Optical Bonding Solutions
Engineered for Automotive & Industrial Displays
Bando Chemical's NT Series OCA offers ultra-thick options from 250 to 2,000μm, made from polyurethane (PU) material with high adhesion, excellent flexibility, and outstanding optical reliability. Widely used in optical bonding for automotive, aerospace, marine, and industrial displays.
① Plastic Cover Bonding
Plastic Cover Bonding
Common challenges with plastic cover bonding:
- Outgassing from plastic covers causes delamination or delayed bubbling during high-temperature testing
- Thermal expansion and contraction of plastic covers leads to delamination during thermal cycling tests
- Uneven plastic cover surfaces create trapped air bubbles or trigger delayed bubble formation during bonding
NT Series solutions:
- Polyurethane OCA: Combines high adhesion with excellent flexibility to accommodate deformation in plastic covers
- Ultra-thick options: Available in 250, 300, 500, 800, 1000, 1200, 1500, and 2000μm — effectively filling print step differences and surface irregularities
- High reliability: No discoloration (no whitening or yellowing), no delamination
- Pre-cut to size: Cut to customer specifications — simply peel and bond, no cutting process required
✅ The NT Series is optimized for plastic cover bonding, and is equally suitable for glass covers and PC, PMMA, and PC/PMMA composite materials.
② Curved Cover Bonding
Curved Cover Bonding
The core challenge of curved bonding: when bonding a flat LCD panel to a curved cover, the LCD's inherent springback force tries to return it to its original flat state — causing edge lift or Mura uniformity defects.
- The OCA must deliver sufficient adhesion to overcome the LCD's springback force
- It must also provide adequate flexibility to prevent stress-induced Mura on the LCD
- Only by achieving both can optimal curved bonding results be realized
✅ The NT-H Series is the ideal solution for curved bonding — simultaneously delivering high adhesion and high flexibility. Especially suited for automotive instrument panels and other curved applications.
③ UV-cut OCA (NT-HU)
UV-Cut OCA (NT-HU)
As display product structures grow more complex, some applications require protection of internal components from UV damage. While UV-cut coatings or films can be applied to the display surface, these approaches may add cost and complexity.
- NT-HU integrates UV-blocking functionality directly into the OCA layer — the most cost-effective solution available
- UV blocking rate of 99%+, with a low b* value ensuring no color shift toward yellow
- Test conditions: Glass / OCA / Glass construction, calculated per JIS A 5749 standard
✅ NT-HU combines UV-blocking performance with the high reliability of the NT Series — ideal for outdoor, automotive, and other high-UV environments.
④ Smoked OCA (SM Series)
Smoked OCA (SM Series)
Standard OCA applications require total light transmittance of 90% or above, but some applications need controlled light transmission to adjust display brightness or color performance.
- Bando SM Series is a smoke-tinted OCA with adjustable transmittance to suit specific requirements
- SM70 standard product: total light transmittance controlled to approximately 70%
- Adhesion maintained at the same level as the NT Series (Glass substrate, pull speed 30mm/min, 24H after bonding, 180° peel evaluation)
- Custom total light transmittance specifications available on request
✅ The SM Series allows display designers to control light transmission within the same bonding step — eliminating the need for a separate light-blocking film process.
OCA Series Specification Comparison
The table below compares Bando NT Series against common OCA materials on the market. Contact us for complete technical data sheets and pricing.
| Comparison Item | OCR-1 | OCR-2 | OCA-1 | OCA-2 | Bando NT Series |
|---|---|---|---|---|---|
| Material Type | Acrylic | Silicone | Acrylic | Silicone | Polyurethane (PU) |
| Glass Cover Bonding | Good | Fair | Good | Fair | Excellent |
| Plastic Cover Bonding | N/A | N/A | Limited | N/A | Suitable |
| Thick Bonding (≥ 1.0mm) | Poor yield | Poor yield | N/A | Limited | Suitable |
| Curing Process | UV cure | Heat cure | UV cure | Heat cure | No curing required |
| Reworkability | Difficult | Difficult | Not easy | Not easy | Easy |
| Curved Bonding | N/A | N/A | Limited | N/A | Suitable (automotive dash) |
| Wide Temperature Range | Fair | Good | Fair | Good | Automotive / Aerospace grade |
| UV / Weather Resistance | Poor / Yellowing | Fair | Prone to yellowing | Fair | Excellent, no discoloration |
| UV-Blocking Function | None | None | None | None | NT-HU Series (99%+) |
| Transmittance Control | None | None | None | None | SM Series, customizable (e.g. 70%) |
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