Process arrangement and a method for producing a fiber-reinforced plastic component

Abstract

A process arrangement and a process for the production of a fiber-reinforced plastics component made of at least one continuous-fiber-reinforced semifinished textile fiber product with reactive thermoplastic matrix material, where during the manufacture of the semifinished fiber product trimming residues (m.sub.R, m.sub.A) arise, composed of a composite made of fibers and of the reactive thermoplastic matrix material, and during finishing of the finished plastics component final-trimming residues (m.sub.E) arise, composed of a composite of fibers and of polymerized thermoplastic matrix material, and are further processed in a recycling unit to give a recyclate. The trimming residues arising during the manufacture of the semifinished fiber product are polymerized in a preparatory unit and then are delivered in the invention to the recycling unit.

Claims

1. A process arrangement for the production of a fiber-reinforced plastics component, comprising: a manufacture and assembly unit configured to preimpregnate at least one continuous web made of a textile structure with a liquid starting component of the reactive thermoplastic matrix material in the manufacturing unit in a continuous process, wherein the manufacture and assembly unit includes a first cutter configured to edge-trim the at least one preimpregnated continuous web resulting in edge-trimming residues, wherein the edge trimming residues are made of a composite of fibers and of the reactive thermoplastic matrix material, a press unit and/or thermoforming unit in which the continuous-fiber-reinforced semifinished textile fiber product with reactive thermoplastic matrix material is heated to a temperature above the polymerization temperature and at the same time can be pressed and/or thermoformed into a shaped plastics component, a finishing unit having a second cutter configured to edge-trim the shaped plastics component thereby forming final-trimming residues made of a composite of fibers and of the polymerized matrix material, a preparatory unit having an oven configured to polymerize the edge-trimming residues, and a recycling unit having a granulator configured to comminute the final-trimming residues and the polymerized edge-trimming residues, thereby forming recyclate for use in an injection-molding or press process.

2. The process arrangement according to claim 1, wherein, in the assembly unit, the continuous-fiber-reinforced semifinished textile fiber product can be mutually superposed in layers to give a layer package in a lay-up procedure and/or the assembly unit includes a third cutter configured to cut to size the continuous-fiber-reinforced semifinished textile fiber product in accordance with a final shape of the shaped plastics component, with formation of an assembly-trimming residue composed of the composite made of fibers and of reactive thermoplastic matrix material.

3. The process arrangement according to claim 2, wherein: the fiber contents in the final-trimming residue and in the assembly-trimming residue are identical, and the fiber content in the edge-trimming residue is lower than that in the final-trimming or assembly-trimming residue, and a polymerized matrix material can be added to the trimming residue passed into the recycling unit in accordance with the required fiber volume content of the recyclate.

4. The process arrangement according to claim 1, wherein the continuous-fiber-reinforced semifinished textile fiber product has an exterior component edge which is required for the press procedure and/or thermoforming procedure and which forms a projecting rim that can be removed from the shaped plastics component in the finishing unit, with formation of the final-trimming residue.

5. The process arrangement according to claim 1, wherein perforations or cutouts can be incorporated into the shaped plastics component in the finishing unit, with formation of the final-trimming residue.

6. The process arrangement according to claim 1, wherein the assembly unit includes a third cutter configured to cut to size the continuous-fiber-reinforced semifinished textile fiber product, thereby forming an assembly-trimming residue composed of the composite made of fibers and of reactive thermoplastic matrix material, wherein the oven of the preparatory unit is further configured to polymerize the assembly-trimming residue, wherein the granulator is further configured to comminute the polymerized assembly-trimming residue, and wherein the recyclate is formed by combining the comminuted final-trimming residues, comminuted polymerized edge-trimming residues, and comminuted polymerized assembly-trimming residue.

7. The process arrangement according to claim 6, wherein the final-trimming residue can be mixed in various ratios by weight with the assembly-trimming residue and/or the edge-trimming residue, in each case upstream or downstream of the granulator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention and its advantageous embodiments, and also advantages thereof, are explained in more detail below with reference to drawings.

(2) FIGS. 1 to 4 in each case show process units for the production of the fiber-reinforced plastics component; and

(3) FIG. 5 is a block diagram of the process sequence inclusive of a recycling unit and of an associated preparatory unit.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIGS. 1 to 4 depict the process units I to VI for the production of a fiber-reinforced plastics component 1 (FIGS. 3 and 4) to the extent required for understanding the invention. Accordingly, a manufacturing unit I first by way of example brings two fiber layers 2 onto a continuous transport belt 5 in a continuous process with insertion therebetween of a first film 3 made of, for example, polyamide or of another suitable material. The resultant textile layer structure 7 is saturated with a starting component 8 of a reactive thermoplastic matrix material, for example lactam, and specifically with exposure to heat 10 at a temperature below the initiation temperature for polymerization of the starting component of the reactive thermoplastic matrix material.

