The waste rubber is regenerated to produce softened oil
the waste rubber is cracked under the action of supercritical high temperature and high pressure water, and then through a series of separation, filtration and other procedures, the softened oil for rubber processing can be prepared again
according to the description of the patent, first crush the waste rubber products and remove non rubber components such as fiber and steel wire. The obtained rubber powder is put into a reactor, and then high temperature (374.2 ℃) and high pressure (218.5kg/cm2) water is introduced into it. The water is weakly alkaline to neutralize the acidic components in the waste rubber. In the continuous oscillation of the reactor, the ultrafiltration membrane is 3million square meters, and the rubber molecules react with the active water molecules under supercritical conditions. Under high temperature and high pressure, the water becomes the active molecules and enters the rubber molecules to break the sulfur bond. At the same time, the hydrophilic molecules (antioxidants, accelerators) in the vulcanizate will be dissolved in water to meet the requirements of this ecological link. The reaction time is about 10-30 minutes. After the reaction is terminated, cool the reactor, first filter out the water and water-soluble substances, then separate the remaining oil from the solid substances (carbon black and uncracked vulcanizate), remove the liquid substances after removing the solid substances, and then remove the low molecular weight (molecular weight less than 100), which is the required softened oil for rubber. The molecular weight of this softened oil is below 200000. Taking the regeneration of EPDM waste rubber as an example, the nuclear magnetic resonance test results show that this oil is similar to the basic structure of EPDM when the experimenter sees that the oil delivery valve is opened in the experiment. When this oil is used in the rubber formula, the product performance is similar to the commercial alkane softening oil. Because of its similar structure with rubber molecules, it has good compatibility with rubber. This method is applicable to the regeneration of vulcanizates of NR, Br, SBR, EPDM and other rubbers. Moreover, the recovery rate is high, and the oily product is about 85% of the raw rubber powder (except carbon black)
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