DE102022000134A1 - Method of curing a glass fiber composite material - Google Patents

Abstract

The invention relates to a method for curing a glass fiber composite material, comprising at least one step of free-radical curing of a glass fiber composite material by means of narrow-band UV-LED radiation, which is generated using light-emitting diodes (LED) as a radiation source, the wavelength of which is in a wavelength range from 365 nm to 440 nm and a wavelength half-width of at most ±10 nm, the glass fiber composite material to be cured by this radiation having glass fibers as Having reinforcing fibers and a matrix containing polymerizable matrix components and at least one photosensitizer for catalyzing at least one photo-induced radical polymerization.

Description

The invention relates to a method for curing a glass fiber composite material by means of UV-assisted polymerisation. This method comprises at least one step of radical hardening of the glass fiber composite material using narrow-band UV LED radiation.

The application relates to the field of polymerisation thermosets and processes in which electromagnetic radiation can penetrate the composite and trigger polymerisation reactions. These include pultrusion processes with an open profile, winding technology and the field of impregnated semi-finished products, so-called prepregs.

The polymerisation of duroplastic composite materials and the production of impregnated semi-finished products as prepreg primary materials are state of the art. Such a polymerization can take place thermally or by means of radiation or rays with wavelengths in the ultraviolet range, hereinafter referred to as UV radiation or UV rays.

The processes of photo-induced polymerization and radiation curing processes using UV rays are well known (cf.: P. Glöckner, T. Jung, S. Struck, K. Studer, "Radiation Curing", Verlag: Vincentz Network, 2009, ISBN: 978-3-86630-907-4, pp. 17 to 21 and pp. 30 to 39). They are also used in a variety of forms, for example in coating and printing processes. However, the limited penetration depths of the radiation have so far been disadvantageous and have a lasting effect on the polymerization process. The main cause is the physical composition of the radiation. In the case of curing exclusively with UV radiation, complete conversion does not take place. As an alternative, post-curing at elevated temperature is carried out after the process, which is also referred to as tempering. However, this also represents a limitation on productivity.

A more or less strong volume shrinkage occurs during the polymerization process. This causes tensile stress in the fiber-matrix system and thus reduced adhesion of the fiber fibrils to the surrounding matrix. As a result, the mechanical properties of the composites produced are reduced. In order to keep the process manageable, the concentration of radicals is limited and the speed reduced. This means a comparatively significant reduction in productivity.

In addition, the half-lives of the radical formation of the thermal initiators are highly temperature-dependent and cannot be interrupted. The hardening cannot therefore be carried out optimally, since the formation of free radicals increases and is difficult to influence due to the accumulation of reaction heat in the system.

Composites that are produced in the presence of atmospheric oxygen tend to be sticky on the surface because the oxygen is inhibited by the matrix surface.

The object of the invention is to provide a method with UV-assisted polymerization for the production of duroplastic fiber-reinforced plastics, this method being faster than previous methods and at the same time being controllable, which would result in an overall increase in productivity. In addition, the surface tack should be reduced. A further object of the invention is to design the polymerization process in such a way that systems which are opaque per se can be polymerized by means of UV radiation.

The solution to the object of the invention consists in a method for curing a glass fiber composite material, the method comprising the features of claim 1. Preferred embodiments and developments are specified in the dependent claims.

The method according to the invention comprises at least one step of free-radical curing of the glass fiber composite material by means of narrow-band UV-LED radiation. This UV LED radiation is generated using light-emitting diodes (LED) as a radiation source, lies in a wavelength range from 365 nm to 440 nm and has a maximum wavelength half-width of ±10 nm. The glass fiber composite material to be cured by this radiation has glass fibers as reinforcing fibers and a matrix containing polymerizable matrix components and at least one photosensitizer for catalyzing at least one photo-induced radical polymerization.

Such a method that shapes the polymerisation process using narrow-band UV radiation, i.e. of a maximum of ± 10 nm, at a wavelength of around 400 nm and the scattering of the incident the narrow-band UV radiation used to polymerize matrix materials that contain finely divided, radiation-opaque solids is not known to date. Light-emitting diodes (LED) as a radiation source can meet these requirements because they inherently generate light of a narrow-band wavelength.

By using the narrow-band UV radiation, a maximum transmission of the penetrating radiation through the reinforcing fiber and matrix as well as a sufficient sensitization interaction for the formation of radicals are achieved. In particular, the narrow-band nature of the irradiation requires a fixed extinction coefficient of the photosensitizer and allows optimal adjustment of the sensitizer concentration and the power of the radiation source.

