阅读说明：本技术 用于注射成型应用的具有优异可再循环性的聚合物复合材料 (Polymer composites with excellent recyclability for injection molding applications ) 是由 S·阿佩尔特 于 2021-06-29 设计创作，主要内容包括：本发明涉及用于注射成型应用的具有优异可再循环性的聚合物复合材料。本发明的主题是聚合物复合材料(1),其包含至少一种热塑性基体聚合物(2)和至少一种增强纤维(3),其中所述增强纤维(3)包含至少一种聚合物材料,其特征在于,所述增强纤维(3)包含至少一种交联聚合物材料；所述增强纤维(3)具有1至10 mm的平均纤维长度；和所述增强纤维(3)具有10至20μm的平均纤维直径。本发明的主题还是用于制造聚合物复合材料(1)的方法,以及所述聚合物复合材料(1)用于制造纤维增强成型体的用途。(The present invention relates to polymer composites with excellent recyclability for injection molding applications. The subject of the present invention is a polymer composite (1) comprising at least one thermoplastic matrix polymer (2) and at least one reinforcing fiber (3), wherein the reinforcing fiber (3) comprises at least one polymer material, characterized in that the reinforcing fiber (3) comprises at least one crosslinked polymer material; the reinforcing fibers (3) have an average fiber length of 1 to 10 mm; and the reinforcing fibers (3) have an average fiber diameter of 10 to 20 μm. The invention also relates to a method for producing a polymer composite (1) and to the use of the polymer composite (1) for producing fiber-reinforced molded bodies.)

1. Polymer composite (1) comprising at least one thermoplastic matrix polymer (2) and at least one reinforcing fiber (3), wherein the reinforcing fiber (3) comprises at least one polymer material, characterized in that,

the reinforcing fibers (3) comprise at least one crosslinked polymeric material;

the reinforcing fibers (3) have an average fiber length of 1 to 10 mm; and

the reinforcing fibers (3) have an average fiber diameter of 10 to 20 μm.

2. The polymer composite (1) according to claim 1, wherein the polymer material of the thermoplastic matrix polymer (2) and the reinforcing fibers (3) essentially consists of repeating units derived from the same monomer.

3. The polymer composite (1) according to claim 1 or 2, wherein the polymer material of the thermoplastic matrix polymer (2) and the reinforcing fibers (3) comprises a polymer selected from the group consisting of polyolefins, polyamides, polyesters and mixtures thereof.

4. The polymer composite (1) according to claim 3, wherein the polymer material of the thermoplastic matrix polymer (2) and the reinforcing fibers (3) comprises a polymer selected from the group consisting of polypropylene, polyamide 6, polyamide 6.6, polybutylene terephthalate and mixtures thereof.

5. The polymer composite (1) according to any one of claims 1 to 4, wherein the polymer material of the reinforcement fibers (3) is crosslinked by means of radiation crosslinking.

6. The polymer composite (1) according to any one of claims 1 to 5, obtained by mixing the at least one thermoplastic matrix polymer (2) and the at least one reinforcing fiber (3).

7. Method for manufacturing a polymer composite (1) comprising at least one thermoplastic matrix polymer (2) and at least one reinforcing fiber (3), wherein the reinforcing fiber (3) comprises at least one polymer material, characterized in that the method comprises at least the following method steps:

(i) providing at least one matrix polymer (2);

(ii) providing at least one reinforcing fiber (3), wherein the reinforcing fiber (3) has an average fiber length of 1 to 10 mm and an average fiber diameter of 10 to 20 μm and comprises at least one crosslinked polymeric material;

(iii) heating the at least one matrix polymer (2) to obtain a polymer melt of the at least one matrix polymer (2);

(iv) mixing the polymer melt of the matrix polymer (2) with the at least one reinforcing fiber (3) to obtain a homogeneous polymer composite (1).

8. The method for manufacturing a polymer composite (1) according to claim 7, wherein a polymer melt of the matrix polymer (2) is mixed with the at least one reinforcing fiber (3) by means of an extruder (10).

