CN-122008424-A - Process for improving tensile product of rubber

CN122008424ACN 122008424 ACN122008424 ACN 122008424ACN-122008424-A

Abstract

The invention provides a process for improving the tensile product of rubber, and relates to the technical field of rubber processing. The process comprises a low-temperature mixing stage of an internal mixer and a continuous mixing stage of an open mill, wherein the process steps of the low-temperature mixing stage of the internal mixer are to put rubber and all carbon black fillers in a formula into the internal mixer, press a ram, control the ram pressure to be 5.5MPa, the rotor rotating speed of the internal mixer to be 48r/min, raise the ram and keep 8s when the temperature is raised to 120 ℃, then reduce the rotor rotating speed to 40r/min, press the ram again and keep the pressure to be 5.5MPa, raise the ram and keep 10s when the temperature is continuously raised to 140 ℃, reduce the rotor rotating speed to 37r/min, press the ram for the third time and keep the pressure to be 5.5MPa, and discharge the rubber material to the open mill when the temperature is raised to 148 ℃. According to the invention, all carbon black is added at one time by adopting the low-temperature mixing of an internal mixer, so that the oxidation irregular breakage of rubber molecular chains in a high-temperature environment is effectively reduced, the integrity of the rubber molecular chains is ensured, and the elongation at break of rubber is improved.

Inventors

NING ZHENWEI
XIANG CHAN
MA HAO

Assignees

中策橡胶(建德)有限公司

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (1)

1. A process for improving the tensile product of rubber comprises a low-temperature mixing stage of an internal mixer and a continuous mixing stage of an open mill, and is characterized in that the process steps of the low-temperature mixing stage of the internal mixer are that rubber and all carbon black fillers in a formula are put into the internal mixer, a top plug is pressed, the pressure of the top plug is controlled to be 5.5MPa, the rotating speed of a rotor of the internal mixer is controlled to be 48r/min, the top plug is raised and kept for 8s when the temperature is raised to 120 ℃, then the rotating speed of the rotor is reduced to 40r/min, the top plug is pressed again and kept for 5.5MPa, the top plug is raised and kept for 10s when the temperature is continuously raised to 140 ℃, the rotating speed of the rotor is reduced to 37r/min, the top plug is pressed for the third time and kept for 5.5MPa, and the rubber is discharged to the open mill when the temperature is raised to 148 ℃; Continuous mixing in an open mill, namely, adjusting the roll gap of the open mill to 3.0mm, passing the sizing material discharged from the internal mixer through rolls for 35s, reducing the temperature of the sizing material to 125 ℃, adjusting the roll gap of the open mill to 1.5mm, mashing the sizing material for 360s, adjusting the roll gap of the open mill to 4.0mm, adding small molecular component materials in a formula, passing through rolls for 120s, adjusting the roll gap of the open mill to 1.0mm, mashing the sizing material for 540s, adjusting the roll gap of the open mill to 3.0mm, and discharging the sizing material after passing through rolls for 120s to complete mixing.

Description

Process for improving tensile product of rubber Technical Field The invention relates to the technical field of rubber processing, in particular to a process for improving the tensile product of rubber. Background The carbon black reinforced rubber with high structural degree has the outstanding advantages of high breaking strength, excellent wear resistance and the like, and is widely applied to the field of rubber products such as tire manufacturing and the like. The carbon black with high structure degree has small particle size and large specific surface area, and a large number of hydrogen bonds and hydroxyl groups exist on the surface of the carbon black, and the structural characteristic causes that the carbon black filler is difficult to uniformly disperse in a rubber polymer matrix, and the agglomeration phenomenon is extremely easy to occur even after the carbon black filler is dispersed. The problems of uneven dispersion and agglomeration of carbon black can directly cause the reduction of elongation at break and the reduction of tensile product of rubber products, and can also cause the problems of local stress concentration and overhigh deformation heat generation in the application of tires, finally cause early void damage of the tires, and seriously affect the service performance and service life of the rubber products. In order to solve the problem of dispersing high-structure carbon black in rubber, the rubber industry commonly adopts a multi-stage high-temperature mixing process at present, namely, part of carbon black is added in each stage of mixing, rubber molecular chains are broken by utilizing high-temperature conditions, and the broken molecular chains react with hydrogen bonds and hydroxyl groups on the surfaces of the carbon black, so that the dispersion performance of the carbon black is improved, however, the prior art has obvious technical defects, the breaking process of the rubber molecular chains is irregular under the high-temperature environment, the molecular weight distribution of the broken rubber molecular chains is wide, meanwhile, the combination degree of the carbon black and the rubber molecular chains which are added in different mixing stages is different in a batch mode is different, the carbon black combination rubber quantity distribution is wide, the problems directly lead to large fluctuation of the breaking strength and the breaking elongation of the high-structure carbon black and rubber mixture of different batches, the rubber materials often need to be repeatedly processed, the production procedure and the cost are increased, the tensile product of the rubber is further reduced, and the requirements of rubber products, especially the tire production, on performance stability and high quality are difficult to meet. Therefore, the invention provides a process method which can solve the defects of the existing multistage high-temperature mixing process, effectively control the breaking degree of rubber molecular chains, improve the dispersion uniformity and the combination stability of carbon black, and further remarkably improve the tensile product of rubber. Disclosure of Invention Aiming at the technical defects that the existing multistage high-temperature mixing process has wide molecular weight distribution and wide carbon black combined rubber quantity distribution caused by irregular breakage of a rubber molecular chain, so that the tensile strength and elongation of rubber are unstable and the tensile product is reduced, and the rubber material needs to be repeatedly processed, the production efficiency is low and the energy consumption is high, the invention aims to provide the process for improving the tensile product of rubber. In order to achieve the above purpose, the invention is realized by the following technical scheme: A process for improving the tensile product of rubber comprises a low-temperature mixing stage of an internal mixer and a continuous mixing stage of an open mill, wherein the process steps of the low-temperature mixing stage of the internal mixer are to put rubber and all carbon black fillers in a formula into the internal mixer, press a top plug, control the pressure of the top plug to be 5.5MPa, the rotating speed of a rotor of the internal mixer to be 48r/min, raise the top plug to be kept for 8s when the rotating speed of the rotor of the internal mixer is raised to 120 ℃, then lower the rotating speed of the rotor to be 40r/min, press the top plug again to be kept at the pressure of 5.5MPa, continuously raise the rotating speed of the rotor to be 37r/min, press the top plug for the third time and keep the pressure of 5.5MPa, and discharge rubber material to the open mill when the rotating speed of the rotor is raised to 148 ℃; Continuous mixing in an open mill, namely, adjusting the roll gap of the open mill to 3.0mm, passing the sizing material discharged from the internal mixer through rolls for 35s, reducing the tem