The process according to the invention enables the polymerization process to be controlled in such a way that the temperature increase and the formation of free radicals are separated in time. This makes it possible without any problems to allow the polymerization to proceed at the optimum point in time after the temperature has risen above the glass transition temperature. The productivity disadvantage is overcome by the significant increase in speed that can be achieved. At the same time, surface stickiness of the finished product is prevented.

Curing with UV LED rays differs from the process of radical polymerization only in the first step of radical formation. This means that all systems of radical polymerization can be adopted (cf.: H.-J. Timpe, H. Baumann, "Photopolymers, principles and applications", VEB Deutscher Verlag für Grundstoffindustrie, 1988, ISBN: 3342002158, p. 17 to 20, pp. 89 to 92 and pp. 270 to 273).

• - ungesättigte Polyesterharze (UP),
• - Vinylesterharze (VE),
• - Phenacrylatharze (PAH),
• - Methacrylatharze (MA).

The polymerizable matrix components are preferably selected from reaction resin types in order to obtain certain properties of the composite materials:

• - unsaturated polyester resins (UP),
• - vinyl ester resins (VE),
• - phenacrylate resins (PAH),
• - Methacrylate resins (MA).

Furthermore, monomers can also be polymerized, such as acrylates, methacrylates and/or vinyl aromatics.

• Glasfasern: von 5 % bis 80 %,
• Matrix: von 20 % bis 95 %.

As a rule, the glass fiber composite material has the following composition, with the information in % by mass:

• glass fibres: from 5% to 80%,
• Matrix: from 20% to 95%.

• - Bis(2,4,6-trimethylbenzoyl)-phenylphosphinoxid,
• - Bis(.eta.5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)-titanlV,
• - Bis(cyclopenta-1,3-dien-bis(2,6-difluor(1 H-pyrrol-1-yl)phenolid)-titanlV,
• - 2,4,6-Trimethylbenzoyl-diphenylphosphinoxid,
• - 2,4,6-Trimethylbenzoyl-diphenylphosphinat.

The proportion of the photosensitizer in the matrix is from 0.01% to 6%. The photosensitizer can be selected from for example:

• - bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide,
• - Bis(.eta.5-2,4-cyclopentadien-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titaniumV,
• - bis(cyclopenta-1,3-dienebis(2,6-difluoro(1H-pyrrol-1-yl)phenolide)titanium IV,
• - 2,4,6-trimethylbenzoyl-diphenylphosphine oxide,
• - 2,4,6-trimethylbenzoyl diphenylphosphinate.

Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is also known by its synonym bisacylphosphine oxide with the trade name Omnirad 819.

The UV radiation is generated by UV LED lamps with a wavelength range preferably in the range from 410 to 415 nm. The maximum transmission can be achieved in this wavelength range. Scattered radiation and internal reflection from solid parts lead to scattered light polymerisation of non-transparent composite materials. The radiation penetrating the composite inhibits the diffusion of atmospheric oxygen into the composite surface and leads to a tack-free curing of the same.

Together with a photosensitizer, which causes radical formation and radical reaction, the polymerization starts independently of the temperature.

According to an advantageous embodiment of the invention, thermal polymerization and UV-assisted polymerization are connected in series in a specific sequence or in specific sequences in the process. This makes it easy to separate the formation of radicals and the increase in temperature and also to integrate tempering into the process.

Thermal preheating can advantageously take place at the beginning of the process in order to increase the temperature of the matrix to a value above the glass transition temperature. The subsequent process is characterized by a multi-stage arrangement of thermal systems and UV systems. In each case, a radical reaction is promoted in a UV system, during which the glass transition temperature increases. The thermal systems ensure that the material is heated to the required value above the existing glass transition temperature. With increasing polymer conversion, the mobility of the polymer chain segments, which is decisive for the glass transition, decreases one after the other. The maximum value of the glass transition temperature is only reached when the conversion is complete (cf.: H.-G. Elias "Macromolecules", publisher: Wiley-VCH 2002, ISBN: 3527299599, pp. 427 to 429).

With reasonable residence times in the process, a degree of conversion of around 80 - 85% is achieved in the UV systems. In order to achieve complete conversion, thermal heating is arranged as tempering at the end of the process. Here, the double bond-containing reactants still present react with one another due to diffusion under the influence of heat.

