Adhesive type
What is OCA approved by car manufacturers?
It is a highly reliable OCA that achieves both high adhesion and stretchiness, which was not possible with conventional acrylic and silicone OCAs. It enables optimizing of various components, and passes the Automotive spec reliability tests.
Three features of BANDO OCA
Wide thickness range
300-2000 μm
Good Color change resistance
High adhesion & Stretchiness
Basic data
| Category | Test Items | Test method / conditions | NT series 0.5mm(t) |
|
|---|---|---|---|---|
| Optical properties | Haze (%) | Haze meter (Glass / OCA / Glass configuration) |
room temperature | 0.5＞ |
| Total light transmittance (%) | Haze meter (Glass / OCA / Glass configuration) |
room temperature | 91＜ | |
| b* | Haze meter (Glass / OCA / Glass configuration) |
room temperature | 0.5＞ | |
| Refractive index | JIS K 7142 | T=23℃ l=589nm (Na, D Line) |
1.48 | |
| Adhesive properties | 180 ° peel strength (N/25mm) |
Peeling speed: 30 mm / min | vs Glass | 38 |
| vs PC （Polycarbonate） |
28 | |||
| vs Polarizer (TAC) | 25 | |||
* Values are measured values, not guaranteed values.
Customer evaluation pass record
| Category | Test items | Test method / conditions | Remarks | |
|---|---|---|---|---|
| Optical reliability test | High temperature test | 95℃ | 1000 hours | Depending on the customer, passed 105 ℃ |
| Low temperature test | -40℃ | 1000 hours | Automotive industry standard | |
| High temperature and high humidity test | 85℃ 85% | 1000 hours | Automotive industry standard | |
| Thermal shock test | -40℃⇔90℃ | 1000 cycles | Automotive industry standard | |
| UV test | Customer specification conditions | 1000 hours | JIS D0205、 DIN75220etc |
|
| Other | High altitude test | MIL-STD810 | Pass | ― |
* Values are actual measurements, not guaranteed values.
In the optical reliability test, the acceptance criteria are that there is no whitening, yellowing, delamination, delayed bubbles, abnormal operation, display MURA, etc. after the test.
General challenges in optical bonding
Bubbles / Delamination
Bubble and Delamination in the reliability test
Display MURA
Display MURA (ripple) by the uneven bonding
Color Change
Whitening or yellowing for reliability tests and long-term use
Cost Reduction
Long production time for lamination process. Low yield rate.
Free Crystal solves these challenges!
Bonding reliability which can pass the tough reliability tests
No bubbles and/or delamination occur even in the reliability test of Automotive specifications and the high altitude test for avionics applications (equivalent to an altitude of 55,000 ft).
Both high adhesion and stretchiness
High bonding performance and stress relief during bonding due to its high adhesion and flexibility. Even when bonded to a curved surface or plastic cover, delamination and display MURA will not occur.
Excellent optical reliability with a good color change resistance
Even when exposed to sunlight or high temperature for a long time, whitening and yellowing are unlikely to occur, and the design and visibility of the product are not impaired.
Shortening process time and reducing material loss
Lineup from 300 to 2000 μm OCA thickness. The process time required for OCA multi-layering and OCR lamination can be reduced. No UV or heat curing process is required.
Reworking is possible and the loss of parts in the bonding process is reduced.
Customer reviews
It was difficult to achieve both bonding quality and display quality in curved designs, which is a trend of Automotive displays, especially for those with a sharp curvature. When Free Crystal is used, the reliability test is passed even for curved surface bonding with R = 500. Both the bonding quality and the display quality have been passed the tests, and it has become possible to propose to end customers.
All other OCAs failed when bonded to a special plastic material, but Free Crystal was the only one to pass. Until now, we have been considering OCA for each components, but we expect that Free Crystal will be able to handle a wide range of components and shorten the examination time.
We were in trouble because there was no super-thick OCA that passed the high altitude test equivalent to 55,000ft, but Free Crystal passed the test. We were able to meet customer requirements in a short period of time.
We were considering another company's OCA, but we were in trouble because of bubbles and yellowing in the UV test. It was solved by changing to Free Crystal, and the development proceeded as planned.
In the outdoor display project, the OCA used in the past could not pass the UV test due to yellowing. By adopting Free Crystal, we were able to pass the test and receive an purchase order for the project.
Super-thick OCA of other companies had troubles such as delay bubbles due to deformation during handling and bonding in the lamination process. Since Free Crystal has moderate elasticity, handling was improved, process margin has expanded, and productivity was improved.
We used to apply 5 or 6 types of OCR depending on the component, but by using Free Crystal, we can cover all the projects by one OCA. Bonding materials can be unified, and management has become easier.
Good that neither UV curing nor heat curing is required! It also shortens the time, does not shrink due to curing, and is less likely to cause display MURA.
We also support your bonding!
Self-healing type
An optical film that has both flexibility and robustness that surprised the world
Self-healing type application examples
Self-healing surface protection sheet
Foldable display cover
Easy Writability sheet
Basic data
| Category | Test items | Test method / conditions | F101 0.1mm(t) |
|
|---|---|---|---|---|
| Optical properties | Haze (%) | Haze meter | room temperature | 1.0＞ |
| Total light transmittance (%) | Haze meter | room temperature | 91＜ | |
| b* | Haze meter | room temperature | 0.5＞ | |
| Refractive index | JIS K 7142 | T=23℃ l=589nm (Na, D Line) |
1.51 | |
| Mechanical characteristics | Repeated bending | Curvature radius: 1.0mm Speed：60r/min Thickness：100µm Inner fold & outer fold |
100,000 times | No change in appearance*1 |
| 200,000 times | No change in appearance*1 | |||
| 300,000 times | No change in appearance*1 | |||
| Pencil hardness | BANDO test method based on JIS-K5600 | 6H*2 | ||
* Values are actual measurements, not guaranteed values.
* 1 The deformation of the folds recovers over time.
* 2 Results will vary depending on the structure of the test piece.
Method of repeated bending evaluation
Image of repeated bending test
Hold the sample horizontally to the tilt clamp, and repeat bending.
Other company's PI film (folding line can be seen)
Our PU film (no folding line)
Self-healing type product
Self-healing sheet
Easy writability sheet
Bendable sheet
Foldable cover sheet