Abstract: A method for bonding fluororesin films, a wide fluororesin film obtained by the method, and a covering material for agricultural use, made thereof, are presented. A method of bonding films (A), wherein two sheets of films (A) made of a fluororesin, are disposed so that their edges overlap each other, a central part (b1) of the overlapping portion (B) is press-bonded under heating at a temperature within a range of from lower by 5° C. to higher by 20° C. than the melting point of the fluororesin, and then the entire area of the portion (B) is press-bonded at a temperature within a range of from lower by 30° C. to lower by more than 5° C., than the melting point, to weld the two sheets of films (A); a wide fluororesin film obtained by the method; and a covering material for agricultural use, made thereof.

Abstract: A method for bonding fluororesin films, a wide fluororesin film obtained by the method, and a covering material for agricultural use, made thereof, are presented. A method of bonding films (A), wherein two sheets of films (A) made of a fluororesin, are disposed so that their edges overlap each other, a central part (b1) of the overlapping portion (B) is press-bonded under heating at a temperature within a range of from lower by 5° C. to higher by 20° C. than the melting point of the fluororesin, and then the entire area of the portion (B) is press-bonded at a temperature within a range of from lower by 30° C. to lower by more than 5° C., than the melting point, to weld the two sheets of films (A); a wide fluororesin film obtained by the method; and a covering material for agricultural use, made thereof.

Abstract: A method for bonding fluororesin films, a wide fluororesin film obtained by the method, and a covering material for agricultural use, made thereof, are presented. A method of bonding films (A), wherein two sheets of films (A) made of a fluororesin, are disposed so that their edges overlap each other, a central part (b1) of the overlapping portion (B) is press-bonded under heating at a temperature within a range of from lower by 5° C. to higher by 20° C. than the melting point of the fluororesin, and then the entire area of the portion (B) is press-bonded at a temperature within a range of from lower by 30° C. to lower by more than 5° C., than the melting point, to weld the two sheets of films (A); a wide fluororesin film obtained by the method; and a covering material for agricultural use, made thereof.

Abstract: A method for joining films having a hydrophilized surface at a single surface and an excellent melt-bonding force at the melt-bonded portion, which is formed by disposing two films (A) having a hydrophilized surface at a single surface, to align the hydrophilized surfaces so as to butt each end portion; overlaying a film (B) on a side of non-hydrophilized surface of the films (A), so as to bridge the butting portion, and hot-pressing the overlapping portion (c1)5 to join the two films (A). A wide film obtained by the above-mentioned method is suitable for a covering material for agricultural use.

Abstract: A method for joining films having a hydrophilized surface at their single surface and an excellent melt-bonding force at the melt-bonded portion, which is formed by disposing two film (A) having a hydrophilized surface at their single surface to align the hydrophilized surfaces so as to butt each end portion; overlaying a film (B) on a side of non-hydrophilized surface of the films (A) so as to bridge the butting portion, and hot-pressing the overlapping portion (c1) to join the two films (A). The wide film obtained by the above-mentioned method is suitable for a covering material for agricultural use.

Abstract: An ion exchange membrane for electrolysis comprising a first layer of a fluoropolymer having carboxylic acid groups as its ion exchange groups and facing a cathode, a second layer of a fluoropolymer having ion exchange groups, a specific resistance lower than that of the first layer and a thickness of at least 50% of the total thickness of the membrane, and a third layer of a fluoropolymer having ion exchange groups, a swelling degree higher by at least 5% than that of the second layer and a specific resistance lower by at least 30 .OMEGA..cm than that of the second layer, the first, second and third layers being laminated in this order.

Abstract: Lamination of plastic film and shaped metal substrates is carried out by a pair of rolls which comprises one heat-resistant roll having a hollow for receiving at least a forward edge of the shaped metal substrate, on at least one of the surfaces of the roll. A laminated product having no defect or crease of the plastic film can be obtained.