In the realm of manufacturing, selecting the right blow molding materials is crucial for achieving optimal performance and durability. This guide delves into the most common materials used in blow molding, highlighting their unique properties and diverse applications. Additionally, we provide expert insights on how to choose the perfect plastic for your specific project needs, ensuring a successful production outcome. Explore the intricacies of blow molding to enhance your manufacturing processes.

Read more: What Is Blow Molding: A Comprehensive Guide

1. Most Common Blow Molding Materials

Blow molding machines are compatible with various blow molding plastic types, each offering distinct benefits. Understanding the properties of these plastics is crucial for manufacturers looking to optimize production efficiency. By choosing the right blow molding raw materials, businesses can improve product performance and meet specific industry requirements. Here are some of the most widely used plastics in blow molding, along with their key properties and applications:

1.1 High-Density Polyethylene (HDPE)

  • Cost: $0.70/lb
  • Density: 0.95 g/cc
  • Low Temperature Resistance: -75°F
  • High Heat Deflection: 160°F
  • Flexural Modulus: 1,170 MPa
  • Hardness: Shore 65D

High Density Polyethylene (HDPE) is the most widely utilized plastic in blow molding, renowned for its versatility and durability. As the world’s leading plastic material, HDPE is employed in a diverse range of products, including consumer liquid containers like shampoo and motor oil bottles, as well as coolers, fuel tanks, play structures, industrial drums, and carrying cases. Its user-friendly characteristics make it easy to mold, while its translucent nature allows for easy coloring.

Additionally, HDPE is chemically inert, FDA-approved, and recognized as one of the safest plastics available. With a recycling code designation of 2, it is also the most commonly recycled resin, making it a sustainable choice among blow molding materials.

HDPE - the most widely utilized blow molding material - is famous for its toughness, chemical resistance, and low cost
HDPE – the most widely utilized blow molding material – is famous for its toughness, chemical resistance, and low cost (Source: Internet)

1.2 Polypropylene (PP)

  • Cost: $0.75/lb
  • Density: 0.90 g/cc
  • Low Temperature Resistance: 0°F
  • High Heat Deflection: 170°F
  • Flexural Modulus: 1,030 MPa
  • Hardness: Shore 75D

When discussing the commonly used blow molding raw materials, one cannot overlook PP plastic. Polypropylene (PP) is the second most widely used plastic worldwide, known for its excellent performance in injection molding.

Compared to High Density Polyethylene (HDPE), PP is slightly stiffer and has a lower density, making it advantageous for high-temperature applications like dishwasher tubes and medical components requiring autoclave sterilization. Its easy molding properties and translucent nature allow for straightforward coloring. With a recycling code of 5, PP is also favored for sustainable practices in the industry.

PP plastic, as the second most widely used blow molding raw material, is known for its flexibility, toughness, and durability
PP plastic, as the second most widely used blow molding raw material, is known for its flexibility, toughness, and durability (Source: Internet)

1.3 Polyvinyl Chloride (PVC)

  • Cost: $1.15/lb
  • Density: 1.30 g/cc
  • Low Temperature Resistance: -20°F
  • High Heat Deflection: 175°F
  • Flexural Modulus: 2,300 MPa
  • Hardness: Shore 50D

Polyvinyl Chloride (PVC) ranks as the third most widely used plastic globally, particularly in blow molding materials. While it has faced scrutiny for the use of cadmium and lead stabilizers, as well as the release of hydrochloric acid during processing, advancements have significantly mitigated these concerns.

PVC is available in both rigid and soft forms, with the latter being commonly utilized in applications such as soft medical components, bellows, and traffic cones. Its translucent nature and versatility make it a popular choice in various industries. Additionally, PVC can be recycled under code 3, supporting sustainable manufacturing practices.

PVC is available in both rigid and soft forms, with the latter being commonly utilized in various applications, particularly in blow molding
PVC is available in both rigid and soft forms, with the latter being commonly utilized in various applications, particularly in blow molding (Source: Internet)

1.4 Low-Density Polyethylene (LDPE)

  • Cost: $0.85/lb
  • Density: 0.92 g/cc
  • Low Temperature Resistance: -80°F
  • High Heat Deflection: 140°F
  • Flexural Modulus: 275 MPa
  • Hardness: Shore 55D

Low Density Polyethylene (LDPE) is a versatile plastic used in blow molding applications, particularly valued for its flexibility and high resistance to stress cracking. Variants such as linear-low density polyethylene (LLDPE) and blends with ethyl-vinyl acetate (LDPE-EVA) enhance its softness, making it ideal for products like squeeze bottles, traffic channelizers, and boat fenders.

