Reworkable Adhesive Composition for Optical Electronics

The patent applies parameter changes by utilizing temperature-dependent glass transition behavior of (meth)acrylic polymers. The adhesive is formulated with specific glass transition temperatures (Tg) that allow it to be rigid and strong at room temperature, then become soft and reworkable at elevated temperatures (above 60°C). This resolves the contradiction by changing the physical state parameter (Tg) based on temperature conditions.

The adhesive exhibits dynamic properties that change with temperature. At room temperature, the polymer chains are frozen in a glassy state providing high strength. When heated above 60°C, the material transitions to a rubbery state where chains can move, enabling reworkability. This dynamic behavior resolves the contradiction between strength and reworkability.

The patent utilizes the glass transition temperature parameter to achieve a balance between strength and flexibility. The (meth)acrylic polymer with controlled Tg provides a rubbery phase that imparts flexibility and elongation at break, while the crosslinked network maintains bonding strength. This resolves the contradiction by optimizing the Tg parameter.

The adhesive forms a composite structure combining crosslinked polymer networks (for strength) with rubbery phases or plasticizers (for flexibility). This composite approach allows simultaneous achievement of high bond strength and material flexibility to accommodate substrate expansion and contraction.