DE102017108079A1 - Carbon fiber reinforced plastic sheet, process for its production and its use - Google Patents

Abstract

The present invention relates to a sheet-like carbon fiber-based plastic semifinished product having a length and a width comprising a polymer matrix and carbon fibers oriented substantially in the direction of the length of the plastic semifinished product and having a fiber-directional thermal conductivity of at least 300 W / m · K.
Furthermore, the invention relates to a carbon fiber reinforced plastic plate having a length and a width consisting of at least two longitudinally superimposed layers of the planar carbon fiber-based plastic semi-finished product according to the invention. Moreover, the invention relates to a method for producing the carbon fiber reinforced plastic plate, a hot press for carrying out the method, and a plate heat exchanger, in which the carbon fiber reinforced plastic plates according to the invention are arranged.

Description

The present invention relates to a sheet-like carbon fiber-based plastic semi-finished product, a carbon fiber-reinforced plastic sheet produced therefrom, and to the production and use thereof. Furthermore, the invention relates to a device for carrying out the method.

In many industrial applications, the plate heat exchanger has prevailed over alternative designs. The market share of plate systems in the entire market of heat transfer is more than 20% with a strong upward trend. To connect the plates, there are different variants with respective advantages and disadvantages.

Thus, in the prior art bolted plate heat exchangers are known, which are mainly used for cooling and heating of liquids. The advantage of these systems is the ease of maintenance and cleaning. Since the profile plates are bolted together by pressure plates and an anchor pull system, they can be disassembled, cleaned or replaced in a short time. Operating pressures up to 25 bar and operating temperatures of - 40 ° C to 180 ° C can be realized. These parameters are determined by the elastomeric seals between the plates, which also have limited chemical resistance in the thermal treatment of aggressive media.

Also known are soldered plate heat exchangers, which are used in a very wide range of applications due to a variety of favorable properties in terms of efficiency, compressive strength, size and economy. The most important areas here are the processing of liquid media as well as the use as evaporator, condenser, gas cooler and compressed air dryer. Instead of an elastomer seal, copper or nickel-based foils are placed between the profile plates and the entire profile plate pack is brazed in a vacuum oven. The lifetime of these plate systems is estimated to be about 10 to 15 years, depending on the application. In the processing of oxygen-containing drinking or cooling water, however, has shown that after a very short periods of operation corrosion damage, especially at the copper solder occurred.

In aggressive media such as ammonia or at high pressure loads above 25 bar and high temperatures above 200 ° C, the use of sealed plate heat exchangers is very difficult. Semi-welded or fully welded plate heat exchangers made of stainless steel, nickel and titanium alloys have been developed as an alternative to sealed and soldered systems. In semi-welded systems, two plates are welded together and form a hermetically sealed flow channel for the critical medium to be processed. The flow channels between the individual cassettes guide the less critical medium and are conventionally sealed. As a result, easy maintenance by exchanging individual disk cartridges in contrast to fully welded plate systems is possible at any time. However, for both semi-welded and fully welded plate heat exchangers due to the high compressive stress additional pressure racks are provided, on the one hand allow a higher system pressure on the other hand, but significantly increase the system weight, which is disadvantageous.

Essential for the properties of plate heat exchangers are the materials used for the plates.

For the profile plates of plate heat exchangers, in spite of the low thermal conductivity of approx. 15 ^W / _{m * K,} mainly stainless steel (density ρ = 7.9 g / cm ³ ) is currently used as plate material to ensure the required corrosion and media resistance. For high-stress liquids, it is necessary to use more complex nickel-chromium-molybdenum alloys, which in addition to the higher density (8.9 g / cm ³ ) also have a lower thermal conductivity (10.8 W / m * K).

