Heat-cured powder adhesive for high-strength composites - has homogeneous mixt. of solid and liq. epoxy] resins, PVAC plastomer, hardener and/or fillers

摘要

One-component solvent-free, heat-curing, epoxide/ plastomer-based powder adhesive (I) for high-strength composites consists of a homogeneous mixt. of solid and liq. epoxy esins with PVAc plastomer and hardener, and possibly other additives such as elastomers, accelerators, and/or fillers. (I) is produced by mixing the resin mixt. and the PVAc in a kneader, opt. with heating, esp. at 150-180 deg.C, allowing to cool and granulating at room temp. or with cooling, incorporating the hardener (and opt. accelerator), and processing the mixt. at room temp. or below to a free-flowing powder, pref. in a turbo-mill. (I) contains 15-50 (esp. 20-40) wt.% liq. epoxy resin, 10-40 (esp. 15-35) wt.% solid epoxy resin, 10-45 (esp. 15-35) wt.% PVAc, 2.5-10 (esp. 4-8) wt.% hardener, 0-15 (esp. 1-2) wt.% accelerator and 0-90 (esp. 1.5-4.5) wt.% filler; (I) contains nitrile rubber as elastomer, dicyandiamide as hardener and mineral additives as filler; pref. (I) contains 6.0 pts.wt. liq. epoxy resin, 6.2 pts.wt. solid epoxy resin, 5.0 pts.wt. PVAc, 1.0 pt. wt. hardener, 1.0 pt.wt. elastomer, 0.3 pt.wt. accelerator and 0.5 pt.wt. filler. USE/ADVANTAGE - (I) Is useful for bonding friction linings with steel, esp. in brake and clutch linings for vehicles (claimed). The invention provides a homogeneous, 1-component adhesive which meets the demanding requirements for this application (high bond strength, high temp. stability, etc.) (contrast prior-art solvent-free powder adhesives).