The predominant application of LDPE is in blown film for plastic bags. Its user-friendly characteristics, including translucency, ease of coloring, and chemical inertness, contribute to its popularity in the industry. Additionally, LDPE is commonly recycled under code 4, aligning with sustainable practices.

LDPE is commonly recycled under code 4, aligning with sustainable practices
LDPE is commonly recycled under code 4, aligning with sustainable practices (Source: Internet)

1.5 Polyethylene Terephthalate (PET)

  • Cost: $0.85/lb
  • Density: 1.30 g/cc
  • Low Temperature Resistance: -40°F
  • High Heat Deflection: 160°F
  • Flexural Modulus: 3,400 MPa
  • Hardness: Shore 80D

Polyethylene Terephthalate (PET) is a widely used polyester, predominantly employed in injection blow molding to create clear containers. Although extrusion blow molding of PET is possible, it is less common due to the resin’s need for extensive drying.

PET is used to make plastic blow molding products like soft drink and water bottles, reflecting its popularity in the beverage industry.

With recycling rates on the rise under recycle code 1, PET is increasingly recognized for its sustainability, making it a responsible choice for manufacturers focused on eco-friendly practices.

Polyethylene Terephthalate (PET), known for its high flexibility and transparency, is the ideal blow molding material for manufacturing soft drink and water bottles.
Polyethylene Terephthalate (PET), known for its high flexibility and transparency, is the ideal blow molding material for manufacturing soft drink and water bottles. (Source: Internet)

1.6 Thermoplastic Elastomers (TPE)

  • Cost: $2.25/lb
  • Density: 0.95 g/cc
  • Low Temperature Resistance: -18°F
  • High Heat Deflection: 185°F
  • Flexural Modulus: 2,400 MPa
  • Hardness: Shore 50D

Thermoplastic Elastomers (TPE) are innovative materials designed to replace natural rubber in molded components. These opaque materials can be easily colored, with black being the most common option.

TPEs are widely utilized in applications such as automotive suspension covers, air intake ducts, bellows, and grip surfaces, thanks to their excellent molding capabilities after drying and good reprocessing characteristics.

While TPEs offer numerous advantages, recycling rates remain somewhat limited under code 7 (other plastics), highlighting the need for improved sustainability practices in their lifecycle management.

TPEs are widely utilized in applications such as automotive suspension covers, air intake ducts,...
TPEs are widely utilized in applications such as automotive suspension covers, air intake ducts,… (Source: Internet)

1.7 Acrylonitrile Butadiene Styrene (ABS)

  • Cost: $1.55/lb
  • Density: 1.20 g/cc
  • Low Temperature Resistance: -40°F
  • High Heat Deflection: 190°F
  • Flexural Modulus: 2,680 MPa
  • Hardness: Shore 85D

Acrylonitrile Butadiene Styrene (ABS) is a robust plastic widely utilized in blow molding applications, notably for football helmets. This opaque material, often colored, is also employed in the production of electronics housings and small appliances due to its excellent molding properties after drying.

While ABS plastic offers impressive toughness, it is less chemically resistant compared to polyethylene plastic (PE) or polypropylene plastic (PP), necessitating caution when in contact with chemicals.

Additionally, various grades of ABS can achieve the UL 94 flammability standard, making it a reliable choice for safety-critical applications. Although recyclable under code 7, its durability can complicate grinding processes for recycling.

ABS provides hardness, heat and chemical resistance to the product
ABS provides hardness, heat and chemical resistance to the product (Source: Internet)

1.8 Nylon/Polyamides (PA)

  • Cost: $3.20/lb
  • Density: 1.13 g/cc
  • Low Temperature Resistance: -40°F
  • High Heat Deflection: 336°F
  • Flexural Modulus: 2,900 MPa
  • Hardness: Shore 77D

Nylon, a type of polyamide, is a versatile and reasonably priced translucent material commonly used in injection molding and, to a lesser extent, in extrusion blow molding with variants like nylon 6 and nylon 6-6. Known for its decent chemical resistance and high heat performance, nylon is frequently utilized in automotive applications, such as tubes and reservoirs in engine compartments.