9. Use of the polymer composite (1) according to any one of claims 1 to 6 for producing fiber-reinforced moldings in an injection molding process.

10. Use of a polymer composite (1) according to claim 9, wherein the shaped body is a recyclable fibre-reinforced shaped body.

Technical Field

The subject of the invention is a polymer composite comprising at least one matrix polymer and at least one reinforcing fiber, which can be used in injection molding and is recyclable.

Background

Material recycling and disposal of plastic waste is becoming increasingly important. A prerequisite for this is that the high quality standards for recycled plastics are adhered to. In order to set the desired property profile, conventional plastics generally contain additives, in particular fillers and additives, and reinforcing materials. A significant obstacle to the reuse of engineering plastics is glass or carbon fiber reinforcement. Such reinforced plastics are currently not recycled of material, but are subjected to thermal disposal.

US 2017/0173861 a1 discloses a method for manufacturing a thermoplastic resin composite, wherein the method provides a laminate of a matrix resin layer and a reinforcement resin layer.

WO 2013/174943 a1 relates to a method for producing a fiber composite material, wherein both the reinforcing fibers and the matrix are based on polyamide, wherein as a reinforcing structure based on polyamide, use is made of monofilaments or multifilaments, yarns, twisted yarns, rovings, mats, nonwovens, wovens, pavements or knits, which are based solely on polyamide and are themselves made of drawn fibers.

EP 2818297 a1 relates to an injection molding process in which a combination of polyamide-based molding compounds and polyamide-based reinforcing structures is used to produce a simple class of low-temperature impact-resistant fiber composite materials. As the polyamide-based reinforcing structure, a polyamide-based textile reinforcing material made of polyamide continuous fibers, polyamide threads, polyamide rovings, polyamide-based woven mesh (which is preferably welded at the intersection points), polyamide nonwoven fabric or polyamide nonwoven fabric may be used.

WO 2009/127864 a1 relates to a method for manufacturing a self-reinforced plastic material, wherein the method comprises:

(a) forming a mixture of a first type of plastic material and a second type of plastic material, wherein at least the second type of plastic material is present in the form of an elongated element and the first type of plastic material is selectively heatable, and

(b) the mixture so formed is treated so that the first type of plastic material melts to produce a continuous phase, while the elongated elements of the second type of plastic material remain intact or substantially intact, with these elements dispersed in the continuous phase.

Disclosure of Invention

The subject of the invention is a polymer composite comprising at least one thermoplastic matrix polymer and at least one reinforcing fiber, wherein the reinforcing fiber comprises at least one polymer material, characterized in that

The reinforcing fibers comprise at least one crosslinked polymeric material;

the reinforcing fibers have an average fiber length of 1 to 10 mm; and

the reinforcing fibers have an average fiber diameter of 10 to 20 μm.

The polymer composite comprises at least one thermoplastic matrix polymer. The matrix polymer comprises at least one thermoplastic polymer. Preferably, the at least one matrix polymer comprises at least one thermoplastic polymer selected from the group consisting of polyolefins, polyamides, polyesters, polyphenylene sulfides, polyetheretherketones, and mixtures thereof.

Examples of suitable polyolefins include in particular polymers of repeating units derived from ethylene, propylene, styrene and mixtures thereof. In other words, suitable polyolefins are in particular obtainable by (co) polymerization of monomers selected from ethylene, propylene, styrene and mixtures thereof. Suitable polyolefins are, inter alia, polyethylene, polypropylene, ethylene/propylene copolymers (poly (ethylene-co-propylene)) and polystyrene and mixtures thereof. In a preferred embodiment, the matrix polymer comprises at least polypropylene.

Examples of suitable polyamides include, inter alia, polymers of repeat units derived from hexamethylenediamine, adipic acid, dodecanedioic acid, sebacic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, epsilon-caprolactam, laurolactam and mixtures thereof. In other words, suitable polyamides are obtained in particular by (co) polymerization of monomers selected from hexamethylenediamine, adipic acid, dodecanedioic acid, sebacic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, epsilon-caprolactam, laurolactam and mixtures thereof. Suitable polyamides are, in particular, polyamide 6.6, polyamide 6, polyamide 6.10, polyamide 6.12, polyamide 11 and polyamide 12 and mixtures thereof. In a preferred embodiment, the matrix polymer comprises at least polyamide 6.6, polyamide 6 and mixtures thereof.