The high weight of the material, the low thermal conductivity and the susceptibility to corrosion are particularly in mobile applications such. As in engines for motor vehicles, aircraft and ships a significant drawback. Although the heat exchangers installed here have a relatively good efficiency, but this reduces, when considering the overall energy balance, crucial by the high weight and size. Another significant disadvantage of conventional plate heat exchangers with classic isotropic construction materials for profile plates is the need for additional insulators to reduce the undesirable heat flow to the environment.

In order to be able to realize the high heat transfer rates demanded today, a large number of flow-optimized profile plates had previously to be incorporated into the heat transfer system. This results in both a high component weight and a considerable space requirement for the plate heat exchanger. So far, the corrosion susceptibility of currently used materials has only been limited by costly coatings, which result in an additional reduction in heat conduction and an increase in component weight.

As noted above, the prior art plate heat transfer systems typically use classically isotropic treadstock materials due to their high corrosion resistance.

Examples are stainless steel (ρ = 7.9 ^g / _cm ³ , λ = 15 ^W / _{m · K} ), copper alloys (ρ = 8.9 ^g / _cm ³ , λ = 46 ^W / _{m · K} ) and titanium alloys (ρ = 4.6 ^g / _cm ³ , λ = 22 ^W / _{m · K} ) with plate thicknesses between t = 0.4 - 1.2 mm, where ρ stands for density and λ for thermal conductivity.

But the use of alternative materials is known. For example, graphite impregnated with synthetic resin is already being used in plate heat exchangers and is characterized by at least high corrosion resistance.

The use of tantalum-coated stainless steel in plate heat exchangers, especially when used in contact with highly corrosive thermal fluids is also known. Tantalum is one of the most corrosion resistant metals, but due to its high density (16.65 ^g / _cm ³ ) it is also very heavy and very expensive. Due to the high corrosion resistance compared to other high-resistant materials such as graphite, silicon carbide or glass to achieve a reduction in operating costs. In order to implement this, a special treatment method is necessary, which provides the actual stainless steel heat exchanger with a layer of tantalum at locations at risk of corrosion.

Due to the very low material costs in comparison with metals, plastics such as polypropylene (PP) or polyethylene (PE) are increasingly used despite their extremely low thermal conductivity (λ = 0.017 ^W / _{m · K} ) for use in plate heat exchangers. The plates used for this purpose are usually interspersed with a variety of channels, which should allow a large transfer area.

There remains a need in the art for plate heat exchangers comprising high thermal conductivity plates which have high strength. Furthermore, there is a need for the plates to be resistant to corrosive media and to be lighter and less expensive than plates made of metals and metal alloys.

In the prior art, there are no plate heat exchangers based on highly thermally conductive carbon fiber reinforced plastic (CFRP). Developments in the use of composite materials for plate heat exchangers refer exclusively to the specific strength and stiffness properties of carbon fibers through a parallel to the component level oriented fiber orientation. However, in the prior art no plate heat transfer systems are known in which the plastic sheets of the invention are used.

Object of the present invention is therefore to overcome the disadvantages of the prior art and provide plates for plate heat exchangers, which are advantageous over the prior art.

The advantageous properties of the panels according to the invention over those of the prior art also have the effect that plate heat exchangers equipped therewith are advantageous over devices of the prior art. In particular, a considerable increase in energy efficiency while reducing the system weight should be achieved.

Surprisingly, it has now been found that advantageous highly heat-conductive carbon fiber reinforced plastic plates can be provided which are also suitable for use in plate heat exchangers. Thus, plate heat exchangers can be provided with plates based on highly heat conductive carbon fiber reinforced plastic (CFRP).

For this purpose, plastic sheets are produced from the sheet-like carbon fiber-based plastic semi-finished products according to the invention. The production takes place in a specially developed device after a inventive production process. These plastic sheets can be used in plate heat exchangers.

Even the existing despite the low weight stability of the carbon fiber reinforced plastic is an advantage over conventionally used metallic materials. Furthermore, the CFRP heat transfer plates according to the invention are resistant to corrosion and, due to the selection of the plastic matrix, allow a great variability of the properties with respect to the resistance to media and environmental conditions such as temperature and pressure.