While nylon can be reprocessed under recycling code 7, its unique properties make it a valuable choice among blow molding materials.

Nylon, with its decent chemical resistance and high heat performance, is the common plastic used in extrusion blow molding
Nylon, with its decent chemical resistance and high heat performance, is the common plastic used in extrusion blow molding (Source: Internet)

1.9 Polycarbonate (PC)

  • Cost: $2.00/lb
  • Density: 1.20 g/cc
  • Low Temperature Resistance: -40°F
  • High Heat Deflection: 290°F
  • Flexural Modulus: 2,350 MPa
  • Hardness: Shore 82D

Polycarbonate (PC) is a remarkably tough and transparent material, making it ideal for a wide range of applications, from eyeglasses to bullet-proof glass in jet cockpits. It is also commonly used in the production of 5-gallon water bottles. While PC molds effectively into basic shapes, it requires careful consideration for more complex designs.
Additionally, it must be dried before processing and is challenging to grind, yet it can be reprocessed under recycling code 7. Its unique combination of strength and clarity makes polycarbonate a valuable choice in various industries.

Polycarbonate is know as a remarkably tough and transparent material
Polycarbonate is know as a remarkably tough and transparent material (Source: Internet)

1.10 Polyphenylene Oxide (PPO)

  • Cost: $3.50/lb
  • Density: 1.10 g/cc
  • Low Temperature Resistance: -40°F
  • High Heat Deflection: 250°F
  • Flexural Modulus: 2,550 MPa
  • Hardness: Shore 83D

Polyphenylene Oxide (PPO) is an opaque resin known for its stiffness and strength, making it suitable for applications requiring durable components. This material must be dried before processing and has a limited drawdown capacity during molding, which confines design possibilities to parts with generous blow ratios or flat shapes, such as panels and desktops. PPO grades can meet UL 94 V-0 flammability standards, ensuring safety in various applications.

Additionally, it can be reprocessed, with some recyclers accepting it under recycling code 7, making it a practical choice in sustainable manufacturing.

PPO grades can meet UL 94 V-0 flammability standards, ensuring safety in various applications
PPO grades can meet UL 94 V-0 flammability standards, ensuring safety in various applications (Source: Internet)

2. How to Choose the Right Plastic Material for Your Blow Molding Project?

Choosing the right plastic material for your blow molding project is crucial for achieving optimal performance and product quality. Several key factors must be taken into account when selecting the appropriate blow molding materials, including:

  • The type of material being molded: Selecting the appropriate mold material is essential for the success of molded products. Key properties such as melting point, shrinkage rate, and moldability of the selected plastic must be evaluated. This is particularly important for high-temperature materials like PPS or PPSU, which require a compatible mold material to ensure optimal performance and quality.
  • The mechanical and electrical properties of the material being molded: The choice of molding materials should align with the project’s specific physical and chemical requirements. Options that offer abrasion resistance or corrosion protection are vital for environments demanding enhanced durability. By selecting a suitable mold material, you can ensure your product performs reliably over time.
  • The desired finish and dimensional accuracy of the products: The selection of blow molding materials greatly influences the end product’s characteristics. For achieving precise dimensions and a smooth finish, it is crucial to choose the right material tailored to your project needs. Whether aiming for sharp edges or rounded surfaces, there is an injection mold solution that will meet your specifications.
  • The cost of the blow molding materials: Cost considerations play a significant role in the selection of mold materials, as they can impact the overall project budget. With a variety of materials available, finding the right balance between performance and cost-effectiveness is essential. Careful evaluation of material options can lead to significant savings without compromising quality.
The selection of blow molding materials greatly influences the end product’s characteristics
The selection of blow molding materials greatly influences the end product’s characteristics (Source: Internet)

3. Conclusion

In conclusion, choosing the right blow molding materials is essential for optimal performance and durability. Understanding the properties of polymers allows manufacturers to tailor their selections for specific applications, ensuring efficiency and cost-effectiveness. A strategic approach to material choice enhances functionality and competitiveness, enabling you to meet production needs and elevate product quality effectively.

If you’re in search of top-notch, dependable plastic materials for the blow molding process, EuP Egypt is your ultimate destination! Our expertly formulated blends of filler materials like calcium carbonate and talc within a robust polymer matrix guarantee exceptional durability and performance. Don’t wait any longer – reach out to contact us today for competitive quotes and discover the ideal solutions tailored to your production needs.