Examples of suitable polyesters include, inter alia, polymers of repeat units derived from terephthalic acid, isophthalic acid, phosgene, 1, 4-butanediol, 1, 3-propanediol, 1, 2-ethanediol, bisphenol A, and mixtures thereof. In other words, suitable polyesters are obtained in particular by (co) polymerization of monomers selected from the group consisting of terephthalic acid, isophthalic acid, phosgene, 1, 4-butanediol, 1, 3-propanediol, 1, 2-ethanediol, bisphenol-A and mixtures thereof. Suitable polyesters are, in particular, polyethylene terephthalate, polybutylene terephthalate and polycarbonate and mixtures thereof. In a preferred embodiment, the matrix polymer comprises at least polybutylene terephthalate therein.

Polyphenylene sulfide can be obtained, for example, by polycondensation of 1, 4-dichlorobenzene with sodium sulfide. Polyetheretherketone can be obtained, for example, by the reaction of 4,4' -difluorobenzophenone with hydroquinone sodium salt.

In addition, the matrix polymer may contain commonly used auxiliaries and additives. Suitable additives for adapting the properties of the matrix polymer or polymer composite are known to the person skilled in the art. Mention may be made, by way of example, of adhesion-promoting agents, flame retardants, impact modifiers, pigments, dyes, fillers, antioxidants, UV stabilizers, peroxide destroyers, antistatic agents, lubricants, mold release agents, and combinations of two or more thereof.

In one embodiment of the invention, the thermoplastic matrix polymer comprises at least one auxiliary agent and/or at least one additive.

In an alternative embodiment of the invention, the thermoplastic matrix polymer does not comprise a filler.

In another alternative embodiment of the invention, the thermoplastic matrix polymer does not comprise auxiliaries and/or additives.

In an alternative embodiment of the invention, the thermoplastic matrix polymer does not contain other reinforcing fibers or fibrous fillers than the reinforcing fibers according to the invention, in particular does not contain glass fibers and/or carbon fibers.

In one embodiment of the invention, the matrix polymer comprises, in addition to the above-described repeat units derived from monomers, repeat units derived from at least one adhesion promoter. For which it is possible to improve the adhesion between the matrix polymer and the polymer material of the reinforcing fibers. Suitable adhesion promoters are derived, for example, from maleic anhydride.

In an alternative preferred embodiment of the invention, the matrix polymer does not comprise, in addition to the above-mentioned recurring units derived from the monomer, recurring units derived from at least one adhesion-promoting agent. In this case, the matrix polymer and the polymer material of the reinforcing fiber are substantially composed of the same repeating unit, so that improvement of adhesion is not required.

The polymer composite comprises, in addition to the at least one thermoplastic matrix polymer, at least one reinforcing fiber comprising at least one crosslinked polymer material. The polymeric material of the reinforcing fibers preferably comprises at least one polymer selected from the group consisting of crosslinked polyolefins, crosslinked polyamides, crosslinked polyesters, crosslinked polyphenylene sulfides, crosslinked polyetheretherketones, and mixtures thereof.

Examples of suitable crosslinked polyolefins include in particular crosslinked polymers of repeating units derived from ethylene, propylene, styrene and mixtures thereof. In other words, suitable crosslinked polyolefins are obtainable in particular by (co) polymerization of monomers selected from ethylene, propylene, styrene and mixtures thereof. Suitable crosslinked polyolefins are, in particular, polyethylene, polypropylene, ethylene/propylene copolymers (poly (ethylene-co-propylene)) and polystyrene and mixtures thereof. In a preferred embodiment, the polymeric material of the reinforcing fibers comprises at least crosslinked polypropylene.

