Comparison of Transparent Polymer Types and Properties | Weather Resistance and Moisture Absorption
Transparent resins are used in a wide range of fields, including optical components, housings, covers, medical devices, and outdoor applications.
This article summarizes the properties of typical transparent resins and introduces the features and advantages of Tefabloc™ CP, which boasts excellent weather resistance and moisture absorption.
Table of Contents [hide]
Transparent polymers
Transparent resins vary greatly in transparency, weather resistance, moisture absorption, and processability depending on the material. Selecting the appropriate material for the application is crucial. Below are some major transparent resins, their characteristics, and examples of applications.
PS (Polystyrene)
PS is a general-purpose resin characterized by its high transparency and low cost.
• High transparency and high gloss
• Good moldability
- Impact resistance and weather resistance are relatively low.
Examples of uses: Indoor covers, simple containers, display components
PMMA (acrylic resin)
PMMA is a transparent resin with excellent optical properties and weather resistance.
• Very high transparency
• Weather resistance proven even in outdoor applications
- It has moderately high moisture absorption.
Examples of applications: lighting covers, signs, optical components
PC (Polycarbonate)
PC is an engineering plastic that combines transparency and impact resistance.
• High impact resistance and heat resistance
• High mechanical strength
• Protection against yellowing caused by ultraviolet light is necessary.
• Examples of applications: Outdoor covers, protective components, electronic equipment enclosures
DURABIO™
DURABIO™ is a bioengineered plastic unique to Mitsubishi Chemical, designed to combine the high impact resistance and heat resistance of PC with the high transparency and surface hardness of PMMA, while using plant-derived isosorbide as its main raw material.
• High transparency and low birefringence (optical properties equivalent to PMMA)
• Excellent UV resistance and weather resistance (less yellowing, which is a problem with PCs)
•High surface hardness and scratch resistance
• Plant-derived and BPA-free
• Examples of applications: Automotive interior and exterior design parts, in-vehicle transparent panels, optical films, high-end cosmetic containers
COP (Cycloolefin Polymer)
COP is a cyclic olefin polymer, a transparent resin used in films and medical applications.
・Low moisture absorption
• High transparency and film processability
• High cost of raw materials
Examples of applications: Optical films, medical packaging materials
COC (Cycloolefin Copolymer)
Like COP, COC is a cyclic olefin polymer and is a transparent resin with excellent optical properties.
・Low moisture absorption
• Low birefringence, high transparency, high rigidity
Film processing is difficult.
• Examples of applications: Lenses and optical components
Tefabloc™ CP
Tefabloc™ CP is a transparent resin with excellent weather resistance and adhesion to dissimilar materials.
• High transparency
• Excellent weather resistance and low moisture absorption
- Heat welding with other resins is possible.
• High cost of raw materials
• Example applications: High-weather-resistant outdoor covers, integrated functional components
Weather resistance
For outdoor applications and products intended for long-term use, weather resistance to ultraviolet rays, heat, and humidity significantly impacts the product's lifespan.
Weather resistance of each resin
Resins and materials | Relative evaluation of weather resistance | Supplementary information regarding the evaluation |
|---|---|---|
PS | △ Limited | It may not be suitable for long-term outdoor use. |
PMMA (ACRYPET™) | ◎ Very high | Proven track record of outdoor use |
PC (XANTAR™) | ○ High | Measures to prevent yellowing due to ultraviolet light may be necessary. |
Biopolycarbonate (DURABIO™) | ◎ Very high | It exhibits weather resistance similar to PMMA. |
COP | △ Limited | Prior evaluation is necessary depending on the usage environment. |
COC | ○ High | Prior evaluation is necessary depending on the usage environment. |
Amorphous olefin compound (Tefabloc™ CP) | ◎ Very high | Material design that achieves both transparency and weather resistance is possible. Physical properties can be adjusted according to customer requirements. |
Color change due to accelerated weathering test (60°C, with rain)
Hygroscopic
Moisture absorption of each resin
Moisture absorption is an important factor that affects dimensional stability, appearance quality, and optical properties.
Low-hygroscopic materials are suitable for outdoor applications, precision components, and optical applications.
PS | Very low |
|---|---|
PMMA | expensive |
PC (XANTAR™) | Slightly expensive |
DURABIO™ | Medium |
COP | Very low |
COC | Very low |
Tefabloc™CP | Very low |
Weather-resistant polymers; Tefabloc™ CP
Tefabloc™ CP is a material that achieves a high level of weather resistance, low moisture absorption, and design flexibility in transparent resin applications.
Excellent weather resistance and low moisture absorption
• Maintains transparency even after long-term outdoor exposure
- Minimal dimensional change due to moisture absorption
- Minimizes external deterioration and achieves high reliability.
Suitable for outdoor covers and light-transmitting components.
Heat-weldability with other resins
Tefabloc™ CP can be heat-welded with olefin resins.
- Can be integrally molded with general-purpose resins such as PP and PE.
By leveraging these characteristics, it is possible to rationalize costs and mechanical properties by applying expensive transparent resin only to the necessary parts, rather than using it for the entire enclosure.
Tefabloc™ CP also includes grades that can transmit UV-C light, which is not transmitted by typical transparent resins. We will propose the optimal material to suit your usage environment and required performance.
