Adesivos Sensíveis à Pressão Produtos Químicos
Químicos para adesivos sensíveis à pressão (PSA) incluem emulsões acrílicas e acrílicos em solução, compostos de borracha natural e sintética, resinas tackificantes (ésteres de resina de colofônia, resinas de hidrocarbonetos) e agentes de reticulação para rótulos, fitas, produtos médicos e filmes de proteção. Nossas matérias-primas PSA são otimizadas para excelente pegajosidade inicial, resistência ao pelado e resistência ao cisalhamento.
Perguntas Frequentes — Adesivos Sensíveis à Pressão Produtos Químicos
What are the main polymer systems used in pressure-sensitive adhesives?
Acrylic PSAs (solvent-based acrylic copolymers or acrylic emulsions) dominate the label and tape markets due to excellent UV and aging resistance, clarity, and formulatability. Natural rubber-based PSAs provide unmatched initial tack (quick stick) and are used in masking tapes and general-purpose applications. Silicone PSAs are used for medical skin contact and high-temperature applications.
What is the role of tackifier resins in PSA formulation?
Tackifier resins increase tack (initial grab), peel strength, and adhesion of base polymers. Rosin esters (hydrogenated, disproportionated) and C5/C9 hydrocarbon resins are the main types. Low softening point tackifiers increase tack; higher softening point resins increase cohesive strength. Selection depends on polymer compatibility and the required tack-peel-shear balance.
How are PSA crosslinkers used and what do they achieve?
Crosslinkers in PSAs increase cohesive strength (shear resistance) and reduce cold flow without significantly reducing tack and peel. In acrylic PSAs, aluminum acetylacetonate (Al-AcAc), isocyanates, or aziridines are added at 0.05–2% on binder. UV crosslinking using benzophenone-type initiators is used in UV-crosslinked PSA tapes. Over-crosslinking causes brittle film with poor tack — the balance is critical.
What test methods characterize PSA performance?
Standard PSA tests are: 180° peel (PSTC-101 or FINAT FTM 1), loop tack (FTM 9), and shear adhesion (FTM 8 or PSTC-107). Peel measures bond strength to substrate, tack measures initial grab, and shear measures cohesive strength. Each must be balanced for the application — labels need high tack and low shear, while industrial duct tape needs high shear with controlled peel.
How are removable and repositionable PSAs formulated?
Removable PSAs use lower-MW base polymers, selectively compatible tackifiers, and often microsphere geometry to limit substrate contact area. Acrylic microsphere PSAs (the Post-it Note technology) achieve true repositionability through partial wetting. Removable adhesion is typically 1–4 N/inch peel — enough to hold but allowing clean removal without residue, even after long storage.
How do solventborne and waterborne PSAs differ in performance?
Solventborne acrylic PSAs offer the highest performance — superior peel/shear balance, optical clarity, and aging — but VOC regulations are pushing replacement. Waterborne acrylic emulsion PSAs have closed most of the performance gap and dominate label adhesives now. Hot-melt PSAs (SBS/SIS/SEBS-based) offer 100% solids and fast processing for tape applications. Each chemistry has different processing requirements and equipment needs.
Procura matérias-primas específicas?
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