(5) In the further course of the process, a second film 9 is also then applied, and the textile layer structure 7 is cooled in a cooling unit 11 (i.e. consolidated), and also trimmed to size in a downstream cutting unit II to give individual preimpregnated semifinished textile fiber products 15. In the cutting unit II, edge trimming takes place in which the prepregnated continuous structure 7 is cut to size to give the continuous-fiber-reinforced semifinished textile fiber products 15 (for which the term prepregs is also used below). FIG. 1 indicates only the cutting-to-length procedure. Edge trimming takes place in FIG. 1 at right angles to the cutting-to-length procedure in the plane of the drawing.

(6) An edge-trimming residue m.sub.R is thus produced, composed of a composite made of fibers and of reactive (i.e. as yet unpolymerized) thermoplastic matrix material. The edge-trimming residue m.sub.R is diverted from the process sequence as waste material. The fibers in the edge-trimming residue m.sub.R have not been completely wetted by the reactive matrix material, or are present in the absence of any matrix material, the proportion of fiber in the edge-trimming residue m.sub.R therefore being very high.

(7) The trimmed-to-size semifinished textile fiber products 15 are mutually superposed in a subsequent stacking unit III to give a stack, and are stored. The semifinished fiber products 15 mutually superposed in a stack are transferred as required to an assembly unit IV, which is downstream in the process and is indicated in FIG. 2. In the assembly unit IV the preimpregnated semifinished textile fiber products 15 are cut to size and mutually superposed in layers to give a layer package 16 (FIG. 2). The prepreg 15 mutually superposed in layers to give the layer package 16 are moreover cut to size in accordance with the loading requirements placed upon the finished plastics component 1. This results in further waste material, which is diverted from the process sequence as assembly-trimming residue m.sub.A. The assembly-trimming residue m.sub.A is composed of a composite made of fibers and of reactive thermoplastic matrix material. The fibers in the assembly-trimming residue m.sub.A, unlike those in the edge-trimming residue m.sub.R are completely surrounded by matrix material, i.e. are fully impregnated. The proportion of fiber in the assembly-trimming residue m.sub.A is therefore higher than in the edge-trimming residue m.sub.R and in essence is the same as the proportion of fiber in the finished plastics component 1.

(8) In the further course of the process, the layer package 16 is transferred to the press unit and/or thermoforming unit V indicated in broad terms in the diagram of FIG. 3, in which the layer package 16 is heated to a temperature above the polymerization temperature and at the same time is thermoformed/pressed to give the shape of the required plastics component 1. In a finishing unit VI (FIG. 4), which is downstream in the process, the plastics component 1 is subjected to edge-trimming in which by way of example an exterior component edge 17 required for the thermoforming procedure is removed from the plastics component 1, and specifically with formation of a final-trimming residue m.sub.E, composed of a composite made of fibers and of polymerized matrix material.

(9) Downstream of the process sequence I to VI for the production of the plastics component 1 in FIG. 5 there is a recycling unit VII into which the final-trimming residues m.sub.E are passed. In the recycling unit VII there can, where appropriate, be a granulator arranged which comminutes the final-trimming residues m.sub.E. The final-trimming residues m.sub.E are further processed in the recycling unit VII to give a recyclate R that is suitable for use in an injection-molding or press process.

(10) As is further apparent from FIG. 5, there is a preparatory unit VIII associated with the recycling unit VII. The edge-trimming residues m.sub.R and the assembly-trimming residues m.sub.A can be delivered to the preparatory unit VIII. The two trimming residues m.sub.R, m.sub.A are composed of a composite made of fibers with reactive (i.e. as yet unpolymerized) thermoplastic matrix material, and are therefore not directly processable in the recycling unit VII to the recyclate R.

(11) The reactive thermoplastic matrix material of the two trimming residues m.sub.R, m.sub.A is polymerized in the preparatory unit VII. The resultant composite made of fibers and of polymerized matrix material is then combined in the recycling unit VII with the final-trimming residues m.sub.E, and is further processed therein.

(12) Alternatively and/or additionally, it is also possible that the preparatory unit VIII comprises a granulator in which the trimming residues m.sub.R and m.sub.A are comminuted. Processing of the edge-trimming residues and of the assembly-trimming residues m.sub.R, m.sub.A in the granulator preferably takes place only after these have been polymerized.

(13) As indicated by a broken line in FIG. 5, it is possible in an alternative design variant that the final-trimming residue m.sub.E is combined with the polymerized trimming residues m.sub.A, m.sub.R at a collection point 21 upstream of the recycling unit VII, and it is then passed onward into the recycling unit VII. It is moreover possible that, if necessary because of the required fiber volume content of the recyclate R, polymerized matrix material is also added to the respective trimming residues m.sub.R, m.sub.A m.sub.E in order, where appropriate, to reduce the proportion of fiber in the recyclate R.

(14) It is additionally possible to add admixtures to the recyclate R produced in the recycling unit VII. In the further course of the process, the recyclate R can be plastified, and also delivered to a screw-based extruder, and then processed in the injection-molding or press process.