Furthermore, the inventors have surprisingly found that it is possible to set a desired thermal conductivity up to the maximum thermal conductivity in the production of heat exchanger plates according to the invention. For this purpose, the carbon fibers are aligned in the plastic plate substantially at a certain angle to the plate plane.

The object of the invention is thus achieved by the provision of thin-walled carbon fiber-based plastic semi-finished products from which CFRP profile plates can be produced by means of the method according to the invention, which have a certain thermal conductivity.

It is particularly advantageous that it is possible to produce carbon fiber reinforced plastic plates from one embodiment of the semifinished product according to the invention, which differ in their heat conduction.

This provides carbon fiber reinforced plastic panels suitable for a wide variety of applications.

• 1 zeigt eine schematische Darstellung einer erfindungsgemäßen hochwärmeleitfähigen Wärmeübertragerprofilplatte;
• 2a: den Temperaturverlauf bei einem Edelstahl-Plattenwärmeübertrager;
• 2b: den Temperaturverlauf bei einem erfindungsgemäßen CFK-Plattenwärmeübertrager, nämlich mit erfindungsgemäßer Kohlenstofffaserverstärkter Kunststoffplatte;
• 3a: die Bildung der hochwärmeleitfähigen erfindungsgemäßen Kohlenstofffaser-verstärkten Kunststoffplatte durch mehrlagig, mäanderförmig angeordnete Bahnen des Kohlenstofffaser-basierten Kunststoffhalbzeugs (auch als Prepreg bezeichnet) mit Querversteifung,
• 3b: eine Detailansicht der in 3a gezeigten Darstellung;
• 4a - 4c: eine schematische Darstellung des verfahrenstechnischen Ansatzes zur fertigungstechnischen Umsetzung der erfindungsgemäßen Kunststoffprofilplatten;
• 5: eine schematische Darstellung des erfindungsgemäßen modularen Pressenwerkzeuges;
• 6a: eine schematische Darstellung der erfindungsgemäßen Kohlenstofffaser-verstärkten Kunststoffplatte, ausgebildet als Profilplatte, und
• 6b: eine schematische Darstellung eines erfindungsgemäßen Plattenwärmeübertragers.

The present invention will be explained in more detail with the accompanying drawings. It shows:

• 1 shows a schematic representation of a highly heat-conductive Wärmeübertragerprofilplatte invention;
• 2a : the temperature profile of a stainless steel plate heat exchanger;
• 2 B : the temperature profile in a CFRP plate heat exchanger according to the invention, namely with inventive carbon fiber reinforced plastic plate;
• 3a : the formation of the highly heat-conductive carbon-fiber reinforced plastic plate according to the invention by multilayer, meandering paths of the carbon fiber-based plastic semi-finished product (also referred to as prepreg) with transverse reinforcement,
• 3b : a detailed view of in 3a shown illustration;
• 4a - 4c : a schematic representation of the procedural approach to the manufacturing implementation of the plastic profile plates according to the invention;
• 5 a schematic representation of the modular press tool according to the invention;
• 6a : A schematic representation of the carbon fiber reinforced plastic sheet according to the invention, designed as a profile plate, and
• 6b : a schematic representation of a plate heat exchanger according to the invention.

The object of the invention is achieved by the provision of a sheet-like, carbon fiber-based plastic semi-finished product, a carbon fiber reinforced plastic sheet produced therefrom, a method and a device for the production thereof, and their use.

According to the invention, a carbon fiber-based plastic semi-finished product having a length and a width comprising a polymer matrix and carbon fibers aligned therein substantially in the direction of the length of the plastic semifinished product and having a thermal conductivity in the fiber direction of at least 300 W / m K is provided.

In a preferred embodiment of the invention, the sheet-like carbon fiber-based plastic semi-finished product is characterized in that the carbon fibers are selected from high modulus and ultra high modulus carbon fibers.

