Abstract: Provided are: a porous film for a heat-sealable bag-constituting member which has a high seal strength and is resistant to edge tear when heat-sealed to form a bag, and excels in workability (bag productivity); and a porous film for a heat-sealable bag-constituting member which enables the use of a polyolefinic nonwoven fabric to be laminated (combined) therewith. The porous film (11) for a heat-sealable bag-constituting member includes a porous film layer (layer A) (11a) and another porous film layer (layer B) (11b). Resinous component(s) constituting the layer A (11a) contains 50 percent by weight or more of at least one polyethylene (a) having a melting point of 90° C. or higher and lower than 110° C., and resinous component(s) constituting the layer B (11b) contains 50 percent by weight or more of at least one polyethylene (b) having a melting point of 110° C. or higher and 140° C. or lower.

Abstract: A disposable warmer of the present invention has a bag including a bag member (A) and a bag member (B); a heater; a heat-sealed portion where the bag member (A) and the bag member (B) are heat-sealed; and a portion with the heater sealed therein. The bag members (A) and (B) are heat-sealed with each other to form the bag, the bag member (A) includes at least a layered structure with a porous film and a nonwoven fabric layer, and the bag member (B) includes at least another layered structure with a stretchable film and another nonwoven fabric layer. The disposable warmer comprises two or more of the portions with the heaters sealed therein independently, and a slit in at least the porous film constituting the bag member (A) of the bag members (A) and (B) in at least one region between the adjacent portions with the heaters sealed therein.

Abstract: A porous film for a heat-sealable bag-constituting member is prepared by stretching an unstretched film to be porous. The unstretched film includes an ultrahigh-molecular-weight polyethylene having a weight-average molecular weight of 30×104 to 250×104, a polyolefin component other than the ultrahigh-molecular-weight polyethylene, and an inorganic filler as essential components, and the content of the ultrahigh-molecular-weight polyethylene is 1 percent by weight or more based on the total amount of polymer components constituting the porous film. Even when produced by stretching at a low draw ratio, the film does not suffer from uneven stretching and shows high productivity. When the film is heat-sealed into a bag, the bag has a high seal strength and does not suffer from edge tear. The film is therefore useful particularly as a bag-constituting member to be heat-sealed into a bag typically as a disposable body warmer.

Abstract: A disposable warmer of the present invention has a bag including a bag member (A) and a bag member (B); a heater; a heat-sealed portion where the bag member (A) and the bag member (B) are heat-sealed; and a portion with the heater sealed therein. The bag members (A) and (B) are heat-sealed with each other to form the bag, the bag member (A) includes at least a layered structure with a porous film and a nonwoven fabric layer, and the bag member (B) includes at least another layered structure with a stretchable film and another nonwoven fabric layer. The disposable warmer comprises two or more of the portions with the heaters sealed therein independently, and a slit in at least the porous film constituting the bag member (A) of the bag members (A) and (B) in at least one region between the adjacent portions with the heaters sealed therein.