Method for bonding fibrous web materials
AssigneeFirma Carl Freudenberg
InventorsWalter Fottinger, Bohuslav Tecl, Erich Fahrbach
Life of this patent
Estimating the term…
Abstract
A method for bonding an unbonded fibrous web of natural and/or synthetic fibers by means of a binder which is cured by exposure to UV light, wherein the fibrous web is first compressed, smoothed, and heated, then one or both surfaces of the web is printed with a pattern of a prepolymer binder having a viscosity of from about 500 to 5000 centipoise and the prepolymer binder is cured by exposing the printed fibrous web to ultraviolet light.
Claims19
A method for bonding a fibrous web comprising the steps of:
- (a) compressing and smoothing a fibrous web by passing said web through heated rollers, said rollers being at a temperature at least about 20.degree. C. below the melting point of the fibers comprising said web, and wherein said fibrous web is heated by said rollers but the fibers comprising said web are not bonded together;
- and
- (b) applying a UV hardenable solvent-free prepolymer binder composition to said fibrous web, said prepolymer having a viscosity of from about 500 to about 5000 centipoise during application;
- and
- (c) curing said prepolymer binder by exposing said treated fibrous web to ultraviolet radiation.
In a method for bonding a fibrous web by printing a prepolymer binder onto one or both surfaces of the fibrous web, and subsequently cross-linking said prepolymer binder, the improvement which comprises:
- (a) compressing, smoothing and heating said fibrous web immediately prior to printing a solvent-free prepolymer binder onto said web, wherein said fibrous web is passed through rollers heated to a temperature at least about 20.degree. C. below the melting point of the fibers comprising said web, such that said web is compressed, smoothed and heated but the fibers of said web are not bonded together and wherein said prepolymer binder has a viscosity of from about 500 to 5000 centipoise, and is printed onto said fibrous web in an amount comprising from about 5 to about 30% of the weight of said fibrous web;
- and
- (b) subsequent to printing said prepolymer binder onto said fibrous web, immediately exposing said fibrous web to ultraviolet light to cure said prepolymer binder.
Dependencies are inferred from the claim text.