An embodiment in which the polymer matrix of the sheet-like carbon fiber-based plastic semifinished product is formed from polypropylene, polyethylene or polyamide or mixtures thereof is advantageous.

Furthermore, the object of the invention is achieved by providing a carbon fiber reinforced plastic plate having a length and a width consisting of at least two longitudinally stacked layers of the planar carbon fiber-based plastic semi-finished product according to the invention.

A preferred embodiment of the invention is a carbon fiber reinforced plastic plate in which the carbon fibers are aligned in the plastic plate substantially at an angle between 10 ° to 90 ° to the plate plane.

Particularly preferred is an embodiment of the carbon fiber reinforced plastic sheet according to the invention, which further comprises stiffness fibers.

In addition, the object of the invention by a method for producing the carbon fiber reinforced plastic sheet according to the invention is achieved, wherein one arranges at least two layers of the sheet-like carbon fiber-based plastic semi-finished product according to the invention one above the other in the longitudinal direction and interconnects.

Advantageously, a method in which the layers of the planar carbon fiber-based plastic semi-finished product according to the invention are arranged one above the other such that the carbon fibers in the plastic plate are substantially aligned at an angle between 10 ° to 90 ° to the plate plane.

Particularly preferred is a method in which the layers of the planar carbon fiber-based plastic semi-finished product according to the invention are aligned meander-shaped and form the carbon fibers in the plastic plate substantially an angle of 10 ° to 90 ° to the plate plane.

Also advantageous is a method in which stiffness fibers in the transverse direction to the layers of the planar carbon fiber-based plastic semi-finished product according to the invention are arranged on at least one of the layers before the layers are joined.

Particularly preferred is a method in which arranges the layers of the sheet-like carbon fiber-based plastic semi-finished product according to the invention in a hot press, compressed, plasticized and solidified.

Furthermore, the object of the invention is achieved by providing a hot press for producing a carbon fiber reinforced plastic sheet according to the invention, which stiffness fiber guides 9 . 10 , and fiber coils 14 . 17 , having.

In addition, the object of the invention is achieved by providing a plate heat exchanger in which carbon fiber reinforced plastic plates according to the invention are arranged.

By using the thin-walled carbon fiber-based plastic semi-finished products according to the invention, it is possible to provide thermally conductive heat exchanger systems with a significantly reduced component weight compared with the prior art. The high-modulus carbon fibers used for this purpose are characterized not only by their high thermal conductivity in the fiber direction (≈1200 W / m · K), but also by their high specific strength and stiffness properties.

Ultra high modulus (UHM) special carbon fibers have their highest thermal conductivity, their heat conduction 3 -fold higher than pure copper and 50-fold compared to stainless steel.

By a special orientation of the carbon fibers in the plastic sheet produced from the semifinished products, for example a substantially inclined meandering orientation of the fibers with a high normal content to the plate plane, the enormous thermal conductivity of the carbon fiber reinforced plastic (ρ = 2.2 ^g / _cm ³ ) exploited in the fiber direction and a high strength and rigidity of the profile plates can be achieved.

In addition, there is a huge reduction in system weight, as well as a significant improvement in corrosion resistance through the use of a thermoplastic matrix.

The starting point for the production of the highly heat-conductive CFRP profile plates are high-modulus or ultra-high-modulus carbon fibers which are fixed by a thin thermoplastic matrix in a prepreg semifinished product. In static hot pressing these prepreg layers are stacked and according to the required fiber orientation in the plate mold of tempering and coolable upright press arranged in a desired manner, for example meandering and simultaneously at processing temperature (about matrix melt temperature) compressed and processed into profile plates for plate heat transfer systems.

Carbon fiber-based plastic semi-finished products are thus used according to the invention for producing the profiled sheets according to the invention. High-modulus (HM) carbon fibers are preferably used for the production of these plastic semi-finished products according to the invention, which in addition to the high thermal conductivity in the fiber direction of at least 300 W / m · K are characterized by high specific strength and stiffness properties.