Examples of suitable crosslinked polyamides include, inter alia, crosslinked polymers of repeat units derived from hexamethylenediamine, adipic acid, dodecanedioic acid, sebacic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, epsilon-caprolactam, laurolactam and mixtures thereof. In other words, suitable crosslinked polyamides are obtained in particular by (co) polymerization of monomers selected from hexamethylenediamine, adipic acid, dodecanedioic acid, sebacic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, epsilon-caprolactam, laurolactam and mixtures thereof. Suitable crosslinked polyamides are, in particular, polyamide 6.6, polyamide 6, polyamide 6.10, polyamide 6.12, polyamide 11 and polyamide 12 and mixtures thereof. In a preferred embodiment, the polymeric material of the reinforcing fibers comprises at least crosslinked polyamide 6.6, crosslinked polyamide 6 and mixtures thereof.

Examples of suitable crosslinked polyesters include, inter alia, crosslinked polymers of repeat units derived from terephthalic acid, isophthalic acid, phosgene, 1, 4-butanediol, 1, 3-propanediol, 1, 2-ethanediol, bisphenol A, and mixtures thereof. In other words, suitable crosslinked polyesters are obtainable in particular by (co) polymerization of monomers selected from the group consisting of terephthalic acid, isophthalic acid, phosgene, 1, 4-butanediol, 1, 3-propanediol, 1, 2-ethanediol, bisphenol A and mixtures thereof. Suitable crosslinked polyesters are, in particular, polyethylene terephthalate, polybutylene terephthalate and polycarbonate and mixtures thereof. In a preferred embodiment, the polymeric material of the reinforcing fibers comprises at least cross-linked polybutylene terephthalate therein.

Crosslinked polyphenylene sulfides can be obtained, for example, by polycondensation of 1, 4-dichlorobenzene with sodium sulfide. Crosslinked polyetheretherketone can be obtained, for example, by reaction of 4,4' -difluorobenzophenone with hydroquinone sodium salt.

Furthermore, the polymeric material of the reinforcing fibers may contain commonly used auxiliaries and additives. Suitable additives for adapting the properties of the matrix polymer or polymer composite are known to the person skilled in the art. Mention may be made, by way of example, of crosslinking agents, adhesion-promoting agents, flame retardants, impact modifiers, pigments, dyes, fillers, antioxidants, UV stabilizers, peroxide destroyers, antistatic agents, lubricants, mold release agents, and combinations of two or more thereof.

In one embodiment of the invention, the polymeric material of the reinforcing fibers comprises, in addition to the above-mentioned recurring units derived from the monomer, recurring units derived from at least one crosslinking agent. Suitable crosslinking agents are, in particular, compounds having at least two, preferably at least three, polymerizable functional groups. Examples include dienes, trienes, triamines, triols, tricarboxylic acids, and mixtures thereof.

In an alternative preferred embodiment of the invention, the polymeric material of the reinforcing fibers does not comprise, in addition to the above-mentioned recurring units derived from the monomer, recurring units derived from at least one crosslinking agent. In this case, the crosslinking of the polymer material is carried out by radiation crosslinking.

In one embodiment of the invention, the polymeric material of the reinforcing fibers comprises, in addition to the above-mentioned recurring units derived from monomers, recurring units derived from at least one adhesion-promoting agent. For which it is possible to improve the adhesion between the matrix polymer and the polymer material of the reinforcing fibers. Suitable adhesion promoters are derived, for example, from maleic anhydride.

In an alternative preferred embodiment of the invention, the polymeric material of the reinforcing fibers does not comprise, in addition to the above-mentioned recurring units derived from monomers, recurring units derived from at least one adhesion-promoting agent. In this case, the matrix polymer and the polymer material of the reinforcing fiber are substantially composed of the same repeating unit, so that improvement of adhesion is not required.

The thermoplastic matrix polymer and the polymeric material of the reinforcing fibers may be substantially the same or different from each other. This means that the thermoplastic matrix polymer and the polymeric material of the reinforcing fibers may consist essentially of repeating units derived from the same monomer or may consist of repeating units derived from monomers different from each other.

In one embodiment of the invention, the thermoplastic matrix polymer and the polymeric material of the reinforcing fibers are different from each other. In this case, at least the polymeric material of the thermoplastic matrix polymer and/or the reinforcing fibers preferably comprises at least recurring units derived from at least one adhesion-promoting agent.

