Low-haze stiffness-increasing master batch and preparation method thereof

The invention discloses a low-haze stiffness increasing master batch which comprises the following components: 45-55% of homo-polypropylene, 35-45% of stiffness increasing agent, 6-11% of compatilizer, 0.1-1% of nucleating agent and 0.3-1.1% of antioxidant, a preparation method of a low-haze stiffness-increasing master batch comprises the following steps: fully and uniformly mixing homo-polypropylene, a stiffness-increasing agent, a compatilizer, a nucleating agent and an antioxidant, putting the mixture into an extruder, heating and melting the mixture to form a melt, injecting supercritical carbon dioxide into the front section of a second-section extruder, uniformly mixing the supercritical carbon dioxide with the melt, and extruding the foamed stiffness-increasing master batch through a die head, so as to obtain the low-haze stiffness-increasing master batch. The low-haze stiffness-increasing master batch is obtained. According to the invention, the stiffness of the film is effectively improved through sy