초록 ▼

New, flexible intumescent protection sheeting of unusually uniform thickness have been prepared from epoxy-polysulfide compositions containing microfibers and the ammonium salt of 1,4-nitroaniline-2-sulfonic acid, as disclosed in U.S. Pat. No. 3,663,464, except that an ammonium salt particle size in

New, flexible intumescent protection sheeting of unusually uniform thickness have been prepared from epoxy-polysulfide compositions containing microfibers and the ammonium salt of 1,4-nitroaniline-2-sulfonic acid, as disclosed in U.S. Pat. No. 3,663,464, except that an ammonium salt particle size in the order of 5 to 8 microns and a fiber size of about 1/128th inch in length and 3 to 5 microns in diameter have been found critical to obtain the required density of 1.46 to 1.50 g/cc. The insulation sheeting is prepared by a continuous process involving vacuum mixing, calendering, and curing under very strict conditions which depend to some extent upon the thickness of the sheet produced. The resulting flexible sheet can be wrapped easily and tightly around small diameter missiles, thus affording them for the first time, protection from fire for at least 5 minutes. The material is also suited for the protection of other articles with convoluted or contoured surfaces, which require covering of highly uniform thickness.

대표청구항 ▼

A process for the manufacture of thermal protection sheeting of uniform composition and thickness, which comprises: preparing by vacuum mixing an intumescent paste which comprises: (a) an epoxy resin and (b) a mercaptan-terminated polysulfide polymer having a molecular weight within the range of 600

A process for the manufacture of thermal protection sheeting of uniform composition and thickness, which comprises: preparing by vacuum mixing an intumescent paste which comprises: (a) an epoxy resin and (b) a mercaptan-terminated polysulfide polymer having a molecular weight within the range of 600 to 8000, said resin and polymer being present in proportions such that the glass transition temperature of the mixture is at or below room temperature, (c) 20 to 95% by weight, based on the resin-polymer mixture, of ammonium 4-nitroaniline-2-sulfonate having a particle size not greater than about 10 microns; (d) about 2 to 10 parts by weight of microfibers having an average length of within the range of about 1/64 to 1/128 inch and an average diameter of 3 to 5 microns; and (e) up to about 12% of the epoxy resin weight of an amine curing agent; calendering the paste to form a sheet having a thickness within the range of about 0.010 to 0.100 inch; cutting the sheet obtained into missile wrapping lengths; and within 20 minutes of the amine curing agent addition, heating the sheet rapidly to 90°C. and keeping it at 90°C. for a period of exactly 5 to 5.5 minutes.