PP Injection Molding| Custom Injection Molded Parts| Echofast

Polypropylene (PP), also known as polypropene, is a thermoplastic polymer with a semi-crystalline structure. It is used predominantly in injection molding applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene injection molding refers to the process of heating a thermoplastic polymer above its melting point and converting it into a solid polymer and a molten fluid. Then, this molten polypropylene is injected into the mold and the desired shape of the part can be obtained. You can have splendid PP injection molding services in Echofast.

Types of Polypropylene

Homopolymer polypropylene is the default state of PP plastic. It is also considered to be a general-purpose grade plastic.
Block copolymer polypropylene has co-monomer units arranged in blocks in a regular pattern. It contains ethylene which can be anywhere between 5% to 15%. Ethylene in block copolymer polypropylene improves the impact resistance property of the plastic.
Random copolymer polypropylene has also co-monomer units but they are arranged in irregular or random patterns. Random copolymer polypropylene also contains ethylene and here, it is usually between 1% to 7%. This type of PP plastic is usually selected for projects that require malleable and clearer product manufacturing.

Ploypropylene (pp) Injection Molding Process

Feeding
Plasticization
Injection
Pressure Holding
Cooling
Ejection

Ploypropylene (pp) Materials Properties

Properties	Polypropylene
Density (g/cm3)	0.9
Ultimate Tensile Strength (MPa)	23.4
Izod Impact (Notched) (J/cm)	4.27
Hardness (Shore D)	72
Max Service Temperature (Air) (°C)	82.2
Melting Temperature (°C)	160 - 168
UV Resistance	Poor
Chemical/ Corrosion Resistance	Resistant to diluted and concentrated acids like nitric acid, as well as alcohols and bases
Water Absorption (ASTM D570) (% by weight)	0.02

Advantages of Ploypropylene (PP) Injection Molding

PP injection molding features a variety of unique qualities, and it becomes an ideal choice for a diversity of application projects. It is highly useful for manufacturing various products with a host of advantages. Some of the most common advantages of using PP include:

PP plastic is a relatively inexpensive material.
It possesses a high flexural strength due to its semi-crystalline property.
It has a strong resistance to fatigue and chemical corrosion.
It’s resistant to moisture absorption.
It can an act as a great electrical insulator.
It has a great impact strength.
PP is characterized by a relatively slippery surface.

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Disadvantages of Ploypropylene (PP) Injection Molding

Despite the fact that PP is a great injection molding material, it also has some disadvantages. Here are disadvantages in more detail:

Susceptible to UV deterioration
Sensitive to aromatics and chlorinated solvents
Highly flammable
Prone to oxidation
Difficult to paint due to its poor bonding qualities

Health concerns

The advocacy organization Environmental Working Group classifies PP as of low to moderate hazard.PP is dope-dyed; no water is used in its dyeing, in contrast with cotton. In 2020 researchers reported that polypropylene infant feeding bottles with contemporary preparation procedures were found to cause microplastics exposure to infants ranging from 14,600 to 4,550,000 particles per capita per day in 48 regions. Microplastics release is higher with warmer liquids and similar with other polypropylene products such as lunchboxes.

Ploypropylene (PP) Injection Molding Applications

Polypropylene is a popular material due to its low cost, ease of use, low density and weight. It can be used for various products of different industries , which include:

Children's toys
Sporting goods
Textiles materials
Caps
Closures
Automotive applications
Special devices like living hinges
Medical instruments
Food trays

Packaging for consumer products like food containers
Cups and to-go containers
Household goods and appliances like dishwashers