How to choose new and recycled materials for PP injection molding

author: Universe plastic

2024-06-11

What is PP material

PP material is a common polypropylene material, which is a thermoplastic polymer. Polypropylene has many excellent properties that make it widely used in injection molding manufacturing. With manufacturing costs and environmental protection requirements, more and more injection molding manufacturing of polypropylene plastic products begins to use polypropylene recycled materials. So how should we choose between new and recycled polypropylene materials during injection molding? Let’s first understand the differences between them, and then choose the appropriate injection molding application.

PP material properties

1. Light material: low density and lighter than many plastic materials.

2. High strength: It has good mechanical strength and toughness, especially at room temperature.

3. Chemical resistance: It has good resistance to most acids, alkalis and solvents.

4. Heat resistance: The melting point is relatively high, generally between 160-170 degrees Celsius, and can be used at higher temperatures.

5. Insulation: It has good electrical insulation properties and is suitable for manufacturing insulation parts for electrical equipment.

6. Transparency: Most materials are translucent, and the transparency can be improved through some processing techniques.

Mechanical properties of PP materials

Property	PP-H	PP-B	PP-R
Density	0.90-0.91 g/cm³	0.90-0.92 g/cm³	0.90-0.91 g/cm³
Tensile Strength	30-40 MPa	20-30 MPa	20-30 MPa
Flexural modulus	1300-1800 MPa	900-1500 MPa	600-1200 MPa
Elongation at break	200-500%	500-800%	400-700%
Heat distortion temperature	100-120°C	90-110°C	70-100°C

Application of PP materials

1. Packaging materials: food packaging bags, plastic wrap, food containers, pharmaceutical packaging bottles, medicine boxes, industrial packaging bags, woven bags, strapping ropes, etc.

2. Household products: daily necessities, plastic cups, plastic bowls, storage boxes, trash cans, home appliance casings, washing machines, microwave ovens, fans, etc.

3. Automobile industry: interior and exterior trim parts, instrument panels, door panels, seat parts, bumpers, radiator grilles, battery cases.

4. Building materials: pipes and fittings, hot and cold water pipes, drainage pipes, floors, decorative materials.

5. Textiles: non-woven fabrics, hygiene products, medical supplies, protective clothing, carpets, ropes and nets.

6. Medical devices: syringes, disposable syringes, laboratory vessels, experimental containers, test tubes, centrifuge tubes.

7. Electronic and electrical: insulation layer of wires and cables, housing of electronic components.

8. Industrial applications: industrial storage tanks, transportation containers, mechanical parts, gears, bearing seats, etc.

9. Agriculture: agricultural mulch film, greenhouse film, seedling trays, fruit baskets, etc.

10. Sporting goods: sporting goods, swimming pools, sports protective gear, sports bottles, folding chairs, etc.

Parameter comparison of new PP and recycled PP

Property	New PP Material	Recycled PP Material
Density	0.90-0.91 g/cm³	0.90-0.95 g/cm³
Tensile Strength	30-40 MPa	20-30 MPa
Flexural modulus	1300-1800 MPa	800-1500 MPa
Elongation at break	200-500%	100-300%
Impact strength	50-80 J/m	20-50 J/m
Melting point	160-165°C	150-165°C
Heat distortion temperature	100-120°C	90-110°C
Vicat softening point	150-160°C	140-155°C
Chemical resistance	Excellent	Better
Corrosion resistance	Excellent	Better
Water absorption	0.01-0.03%	0.02-0.05%
Appearance Quality	Smooth and even	There may be color difference and impurities
Processability	good	Better, but sometimes the process needs to be adjusted
Environmental protection	lower	high
cost	higher	lower

The main differences between new materials and recycled materials

1. Mechanical: The mechanical properties of the new material are better than those of the recycled material, especially in terms of tensile strength, flexural modulus and elongation at break. Recycled materials may suffer from degradation due to degradation and impurities during the recycling process.

2. Thermal performance: The new material has slightly better thermal properties, with higher melting point and heat distortion temperature, as well as a higher Vicat softening point. This gives the new material an advantage in high-temperature applications.

3. Chemical properties: The chemical properties of new materials are often better than those of recycled materials, with better chemical and corrosion resistance. The chemical properties of recycled materials may be affected by impurities mixed in during the regeneration process.

Conclusion

The new PP material has clear advantages in performance and is suitable for injection molding applications that require high performance, reliability and aesthetics. However, recycled PP materials have significant advantages in terms of environmental protection and economy, and are suitable for applications that have relatively low performance requirements and emphasize sustainability. Universe Plastic Factory recommends that in actual selection, you need to decide which type of PP material to use based on specific application needs, performance requirements, cost budget and environmental considerations.

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