CS223243B1 - A method for producing reinforced thermosetting bodies - Google Patents

Abstract

The invention solves a method of manufacturing bodies from reinforced thermosets, which are intended for high tensile stresses. The essence of the solution lies in the fact that the impregnated strand is wound into a profile formed from two or more parts of a split core and after winding a predetermined amount of fibers, the finished winding is pressed on the upper functional surfaces with a shaped preparation, which rests on the split core and thus guarantees the required content of reinforcement and binder.

Description

The invention solves a method of manufacturing bodies from reinforced thermosetting plastics intended for high tensile stresses.

Bodies designed for high physico-mechanical stresses based on reinforced thermosetting plastics are currently produced in several ways. One of the oldest methods is the manual preparation of these bodies from special so-called unidirectional reinforcements in which the fibers are predominantly oriented in the direction of future tension. The fabrics are brushed, and the products cannot be used under extreme conditions, since the constant properties of the bodies cannot be guaranteed in this process.

Similarly, unilaterally stressed bodies are produced - again in a contact manner - from bundles of composite glass or textile fibers, which are again impregnated by hand and placed in molds. Also this technology is not particularly productive, the variability of physico-mechanical properties is again in the range up to 30 ° / o.

More suitable; and a much more productive way is to manufacture said bodies by precision core winding technology. The parts are made of radial or cross winding, their properties are considerably better than in the previously described methods and with regard to machine production the quality and thus the overall physical-mechanical properties are stable. Likewise, productivity is also significantly higher.

However, a significant disadvantage of this currently state-of-the-art method is the fact that it is not possible to produce parts with higher binder contents (given the necessity of some pre-tensioning of the wound fiber before winding). shaped profile. A further disadvantage of the described process is that the machine winding equipment is extremely expensive, which greatly increases the overall cost of production and is not suitable for the production of large series of small parts.

The above-mentioned disadvantages are largely eliminated by the solution according to the invention, characterized in that the impregnated strand is wound into a profile formed of two or more portions of the split core and after winding a predetermined amount of fibers the finished winding on the upper functional surfaces is pressed. The bead which bears against the split core guarantees the required reinforcement and binder content.

According to a further feature, inserts can be placed on the split core at predetermined locations, which are laminated into the product or which serve as spacers for optimum body composition.

Non-alkaline, glass, metal, mineral, natural, or thermoplastic, ceramic or carbon fibers can be used for the process described.

The advantages of said process are obvious. The solution allows the production of large series and very small parts, which can be provided with one or more internal metal inserts without the need for costly production facilities. The quality of the parts produced is constant, since the binder content is not dependent on the prestressing of the wound fiber, the product is homogeneous and, in particular, allows the production of binder parts with 40% by weight. and more. This has the considerable advantage that, while maintaining the required physico-mechanical parameters, satisfactory electrical properties of the product can be achieved, and unsaturated polyester resins may be used in addition to epoxy. These resins have even better processing parameters, notwithstanding the price, which is up to 70% lower than epoxy binders.

A considerable advantage is also the fact that it is possible to produce various complex profiles of the wound parts without the need of additional machining, which always represents an increased laboriousness with regard to the character of the product and a significant reduction of the final properties.

Said process can be used both for manual production on simple stands, as well as for machine production where the mold is fixed in a modified lathe or in a simple single-purpose rotary device. The resulting products can be advantageously used for electrical insulating couplings of overhead lines, or for other similar applications.

Exemplary embodiments made by the method of the invention are shown in the accompanying drawing, in which Figures 1 to 4 show couplings for overhead contact lines.

Example 1

The overhead contact coupling shown in FIGS. 1 and 2 was made by placing two metal inserts 3 in a mold formed by the two core sections 2 after separation. The mold was screwed on and fixed in a simple rotary jig. 50 glass strands 1, impregnated with an initiated unsaturated polyester resin of the isophthalic type, were gradually wound into the profile. Upon completion, the molded articles 4 were applied to the winding mold and tightened to the liner 3 with a clamp.

Example 2

The overhead contact coupling shown in FIG. 3 has been fabricated into an assembled multi-part mold of six core sections 2. 60 strands of 1 finished polyester fiber impregnated with a palm-type epoxy resin were wound into the profile. Upon completion, the shaped jigs 4 were placed in the profile and fastened by a screw.

Example 3

The connector shown in FIG. 4 is produced by placing two molded thermosetting inserts 3 in the spinning of the separated mold and fixed in a profile formed by the four parts 2 of the split core. 30 glass strands 1, impregnated with an unsaturated polyester resin of bisphenol type, were wound into the profile and a metal split liner 3 was deposited, a further 20 strands 1 were wound.

SUBJECT

1. A process for the manufacture of bodies made of reinforced thermosetting plastics, characterized in that the impregnated strand is wound into a profile formed from at least two parts of the split core and after winding, optionally during the winding of a predetermined amount of strands, is impregnated.

Claims (2)

BACKGROUND OF THE INVENTION is pressed onto the functional surfaces by a shaped jig. 2. A method according to claim 1, characterized in that inserts intended to be laminated or profiled are fastened to one or more parts of the split core.