What is the Difference Between ABS and Polypropylene (PP)?

As an engineer or product designer, you already know that there are hundreds of commercial-grade thermoplastics available for prototyping and production parts. However, among the wide variety of plastics, there are two materials that are more popular or more widely used. These two plastic materials are ABS and polypropylene.

ABS and polypropylene are used for industrial-grade 3D printing (additive manufacturing), CNC machining, and injection molding. Below we look at the advantages and applications of these two main materials. Then use the table to compare the typical material properties of these two plastics for machining, injection molding, and 3D printing.

What is ABS?

ABS (acrylonitrile-butadiene-styrene) is a mixture of many different molecules. In addition, ABS is one of the most cost-effective thermoplastics. It has good mechanical properties as well as strong thermal deformation capabilities such as durability and rigidity. In addition, ABS is easy to process and fabricate with good “workability”.

Advantages and Applications of ABS

In fact, ABS has proven to be a versatile choice. Not only is it quick and easy to process, but it also offers good impact resistance, strength, and stiffness over a wide temperature range. ABS has become a popular material for 3D printing due to its heat resistance, creep resistance, low bleed-through, and low stringiness. It is also a common choice for injection molding when low-cost, strong, and rigid plastics are required.

Advantages of ABS

• Inexpensive: ABS is a fairly inexpensive material for injection molding. That’s why it’s so popular with molding manufacturers. In addition, it is compatible with a wide range of molding techniques and almost all molding equipment in use today.
• Slow Degradation: ABS is a very strong polymer. It can withstand the harshest conditions without losing its properties. It can be heated, converted to a liquid, and then back to a solid with little loss of its beneficial properties. This is why items made from ABS retain their clean, elegant appearance even after continuous use.
• Solubility: ABS is soluble in other liquids, such as acetone, so it is easy to make changes to ABS fabrications. This includes adding engraving and smoothing out any anomalies. This flexibility benefits manufacturers.
• Works Well with Mechanical Parts: ABS has excellent compatibility with mechanical and moving parts. This is why it is commonly used in automotive prototyping and the aerospace industry. ABS has a higher degree of ductility and extensibility. This means that it can be molded into any shape without breaking.

Disadvantages of ABS

• Unpleasant Odor: ABS has one of the most unpleasant odors, especially when heated, and is difficult to handle. This is why manufacturers of these materials often rely on good ventilation to ensure that workers do not develop respiratory problems.
• Heat Shrinkage: ABS retains the key properties that make it an attractive raw material. However, it shrinks when exposed to heat. The longer it is exposed to heat, the more it shrinks. Eventually, there will not be enough material to process.
• A Lot of Heat is Needed: Melting ABS is easy because it has a very low melting point. But it is difficult to keep it that way. To feed ABS into an injection molding machine, for example, high levels of heat must be maintained. Otherwise, the material may cool too quickly, resulting in structural defects in the finished product.

Uses of ABS

ABS is suitable for a wide range of uses, applications, and products. For example:

• Aerospace applications
• Appliances
• Automotive applications
• Construction and industrial applications
• Electronics (consumer and commercial)
• Household goods
• Housings
• Lawn and garden equipment
• Lenses
• Lighting
• Medical/Health Care (surgical instruments, IV-system components, medical devices, test kits, etc.)
• Toys

What is Polypropylene?

Polypropylene is also a cost-effective thermoplastic, and in most cases costs less than ABS. It costs less than ABS in most cases and is stronger, more flexible, lighter, and less prone to moisture absorption than other plastics.

Since polypropylene has a density of less than 1 gram per milliliter, it can float on water. Polypropylene has similar qualities to polyethylene, but is slightly stronger and has better heat resistance. In fact, it is superior to ABS in this respect.

Advantages and Applications of Polypropylene (PP)

Polypropylene is the most commonly used plastic material because it is easy to extract. It also has very high chemical resistance, which makes it ideal for storing highly corrosive substances.