In an alternative, particularly preferred embodiment of the invention, the thermoplastic matrix polymer and the polymeric material of the reinforcing fibers are the same. This means that the thermoplastic matrix polymer and the polymeric material of the reinforcing fibers essentially consist of repeating units derived from the same monomer. In this case, comonomers, additives and auxiliaries for adhesion optimization can be omitted.

The polymeric material of the reinforcing fibers is a crosslinked polymer. In principle, all methods known to the person skilled in the art for crosslinking polymers are suitable. It is emphasized that crosslinking is achieved by recombination of free radicals in the polymer, which radicals are generated by addition of free-radical formers or by high-energy radiation (so-called radiation crosslinking); crosslinking is achieved by polycondensation of suitable functional groups in the polymer, with or without the addition of an additional crosslinking agent; crosslinking is achieved by addition polymerization of suitable functional groups in the polymer, with or without the addition of an additional crosslinking agent, and combinations thereof.

In a preferred embodiment of the invention, the polymer material of the reinforcing fibers is crosslinked by means of radiation crosslinking. Radiation crosslinking of polymers is a method known to the person skilled in the art, in which the polymer is irradiated with high-energy radiation, preferably high-energy beta-and/or gamma-radiation. By means of the radiant energy, free radicals are generated in the polymer, which by means of a combination reaction lead to the formation of crosslinking points. In principle, various radiation crosslinking methods can be used. In a preferred embodiment, the reinforcing fibers made of the polymeric material are first provided and subsequently crosslinked by radiation crosslinking. Forming fibers from uncrosslinked polymeric materials can be achieved by a simpler process than in the case of crosslinked polymeric materials.

The reinforcing fibers are short fibers and have an average fiber length of 1 to 10 mm and an average fiber diameter of 10 to 20 μm. The reinforcing fibers preferably have a ratio of fiber length to fiber diameter of from 1000:1 to 50:1, preferably from 500:1 to 100: 1. The fiber length can be specifically adjusted by cutting the continuous fibers.

The polymer composite according to the present invention is preferably obtained by mixing the at least one matrix polymer and the at least one reinforcing fiber with each other to obtain a homogeneous polymer composite. In principle, the mixing of the components with one another can be carried out in various ways suitable therefor and at various temperatures. The mixing of the components is preferably carried out at a temperature of from 100 ℃ to 400 ℃, more preferably from 150 ℃ to 350 ℃, in particular from 200 ℃ to 300 ℃. Alternatively, the compounding can also be carried out at a temperature of from 15 ℃ to 100 ℃, for example at (about) 20 ℃. For example, the components can be mixed with one another in an optionally heated kneading reactor (e.g. an internal kneader), an optionally heated extruder or an optionally heated twin-screw extruder. Mixing at elevated temperatures may also be referred to herein as melt compounding or melt extrusion. The mixing of the components with one another can be carried out sequentially or simultaneously. Thus, the components may be added all at once or sequentially.

The polymer composite is preferably obtained by melt compounding or melt extrusion in an optionally heated extruder. In a particularly preferred embodiment, the components are added here sequentially to the melt compounding or melt extrusion process. For this purpose, the matrix polymer is preferably first melted and then the reinforcing fibers and optionally additives and/or auxiliaries are added.

The polymer composite according to the invention preferably comprises

30 to 90 wt. -%, preferably 40 to 85 wt. -%, in particular 50 to 80 wt. -%, based on the total weight of the polymer composite, of the at least one thermoplastic matrix polymer;

10 to 70 wt. -%, preferably 15 to 60 wt. -%, in particular 20 to 50 wt. -%, based on the total weight of the polymer composite, of the at least one reinforcing fiber; and

0 to 10 wt.%, preferably 0 to 7 wt.%, in particular 0 to 5 wt.%, based on the total weight of the polymer composite, of auxiliaries and/or additives.

