| This study was devoted to an investigation of applying radiation-curable binders to nonwoven fabrics and of the effects of binder properties, binder composition, and adhesion on the properties of radiation-cured nonwoven fabrics.;The relationship between the factors of the binder properties and the resulting bonded fabric properties was studied with radiation-cured binders. A series of different compositions of acrylo-urethane oligomers and monomers was cured by electron beam for either film study or binder study in the nonwovens. For the nonwovens bonded with flexible binders, the binder toughness, in addition to the binder strength, was found to contribute to fabric strength. The addition of small amounts of chain transfer agents in the binder formulation, which increased the binder toughness, seems to be a good way to improve nonwoven fabric strength without much increase in fabric stiffness. For the stiff binders, increasing the tenacity of the fiber is the only way to improve fabric strength. The surfactant added to the flexible binder formulations lowered the fabric strength, probably due to the lower adhesion by the presence of surfactant. Improvement of adhesion by exposure to ultraviolet to produce fiber surface oxidation, however, had no effect or even decreased the fabric strength, probably due to the reduced bond strength caused by the decreased contact angle.;The nonwoven fabrics bonded with radiation-curable binders were compared with those bonded with conventional latex binders. Their properties were comparable to those of fabrics treated with latex. Needle-punching was studied as a possible tool for distributing the fairly viscous radiation-curable binders in the thick and heavy webs. The effects of higher needling intensity and calendering were found in better binder distribution and making the fabrics thinner, more isotropic, smoother and stronger. |
