There are many advantages of adding Physical Foaming Nucleating Agent in polypropylene modification. Nucleating agent can promote the crystallization rate of melt, obviously improve the mechanical properties and processing properties of polypropylene products, and benefit the aging resistance and optical properties of products. The functions of these nucleating agents are summarized into 5 points and introduced in 2 articles. This paper introduces two of them, which are the effect on optical properties and processing properties.
Function of Physical Foaming Nucleating Agent point 1: improve the optical properties of polypropylene products.After adding nucleating agent, the crystallization temperature and crystallization speed of PP melt during cooling process increase, and the nucleation rate is the nucleation density of polypropylene is increased and nucleation is promoted by heterogeneous nucleation, so that the spherulites of polypropylene are refined.
When the size of spherulites is smaller than the wavelength of visible light, the scattering and refraction of light will be reduced, and the transmittance of light will be improved high, thus improving the optical properties of polypropylene products.
The effect of Physical Foaming Nucleating Agent point 2: improve the processability of polypropylene products
Adding nucleating agent into polypropylene melt can accelerate the crystallization speed of polypropylene, form fine and compact spherulite morphology and reduce free volume. Even if the cooling speed is fast during injection molding, polypropylene can still crystallize well, which can reduce the degree of shrinkage of products, reduce the molding shrinkage of products, and improve the injection processing performance of polypropylene. In addition, the addition of nucleating agent can reduce the delamination trend, excessive burr, depression and cavity formation in polypropylene injection molding products.
In addition, the addition of nucleating agent can obviously improve the crystallization temperature of polypropylene, accelerate the crystallization speed, obviously shorten the cooling time of injection mold, thus reduce the whole injection cycle, and improve the production efficiency.