The subject of the present invention is therefore also a process for manufacturing a polymer composite comprising at least one thermoplastic matrix polymer and at least one reinforcing fiber, wherein the reinforcing fiber comprises at least one polymer material, characterized in that it comprises at least the following process steps:

(i) providing at least one matrix polymer;

(ii) providing at least one reinforcing fiber, wherein the reinforcing fiber has an average fiber length of 1 to 10 mm and an average fiber diameter of 10 to 20 μm and comprises at least one crosslinked polymeric material;

(iii) heating the at least one matrix polymer to obtain a polymer melt of the at least one matrix polymer;

(iv) mixing the polymer melt of the matrix polymer with the at least one reinforcing fiber to obtain a homogeneous polymer composite.

In a first process step (i), at least one thermoplastic matrix polymer is provided. The previously described description of the matrix polymer can be applied. The matrix polymer may be obtained by various known polymerization methods. If one of the abovementioned auxiliaries and/or additives should be added to the matrix polymer, this can be carried out in process step (i) by mixing the matrix polymer and the auxiliaries and/or additives, for example in a heated kneader reactor. Auxiliaries and/or additives can also be carried out before or after carrying out process step (i), for example before, during and/or after carrying out the compounding according to process step (iv).

In a second method step (ii), at least one reinforcing fiber is provided, wherein the reinforcing fiber has an average fiber length of 1 to 10 mm and an average fiber diameter of 10 to 20 μm and comprises at least one crosslinked polymeric material. The definitions and preferred embodiments of the reinforcing fibers referred to earlier apply accordingly. The fibers can be made from the above-mentioned polymeric materials by all known methods as continuous fibers, which are subsequently cut to the desired length. The fibers may optionally be coated with additives and/or adjuvants before or after cutting.

The polymer material of the reinforcing fibers is crosslinked by means of one of the methods described above before, during or after carrying out method step (ii). Preferably, radiation crosslinking methods are used for this purpose.

In a further process step (iii), the at least one matrix polymer is heated to obtain a polymer melt of the at least one matrix polymer. This can be achieved by supplying thermal energy. However, by introducing mechanical energy, for example in an extruder or kneader reactor, the temperature of the matrix polymer can already be increased so strongly that a polymer melt is obtained without having to introduce additional thermal energy.

In a further process step (iv), the polymer melt of the matrix polymer obtained in process step (iii) is mixed with the at least one reinforcing fiber to obtain a homogeneous polymer composite. As previously mentioned, the mixing can be carried out in an optionally heated kneader reactor (e.g.an internal kneader), an optionally heated extruder or an optionally heated twin-screw extruder. Preference is given to using an optionally heated extruder.

Process step (iii) and process step (iv) may be carried out simultaneously or process step (iv) may be carried out after process step (iii) has been carried out. In a preferred embodiment, process step (iv) is carried out after process step (iii) has been carried out.

If an extruder is used for the production of the polymer composite, the polymer melt of the matrix polymer is first provided in a melting zone of the extruder and the at least one reinforcing fiber is preferably added by lateral supply only in a subsequent mixing zone of the extruder.

The process according to the invention may comprise further optional process steps, such as the addition of further additives and/or auxiliaries. This addition is preferably carried out before, during or after one of the process steps (i) to (iv).

Furthermore, the resulting polymer composite obtained in process step (iv) can be processed into strands or pellets and subsequently further processed or directly into shaped bodies after carrying out the process according to the invention. Such molded bodies can be produced, for example, by injection molding, extrusion and blow molding processes. Another form of processing is the production of shaped bodies by deep drawing from previously produced sheets or films and by the film-post injection molding process. Examples of such shaped bodies are various types of films, profiles, housing parts.

The polymer composite is preferably used for producing fiber-reinforced moldings in an injection molding process. Furthermore, the polymer composite is preferably used for the production of recyclable molded articles. The polymer composite according to the invention is particularly suitable here for the necessary treatment processes for the substantially damage-free recycling of plastic waste, such as, in particular, the filtration and multiple compounding and extrusion of plastic melts.

