"Mitsui Chemicals is a Japanese Chemicals company.
The company mainly deals in performance
materials, petro and basic chemicals and functional polymeric materials."
What is MR Lenses: (MR-8, MR-7, MR-10, MR-174)
Excellent optical materials with high refractive index, high Abbe number, low specific gravity and high impact resistance are provided by polymerizing monomers of MR™ Series. MR™ Series is especially suitable for ophthalmic lenses and is known as the first thiourethane based high index lens material. MR™ Series offers a variety of products to provide the best solution for optical lens users.
R.I. 1.60: MR-8™ |
The best balanced high index lens material with the largest share of the R.I. 1.60 lens material market. MR-8™ is suited to any strength ophthalmic lens and is a new standard in ophthalmic lens material. |
R.I. 1.67: MR-7™ & MR-10™ |
Global standard R.I.1.67 lens material.
Great materials for thinner lenses with strong impact resistance.
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R.I. 1.74: MR-174™ |
Ultra high index lens material for ultra thin lenses. Strong prescription lens wearers are now free from thick and heavy lenses. |
MR™ Series is a brand name of the raw material for optical lenses.
MR™ Series based lenses are available from most leading lens manufacturers.
MR™ Series based lenses are available from most leading lens manufacturers.
Comparison of physical properties of lenses made with MR™ Series vs. other optical materials
MR™ Series | Other | ||||||||
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MR-8™ | MR-7™ | MR-10™ | MR-174™ | Poly carbonate | Aclyric (RI:1.60) | Middle Index | ADC (CR-39® RAV7®) | Crown Glass | |
Refractive Index (ne) | 1.60 | 1.67 | 1.67 | 1.74 | 1.59 | 1.60 | 1.55 | 1.50 | 1.52 |
Abbe Number (νe) | 41 | 31 | 31 | 32 | 28-30 | 32 | 34-36 | 58 | 59 |
Heat Distortion Temp. (ºC) | 118 | 85 | 100 | 78 | 142-148 | 88-89 | - | 84 | >450 |
Tintability | Good | Excellent | Good | OK | None | Good | Good | Good | None |
Impact Resistance | Good | Good | Good | OK | Good | OK | OK | OK | Poor |
Static Load Resistance | Good | Good | Good | OK | Good | Poor | Poor | Good | Good |
MR Series Features:
- High refractive index for thinner and lighter lenses.
With higher index materials, it is possible to achieve thinner lenses with the same strength.
- Superb optical quality for wearer comfort
- Both high refractive index and high Abbe number provide optical performance similar to glass lenses.
- Glass mold-casted MR™ Series shows minimal stress-strain.
High Abbe number material like MR-8™ minimizes prism effect (Chromatic aberration) of lenses and provides comfortable view to all wearers.
High Abbe Number Material
Low Abbe Number Material
MR™ Series resin is uniformly polymerized in a glass mold. Compared to the injection molded Polycarbonate lens, MR™ Series lens shows minimal stress strain and offers stress free clear vision.
Stress Strain Observation
(Crossed Nichol method using the polarizing film and white light source)
(Crossed Nichol method using the polarizing film and white light source)
- Mechanical strength to protect wearers from accidental injury.
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- High impact resistance of MR-8™ helps protect wearers form accidental injury.
FDA Drop Ball Test
MR-8™ shows good impact resistance
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US-FDA (Food and Drug Administration) Sec. 801.410
“Use of impact-resistant lenses in eyeglasses and sunglasses”
“Use of impact-resistant lenses in eyeglasses and sunglasses”
Static Loading Test
Quasi-static loading type test for minimum robustness
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MR-8™ shows good static load resistance
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- MR-8™ lens shows good tensile strength.
- MR-8™ is widely recognized as the best material for rimless frames.
Tensile Test
Tensile test results
MR-8™ lens broke at 72kg tensile force
(All other material lenses broke at smaller forces)
(All other material lenses broke at smaller forces)
Lens deformation
MR-8™ lens showed no deformation of drilled hole
(60kgf Tensile Force)
(60kgf Tensile Force)
- MR-8™ is adequate for the long time usage of rimless glasses.
“ Butterfly Test ”for Rimless Frames
Endurance test under cyclic load for spectacle frames | JIS B7283 Specification; Broke at 20,000 strokes |
- Durability during long time usage under severe conditions
- Good weatherability provides minimal change in lens color after years of usage.
- Good compatibility with coating materials.
Weatherbility Test
Accelerated test to observe lens color change after long-term usage.
QUV Test: 0.50W/m2, 50ºC, 100hrs
MR-8™ shows only minor color change after exposure to strong UV light.
Wearers can enjoy clearer lenses after long-term usage.
Wearers can enjoy clearer lenses after long-term usage.
Heat Resistance Test
Evaluation of cracks in coating after high temperature conditions.
Test condition: 90ºC, 15 min.
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Test condition: 80ºC, 15 min.
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Good heat resistance and coating compatibility of MR-8™ prevent coating cracks under servere conditions.
Cross-cut Adhesion Test
1) Cut a coating layer in a reticular pattern.
2) Apply tape over the pattern and then remove it.
2) Apply tape over the pattern and then remove it.
MR-8™ showed very good compatibility with coating materials.
Lens wearers can enjoy unchanged high performance lens coating after long-term usage.
Lens wearers can enjoy unchanged high performance lens coating after long-term usage.
How the MR lenses are produced?
1. Preparation of MR™ Series
Mix MR™ monomer (component) A & B with additives, then degas the MR™ monomer mixture.
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2. Filling
Fill molds with the MR™ monomer mixture.
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3. Polymerization
Place the filled molds into ovens, where they undergo a heat-cycle, turning the MR™ monomer mixture into a MR™ lens.
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4. Grinding / Polishing
Grind and polish the surface of the MR™ lens to create a curvature for required strength.
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5. Tinting
Tint the surface of the MR™ lens.
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6. Coating
Hard Coating Anti Reflection Coating |
Coat the surface of the MR™ lens to protect from scratches, reflection etc.
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7. Final Inspection
Inspect the coated lens.
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"MR-8 is the best in hi-index lenses"
credit: wikipedia, mitsuichem.com