In a particularly preferred embodiment, "ultra high modulus" (UHM) specialty carbon fibers are used which have particularly advantageous thermal conduction properties. Its heat conduction is 3 times higher than that of pure copper and 50 times higher than stainless steel.

These carbon fibers used in the invention are commercially available.

In contrast to metallic materials in which the heat conduction behaves isotropically, the thermal conductivity of the carbon fibers is generally strongly anisotropic and highest in the fiber direction. UHM fibers are made from polyacrylonitrile (PAN) (50%) or pitch (> 80%) due to the high carbon yield. The high thermal conductivity results from a special graphitization during the manufacturing process at temperatures up to 3000 ° C. As a result, the preorientation of the graphite planes in the direction of the fiber axis is increased, so that a strongly anisotropic material behavior is produced by means of the covalent crystal bonds. As a result, the heat conduction across the fiber direction is about 1 - 2 ^W / _{m · K.} In combination, the thermal conductivity is reduced depending on the fiber content. Thus, for example, in the case of a unidirectional laminate structure with 60% fiber volume content and 40% plastic matrix, a thermal conductivity in the fiber direction of more than 700 ^W / _{m · K can be} achieved.

High modulus fibers (HM - high modulus, C content: 99% by weight) Carbon fibers are electrically conductive. The specific electrical resistance is ρ = 8 (HM fiber)

Ultrahigh modulus fibers (UHM ultrahigh modulus, C content> 99 wt%) UHM grades are also referred to as graphite fibers because the temperature during this second variant of the preparation is usually higher than 2500 ° C.

Fibers with a high degree of graphitization, ie high modulus fibers, oxidize far less and can be used at even higher temperatures. Because carbon fibers consist of more than 90% carbon, they have an extremely low coefficient of thermal expansion.

in N/mm² 3 430 4 510 4 210 2 450 2 150 Dichte ρ_f in g/cm³ 1,74 1,8 1,74 1,81 1,9 Table 1 gives an overview of the properties of different carbon fibers. Table 1, Properties of carbon fibers and their designation HT-fiber ST fiber IM-Fiber HM fiber UHM fiber E-module along E _f∥ in N / mm ² 230,000 245,000 294,000 392,000 450,000 E-modulus across E _f⊥ in N / mm ² 28,000 15,200 G-modulus G _f⊥∥ in N / mm ² 50,000 28 600 _Cross contraction number ν _f⊥∥ 0.23 0.2 Therm. Coefficient of expansion. along α _Tf∥ [10 ^-6 / ° C] -0.455 -1.08 Therm. Coefficient of expansion. transverse α _Tf⊥ [10 ^-6 / ° C] 12.5 31 tensile strenght ${\text{R}}_{\text{f}\Vert }^{+}$

in N / mm ² 3 430 4 510 4 210 2 450 2,150 Density ρ _f in g / cm ³ 1.74 1.8 1.74 1.81 1.9

In one embodiment of the invention, the inventors provide a method for targeted alignment of high thermal conductivity carbon fibers with a high normal content to the plate plane of profile plates for heat transfer systems. Furthermore, the inventors disclose a pressing tool as well as the integration of the semifinished product guide, for example in meandering form, in a pressing tool.

By way of example, the invention can be implemented in highly efficient plate heat transfer systems made of thin-walled (t = <1 mm) highly heat-conductive CFRP profile plates.

Overall, the invention can be used in a wide range of applications. There is a great deal of interest in the manufacturing sector (metal industry, mechanical engineering, motor vehicles, paper products, foodstuffs, electrical industry, chemical products), especially in the field of thermotechnology. Efficient heat recovery and cooling systems are currently in high demand due to the Energy Saving Act (EnEg) and the European Energy Efficiency Directive (EED).

