A method of preparing an electret by saturating a nonwoven fabric with a liquid, such as water, and removing the liquid via suction to generate charges by friction between the fabric fibers and the liquid is described. The saturating can be carried out, for example, by impinging the bottom side of the fabric with a jet or jets of water while the fabric is being pulled under a solid roller. Excess water can also be applied during a water quenching step of a meltblowing or spunbonding process. An apparatus for preparing an electret according to the presently disclosed methods is also described.

The electret of the present invention comprises 90 mass % or more of polyolefin resin; 0.1 to 5 mass % of a hindered phenol compound having an amide bond; and 0.1 to 5 mass % of a nitrogen-containing compound having a hydroxylamine structure.

[Problem] Provided are an electret material which has high charge retention ability and elasticity, and a skin-patch type electret energy harvesting device using the same.

[Solution] An iodine- and/or bromine-containing perfluoroelastomer or a crosslinked elastomer formed by crosslinking this elastomer, is used an electret material. These materials have elasticity and are capable of forming an electret by being charged by means of a soft X-ray. In addition, a skin-patch type electret energy harvesting device is obtained by forming the electret on one of two comb-shaped electrodes that are arranged to be parallel to each other.

Described herein are electrets and electrical components comprising electrets. Electrical components comprising electrets described herein may be incorporated into power substrates, power electronic modules, and laminated busbars.