• ➢ eine signifikante Erhöhung der Durchlaufgeschwindigkeit im Vergleich zum Stand der Technik,
• ➢ Erreichen von klebfreien Oberflächen ohne den Einsatz von Isocyanaten,
• ➢ Integration des Tempervorgangs in den Prozess und
• ➢ UV-Polymerisation von Systemen im Streulicht, die an sich nicht lichtdurchlässig sind.

The following advantages can essentially be achieved with the invention:

• ➢ a significant increase in throughput speed compared to the prior art,
• ➢ Achievement of tack-free surfaces without the use of isocyanates,
• ➢ Integration of the tempering process into the process and
• ➢ UV polymerisation of systems in scattered light that are not translucent per se.

• 1: eine schematische Darstellung einer Anlage für ein Verfahren zur Herstellung von duroplastischen Glasfasercompositmaterialien mit thermischen Anlagen und Anlagen zur photoinduzierten Polymerisation.

Further details, features and advantages of the invention result from the following description of exemplary embodiments with reference to the associated drawing. It shows:

• 1 : a schematic representation of a system for a process for the production of thermoset glass fiber composite materials with thermal systems and systems for photo-induced polymerization.

The process sequence, starting from impregnation to cooling and strip take-off, is carried out on the basis of the data obtained for a strand in the form of a round profile with a diameter of 6 mm with a proportion of 80% by mass of matrix and 20% by mass of glass fibers, wherein the matrix contains 0.63% by mass of the photosensitizer. The test arrangement includes both thermal systems, both in the 1 as well as in Table 1 with Hzg. I - VI (heating I - VI) are named, as well as UV systems, ie systems in which photo-induced polymerization takes place by radiation with wavelengths in the ultraviolet range and in the 1 and Table 1 are denoted by UV 1 and UV 2. The total length of the test facility, i.e. the length of the arrangement of thermal systems Hzg. I - VI and the UV systems UV 1 and UV 2, is 13.63 m here.

The thermal heating takes place with high-temperature infrared dark radiators made of ceramic material. These are characterized by high emissivity and optimal radiation characteristics. The radiation thus penetrates deep into the composite material and heats up the inside of the material at the same time. Table 1 Strand: 6.2 mm profile with 80% by mass glass and 20% by mass matrix; Matrix contains 0.75 parts by mass (MT) of photosensitizer Temperature rise of about 80 K in the strand during adiabatic polymerization of the composite material and 100% conversion Hzg. I Hzg. II Post-jet and UV 1 Hzg. III Hzg. IV UV2 Hzg. V Hzg. VI length in cm 4030 570 4020 4070 Temperature of the thermal heaters 430°C 430°C 430°C 380ºC 380ºC 380ºC Strand withdrawal speed: 12 m/min Dwell time in the plant parts 20s 0.75s 20s 4s 20s Strand surface temperature measured with thermal imaging camera 23°C 75.4°C 81.8°C 116.7°C 146.7°C 450F (205C) Temperature rise between inlet and outlet ΔT 52.3K 6.4K 34.9K 29.7K 58.4K Total ΔT in the UV LED systems 36.1 K 36.1/80 * 100% = 45.1% conversion in 4.75 s distribution About 8% conversion in UV1 / about 37.1% conversion in UV2

example 1

The method according to the invention for curing a glass fiber composite material using narrow-band UV-LED radiation is characterized by maximum transmission of the penetrating radiation both through the reinforcing fiber and the matrix. This is shown by the extinction values listed in Table 2 for various wavelengths in the range from 340 to 410 nm, measured at a layer thickness of 0.1 cm. It is shown that the glass fibers cause an extinction value of 0 in each case, an absorption rate of 1 in each case and an absorbance per cm of 0/cm at irradiated wavelengths of 380 nm to 410 nm. Table 2 Glass fibers λ irradiated [nm] Extinction of the incident light Absorption rate I ₀ /I absorbance 1/cm Ig (I ₀ /I) layer thickness 0.1 cm 410 0 1 0 400 0 1 0 390 0 1 0 380 0 1 0 370 0.085 1.2162 0.85 360 0.200 1.5849 2.00 350 0.370 2.3442 3.70 340 0.600 3.9811 6.00

