Techniques for producing an article having hollow structures are described herein. The disclosed techniques include weaving a plurality of yarns to form a woven fabric, wherein the plurality of yams each comprise a dissolvable core, and the dissolvable core comprises polyvinyl alcohol (PVA) having a water solubility; neutralizing an alkaline before drying the woven fabric to maintain the water solubility of the PVA; and washing the woven fabric or a garment made by the woven fabric to at least partially remove the dissolvable core.

A system and method of generating a coiled actuator fiber. The method includes twisting a fiber to generate a twisted fiber, wrapping the twisted fiber around a core to generate a coil in the twisted fiber; and removing at least a portion of the core to generate a coiled actuator fiber. In some aspects that fiber can be a yarn with one or more fibers or a fiber comprising a single elongated element. In some aspects, a portion of the core includes a removable sacrificial portion. The removable sacrificial portion can be dissolvable in a solvent or physically removable. In some aspects, the core further includes a non-dissolvable portion that is not dissolvable and generating a coiled actuator can include removing the sacrificial portion by treating a twisted fiber on the core to remove the sacrificial portion and leaving the non-dissolvable portion.

A filamentary core for an elastic composite yarn, particularly for an elastic textile composite yarn, comprising at least two elastic performance filaments, wherein each of the at least two elastic performance filaments is capable of being stretched at least about 2 times its package length and has at least 90% up to 100% elastic recovery after having being released from a stretching 2 times its package length.

A filamentary core (3) for an elastic composite yarn (1), particularly for an elastic textile composite yarn, comprising at least two elastic performance filaments (11, 13), each of the at least two elastic performance filaments capable of being stretched at least about 2 times its package length and having at least 90% up to 100% elastic recovery after having being released from a stretching 2 times its package length.

A method for producing a compression garment for a user from an elastic fabric comprises the step of providing a base garment, fitting the garment on a supporting mannequin that has a plurality of independent heating means to independently heat different portions of the garment, measuring the compression applied to the mannequin portions by the garment and heating selected portions of the garment until the compression of the garment on the mannequin has reached a desired value.

In a stretch yarn (1) comprising a stretchable core (2) covered by an inelastic fibers sheath (3) the stretchable core (2) comprises first and second fibers (4, 5) that have elastic properties, the first fiber (4) is an elastomer and the second fiber (5) is a polyester based (co)polymer, the amount of the second fiber being in the range of 60-90% (w/w) of the total weight of the fibers of the stretchable core (2); the first and second fibers are connected together at least at a plurality of points (P).

In a stretch yarn (1) comprising a stretchable core (2) covered by an inelastic fibers sheath (3) the stretchable core (2) comprises first and second fibers (4, 5) that have elastic properties, the first fiber (4) is an elastomer and the second fiber (5) is a polyester based (co)polymer, the amount of the second fiber being in the range of 60-90% (w/w) of the total weight of the fibers of the stretchable core (2); the first and second fibers are connected together at least at a plurality of points (P).

A substantially hollow structured elastic core-spun yarn has a dissoluble core and main stretch core covered with single or multiple slivers. The dissoluble core would be partially or totally removed in yarn processing, or fabric finishing, or garment finishing, and removed with combination of different stages' processing.

A system and method of generating a coiled actuator fiber. The method includes twisting a fiber to generate a twisted fiber, wrapping the twisted fiber around a core to generate a coil in the twisted fiber; and removing at least a portion of the core to generate a coiled actuator fiber. In some aspects that fiber can be a yarn with one or more fibers or a fiber comprising a single elongated element. In some aspects, a portion of the core includes a removable sacrificial portion. The removable sacrificial portion can be dissolvable in a solvent or physically removable. In some aspects, the core further includes a non-dissolvable portion that is not dissolvable and generating a coiled actuator can include removing the sacrificial portion by treating a twisted fiber on the core to remove the sacrificial portion and leaving the non-dissolvable portion.

A filamentary core (3) for an elastic composite yarn (1), particularly for an elastic textile composite yarn, comprising at least two elastic performance filaments (11, 13), each of the at least two elastic performance filaments capable of being stretched at least about 2 times its package length and having at least 90% up to 100% elastic recovery after having being released from a stretching 2 times its package length.