THE ADVANTAGES OF THE PRESENT INVENTION

The invention provides a polymer composite material which can be recycled without any problem. The present invention is due to the use of polymer reinforcement fibers to reinforce the matrix polymer. The advantage of polymer reinforcing fibers is that they have a higher flexibility in the polymer melt and are therefore less significantly shortened due to the multiple mechanical loads on compounding and in injection molding, compared to conventional rigid and brittle carbon or glass fibers. Furthermore, in melt filtration upon reprocessing, the filter is not clogged and the composition of the polymer composite is not altered by uncontrolled filtration out of the reinforcing fibers. The recycled pellets obtained in reprocessing are characterized by a high product quality.

By using polymeric reinforcing fibers composed of the same monomers (from which the matrix polymer is also composed), it is possible to dispense with the use of additional adhesion-promoting agents. The use of crosslinked reinforcing fibers herein ensures that the melting point of the reinforcing fibers is increased relative to the matrix polymer and that the reinforcing fibers retain their structure and shape upon compounding and further processing.

Compared to glass fiber reinforced plastics, the polymer composite according to the invention has a significantly lower density and can therefore be used as a material in lightweight structures.

The process for manufacturing the polymer composite according to the invention can be carried out by conventional methods and tools. The production is carried out with significantly lower energy usage than the methods according to the prior art. Furthermore, the polymer composite according to the invention is less abrasive, whereby the downtime of the processing machines (pulverizers, compounders and injection moulding machines) and injection moulding tools due to maintenance operations is significantly reduced.

The polymer composite according to the invention can be processed in conventional injection moulding processes. Thus, parts with complex geometries and high loads can be manufactured, similar to those manufactured with conventional reinforced plastics. In contrast thereto, self-reinforced plastics are known in the invention in which non-woven or woven fabrics are used for reinforcement.

Drawings

Embodiments of the invention are explained in detail with the aid of the figures and the following description.

Wherein:

fig. 1 schematically shows a method for manufacturing a polymer composite according to the invention.

Detailed Description

In the following description of embodiments of the invention, identical or similar elements are denoted by identical reference numerals, wherein the description of these elements is not repeated in individual cases. The figures only schematically show the subject matter of the invention.

Fig. 1 schematically shows an implementation of a method according to the invention for producing a polymer composite 1 according to the invention. In this embodiment, the process is carried out by means of an extruder 10 which comprises at least one extruder screw 11 and has at least one feed zone 12, at least one melting zone 13, at least one mixing zone 14 and at least one discharge zone 15. The extruder 10 here furthermore has a compression zone 16. The extruder screw 11 conveys the components introduced into the extruder 10 by a rotary movement in the conveying direction 17. The matrix polymer 2 is preferably introduced in the form of pellets or powder into the feed zone 12 of the extruder 10 and conveyed by the extruder screw 11 into the melting zone 13. The matrix polymer 2 is, for example, polypropylene, polyamide 6, polyamide 6.6 or polybutylene terephthalate. In the melting zone 13, the matrix polymer 2 is melted by the supply of thermal energy or by the mere introduction of mechanical energy by means of the extruder screw 11. In the subsequent compression zone 16, the polymer melt is compressed. Optionally, the polymer melt may be degassed in this or another extruder zone. In the mixing zone 14, the reinforcing fibers 3 and optionally auxiliaries and/or additives are fed into the polymer melt via a lateral supply 18. The reinforcing fibers 3 consist according to the invention of a crosslinked polymer material and have an average fiber length of 1 to 10 mm and an average fiber diameter of 10 to 20 μm. The polymer material of the reinforcing fibres 3 is for example cross-linked polypropylene, polyamide 6, polyamide 6.6 or polybutylene terephthalate. Preferably, the polymeric materials of the matrix polymer 2 and the reinforcing fibers 3 comprise or essentially consist of repeating units of the same monomer. In the mixing zone 14, the components are homogeneously mixed to obtain the polymer composite 1. It is conveyed out of the extruder 10 via the discharge zone 15 and can be processed to strands, pellets or directly to shaped bodies.

The present invention is not limited to the embodiments described herein and the aspects emphasized therein. On the contrary, many modifications are possible within the reach of a person skilled in the art within the scope given by the claims.