Table 3 lists the extinction values for styrenic unsaturated polyester resin (UP resin) for various wavelengths in the range from 340 to 420 nm. This shows that the values for extinction, absorption rate and absorbance are lower, the higher the value for the wavelength of the incident light. Table 3: Product styrenic UP resin λ irradiated [nm] Extinction of the incident light Absorption rate I ₀ /I absorbance 1/cm Ig (I ₀ /I) layer thickness 0.1 cm 420 0.0595 1.1468 0.595 415 0.0694 1.1733 0.694 410 0.0818 1.2073 0.818 405 0.0973 1.2511 0.973 400 0.1178 1.3116 1.178 395 0.1435 1.3916 1,435 390 0.1785 1.5083 1,785 380 0.2946 1.9708 2,948 370 0.5061 3.2072 5,062 360 0.8913 7.7852 8,410 350 1.6312 42,776 16,300 340 1.9885 97,386 19,880

Table 4 shows the extinction coefficients in the unit [l/mol cm] for the photosensitizer bisacylphosphine oxide Omnirad 819 for various wavelengths in the range from 320 to 435 nm as a function of the wavelengths λ of the incident light. Table 4 Extinction coefficient photosensitizer: Bisacylphosphine Oxide Omnirad 819 λ irradiated extinction coefficient [nm] [l/mole cm] 435 12.55 420 200 410 376 395 550 390 600 385 620 380 660 365 966 360 1250 350 2000 335 319900 320 5450

example 2

Example 2, see Table 5, shows that the narrow-band nature of the irradiation requires a fixed extinction coefficient of the photosensitizer and allows the concentration of the photosensitizer and the power of the radiation source to be set optimally.

Eλ

Extinktion/Leistung

I

Intensität des transmittierten Lichtes

I0

Intensität des einfallenden (eingestrahlten) Lichtes

c

Konzentration der absorbierenden Substanz in der Flüssigkeit [mol · m^-3] oder [mol · I^-1]

ελ

natürlicher molarer Extinktionskoeffizient bei der Wellenlänge λ [dm³ · mol ^-1 cm ^-1] oder [l · mol ^-1 cm ^-1]

d

Weglänge des Lichtes im Material [cm]

The effect of the radiation can be quantified using the Lambert-Beer law: $${\text{E}}_{\mathrm{\lambda }}=-\text{lg}\left(\frac{\text{I}}{{\text{I}}_0}\right)={\mathrm{e}}_{\mathrm{\lambda }}\cdot \text{c}\cdot \text{i.e}$$

Eλ

absorbance/power

I

Intensity of the transmitted light

I0

Intensity of the incident (irradiated) light

c

Concentration of the absorbing substance in the liquid [mol m ^-3 ] or [mol I ^-1 ]

ελ

natural molar extinction coefficient at wavelength λ [dm ³ mol ^-1 cm ^-1 ] or [l mol ^-1 cm ^-1 ]

i.e

Path length of the light in the material [cm]

It is easy to see that when the radiation power is reduced, the surface reaction speed decreases, but more radiation arrives in the deeper layers compared to the surface. The same effect can be achieved by dimming E _λ .

The aim is to control the polymerisation inside the glass fiber composite material.

• - ein reines Matrixmaterial,
• - eine angenommene Eindringtiefe in die Matrix von 3 mm sowie
• - eine Wellenlänge von 410 nm.

Tabelle 5 Eindringtiefe Matrix 3 mm Konzentration des Sensibilisators Extinktion des einstrahlenden Lichts ankommende Strahlung [Massen-%] % der Ausgangskonzentration Ig (I₀/I) [%] 0,620 100 0,3670 42,6 0,409 66 0,2440 56,7 0,248 40 0,1468 71,4 0,186 30 0,1101 81,9 0,124 20 0,0693 85,4 0,062 10 0,0367 91,4 Boundary conditions of the calculation are:

• - a pure matrix material,
• - an assumed depth of penetration into the matrix of 3 mm and
• - a wavelength of 410 nm.

Table 5 depth of penetration matrix 3mm Concentration of the sensitizer Extinction of the incident light incoming radiation [mass%] % of initial concentration Ig (I ₀ /I) [%] 0.620 100 0.3670 42.6 0.409 66 0.2440 56.7 0.248 40 0.1468 71.4 0.186 30 0.1101 81.9 0.124 20 0.0693 85.4 0.062 10 0.0367 91.4

Example 3

Table 6 contains information about the incoming radiation of the UV LED radiation penetrating a composite material, the incoming radiation being listed for different wavelengths of irradiation. Table 6 also shows the transmittances of the components of the composite material, i.e. the glass fiber material and the matrix, for radiation of the various wavelengths.

