Fibrous product

Abstract

A resilient, thermally bonded, non-woven fibrous batt having a uniform compression modulus in one plane which is more than the compression modulus measured in a direction perpendicular to that plane, and a substantially uniform density across its thickness is obtained by preparing a batt comprising at least 20% by weight of crimped and/or crimpable conjugate fibres having or capable of developing a crimp frequency of less than 10 crimps per extended cm. and a decitex in the range of 5 to 30. The batt is thermally bonded by subjecting it to an upward flow of a fluid heated to a temperature sufficient to heat the batt to a temperature in excess of the softening temperature of the low softening component but below the softening temperature(s) of the other component(s) of the conjugate fibre to effect inter-fibre bonding. The thermally bonded batt is then cooled by an upward flow of cool air.

What I claim is: 
     
       1. In a method for the production of a low-density, high porosity, resilient, thermally bonded, non-woven fibrous batt having a substantially uniform density across its thickness by the steps of forming a lofty fibrous batt from at least 20% by weight of conjugated staple fibres having a length of 0.5 to 6 inches and being selected from the group consisting of crimped and potentially crimpable fibres, the conjugate fibres being composed of at least two fibre forming polymeric components arranged in distinct zones across the cross-section of the fibre and substantially continuous along the length thereof, one of the components having a softening temperature significantly lower than the softening temperature of a second component and being located so as to form at least a portion of the peripheral surface of the fibre, subjecting said batt to a heat treatment to heat the batt to a temperature in excess of the softening temperature of the component having the lower softening temperature but below the softening temperature of the second component to effect inter-fibre bonding, and then causing .[.or permitting.]. the batt to cool, the improvement comprising heating the batt by passing a heated gas upwardly through the batt, the gas having a temperature sufficient to effect thermal bonding of the conjugate fibres and having a velocity such that the batt is supported by the gas in a high-porosity condition without disintegrating the batt therein .Iadd.and causing the batt to cool by an upward passage of cooling air through the batt to quench the fibres and permit them to rapidly redevelop their modulus, .Iaddend.whereby the resulting batt has substantially uniform density across its thickness. .[.2. A method for the production of a resilient, bonded, non-woven fibrous batt as in claim 1 including cooling the thermally bonded batt by 
     
     
        an updraught of cold air..]. 3. A method for the production of a resilient, bonded, non-woven fibrous batt as in claim 1 including 
     
     
        compressing the thermally bonded batt before the cooling stage. 4. A method for the production of a resilient, bonded, non-woven fibrous batt as in claim 1 wherein the fibres have or are capable of developing a crimp 
     
     
        frequency of less that 10 crimps per extended centimeter. 5. A method for the production of a resilient, bonded, non-woven fibrous batt as in claim 1 wherein the conjugate fibres have or are capable of developing a crimp frequency of less than 10 crimps per extended centimeter and a decitex in 
     
     
        the range 5 to 30. 6. A method as in claim 1 wherein the upward stream of gas blows the batt against a foraminous surface disposed above the batt. .[.7. An improved low density, high porosity, resilient, thermally bonded, non-woven fibrous batt having a substantially non-uniform density across its width, made by the process of claim 1..].