High Performance Silicone-based Material, Enabling Breakthrough Foldable Consumer Display Devices

Votes: 5
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The latest foldable display provides a larger screen in less space for a more vivid immersion experience. In these devices, non-metallic materials such as organic foam films (polyurethane, polyether) or high filler-loaded silicone rubber are applied around the metal hinge frame and in other important areas to prevent cracking in the bendable area. However, these designs are less compatible with organic foam films and silicone rubbers with fillers due to their low folding durability.

DOWSIL™ VE-8001 Flexible Silicone Adhesive, a two-part solution for flexible display applications in foldable and rollable consumer devices, provides high-stress neutral line and good elongation for the small folding radius in electronic displays. It is based on thermal curing (80°C for 30 minutes at 300 um thickness) and provides stable mechanical properties after repeated dynamic and static folding for foldable and rollable display devices.

DOWSIL™ VE-8001 Flexible Silicone Adhesive provides an overwhelming performance improvement over competitive technologies in the following aspects:

1. Excellent folding durability
Previous materials used in foldable displays suffered from failure due to deterioration in material properties within 200,000 cycles of the folding durability test. This is the reason why display applications that can be folded or rolled require an elastic material that can dissipate the stress when folded or bent. VE-8001 optimizes the stress dissipation function by introducing silicone resin into the material formulation. This resin improves the elongation and tensile strength of the product, increasing the folding durability without abrasive inorganic fillers. VE-8001 clearly offers superior folding performance compared to competing materials on the market.

2. Reliability improvement
The siloxane backbone structure of VE-8001 provides excellent environmental reliability in a variety of harsh conditions. VE-8001 with the strong siloxane (Si-O) backbone structure provides stable performance compared to the organic carbon-carbon (C-C) backbone. When organic material is applied to the hinge frame of the foldable display, it shows folding durability that can withstand room temperature and room humidity. However, organic material rapidly changes its mechanical properties and loses its folding durability under conditions of 105°C, -40°C, -40°C to 95°C thermal cycle and high temperature and high humidity (85°C/85% RH).

3. Good processability
VE-8001 offers superior processability with a lower viscosity than conventional liquid silicone rubber. Low viscosity allows for faster fluidity in dispensing and mixing processes. And VE-8001 has achieved low viscosity by replacing conventional inorganic fillers with silicone resin in the formulation. VE-8001 with its excellent processability helps reduce overall manufacturing costs.

4. High adhesion
Strong adhesion to the metal frame is very important for the durability and quality of the foldable display. To achieve good adhesion to metal frames, VE-8001 uses an epoxy-functional silane-based adhesion promoter. Silicone elastomers and rubbers themselves have little or no adhesion properties to a variety of substrates, including stainless steel. So VE-8001 uses a heat curing mechanism based on a heat-activated epoxy ring-opening process.

These performance advantages allow consumers to develop a variety of foldable electronics with DOWSIL™ VE-8001 Flexible Silicone Adhesive.

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  • ABOUT THE ENTRANT

  • Name:
    Steven Kim
  • Type of entry:
    team
    Team members:
    Steven Kim (Leader), Johnny Park, Tae-Seung Lee, Youngno Lee, BK Park, Hugh Kim, Minji Jeong, Lucas Lee, Jayden Cho
  • Profession:
    Engineer/Designer
  • Steven is inspired by:
    To meet the needs of the foldable market, Dow has developed DOWSIL™ VE-8001 Flexible Silicone Adhesive with overwhelming performance compared to competing technologies.
    For excellent folding durability performance, inorganic fillers are substituted with “Silicone Resin”. Dow found that good elongation and tensile strength are critical for fold durability function. Generally, inorganic fillers are used to reinforce the silicone network. However, the fillers cause lower folding durability due to rough surface by scratching the hinge frame on flexible display when it is applied with the low thickness (300 μm). The silicone resin is blended in the silicone matrix and enhances mechanical strength.
  • Software used for this entry:
    JMP used for DOE
  • Patent status:
    patented