Should PMMA injection molding choose new materials or recycled materials?

author: Universe plastic

2024-06-20

What is PMMA material?

PMMA (polymethylmethacrylate) is a common thermoplastic commonly known as Plexiglas or acrylic. It is made from methyl methacrylate monomer through polymerization reaction and has the characteristics of high transparency, good mechanical strength and light weight.

PMMA new materials and recycled materials are very common in injection molding manufacturing, but there is a certain gap in performance between them. Which one is suitable for your injection molding project? You can read this article to make it easier to choose.

What types of PMMA materials are there?

1. General PMMA

By liquefying the PMMA material and shaping it into the required plastic parts, it is widely used in injection molding manufacturing and extrusion molding processes.

2. Modified PMMA

By adding rubber or other toughening agents to improve the impact strength of the material, it is used in fields such as automotive parts and electronic product casings that require higher impact resistance.

3. Weather resistance PMMA

By adding anti-ultraviolet (UV) agents and other stabilizers, the weather resistance of the material is enhanced, making it suitable for outdoor applications such as building curtain walls and billboards.

4. Optical PMMA

Offers extremely high transparency and low birefringence for use in precision optics, lenses and lenses.

5. Medical grade PMMA

Meets biocompatibility and strict hygiene standards for medical devices and is used to manufacture contact lenses, intraocular lenses and other medical devices.

Performance of PMMA materials

Degree	1.17-1.20 g/cm³	Water absorption	about 0.2-0.5%
Tensile strength	55-75 MPa	Tensile modulus	2.7-3.3 GPa
Elongation at break	2-5%	Bending strength	70-110 MPa
Flexural modulus	2.7-3.2 GPa	Impact strength	1.5-2.5 kJ/m²
Glass transition temperature	85-105°C	Heat distortion temperature	70-100°C
Light transmittance	92-93%	Refractive index	1.49-1.50
Haze	<1%	Dielectric constant	2.6-3.2
Volume resistivity	>10¹⁵Ω·cm	Dielectric strength	>20 kV/mm
Chemical resistance	Good resistance to dilute acids, dilute alkali and most salt solutions, but not resistant to organic solvents such as ketones, esters, chlorinated hydrocarbons, etc.
stress cracking	It is sensitive to environmental stress cracking and needs to be modified or designed to reduce the risk.

Application of PMMA materials

1. Architectural decoration: glass substitutes, plastic windows, plastic skylights, plastic parts decoration.

2. Automobile industry: car light lenses and lampshades, dashboards and interior parts, protective covers for machinery and equipment, transparent protective covers for solar panels.

3. Medical field: contact lenses, intraocular lenses, dental restoration materials, denture bases, shells and protective covers of medical equipment.

4. Optical electronics: lenses and lenses for mobile phones, computers, TV display screens, cameras, microscopes and other optical equipment.

5. Signage: plastic signs, product information boards, crystal advertising signs.

PMMA plastic beauty box

Parameter comparison between new PMMA and regenerated PMMA

Property	New PMMA Material	Recycled PMMA Material
density	1.17-1.20 g/cm³	1.16-1.19 g/cm³
Tensile Strength	55-75 MPa	45-65 MPa
Tensile modulus	2.7-3.3 GPa	2.5-3.0 GPa
Elongation at break	2-5%	1.5-4%
Bending strength	70-110 MPa	60-90 MPa
Impact strength	1.5-2.5 kJ/m²	1.0-2.0 kJ/m²
Heat distortion temperature	70-100°C	65-95°C
light transmittance	92-93%	85-92%
refractive index	1.49-1.50	1.48-1.50
Dielectric constant	2.6-3.2	2.5-3.1
Volume resistivity	>10¹⁵ Ω·cm	slightly decreased
chemical resistance	Good resistance to dilute acids, dilute alkalis and most salt solutions	slightly lower
environmental stress cracking	Sensitive to environmental stress cracking	Sensitivity may be increased

The main differences between PMMA new materials and recycled materials

1. Mechanical properties

New material: has high tensile strength, bending strength, heat resistance, wear resistance and chemical stability.

Recycled Materials: Recycled materials often have reduced mechanical, thermal and chemical resistance.

2. Chemical properties

New material: higher purity and better resistance to dilute acids, dilute alkali and most salt solutions.

Recycled materials: Chemical resistance may be slightly lower, especially if impurities were introduced during the recycling process.

3. Cost-effectiveness

New materials: Processed from raw materials, the supply cost is high.

Recycled materials: Processed using recycled materials, low cost and environmentally friendly.

Conclusion

New PMMA generally has higher transparency, better mechanical properties and higher chemical resistance, while recycled PMMA has reduced performance due to degradation and impurities during the regeneration process. However, through advanced regeneration technology, the performance of recycled PMMA can be improved to a certain extent, making it still competitive in some applications. In addition, recycled PMMA helps reduce production costs and environmental impact, making it an environmentally friendly choice.

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