Patent ID: 6312542
Filing Date: 2001-11-06
Classification: D04H,G10K,Y10T

Abstract:
A method for producing a fibrous acoustical material for reducing noise transmission, said fibrous acoustical material comprising:(a) a first fiber having a first fineness of from 1.5 to 20 deniers and a first softening point;(b) a second fiber having a second fineness of from 1.5 to 15 deniers, at least a surface of said second fiber having a second softening point which is at least 30.degree. C. lower than said first softening point by; and(c) a third fiber having a third fineness of from 1.5 to 15 deniers, at least a surface of said third fiber having a third softening point which is lower than said second softening point and at least 80.degree. C. lower than said first softening point,wherein said first, second and third fibers are respectively in amounts of 10-90 wt %, 5-85 wt % and 5-85 wt %, based on a total weight of said first, second and third fibers,wherein said first, second and third fibers are each within a range of from 20 to 100 mm in average fiber length,wherein said fibrous acoustical material has an average apparent density of from 0.01 to 0.8 g/cm.sup.3,said method comprising the following steps of:(1) preparing a mixture of said first, second and third fibers;(2) piling said mixture to form a web of said mixture;(3) compressing said web into a compressed web; and(4) heating said compressed web at a temperature between said first softening point of said first fiber and said second softening point of said second fiber, thereby to prepare said fibrous acoustical material having a thickness of from 2 to 80 mm.