PROCESS FOR THE PRODUCTION OF HEAT-ACTIVATABLE MATS FREE FROM SUPPORTS AND RELEASE AGENTS AND THEIR USE FOR BONDING VARIOUS SUBSTRATES

摘要

A PROCESS FOR THE PRODUCTION OF HEAT-ACTIVATABLE MATS FREE FROM SUPPORTS AND RELEASE AGENTS AND THEIR USE FOR BONDING VARIOUS SUBSTRATES A b s t r a c t The invention relates to a process for the production of heat-activatable mats based on hydroxyl polyester polyurethanes which are free from supports and release agents and which have viscosities of 600 to 3500 mPa.s, measured as solution viscosity in methyl ethyl ketone (15% Brookfield LVT viscosimeter, spindle 3, 60 r.p.m., 23.degree.C) and weights per unit area of 5 to 200 g/m2, characterized in that the mats are produced by melt blowing (for example REICOFIL? melt blowing process) at melt temperatures in the range from 230 to 260.degree.C using a receiving conveyor belt of which the constituent material has a surface tension of 18.5x10-5 N/cm to 46x10-5 N/cm. The mats produced by the process according to the invention can be wound into rolls without blocking despite the absence of release agents or spacers and are eminently suitable for bonding various substrates.