Abstract: A string for the stringing of rackets, bows, musical instruments and the like which has a thread-like structure of polyvinylidene fluoride. The string is obtained by extruding a rod of polyvinylidene fluoride at a melt temperature of the polyvinylidene fluoride, cooling the rod at a temperature between 60.degree.-150.degree. C., and then axially stretching the rod at this temperature following by cooling the rod to room temperature and thereafter cold-stretching the monofil. The string is characterized by an elasticity that approaches that of natural gut string.

Abstract: A process for producing colored synthetic resin sheet material having a unicolored or multicolored dye coating applied to one surface thereof and extending into said surface in a uniform manner involves applying a dye-containing material or composition to at least one selective portion of the surface of a synthetic resin sheet material that contains at least one reactive, crosslinkable component, where the dye-containing material is capable of migrating into a non-porous sheet formed of the synthetic resin; controlling the migration of the dye material into the sheet material to a desired depth; and then initiating crosslinking of the crosslinkable component to stop further migration of the dye-containing material.

Abstract: An insulating panel suitable for the covering of roof structures includes a core layer of a synthetic foam material bonded adhesively on its top side to a sealing thermoplastic layer. The core layer is formed of an elastic closed-cell crosslinked polyolefin foamed material.

Abstract: A process for preventing separation of fillers and other dispersed additives from thermoplastic molding compositions during extrusion, calendering or like processing, along metallic contact surfaces of a processing unit, involves admixing a silane additive to a portion of a thermoplastic molding composition containing a thermoplastic molding resin and at least one filler or other dispersed additive that tends to separate out from the molding composition during the processing, processing the portion of thermoplastic molding composition in a processing unit, measuring the electrical energy applied to the processing unit during processing per kilogram of molding composition per unit time, determining if the electrical energy applied has been increased by the addition of the silane additive as compared to the electrical energy required per kilogram of molding composition per unit time for processing another portion of the thermoplastic molding composition free of the silane additive and thereafter adding an effec

Abstract: An arrangement for establishing an underground passage includes a first line of consecutive pipe sections which are pressed through the ground in a path which deviates from the desired course of the passage whenever the first line of pipe sections encounters an obstruction. A second line of the consecutive pipe sections follows the trailing end of first line, and a planing tool support carrying at least one planing tool is interposed between the trailing end of the first line and the leading end of the second line of consecutive pipe sections. The planing tool extends transversely beyond the planing tool support and removes the excess material between the actual path and the desired course, and the removed excess material is deposited between the previous path and the second line of consecutive pipe sections and cemented therein by the introduction of a cementing material into such deposited excess material.

Abstract: The apparatus has an annular body of reinforced centrifugally cast concrete. The leading axial end of the body is provided with a cover of sheet steel which forms a soil-penetrating cutting edge, and the trailing axial end of the body is provided with a steel reinforcing ring and with circumferentially spaced recesses into which respective pressure-exerting instrumentalities can engage, which serve to press the body into the soil and to control its direction of penetration in the same.