In contrast to metallic materials in which the heat conduction behaves isotropically, the thermal conductivity of the carbon fibers is generally strongly anisotropic and highest in the fiber direction. As a result, the heat conduction across the fiber direction is about 1 - 2 ^W / _{m · K.} In combination, the thermal conductivity is reduced depending on the fiber content. Thus, for example, in the case of a unidirectional laminate structure with 60% fiber volume content and 40% plastic matrix, a thermal conductivity in the fiber direction of more than 700 ^W / _{m · K can be} achieved.

Examples

The following examples illustrate the invention in more detail without limiting the scope of the invention.

As with a given semi-finished product (prepreg) optimal thermal conductivity of plates produced therefrom is obtained will be explained with reference to the examples described below.

In a preferred embodiment of the invention, the enormous thermal conductivity of the carbon fiber reinforced plastic (ρ = 2.2 ^g / _cm ³ ) in the fiber direction is utilized by a specially inclined meandering orientation of the carbon fibers with a high normal content to the profile plate plane and high strength and rigidity the plates scored.

In addition, there is a huge reduction in system weight, as well as a significant improvement in corrosion resistance through the use of a thermoplastic matrix. For this purpose, with regard to their mechanical and thermal properties, the materials polypropylene (PP), polyethylene (PE), or polyamide (PA) are used as the matrix material. In addition, the use of bonding technology for connecting and sealing the profile plates enables the substitution of weight-intensive printing plates and thus the exploitation of the full lightweight potential.

For the implementation of the required thin-walled profile plates with inclined to the component level oriented and fixed by plastic matrix UHM fibers, a process for the production of corresponding flat semi-finished products is further developed.

1 shows a schematic representation of a highly heat conductive carbon fiber reinforced plastic sheet according to the invention, which is suitable as a heat exchanger profile plate.

The heat flow in the XY direction and in the Z direction is shown in each case. According to the invention, the heat flow in the XY direction due to the orientation of the carbon fibers is lower than that in the Z direction.

The energetic and weight-related advantages resulting from the use of UHM fibers can be scalarly compared to a thermally transient simulation of a CFRP plate heat transfer system (profile plate thickness 1 mm, fiber volume content 60%, inclination of the UHM fibers to profile plate level 30 °) Stainless steel based plate heat exchanger (profile plate thickness 0.6 mm).

For both systems a heat transfer of α = 800 ^W / _m ² · _K for flowing liquids in plate heat exchangers and an initial temperature gradient of Δt = 83 ° C (90 ° C hot side, 7 ° C cold side) are assumed. After a time of approx. 100 s, the stainless steel-based plate heat exchanger achieves a nearly linear temperature profile with a resulting temperature gradient of 2.8 ° C.

This is in 2a shown.

In comparison, the CFRP plate heat exchanger reaches the same temperature difference after half of the time and after 100 s a temperature gradient of 1.12 ° C, which in 2 B is shown.

It can be seen that assuming a fiber volume content of 60% and compared to the stainless steel plate heat exchanger, same profile plate length and profile plate width, as well as the same temperature conditions, the highly heat-conductive CFRP plate heat exchanger can achieve twice the heat transfer performance. Due to the high thermal conductivity and the very low profile plate thickness resulting from the use of the CFRP profile plates according to the invention in Plattenwärmeübertragern manifold design advantages that allow completely new, more compact and at the same time more powerful designs. In addition, with the help of the CFRP profile plates, an enormous weight saving compared to stainless steel plate heat exchangers of more than 60% is achieved.

• CFK-Profilplatte: 47,43
• Titanlegierung: 71,15
• Edelstahl: 131,5
• Kupferlegierung: 140,73
• Diabon-Graphit: 421,68

If one compares the weight of a standardized plate heat exchanger with a profile plate number of 150 and a total transmission area of 26.36 m ² when using the materials mentioned above, the following values result in kg:

• CFK profile plate: 47.43
• Titanium alloy: 71.15
• Stainless steel: 131.5
• Copper alloy: 140.73
• Diabon graphite: 421.68

Compared: a 1 mm CFK profile plate, a 0.6 mm titanium profile plate, a 0.6 mm stainless steel profile plate, a 0.6 mm copper profile plate and an 8 mm Diabon profile plate.

