موردو جملة المواد اللاصقة والمانعة للتسرب

Epoxy adhesives: two-component systems (A+B mix ratio 1:1 or 2:1) for high-strength bonding (lap shear >25 MPa), gap-filling and potting; single-component heat-cure for electronics. Polyurethane adhesives: flexible 1K or 2K for automotive windscreens (FMVSS 212), wood lamination, and sandwich panels; contact adhesives for footwear. Silicone sealants: acetoxy (acetic acid byproduct) and neutral cure (oxime, alkoxy); high-temp resistance to 300°C (Momentive RTV, Dow Corning); food-grade silicone (FDA 21 CFR 177.2600). Hot-melt adhesives: EVA-based for packaging and bookbinding; polyolefin and metallocene for low-odour food packaging; PUR hot-melt for woodworking laminates (water-resistant). PSA: acrylic emulsion or solvent PSA for labels, tapes, and medical dressings; rubber/resin PSA for masking tape. Cyanoacrylate: instant bonding of metals, plastics, rubber; 1–10 cps for gap filling.

Key mechanical tests: ASTM D1002 (lap shear, aluminium substrates, gives MPa); ASTM D897 (tensile adhesion); ASTM D1876 (peel T-test); ASTM D3163 (adhesive comparison lap shear — bonded plastic). ISO 4587 (lap shear — bonded assemblies) is the European equivalent. Structural adhesives achieve lap shear 15–35 MPa; hot-melts typically 2–8 MPa; PSA peel strength 5–30 N/25mm. Always request test data on the relevant substrate (metal, plastic, glass, wood) as adhesion performance varies significantly by substrate surface energy and preparation.

Silicone sealants: continuous operating temperature −60°C to +300°C; some high-performance grades to +350°C (Dow Corning 730). Epoxy: −40°C to +120°C continuous (−55°C to +175°C with elevated-cure high-Tg systems). Polyurethane: −40°C to +90°C; good chemical resistance to oils and fuels. Cyanoacrylate: poor resistance to water/moisture long-term (bond degrades) and temperatures >80°C. For automotive underbonnet applications requiring 150°C+ resistance: two-component methacrylate or epoxy structural adhesives. For fuel and oil resistance: MS polymer (modified silicone) sealants outperform standard polyurethane.

Solvent-borne adhesives and sealants are regulated under the EU Industrial Emissions Directive (IED 2010/75/EU) and the Paints Directive (2004/42/EC). VOC content limits apply per product category: interior wall and ceiling primers (30 g/L max); high-gloss exterior coatings (300 g/L max). For contact adhesives: chlorinated solvent adhesives (DCM-based) face restrictions; neoprene contact adhesives must reduce VOC to <200 g/L. Water-based PSAs and hot-melts are typically <50 g/L VOC. REACH registration required for solvents in adhesive formulations. Request VOC declaration sheet from suppliers.