| 摘要 |
869,673. Agglutinated fibrous materials. COMPAGNIE DE SAINT-GOBAIN. Nov. 3, 1958 [Nov. 7, 1957], No. 35188/58. Class 140. A process for manufacturing sheets, boards and shaped pieces of thermoplastic mineral fibres comprises subjecting the major surfaces of a mat to a sudden increase in temperature such as to cause a reduction in the mat thickness and at the same time subjecting the mat to tension such that there is little reduction in the size of the mat other than in thickness. As shown, a funnel furnace 1 has electric resistance heating elements 2, 2a and driven idlers 3 and 3a in which is carried the mat 4 of fibres being treated. Rollers 3 are cooled and their speed is slightly less than that of the sheet. Adjacent the outlet of the furnace are cooled calender rolls 5 and 5a, which draw the sheet through the furnace, and immediately beyond are boxes 7 and 7a having a cooling fluid passing through them, and beyond these are driven rollers 8 and 8a whose peripheral speed is a little higher than the speed of the sheet. Before treatment in the above process the fibres can have been agglomerated, felted and bonded together to form the mat. On entering the furnace the mat is thick and upon its upper and lower surfaces being subjected to heat from elements Z and Za it undergoes a collapse which is progressive and very rapid. The mat may be formed of at least two different categories of fibres consisting of a material of the same composition but of different thermoplastic properties in that one has a softening point substantially lower than the other. |