The starting point for the production of highly heat-conductive carbon fiber-reinforced plastic plates form in one embodiment UHM carbon fibers, which are fixed by a thin thermoplastic resin matrix in a prepreg semifinished product.

The development of such prepregs is required because UHM carbon fiber systems of this type are not currently available on the market. The surface formation takes place with the aid of the film stacking method.

In this case, the UHM fibers are combined with the film material present in the form of a film to form a so-called unidirectional single layer.

The semifinished products (prepregs) according to the invention provided thereby form the precursor for the production of the highly heat-conducting plastic sheets. For this purpose, the UHM carbon fibers of the unidirectional prepregs are aligned with a high normal proportion to the profile plate plane.

The inventors have found that a high thermal conductivity of the plastic sheets can be achieved if the carbon fibers in the sheet are oriented at an angle to the later sheet plane, which is between 10 ° and 90 °. Such an orientation of the carbon fibers is achieved according to the invention, for example, by arranging the semifinished product webs in a meandering, multilayered and unidirectional manner before they are pressed into a plate. So that the profile plates, in addition to the high thermal conductivity in the thickness direction, over sufficient Querfestigkeits- and transverse stiffness properties In a preferred embodiment, additional rovings ("stiffness fibers") will be introduced in the component level-in the meandering arches-during profiling.

This embodiment is in the 3a and 3b shown. Shown is the production of highly heat-conductive profile plates by multilayer, meander-shaped, inventive planar carbon fiber-based plastic semi-finished products (here UHM prepreg layers) with transverse reinforcement. A subarea, shown in 3b , is shown enlarged. The carbon fiber-reinforced prepregs are meandered and press-processed.

In static hot pressing, the prepreg layers are stacked and arranged according to the required fiber orientation meandering in the plate mold of the temperature-controlled and coolable stator press and simultaneously compressed at the processing temperature (at about the matrix melt temperature). In order to be able to produce particularly high-quality components, a robust tool system with process monitoring ( _{cavity pressure} p _WZi , temperature), a homogeneous heat distribution (arrangement of heating cartridges) as well as a corresponding control for safe process control and control of the temperature control has been developed. The novel procedural approach is in the 4a . 4b and 4c shown schematically.

5 shows a schematic representation of the novel modular press tool that has been developed for the production of carbon fiber reinforced plastic sheets according to the invention.

Due to the laterally introduced "stiffness fibers", the prepreg semifinished products are converted in a preferred embodiment into a meander-shaped arrangement and the semi-finished products are compressed by means of the pressing tool.

Depending on at which position and in what number the stiffness fibers are introduced, the layers of the semifinished product are at least partially raised before being pressed out of the plane of the cavity of the press. In this case, the layers can project out of the plane of the cavity of the press in a wave-shaped or angled manner. The pressing fixes this arrangement, which causes alignment of the carbon fibers out of the plane of the plate.

Carbon fibers are preferably used as the stiffness fibers, but they do not have to have any special thermal conductivity. Advantageous is the use of carbon fibers, because they are well integrated into the plate during pressing.

The near-net-shape highly heat-conductive profile plates produced in the pressing process are subsequently given their final cut. Here, in addition, the introduction of recesses for the media supply and media removal, as well as the preparation of the interfaces for the adhesive joining of the individual profile plates. The application of bonding technology makes weight-intensive printing plates and additional seals, which are common in screw-type plate heat exchangers, unnecessary, thereby allowing a further reduction in the operating weight to be implemented. 6a shows the schematic design of the manufactured profile plate and 6b the plate heat exchanger according to the invention.