Advantages of Polypropylene (PP)

• Adaptable: Polypropylene is very useful and can be changed at any time. This flexibility allows any errors to be corrected without disrupting the production process. Therefore, the use of polypropylene helps to reduce the possibility of waste.
• Strong and Durable: Materials made from polypropylene are very strong and can last for a long time. As a result, polypropylene can be used in a variety of everyday household products. For example, food containers, electrical insulation, and automotive parts.
• Chemical Resistance: Polypropylene is highly resistant to chemicals. It is the best material for producing storage containers for corrosive compounds used in industrial complexes and hospitals. In addition, it is resistant to a variety of chemicals, including boric, chlorine, and hydrochloric acids.
• Low Density: Polypropylene has a low density but a very strong texture. This makes it an ideal raw material for producing lightweight items. Instead, these lightweight items are as hard as nails, thus solving the age-old problem of quality materials with large volumes. Because of its low density, polypropylene products are very light and easier to transport.

Disadvantages of Polypropylene (PP)

• Rapid Shrinkage: PP, like ABS, shrinks rapidly after being removed from heat, resulting in crystallization. This situation is every mold maker’s nightmare. Crystallization can cause serious structural integrity problems and render the final product useless.
• Poor Adhesion: Polypropylene does not bond well to adhesives, which increases production costs. Other, more expensive adhesives must be selected. Using standard adhesives designed for other materials only weakens the PP product.
• Low Melting Point: Polypropylene melts at the slightest heat, which can be a concern for many people. Because of its low melting point, you should not use PP products in a standard household oven.

Polypropylene (PP) applications

Polypropylene is suitable for a variety of uses, applications, and products. You will see some overlap between PP and ABS in the list. There are many examples:

• Appliances
• Automotive applications
• Caps and closures
• Electronic components
• Fans
• Food containers
• Food trays
• Integral or living hinges
• Household goods
• Medical/health care applications
• Snap fits such as snap-over lids
• Sporting goods
• Thermoformed containers
• To-go containers
• Toys

Differences Between ABS and Polypropylene

Although ABS and polypropylene are both plastic materials. However, they have different properties and advantages.

• ABS is a copolymer consisting of three separate monomers. Polypropylene, on the other hand, is a homopolymer composed of only one monomer.
• ABS has a higher density, melting point, glass transition temperature, tensile strength, flexural strength, impact strength, and hardness than PP. However, its elongation at break, coefficient of thermal expansion, and electrical resistivity are lower than PP.
• ABS is better suited for applications requiring high strength, stiffness, and heat resistance. ABS is better suited for high strength, stiffness, and heat resistance applications. In contrast, PP is better suited for applications requiring high flexibility, lightweight, and electrical insulation.
• ABS and PP each have advantages and disadvantages. These include low cost, good chemical resistance, ease of fabrication, low heat resistance, poor weatherability, and high flammability.
• ABS and PP are used in a wide variety of applications. These include automotive, electronics, medical, consumer products, packaging, textiles, furniture and household products.

Choosing between ABS and PP

So before you start any CNC machining, injection molding, or 3D printing project, you should carefully consider all the fundamentals that affect the design of the part. Examples include the required strength, heat resistance, and flexibility. In fact, the choice of material will most likely depend on the production technology under consideration.

You can also review the list of applications, uses, and developed projects for both plastics. Then compare them to your own part design projects. Here are some quality comparisons of ABS and polypropylene compounds for injection molding, CNC machining, and 3D printing.

The attributes in this table are determined by the actual material grade, part thickness, and geometry used. Please review the data tables for each material individually as they are estimates.

Summary

If you are looking for a reliable and competent plastic CNC machining service company. Then you can contact us. Yonglihao Machinery is a leading customized precision machining company that offers high-quality ABS and PP machining services. We also offer other CNC machining services  and metal machining services.

Yonglihao Machinery has the experience and state-of-the-art equipment to meet your design and application needs. For free pricing and consultation, please visit our website or contact online customer service. We hope you find the most effective solution for your project.