Abstract: A method of manufacturing a heat exchanger in which a laminate prepared by laminating many sheets one upon another so that the neighboring sheets may be formed with bonded portions and non-bonded portions, is expanded in such a direction that the respective sheets are spaced from each other so as to form flow channels or passages between the sheets at the non-bonded portions, and which employs the steps of printing patterns of bonded material onto the sheets, laminating the sheets, and subsequently expanding the laminate of the sheets to form the heat exchanger.

Abstract: A diaphragm for a speaker which is prepared by heating a conjugated sheet obtained by paper-making polyethylene short fibers with other short fibers which have a high modulus of elasticity, such as carbon fiber, to melt and solidify polyethylene short fibers in the conjugated sheet; the process for the production thereof. The diaphragm for a speaker of the invention has a high modulus of elasticity and a high internal loss and a speaker prepared with such a diaphragm has the advantage of having a wider reproducing frequency response and lower distortion. Furthermore, the process for production of the invention possesses another advantage in that diaphragms for speakers can be produced in a continuous process of successively pressing out the speaker diaphragm with a cold mold press.

Abstract: A diaphragm for acoustic equipment molded from a composition mainly consisting of a polyester-polyether block copolymer prepared by condensing a polytetramethylene-terephthalate with a poly(tetramethyleneoxide)glycol or any other polyester-polyether block copolymer. This diaphragm for acoustic equipment has an excellent low-pitched sound reproducing performance and flat acoustic pressure-frequency characteristics.

Abstract: An acoustic diaphragm has a substrate of either a hard resin film or cloth of an organic material, and at least one side of the substrate is laid with a polyurethane elastomer layer. In the case of a cloth substrate, the cloth is optionally metallized by evaporation deposition of Al or Ti and/or impregnated with a thermosetting resin. The elastomer is a copolymer given by condensation of bifunctional polymeric alcohol and a glycol with a diisocyanate. This diaphragm features a flat response curve at medium to high frequencies on account of its relatively large value for Young's modulus and adequately great internal loss, and accordingly is particularly useful for tweeters.