The composite material is in the form of a pultruded round profile with a glass content of 66% by volume or 80% by mass, a matrix content of 34% by volume or 20% by mass on the round profile, a diameter of 8 mm, corresponding to a distance from the profile center of 4 mm in front. Mathematically, these 4 mm are made up of 2.64 mm glass fiber fibrils and a matrix of 1.36 mm. Table 6 Wavelength for irradiation [nm] 410 390 365 Permeability glass fibers [%] 100 100 55 permeability matrix [%] 76.9 31.5 5 Incoming radiation [%] 76.9 31.5 2.75

At wavelengths of 390 nm and 410 nm, the transmittance of the glass fibers for the narrow-band UV radiation is 100%, while the transmittance at a wavelength of 365 nm is only 55%. The maximum permeability of the matrix is for UV radiation at a wavelength of 410 nm, which is still 76.9% and, due to the 100% permeability of the glass fibers, also corresponds to the incoming radiation and is therefore more than twice as high as the value of the incoming radiation of wavelength 390 nm, which is 31.5%. At 365 nm there is still a permeability of the matrix for the UV radiation, whereby the incoming radiation in relation to the insolation ultimately corresponds to only 2.75%.

Table 7 contains information on the incoming radiation based on the UV penetrating a composite material with the same composition, i.e. a glass content of 66% by volume or 80% by mass and a matrix content of 34% by volume or 20% by mass -LED radiation. However, the composite material is in the form of a pultrusion round profile with a diameter twice as large as in the example according to Table 6, ie a diameter of 16 mm and accordingly a distance from the center of the profile of 8 mm.

Mathematically, these 8 mm are made up of 5.28 mm glass fiber fibrils and a matrix of 2.72 mm. Table 7 Wavelength for irradiation [nm] 410 390 365 Permeability glass fibers [%] 100 100 14.2 permeability matrix [%] 59 16.6 0.4 Incoming radiation [%] 59 16.6 0.57

At wavelengths of 390 nm and 410 nm, the transmittance of the glass fibers for the narrow-band UV radiation is still 100%, while the transmittance at a wavelength of 365 nm with this diameter of the round profile is only 14.2%. The maximum permeability of the matrix is for UV radiation at a wavelength of 410 nm, which is still 59% and, due to the 100% permeability of the glass fibers, also corresponds to the incoming radiation. The value of the incoming radiation with a wavelength of 390 nm is still 16.6% with this round profile diameter. At 365 nm, the transmittance of the matrix for UV radiation is only 0.57%.

For the process of curing the glass fiber composite material, UV radiation is generated by UV LED lamps with a wavelength range preferably in the range from 410 to 415 nm. The results confirm this choice, as the values for the incoming radiation were highest at 410 nm.

UV polymerization was carried out with a glass fiber composite material in the form of a round profile of 6.2 mm at this wavelength of 410 nm generated by UV LED lamps. The glass fiber content was 66% by volume while the matrix content was 34% by volume. The matrix contains an unsaturated tes polyester resin (UP resin). The matrix also contains a photosensitizer bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide at 0.63% by mass of the matrix.

rate of polymerization

A conversion of 58.6% could be achieved in 6.33 s, ie 9.257%/s. The second value determined was 45.1% in 4.75 s, ie 9.49%/s as the polymerization rate.

A comparison of the possible throughput speeds of the round profile in thermal polymerisation and UV-LED-assisted polymerisation shows that the possible throughput speed for thermal polymerisation is 5 m/min, while the possible throughput speed for UV-LED-assisted polymerisation is 12 m/min. min is

Example 4:

Table 8 shows the transmission of radiation through glass mats soaked with fire retardant BÜFA®-Firestop S 480 at different wavelengths in the range from 200 to 600 nm.

BÜFA®-Firestop S 480 is a highly pigmented system in which a phosphoric ester is present as a pigment in addition to the fire retardant. The optical behavior of pigmented layers in terms of absorption and scattering is laid down, inter alia, in H. Hunger, W. Herbst, "Industrial Organic Pigments", VCH Verlagsgesellschaft, 1987, ISBN 3-527-26319-5, pp. 52 to 54. The ins Light entering the composite is deflected to a greater or lesser extent in its propagation direction by scattering and converted into heat by absorption.

