Manufacturing Method of Transparent PP (Polypropylene)
I. INTRODUCTION
Transparent PP is a widely used raw material for the production of chemicals, and is widely used in various fields due to its high transparency, heat resistance, cold resistance, electrical insulation and mechanical strength. In this paper, the manufacturing method of transparent PP will be introduced in detail.
II. Material Preparation
1. Propylene Monomer: Propylene is the main raw material for the production of PP, which requires high purity, generally need to reach 99.5% or more.
2. Catalyst: Ziegler-Natta catalyst or metallocene catalyst is generally used.
3. Auxiliaries: such as antioxidants, antistatic agents, and so on.
3. Production process
The production process of transparent PP mainly includes the steps of polymerization, granulation, drying and packaging.
1. Polymerization
In the polymerization reactor, propylene monomer, catalyst and other additives are added in a certain proportion to carry out the polymerization reaction. The polymerization reaction is generally carried out in a continuously stirred kettle reactor (CSTR) or a batch reactor. Factors such as reaction temperature, pressure and catalyst dosage affect the rate of the polymerization reaction and the molecular weight of the PP.
2. Granulation
After the polymerization reaction is completed, the resulting PP powder needs to be granulated by a granulator for subsequent processing and use. Some additives need to be added during the granulation process to improve the processing performance and stability of PP.
3. Drying
After the granulation is completed, the PP particles need to be dried to remove the water and other volatile substances. Generally, airflow drying or vibration drying is used.
4. Packaging
After drying, PP granules need to be packaged to prevent them from moisture and pollution. Polyethylene plastic bags or paper-plastic composite bags are generally used for packaging.
4. Precautions
1. In the polymerization reaction, the reaction conditions need to be strictly controlled to ensure that the molecular weight and molecular weight distribution of PP meet the requirements.
2. In the process of granulation, it is necessary to choose suitable additives and processing conditions to improve the processing performance and stability of PP.
3. In the drying process, it is necessary to control the drying temperature and time to prevent the PP pellets from deformation and discoloration.
4. In the packing process, it is necessary to ensure the sealing and moisture-proof of the bag to prevent the PP pellets from moisture and pollution.
5. Quality control
In order to ensure that the quality of transparent PP meets the requirements, strict quality control is needed. It generally includes the following aspects:
1. Molecular weight and molecular weight distribution: Tested by gel permeation chromatography (GPC) and other methods to ensure that the molecular weight and molecular weight distribution of PP meet the requirements.
2. Transparency: Tested by methods such as measuring light transmittance and haze to ensure that the transparency of PP meets the requirements.
3. Mechanical properties: Tested by methods such as tensile test and impact test to ensure that the mechanical properties of PP meet the requirements.
4. Thermal stability: Tested by heat loss analysis (TGA) and other methods to ensure that the thermal stability of PP meets the requirements.
6. Conclusion
The manufacturing method of transparent PP involves the control of several links and process parameters, which need to be operated in strict accordance with the requirements to ensure that the quality of the product meets the requirements. At the same time, it is also necessary to strengthen the quality control and safety management in the production process to ensure the smooth progress of the production process.
