Dosage of polypropylene is individual plastic range of all the biggest category, also is the most widely application scope, can make classification of different base material within the classification can still different melt flow rate of specifications, the individual may even need to add additional additives area again set USES the specification, such as: single polymer, MFR, 12 or so can be used for general injection products, also can produce multifilament fiber, more broad molecular weight distribution can be deliberately created to improve fiber weaving segment after machining;At the same time, slip agent and anti - phase adhesive can also be added to increase the requirements of the finished products of open plastic bags.Therefore, it can be extended to many specifications, but the general physical properties are the same, in addition to the non-specific main use is the substitution of each other.Here, we try to classify them into different substrates for reference, and explain them one by one.
1. HOMOPOLYMER single polymer, mainland called HOMOPOLYMER, is the raw material of pure propylene polymerization.
2. IMPACT COPOLYMER is a single polymer added with ethylene propylene rubber, the IMPACT strength is mainly determined by the content of rubber, the cold resistance is mainly determined by the content of ethylene.The maximum ethylene content varies from manufacturer to manufacturer.
3. RANDOM COPOLYMER RANDOM COPOLYMER, ethylene COPOLYMER added by propylene, ethylene irregularly distributed in the polymer, mainly reducing the crystallinity of the polymer and improving the transparency.
4. As HIGH ISOTACTICITY or HIGH CRYSTALLINITY reduce the content of dislocation structure in PP polymers, the relative increase of regular structure content will also increase the degree of CRYSTALLINITY.The main improvement of raw material rigidity, thermal denaturation temperature, surface hardness, scratch resistance and gloss.Of course, the addition of nucleating agent will also contribute to the above physical properties
5. Heat sealing (TERPOLYMER) is an extension of the random of polymer, generally contains propylene ethylene (EPR) the highest levels at 3.5%, but there is also a process can be added to 5%, the higher ethylene content in product more soft, thermal deformation temperature, softening point, the lower the heat sealing temperature, sometimes in order to increase ethylene content with the aid of butadiene or other third ingredients become three common polymer properties so as to achieve the above requirements.
6. ALLOY grade: the mixing of different plastic raw materials in a high proportion can be described as ALLOY grade. For example, adding LDPE to PP can improve the softness and impact strength, reduce necking and increase smoothness in processing, and reduce material drop in molding.PP plus EPR plus HDPE can maintain rigidity, reduce albinism caused by high EPR content, and improve impact strength.