By means of the highly heat-conducting profile plates according to the invention, a considerable increase in the energy efficiency of the plate heat exchangers equipped with a simultaneous reduction in the system weight is achieved in comparison to the prior art.

LIST OF REFERENCE NUMBERS

A

transversely

B

longitudinal direction

2

Meander-shaped arrangement of the carbon-based plastic semi-finished product

3

Stiffness fibers (transverse reinforcement)

4

Press above

5

Press below

6

cavity

7

Press below

8th

Carbon-based plastic semi-finished product

9

Stiffness fiber guide above

10

Stiffness fiber guide below

11

Role of carbon-based semi-finished plastics

12

conveying rollers

13

Stack of carbon-based plastic semi-finished products (prepreg stack)

14

Fiber coils below

15

stiffness fibers

16

Guide for carbon-based plastic semi-finished products

17

Fiber coils above

18

Package of carbon fiber reinforced plastic profile plates

19

Media inlet and outlet

101

Carbon fiber reinforced plastic plate

102

Press tool

103

Carbon fiber reinforced plastic profile plate

104

Plate heat exchangers

Claims (13)

A sheet-like carbon fiber-based plastic semi-finished product having a length and a width, comprising a polymer matrix and aligned therein substantially in the direction of the length of the plastic semi-finished carbon fibers having a thermal conductivity in the fiber direction of at least 300 W / m K. Sheet-like carbon fiber-based plastic semi-finished product, according to Claim 1 , characterized in that the carbon fibers are selected from high modulus and ultra high modulus carbon fibers. Sheet-like carbon fiber-based plastic semi-finished product, according to Claim 1 or 2 , characterized in that the polymer matrix is formed from polypropylene, polyethylene or polyamide or mixtures thereof. Carbon fiber reinforced plastic sheet having a length and a width consisting of at least two longitudinally stacked layers of the sheet-like carbon fiber-based plastic semi-finished product according to any one of Claims 1 to 3 , Carbon fiber reinforced plastic plate, according to Claim 4 , characterized in that the carbon fibers are aligned in the plastic plate substantially at an angle between 10 ° to 90 ° to the plane of the plate. Carbon fiber reinforced plastic plate, according to one of Claims 4 or 5 , characterized in that the plastic plate further comprises stiffness fibers. A method of producing a carbon fiber reinforced plastic sheet according to any one of Claims 4 to 6 in which at least two layers of sheet-like carbon fiber-based plastic semi-finished product, according to one of Claims 1 to 3 , one above the other in the longitudinal direction and connects with each other. Method according to Claim 7 , characterized in that the layers of the sheet-like carbon fiber-based plastic semi-finished product, according to one of Claims 1 to 3 , Are arranged one above the other so that the carbon fibers are aligned in the plastic plate substantially at an angle between 10 ° to 90 ° to the plane of the plate. Method according to one of Claims 7 or 8th , characterized in that the layers of the sheet-like carbon fiber-based plastic semi-finished product, according to one of Claims 1 to 3 , meandering are aligned and form the carbon fibers in the plastic plate substantially at an angle of 10 ° to 90 ° to the plate plane. Method according to one of Claims 7 to 9 , characterized in that stiffness fibers in the transverse direction to the layers of the sheet-like carbon fiber-based plastic semi-finished product, according to one of Claims 1 to 3 be arranged on at least one of the layers before joining the layers. Method according to one of Claims 7 to 10 , characterized in that the layers of the sheet-like carbon fiber-based plastic semi-finished product, according to one of Claims 1 to 3 , arranged in a hot press, compressed, plasticized and solidified. Hot press, for producing a carbon fiber reinforced plastic plate, according to one of Claims 4 to 6 comprising stiffness fiber guides (9, 10) and fiber coils (14, 17). Plate heat exchanger, in which carbon fiber reinforced plastic plates, according to one of Claims 4 to 6 , are arranged.

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