SOLVENT AND RUBBER-SWELLING INHIBITOR As pointed out before, the solvent and coupling agent must be an excellent mutual solvent for all of the commonly used ingredients in hydraulic-brake fluid formulations, including castor oil. In general, those solvents that are most powerful coupling agents are also the chemicals which swell natural rubber to a greater degree than is permissible for the finished formulation. Fortunately, glycols will inhibit or reduce the swelling of natural rubber by most of the commonly used hydraulic-brake fluid solvents without appreciably reducing their coupling action. Ethylene glycol iss the most effective rubber-swelling inhibitor, followed by propylene glycol, diethylene glycol, dipropylene glycol, and hexylene glycol. It should be pointed out that in castor-oil formulations, ethylene glycol requires a more powerful coupling agent to maintain lowtemperature miscibility than propylene glycol, and so on, down the list. The choice of glycols is usually made on the basis of the best
地址：山东省烟台市开发区南昌大街48号