The absorption weakens the radiation. The scattering brings parts of the light energy in different propagation directions. This causes part of the incident radiation to re-emerge on the illuminated surface. The size of this fraction depends on the strength of the light scattering and the size of the absorption. Table 8 wavelength [nm] transmittance [%] 200 0 250 0 300 0.02 350 0.04 400 0.05 450 0.06 500 0.07 550 0.08 600 0.08

Table 8 shows the transmission in [%] as a function of the wavelength of the incident radiation. The values show that when the radiation passed through in a straight line, it was almost completely absorbed. When irradiated with a UV LED with a wavelength of 410 nm and polymerisation, a maximum penetration depth of 0.5 mm could only be achieved.

The composite material was in the form of a pultrusion round profile with a glass content of 23.5% by volume or 37.5% by mass, a matrix content (BÜFA®-Firestop S 480) of 76.5% by volume or 62.5% by mass. % on the round profile. The diameter was 5 mm, correspondingly the distance from the center of the profile was 2.5 mm. Complete polymerisation was achieved with a residence time in the UV LED system of 28.5 s at a wavelength of 410 nm.

Example 5

For comparison, a UV polymerization with a glass fiber composite material which has a glass fiber content of 66% by volume and 80% by mass and a matrix content which contains styrenic UP resin of 34% by volume and 20% by mass was carried out Using a conventional, Fe-doped UVH emitter on the one hand and a UV LED emitter at 410 nm on the other hand. When using the UVH radiator, the photosensitizer Omnirad 819 was added to the matrix with 0.0075 parts by mass or a concentration of 0.000071 mol/l. When using the UV LED radiator, 0.75 parts by mass or 0.007142 mol/l of the same photosensitizer could be added to the matrix. The thickness of the pultrusion strand was 2.4 mm in each case.

The result of using the conventional UVH emitter was that the surface dryness of the composite material was only temporary and that there was outdiffusion of low-molecular polymer components and an increase in surface tack, which limited the usability of the product.

On the other hand, the use of a UV LED emitter and thus narrow-band UV LED radiation with a wavelength of 410 nm led to a stable surface dryness and thus to no restrictions in terms of the usability of the product.

Claims (8)

Method for curing a glass fiber composite material, comprising at least one step of free-radical curing of a glass fiber composite material by means of narrow-band UV-LED radiation, which is generated by means of light-emitting diodes (LED) as a radiation source, the wavelength of which is in a wavelength range from 365 nm to 440 nm and a Half width of the wavelength of at most ±10 nm, the glass fiber composite material to be cured by this radiation having glass fibers as reinforcing fibers and a matrix containing polymerizable matrix components and at least one photosensitizer for catalyzing at least one photoinduced radical polymerization. procedure after claim 1 , characterized in that the polymerizable matrix components are selected from ➢ unsaturated polyester resins (UP), ➢ vinyl ester resins (VE), ➢ phenacrylate resins (PAH), ➢ methacrylate resins (MA). procedure after claim 1 or 2 , characterized in that the glass fiber composite material has the following composition: ➢ Glass fibers: from 5% by mass to 80% by mass, ➢ Matrix: from 95% by mass to 20% by mass. procedure after claim 3 , characterized in that the proportion of the photosensitizer in the matrix is from 0.01% by mass to 6% by mass. Procedure according to one of Claims 1 until 4 , characterized in that the photosensitizer is selected from: ➢ bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, ➢ bis(.eta.5-2,4-cyclopentadien-1-yl)-bis(2,6- difluoro-3-(1 H-pyrrol-1-yl)-phenyl)-titanium IV, ➢ bis(cyclopenta-1,3-diene-bis(2,6-difluoro(1 H-pyrrol-1-yl)-phenolide) titanIV, ➢ 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ➢ 2,4,6-trimethylbenzoyl-diphenylphosphinate. Procedure according to one of Claims 1 until 5 , characterized in that the UV-supported polymerisation takes place with UV-LED radiation with a wavelength/wavelengths in the wavelength range from 410 nm to 415 nm. Procedure according to one of Claims 1 until 6 , characterized in that thermal polymerisation and UV-LED-supported polymerisation are connected in series in a specific sequence or in specific sequences in the process. procedure after claim 7 , characterized in that at the beginning of the process, the glass fiber composite material is thermally preheated to increase the temperature of the matrix to a value above the glass transition temperature, followed by passage through a multi-stage arrangement of thermal plants and UV plants.

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