotube-natural rubber flocculating constituent;

s3, thinning and passing the carbon nano tube-natural rubber flocculating constituent obtained in the step S2, extruding excessive water in the flocculating constituent, and drying at 55 ℃ for 2 hours to obtain the rubber composite master batch A.

The carbon nanotube mixed solution obtained in step S1 is sampled, dried and analyzed by a scanning electron microscope, and the SEM photograph is as shown in fig. 1 and 2, in which the surface of the carbon nanotube is uniformly covered with a layer of fluffy material, which is a coupling agent having an active functional group. An SEM photograph of the rubber composite masterbatch prepared in this example is shown in fig. 3, in which a large amount of binder is present on the surface of the carbon nanotubes, and the carbon nanotubes are not agglomerated. XRD data before and after the carbon nano tube reacts with the coupling agent is shown in figure 4, the peak intensity and half-peak width of the carbon nano tube treated by the coupling agent are reduced, which shows that the crystallinity of the carbon nano tube is reduced, the content of amorphous phase is increased, and the coupling agent is an amorphous substance, so that the fact that the surface of the carbon nano tube is coated with the coupling agent can be further inferred.

Example 2

S1, placing 0.4g of silane coupling agent KH550 in 1.0kg of high-purity water for hydrolysis reaction at 85 ℃ for 0.5h, then weighing 20g of carbon nanotubes, adding the carbon nanotubes into the hydrolysate, stirring for reaction for 4h at 85 ℃ to prepare a carbon nanotube mixed solution, and obtaining the carbon nanotubes with the acidic hydrophilic functional groups on the surfaces; the carbon nano tube is directly collected from the carbon nano tube synthetic furnace, and the solid content is 60 percent;

s2, dropwise adding 134g of natural latex into the carbon nanotube mixed solution, and continuously stirring for 0.5h after dropwise adding is finished to obtain a carbon nanotube-natural rubber flocculating constituent;

s3, thinning and passing the carbon nano tube-natural rubber flocculating constituent obtained in the step S2, extruding excessive water in the flocculating constituent, and drying at 55 ℃ for 2 hours to obtain the rubber composite master batch B.

A pair of proportions is set, the carbon nanotubes are not modified in the comparative example, and the following formula is adopted: 100 parts by weight of NR, 3 parts by weight of stearic acid, 5 parts by weight of zinc oxide, 2 parts by weight of sulfur, 1.5 parts by weight of TMTD, 1.0 part by weight of butyl antioxidant, 50 parts by weight of N330 and 4 parts by weight of carbon nanotubes were kneaded uniformly on a two-roll mill by a general rubber mixing process and vulcanized, and the physical properties of the vulcanized rubber sample C obtained were measured, the data of which are shown in Table 1. The rubber composite master batch a prepared in example 1 and the rubber composite master batch B prepared in example 2 were respectively converted into the parts by weight of the corresponding materials in the comparative formulation, and the remaining materials in the comparative formulation were added thereto, and also vulcanized after being uniformly mixed on a two-roll mill by a general rubber mixing process, and the physical properties of the prepared vulcanized rubber samples a and B were measured, and the data thereof are shown in table 1.

TABLE 1 physical Property data

Sample name	Hardness of	Tear strength	Elongation percentage	300 definite elongation	DIN abrasion
						Sample A	62	16.7	453	10.7	110
Sample B	62	16.4	474	10.4	116
						Sample C	63	15.5	448	9	130

The comparison shows that the breaking strength of the sample A and the sample B which are prepared by modifying the carbon nano tube into the rubber composite master batch is improved by more than 7 percent, and the wear resistance is improved by about 15 percent.

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and all simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.