Optimizing Adhesive Layers for Self-Adhesive Protective Films
Self-adhesive protective films are used to protect the surfaces of optical components (prisms, light guides, etc.) and building materials (resin sheets, metal sheets, etc.). TUFTEC™ and S.O.E.™ provide “control of adhesive strength”, “suppression of adhesive enhancement”, and “prevention of adhesive residue”.
TUFTEC™ and S.O.E.™ Offer a Wide Range of Adhesive Strengths
Self-adhesive protective films are in high demand because they do not use organic solvents unlike coating-type protective films, which contributes to reducing environmental impact and improving working conditions.
Among the performance requirements for such self-adhesive protective films, adhesive strength is a crucial property. Self-adhesive protective films must adhere firmly to the substrate and maintain a secure bond. However, the load should be minimized when unrolled the film or peeling it from the substrate. Therefore, the adhesive layer of self-adhesive protective films requires delicate control of adhesive strength.
TUFTEC™ and S.O.E.™ are SEBS materials ideally suited for controlling the adhesive strength of such self-adhesive protective films. They offer a wide range of grades suitable for adhesive strengths ranging from weak to strong. By blending various grades, it is also possible to adjust the adhesive strength.
Suppressing Adhesive Enhancement in Protective Films
When applying protective films to substrates with uneven surfaces, such as prisms, prolonged exposure to heat or environments with temperature fluctuations can lead to increased adhesive strength (adhesive enhancement), making it difficult to peel off the film.
TUFTEC™ and S.O.E.™ exhibit low temperature dependency in their storage modulus (G’), resulting in stable adhesive strength across a wide temperature range. This effectively prevents adhesive enhancement in protective films.
S.O.E.™ Improves Film Unrolled Properties
Polyolefin resins such as polypropylene (PP) and polyethylene (PE) are commonly used as the base layer for protective films. When materials with similar solubility parameters (SP) to the base layer are used in the adhesive layer, excessive adhesion between the adhesive layer and base layer occurs, leading to poor film unrolled properties from the roll.
While reducing adhesion between the adhesive layer and base layer can be achieved by decreasing their affinity, it generally results in a trade-off, leading to reduced adhesive strength.
S.O.E.™ offers a variety of grades with different SP values due to its unique molecular design technology. By adding an appropriate SP value grade to the adhesive layer, the affinity with the olefin-based base material can be adjusted to an appropriate level. This characteristic of S.O.E.™ allows for the creation of protective films that maintain adhesion to the substrate while achieving excellent unrolled properties.
Prevents Adhesive Residue on the Substrate and Achieves Cleanliness
Tackifiers are generally used as adhesives in the adhesive layer of protective films. However, these tackifiers can remain on the surface of the substrate, resulting in “adhesive residue”, which can contaminate the substrate.
S.O.E.™ has a higher SP value compared to other SEBS materials, exhibiting excellent compatibility with various tackifiers. This characteristic is expected to reduce “adhesive residue” where tackifiers transfer to the substrate.
